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WO2021206624A1 - Bandwidth limited search space partitioning - Google Patents

Bandwidth limited search space partitioning Download PDF

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Publication number
WO2021206624A1
WO2021206624A1 PCT/SE2021/050328 SE2021050328W WO2021206624A1 WO 2021206624 A1 WO2021206624 A1 WO 2021206624A1 SE 2021050328 W SE2021050328 W SE 2021050328W WO 2021206624 A1 WO2021206624 A1 WO 2021206624A1
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WO
WIPO (PCT)
Prior art keywords
bandwidth
wireless communication
pdcch
communication device
coreset
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
PCT/SE2021/050328
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French (fr)
Inventor
Anders Wallén
Mohammad MOZAFFARI
Saeedeh MOLOUDI
Yutao Sui
Oscar Ohlsson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
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Publication of WO2021206624A1 publication Critical patent/WO2021206624A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0053—Allocation of signalling, i.e. of overhead other than pilot signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0003—Two-dimensional division
    • H04L5/0005—Time-frequency
    • H04L5/0007—Time-frequency the frequencies being orthogonal, e.g. OFDM(A) or DMT
    • H04L5/001—Time-frequency the frequencies being orthogonal, e.g. OFDM(A) or DMT the frequencies being arranged in component carriers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0037—Inter-user or inter-terminal allocation

Definitions

  • the present disclosure relates to transmission of and monitoring for Physical Downlink Control Channel (PDCCH) in PDCCH candidates in a Control Resource Set (CORESET) and bandwidth limited wireless communication devices.
  • PDCCH Physical Downlink Control Channel
  • CORESET Control Resource Set
  • Ultra-Reliable Low-Latency Communication was introduced in Third Generation Partnership Project (3GPP) Release 15 for both Long Term Evolution (LTE) and New Radio (NR), and NR URLLC is further enhanced in Release 16 within the enhanced URLLC (eURLLC) and Industrial IoT work items.
  • 3GPP Third Generation Partnership Project
  • LTE Long Term Evolution
  • NR URLLC is further enhanced in Release 16 within the enhanced URLLC (eURLLC) and Industrial IoT work items.
  • Narrowband Internet-of-Things NB-IoT
  • LTE-MTC Long Term Evolution for Machine-Type Communication
  • NR was introduced in 3GPP Release 15 and focused mainly on the enhanced Mobile Broadband (eMBB) and cMTC. For Release 17, however, an NR User Equipment (UE) type with lower capabilities will likely be introduced since it is supported and proposed by many companies.
  • UE User Equipment
  • MTC version of NR i.e. Reduced capability NR device (NR-RedCap), which is mid-end, filling the gap between eMBB NR and NB-IoT/LTE-M, e.g., to provide more efficient inband operation with URLLC in industrial use cases.
  • NR-RedCap Reduced capability NR device
  • NR-RedCap Reduced capability NR device
  • 3GPP Third Generation Partnership Project
  • the data rate does not need to reach above 1 Gigabits per second (Gbps), and the latency does not need to be as low as 1 millisecond (ms).
  • Gbps gigabits per second
  • ms millisecond
  • NR-RedCap allows low-cost or low-complexity UE implementation.
  • an NR UE is required to support 100 Megahertz (MHz) carrier bandwidth in Frequency Range 1 (from 410 MHz to 7125 MHz) and 200 MHz carrier bandwidth in Frequency Range 2 (from 24.25 GHz to 52.6 GHz).
  • MHz Megahertz
  • 2 Frequency Range 2
  • NR-RedCap UEs supporting 100 MHz or 200 MHz bandwidth is superfluous.
  • a UE bandwidth of 8.64 MHz might be sufficient if the use cases do not require a data rate higher than 20 Megabits per second (Mbps).
  • PDCCH carries Downlink Control Information (DCI).
  • DCI Downlink Control Information
  • PDCCHs are transmitted in CORESETs which span over one, two, or three contiguous Orthogonal Frequency Division Multiplexing (OFDM) symbols over multiple Resource Blocks (RBs).
  • RBs Resource Blocks
  • a CORESET can span over one or multiple chunks of six RBs.
  • CORESET #0 which is configured during the initial access, can only have 24, 48, or 96 RBs.
  • CORESET #0 must be contiguous in frequency domain, and it is not necessarily aligned with the six-RB grid.
  • a PDCCH is carried by 1, 2, 4, 8, or 16 Control Channel Elements (CCEs).
  • A Aggregation Level
  • Each CCE is composed of six Resource Element Groups (REGs), and each REG is 12
  • REs Resource Elements in one OFDM symbol, as shown in Figure 1.
  • a REG bundle consists of 2, 3, or 6 REGs.
  • a CCE can be composed of one or multiple bundles.
  • Each CORESET is associated with a CCE-REG mapping, which can be an interleaved CCE-REG mapping or a non-interleaved CCE-REG mapping.
  • a CCE-REG mapping can be an interleaved CCE-REG mapping or a non-interleaved CCE-REG mapping.
  • all CCEs in an AL are mapped in consecutive REG bundles of the associated CORESET.
  • REG bundles of CCEs are distributed in the frequency domain over the entire CORESET bandwidth. For CORESET #0, the CCE-
  • REG mapping is always interleaved with predefined parameters.
  • a search space consists of a set of PDCCH candidates where each candidate can occupy multiple search spaces.
  • the number of CCEs used for a PDCCH candidate is referred to as AL, which in
  • NR can be 1, 2, 4, 8, or 16.
  • a higher AL provides higher coverage.
  • Which CCEs to use for a certain PDCCH candidate is determined by a procedure, mainly described by the following excerpt from 3GPP TS 38.213, v.15.7.0.
  • the above procedure establishes that, for each PDCCH candidate with aggregation level L, the UE is required to monitor in a search space the associated set of L CCEs, and thus the corresponding REGs and REs, to which the PDCCH candidate is mapped.
  • these L CCEs are confined to a localized set of RBs, where the number of RBs depends on the number of OFDM symbols configured for the CORESET.
  • a method performed by a wireless communication device comprises receiving a Control Resource Set (CORESET) configuration that defines a CORESET having a first bandwidth and monitoring a plurality of Physical Downlink Control Channel (PDCCH) candidates within the CORESET. Positions of the plurality of PDCCH candidates within the CORESET are defined such that the plurality of PDCCH candidates are located within a second bandwidth that is less than the first bandwidth. In this manner, the wireless communication can monitor PDCCH candidates within a reduced receive bandwidth within a CORESET having a larger bandwidth.
  • CORESET Control Resource Set
  • PDCCH Physical Downlink Control Channel
  • the plurality of PDCCH candidates is all PDCCH candidates monitored by the wireless communication device within a search space within the CO RESET.
  • the plurality of PDCCH candidates comprise PDCCH candidates for two or more different aggregation levels.
  • the wireless communication device supports a bandwidth that is less than the first bandwidth, and the second bandwidth is less than or equal to the bandwidth supported by the wireless communication device.
  • monitoring the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function of a value that corresponds to the bandwidth supported by the wireless communication device.
  • determining the position of the PDCCH candidate as a function of the value that corresponds to the bandwidth supported by the wireless communication device comprises determining an index of a Control Channel Element (CCE) for the PDCCH candidate based on a modulo X operation, where X is a function of N CCE red pi where N CCE red p is a total number of CCEs in the bandwidth supported by the wireless communication device.
  • monitoring the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function of a bandwidth related value that corresponds to a bandwidth that is less than or equal to the bandwidth supported by the wireless communication device.
  • determining the position of the PDCCH candidate as a function of the bandwidth related value, X, that corresponds to a bandwidth that is less than or equal to the bandwidth supported by the wireless communication device comprises determining an index of a CCE for the PDCCH candidate based on a modulo X operation, where X is a function of a number of CCEs that is less than or equal to N CCE red pi where N CCE red p is a total number of CCEs in the bandwidth supported by the wireless communication device.
  • monitoring the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function of a maximum aggregation level ( L max ) supported by the wireless communication device.
  • determining the position of the PDCCH candidate as a function of the maximum aggregation level ( L max ) supported by the wireless communication device comprises determining an index of a CCE for the PDCCH candidate based on a modulo X operation, where X is a function of the maximum aggregation level ( ma ) supported by the wireless communication device.
  • monitoring the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function of a predefined or preconfigured scaling factor.
  • the scaling factor is or is based on a ratio of a first value that corresponds to the bandwidth supported by the wireless communication device and a second value that corresponds to the bandwidth of the CORESET.
  • determining the position of the PDCCH candidate as a function of the predefined or preconfigured scaling factor comprises determining an index of a CCE for the PDCCH candidate based on the predefined or preconfigured scaling factor.
  • the wireless communication device supports the first bandwidth, and the second bandwidth is less than or equal to a bandwidth supported by other reduced-bandwidth wireless communication devices.
  • the plurality of PDCCH candidates are positioned towards a lower end of the first bandwidth.
  • the plurality of PDCCH candidates are positioned relative to a lower end of the first bandwidth based on an offset.
  • the offset is wireless communication device specific. In one embodiment, the offset is preconfigured. In another embodiment, the offset is determined by a function or otherwise based on a parameter which is unique to the wireless communication device, or to the CORESET, or to a search space, or to bandwidth part in which the CORESET is located. In another embodiment, the offset is determined based on the location of CCE(s) used for a PDCCH candidate using a maximum supported aggregation level when placed in the CORESET.
  • monitoring the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function the offset. In one embodiment, determining the position of the PDCCH candidate as a function the offset comprises determining an index of a CCE of the PDCCH candidate as a function of the offset.
  • bandwidth portions within the first bandwidth in which PDCCH candidates for different wireless communication devices are located are uniformly distributed within the bandwidth of the CORESET.
  • the plurality of PDCCH candidates comprise a number of PDCCH candidates for a particular aggregation level, wherein the number of PDCCH candidates for the particular aggregation level is a function of a value that corresponds to the bandwidth supported by the wireless communication device.
  • the method further comprises refraining from monitoring for PDCCH in one or more search spaces within the CORESET, the one or more search spaces comprising one or more CCEs that are mapped to at least one Resource Element Group (REG) that is at least partially outside of a supported bandwidth of the wireless communication device.
  • REG Resource Element Group
  • the first bandwidth and/or the second bandwidth are measured in terms of: a frequency unit, a number of Resource Blocks (RBs), or a number of CCEs.
  • the method further comprises detecting Downlink Control Information (DCI) in one of the monitored plurality of PDCCH candidates.
  • DCI Downlink Control Information
  • the method further comprises detecting a PDCCH transmission in one of the monitored plurality of PDCCH candidates.
  • a wireless communication device is adapted to receive a CORESET configuration that defines a CORESET having a first bandwidth and monitor a plurality of PDCCH candidates within the CORESET. Positions of the plurality of PDCCH candidates within the CORESET are defined such that the plurality of PDCCH candidates are located within a second bandwidth, the second bandwidth being less than the first bandwidth.
  • a wireless communication device comprises one or more transmitters, one or more receivers, and processing circuitry associated with the one or more transmitters and the one or more receivers.
  • the processing circuitry is configured to cause the wireless communication device to receive a CORESET configuration that defines a CORESET having a first bandwidth and monitor a plurality of PDCCH candidates within the CORESET. Positions of the plurality of PDCCH candidates within the CORESET are defined such that the plurality of PDCCH candidates are located within a second bandwidth, the second bandwidth being less than the first bandwidth.
  • a method performed by a network node comprises configuring a wireless communication device with a CORESET having a first bandwidth, selecting a set of CCEs on which to transmit a PDCCH to the wireless communication device from among a plurality of sets of CCEs that correspond to a plurality of PDCCH candidates for the wireless communication device within the CORESET, wherein positions of the plurality of PDCCH candidates are defined such that the plurality of PDCCH candidates are located within a second bandwidth that is less than the first bandwidth.
  • the method further comprises transmitting a PDCCH to the wireless communication device on the selected set of CCEs.
  • a network node is adapted to configure a wireless communication device with a CORESET having a first bandwidth and select a set of CCEs on which to transmit a PDCCH to the wireless communication device from among a plurality of sets of CCEs that correspond to a plurality of PDCCH candidates for the wireless communication device within the CORESET, wherein positions of the plurality of PDCCH candidates are defined such that the plurality of PDCCH candidates are located within a second bandwidth that is less than the first bandwidth.
  • the network node is further adapted to transmit a PDCCH to the wireless communication device on the selected set of CCEs.
  • a network node comprises processing circuitry configured to cause the network node to configure a wireless communication device with a CORESET having a first bandwidth and select a set of CCEs on which to transmit a PDCCH to the wireless communication device from among a plurality of sets of CCEs that correspond to a plurality of PDCCH candidates for the wireless communication device within the CORESET, wherein positions of the plurality of PDCCH candidates are defined such that the plurality of PDCCH candidates are located within a second bandwidth that is less than the first bandwidth.
  • the processing circuitry is further configured to cause the network node to transmit a PDCCH to the wireless communication device on the selected set of CCEs.
  • FIG. 1 illustrates an example of a Control Resource Set (CORESET) including multiple Control Channel Elements (CCEs), where each CCE is composed of six Resource Element Groups (REGs) and each REG is twelve Resource Elements (REs) in one Orthogonal Frequency Division Multiplexing (OFMD) symbol;
  • CCE Control Channel Elements
  • REGs Resource Element Groups
  • REs Resource Elements
  • OFMD Orthogonal Frequency Division Multiplexing
  • Figure 2 illustrates one example of a cellular communications system in which embodiments of the present disclosure may be implemented
  • Figure 3 illustrates an example of Physical Downlink Control Channel (PDCCH) candidates to be monitored for an example search space in accordance with existing New Radio (NR) specifications
  • PDCCH Physical Downlink Control Channel
  • Figure 4 illustrates an example of PDCCFI candidates to be monitored for an example search space wherein locations of the PDCCFI candidates are determined based on a reduced bandwidth in accordance with some embodiments of the present disclosure
  • Figure 5 illustrates another example of PDCCFI candidates to be monitored for an example search space wherein locations of the PDCCFI candidates are determined based on a reduced bandwidth in accordance with some embodiments of the present disclosure
  • Figure 6 illustrates another example of PDCCFI candidates to be monitored for an example search space wherein locations of the PDCCFI candidates are determined based on a reduced bandwidth in accordance with some embodiments of the present disclosure
  • Figure 7 illustrates another example of PDCCFI candidates to be monitored for an example search space wherein locations of the PDCCFI candidates are determined based on a reduced bandwidth and an offset in accordance with some embodiments of the present disclosure
  • Figure 8 illustrates the operation of a network node (e.g., base station such as, e.g., a gNB) and a wireless communication device (e.g., a reduced bandwidth User Equipment (UE)) in accordance with at least some embodiments of the present disclosure
  • a network node e.g., base station such as, e.g., a gNB
  • a wireless communication device e.g., a reduced bandwidth User Equipment (UE)
  • Figures 9 through 11 are schematic block diagrams of example embodiments of a network node
  • Figures 12 and 13 are schematic block diagrams of example embodiments of a wireless communication device
  • Figure 14 illustrates an example embodiment of a communication system in which embodiments of the present disclosure may be implemented
  • Figure 15 illustrates example embodiments of the host computer, base station, and UE of Figure 14;
  • FIGS 16 through 19 are flow charts that illustrate example embodiments of methods implemented in a communication system such as that of Figure 14. Detailed Description
  • Radio Node As used herein, a "radio node” is either a radio access node or a wireless communication device.
  • Radio Access Node As used herein, a “radio access node” or “radio network node” or “radio access network node” is any node in a Radio Access Network (RAN) of a cellular communications network that operates to wirelessly transmit and/or receive signals.
  • RAN Radio Access Network
  • a radio access node examples include, but are not limited to, a base station (e.g., a New Radio (NR) base station (gNB) in a Third Generation Partnership Project (3GPP) Fifth Generation (5G) NR network or an enhanced or evolved Node B (eNB) in a 3GPP Long Term Evolution (LTE) network), a high-power or macro base station, a low-power base station (e.g., a micro base station, a pico base station, a home eNB, or the like), a relay node, a network node that implements part of the functionality of a base station (e.g., a network node that implements a gNB Central Unit (gNB-CU) or a network node that implements a gNB Distributed Unit (gNB-DU)) or a network node that implements part of the functionality of some other type of radio access node.
  • a base station e.g., a New Radio (NR) base station (gNB)
  • a "core network node” is any type of node in a core network or any node that implements a core network function.
  • Some examples of a core network node include, e.g., a Mobility Management Entity (MME), a Packet Data Network Gateway (P-GW), a Service Capability Exposure Function (SCEF), a Home Subscriber Server (HSS), or the like.
  • MME Mobility Management Entity
  • P-GW Packet Data Network Gateway
  • SCEF Service Capability Exposure Function
  • HSS Home Subscriber Server
  • a core network node examples include a node implementing an Access and Mobility Management Function (AMF), a User Plane Function (UPF), a Session Management Function (SMF), an Authentication Server Function (AUSF), a Network Slice Selection Function (NSSF), a Network Exposure Function (NEF), a Network Function (NF) Repository Function (NRF), a Policy Control Function (PCF), a Unified Data Management (UDM), or the like.
  • AMF Access and Mobility Management Function
  • UPF User Plane Function
  • SMF Session Management Function
  • AUSF Authentication Server Function
  • NSSF Network Slice Selection Function
  • NEF Network Exposure Function
  • NRF Network Exposure Function
  • NRF Network Exposure Function
  • PCF Policy Control Function
  • UDM Unified Data Management
  • a "communication device” is any type of device that has access to an access network.
  • Some examples of a communication device include, but are not limited to: mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or Personal Computer (PC).
  • the communication device may be a portable, hand-held, computer-comprised, or vehicle- mounted mobile device, enabled to communicate voice and/or data via a wireless or wireline connection.
  • One type of communication device is a wireless communication device, which may be any type of wireless device that has access to (i.e., is served by) a wireless network (e.g., a cellular network).
  • a wireless communication device include, but are not limited to: a User Equipment device (UE) in a 3GPP network, a Machine Type Communication (MTC) device, and an Internet of Things (IoT) device.
  • UE User Equipment
  • MTC Machine Type Communication
  • IoT Internet of Things
  • Such wireless communication devices may be, or may be integrated into, a mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or PC.
  • the wireless communication device may be a portable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice and/or data via a wireless connection.
  • Network Node As used herein, a "network node” is any node that is either part of the RAN or the core network of a cellular communications network/ system.
  • the procedure for determining which Control Channel Elements (CCEs) to use for a Physical Downlink Control Channel (PDCCH) candidate results in the PDCCH candidate being mapped to a contiguous set of Resource Blocks (RBs) when non-interleaved mapping is used.
  • a bandwidth-limited UE such as an NR Reduced Capacity (NR-RedCap) UE
  • NR-RedCap NR Reduced Capacity
  • AL maximum aggregation level
  • an NR-RedCap UE may be restricted to use only a subset of the available ALs at any given time, namely the ones whose candidates are being mapped to the RBs coinciding with the current frequency range of the receiver.
  • the NR-RedCap UE could potentially receive different frequency ranges at different times such that different sets of candidates/ALs are being monitored in a time-multiplexing fashion. This may, however, significantly reduce the PDCCH scheduling flexibility.
  • CORESETs Control Resource Sets
  • Certain aspects of the present disclosure and their embodiments may provide solutions to the aforementioned or other challenges.
  • Systems and methods are provided for restricting CCEs used for PDCCH candidates in a CORESET such that PDCCH candidates with different aggregation levels are mapped to a portion of the bandwidth of the CORESET.
  • this restriction may be such that PDCCH candidates with different aggregation levels are mapped to a subset of one contiguous set of CCEs, where the subset of the CCEs include only CCEs that are mapped to REGs that are within the portion of the bandwidth of the CORESET.
  • This portion of the bandwidth of the CORESET may for example be less than or equal to a bandwidth supported by a reduced bandwidth UE (e.g., a RedCap UE) to which the PDCCH is transmitted.
  • a reduced bandwidth UE e.g., a RedCap UE
  • This smaller bandwidth may, for example, correspond to the supported receiver bandwidth of a reduced bandwidth UE (e.g., an NR-RedCap UE) monitoring the search space.
  • the restriction of the CCEs to which the PDCCH candidates are mapped is done by modifying the existing hash function (such as the hash function above from 3GPP TS 38.213, v.15.7.0) used for determining the CCEs for a PDCCH candidate such that:
  • All CCEs used are confined to within a range of CCE indices within the bandwidth of a reduced bandwidth UE (e.g., an NR REDCAP UE), and
  • a CCE start index offset is added in order to allow for frequency multiplexing within the large CORESET.
  • Some embodiments of the present disclosure apply both to CORESETS used for common search space and UE-specific search space, whereas others primarily target the latter.
  • a bandwidth-limited part of a larger CORESET can be defined such that all PDCCH candidates monitored by a bandwidth-reduced wireless device will be located inside its receiver bandwidth, even if the search space is associated with the larger CORESET.
  • the solutions presented herein include different ways of restricting the range of the CCEs used for the monitored PDCCH candidates.
  • Certain embodiments may provide one or more of the following technical advantage(s).
  • the proposed solutions ensure that a UE (e.g., an NR-RedCap UE) with reduced receive bandwidth can monitor PDCCH candidates with different aggregation levels within a CORESET having a bandwidth which is larger than the UE receiver bandwidth. Therefore, it is more efficient if the reduced bandwidth UE (e.g., an NR- RedCap UE) can utilize the resource in the larger CORESETs that are also used by the legacy NR UEs.
  • Another advantage with using a part of a larger CORESET, rather than a separate smaller CORESET for a reduced bandwidth UE, is that it may result in better frequency diversity in that different PDCCH transmissions may be mapped to different frequency regions at different times.
  • FIG. 2 illustrates one example of a cellular communications system 200 in which embodiments of the present disclosure may be implemented.
  • the cellular communications system 200 is a 5G System (5GS) including a Next Generation RAN (NG-RAN) and a 5G Core (5GC).
  • the RAN includes base stations 202-1 and 202-2, which in the 5GS include NR base stations (gNBs) and optionally next generation eNBs (ng-eNBs) (i.e., LTE RAN nodes connected to the 5GC), controlling corresponding (macro) cells 204-1 and 204-2.
  • the base stations 202-1 and 202-2 are generally referred to herein collectively as base stations 202 and individually as base station 202.
  • the (macro) cells 204-1 and 204-2 are generally referred to herein collectively as (macro) cells 204 and individually as (macro) cell 204.
  • the RAN may also include a number of low power nodes 206-1 through 206-4 controlling corresponding small cells 208-1 through 208-4.
  • the low power nodes 206-1 through 206-4 can be small base stations (such as pico or femto base stations) or Remote Radio Heads (RRHs), or the like.
  • RRHs Remote Radio Heads
  • one or more of the small cells 208-1 through 208-4 may alternatively be provided by the base stations 202.
  • the low power nodes 206-1 through 206-4 are generally referred to herein collectively as low power nodes 206 and individually as low power node 206.
  • the small cells 208-1 through 208-4 are generally referred to herein collectively as small cells 208 and individually as small cell 208.
  • the cellular communications system 200 also includes a core network 210, which in the 5GS is referred to as the 5GC.
  • the base stations 202 (and optionally the low power nodes 206) are connected to the core network 210.
  • the base stations 202 and the low power nodes 206 provide service to wireless communication devices 212-1 through 212-5 in the corresponding cells 204 and 208.
  • the wireless communication devices 212-1 through 212-5 are generally referred to herein collectively as wireless communication devices 212 and individually as wireless communication device 212.
  • the wireless communication devices 212 are oftentimes UEs and as such sometimes referred to as UEs 212, but the present disclosure is not limited thereto.
  • at least some of the wireless communication devices 212 are reduced bandwidth devices such as, e.g., NR-RedCap UEs.
  • NR-RedCap UEs any type of wireless communication device 212 that supports a reduced bandwidth (i.e., supports a receive bandwidth that is less than a full bandwidth of a CORESET).
  • This may, for example, refer to a situation where the wireless communication device 212 in fact is capable of supporting the full bandwidth of a CORESET, but for some reason is configured to follow procedures that apply to reduced bandwidth devices, such as a NR-RedCap UE, for example in order to be able to utilize some other functionality which are supported only for NR-RedCap UEs.
  • one or more modifications to the hash function for determining CCEs for a PDCCH candidate are provided.
  • P is the number of CCEs, numbered from 0 to /V CCEp - 1, in CORESET p.
  • These CCEs are located across the full bandwidth of the CORESET which, here, is assumed to be larger than the bandwidth of the NR-RedCap UE, which is reduced compared to a legacy NR UE.
  • N CCE red p denotes the number of CCEs in a bandwidth-limited part of a CORESET p.
  • L max denotes the maximum aggregation level supported by the UE, i.e., received within the UE receiver bandwidth assuming non- interleaved CCE-REG mapping. It can be noted that L max £ N CCE red pi such that PDCCH candidates with the maximum supported aggregation level always lie within the UE receiver bandwidth, but does not necessarily cover the full UE receiver bandwidth. It can further be noted that there is no restriction here on whether all aggregation levels defined for Rel-15 NR, ⁇ 1,2,4,8,16 ⁇ , are supported or only a subset of them are supported.
  • L max may be 16 but may also be 8 or lower.
  • the description herein also covers the case when new (maximum or other) aggregation levels are introduced, possibly with L being a non-power of two integer (i.e., L can adopt values other than ⁇ 1,2,4,8,16 ⁇ ).
  • L can adopt values other than ⁇ 1,2,4,8,16 ⁇ .
  • the main problem when using a CORESET larger than the UE bandwidth is that the CCE indices for different candidates may vary such that not all (or none) of the CCEs (for all monitored PDCCH candidates of all aggregation levels) are confined within N CCE, red, p CCEs.
  • the embodiments can be readily modified to also cover the case with cross-carrier scheduling, for example by considering n CI as an offset value added to in the embodiments described below.
  • the main purpose of the description herein is to provide solutions for UEs with reduced capabilities, carrier aggregation in general and cross carrier scheduling in particular are not considered a main scenario.
  • CCE 0 Ll the index of the first CCE for a legacy PDCCH candidate with aggregation level L
  • CCE start index or simply a start index
  • CCE 0 L represents the CCE start index for legacy PDCCH candidates.
  • the indices for all of the CCEs in the legacy PDCCH candidates are found by adding the index /to the Equation for CCE 0 L .
  • an illustrative example is considered for the purpose of showing how CCEs for different PDCCH candidates may be distributed for a legacy mapping, i.e., without using the bandwidth-limited CORESET part disclosed herein.
  • CCE 0 L will now be modified in various embodiments in order to make the search space located to within a limited bandwidth, lower than the full CORESET bandwidth.
  • a network node such as base station 202 (e.g., a gNB), and a wireless communication device 212, such as NR-RedCap (or other) UE, in that both nodes need to have the same knowledge of possible CCE allocation for the monitored PDCCH candidates.
  • SCS Common Search Space
  • USS UE Specific Search Space
  • the total number of CCEs iV C c E,P in the CORESET is replaced in the formula with a lower number (e.g., N CCE red p ) determined based on the UE reduced bandwidth.
  • N CCE red p the divisor
  • N C CE ,p J applied to the modulo operator in the expression for CCE 0 L plays the role of limiting the CCE start index of all PDCCFI candidates in the search space to within an allowable range in the NR CORESET.
  • JV C CE, P with a lower number therein a bandwidth reduced mapping can be achieved.
  • the legacy CCE 0 L for representing the CCE start index is replaced by CCE X L , where the number of CCEs within the bandwidth-limited CORESET part, typically coinciding with the receiver bandwidth, is used instead of the total number of CCEs in the CORESET, i.e.:
  • N CCE red p 10 in Figure 4, which can be compared with the legacy mapping used in Figure 3, where the CCEs are distributed across the whole CORESET.
  • N CCE red p is replaced by L max in the expression for CCE 1 L , as shown below:
  • bandwidth-limited CORESET part being smaller than the UE receiver bandwidth (thus not utilizing the entire UE bandwidth), but it may be advantageous for other reasons, e.g. to better align the bandwidth-limited CORESET part with PDCCFI candidates used for legacy UEs which use the full size of the CORESET.
  • CCEs used for different PDCCFI candidates are shown in Figure 5.
  • the start index CCE 2 L can be defined as a function of the legacy CCE 0 L and a scaling factor n r .
  • the function / can be selected in such a way that the search space is shrunk by the scaling factor n r ⁇
  • CCE 2 L can be defined as
  • the CCEs used will always be placed towards the lower end of the total range of available CCEs in the full, unrestricted CORESET. For example, if it's possible to fit only one PDCCFI candidate with the maximum supported AL within the bandwidth-limited CORESET part, i.e., L max > N CCE red p /2, its lowest CCE index will always be zero. This may, in some cases, be a desired property. For example, for a legacy CSS, there will be (at least) one candidate for each monitored AL that start with
  • RedCap UE to monitor PDCCH candidates both within the CSS and a USS in a bandwidth-limited CORESET part defined according to the above embodiments, assuming non-interleaved CCE-REG mapping is used (which excludes the application to CORESET #0).
  • the PDCCH candidates in the CSS may refer to, e.g. scheduling of paging messages, System Information Blocks (SIBs) and Random Access Response (RAR), which may be common to both legacy UEs and NR-RedCap UEs.
  • SIBs System Information Blocks
  • RAR Random Access Response
  • a start index offset (A CCE ) is added such that, with a start index offset larger than zero, none of the PDCCH candidates within the bandwidth- limited CORESET part may start at CCE index 0.
  • This may, for example, be expressed as a modified start index expression CCE 3 L .
  • a modified start index expression can be defined as: where A C CE represents the CCE start index offset for the bandwidth-limited CORESET part.
  • a modified start index expression can instead be based on CCE 2 L defined above with a CCE start index offset added.
  • the start index offset may be a fixed constant value.
  • the offset is UE-specific.
  • the start index offset may instead be common between the UEs for such search spaces.
  • this start index offset is described to be applied directly to the CCE index in the CORESET, but an offset can equivalently be expressed in terms of an offset to REGs or RBs, given the present mapping between the entities.
  • a CCE index offset of 8 would correspond to an RB index offset of 48, 24, or 16, respectively.
  • the start index offset (A CCE ) is determined via higher layer signaling (e.g., via Radio Resource Control (RRC) configuration).
  • RRC Radio Resource Control
  • the configured value may be set using UE-specific configuration (e.g., UE-specific RRC configuration).
  • the start index offset may be configured per UE, per CORESET, per search space, per bandwidth part, per carrier, or for any other appropriate entity.
  • the start index offset is determined from a function, or otherwise based on a parameter which is unique to the UE, CORESET, search space, bandwidth part, or similar. The determination may result in a constant start index offset value, or a varying value, for example between slots, and for example in a pseudo-random manner.
  • the start index offset (A CC£ ) may be a function of one or more of:
  • a UE identity such as an International Mobile Subscriber Identity (IMSI), a Temporary Mobile Subscriber Identity (TMSI) or 5G S-TMSI, or any other physical or higher layer UE-specific identity,
  • IMSI International Mobile Subscriber Identity
  • TMSI Temporary Mobile Subscriber Identity
  • 5G S-TMSI 5G S-TMSI
  • RNTI Radio Network Temporary Identifier
  • C-RNTI C-RNTI
  • SI-RNTI SI-RNTI
  • RA-RNTI RA-RNTI
  • P-RNTI P-RNTI
  • searchSpaceld searchSpaceld field comprised in an RRC configuration message
  • a time index such a slot number or a System Frame Number (SFN).
  • the start index offset ( A CCE ) is determined based on the location of the CCEs used for a PDCCH candidate using the maximum supported aggregation level L max , when placed in the full, unrestricted CORESET. This can, for example, be accomplished by using the following expression for A CCE ⁇
  • the bandwidth-limited CORESET part for different NR-RedCap UEs will be distributed essentially uniformly across the whole bandwidth of the full, unrestricted CORESET, according to where a legacy UE would have its first PDCCH candidate located.
  • an illustration of the CCEs used for all PDCCH candidates is shown in Figure 7. It is noted that the PDCCH candidate with AL 8 uses the same CCEs for the legacy mapping (c.f. Figure 3), whereas the relative placement of the CCEs follows that of when expression CCE L is used (c.f. Figure 4).
  • N CCE red p is replaced by L max in the expression for CCE 3 L such that:
  • the maximum supported AL L max is replaced by another (typically larger) number, for example the highest defined AL in the NR system.
  • the start index offset (A CCE ) is determined as the maximum AL used in another search space, such as a common search space. This has the effect that the bandwidth-limited CORESET part does not overlap with at least one PDCCH candidate for each AL in the common search space.
  • the common search space may be a legacy, Rel-15, common search space, or a new defined common search space applicable for an NR-RedCap UE.
  • start index offset A CCE The primary motivation for introducing the start index offset A CCE above was to move the whole bandwidth-limited CORESET part inside the full, unrestricted CORESET. It is also possible to move the PDCCH candidates within the UE receiver bandwidth. In one embodiment, this is accomplished by adding a start index offset, e.g., fulfilling A CCE ⁇ 1 - 1 ⁇ In a related embodiment, the start index offset is additionally or alternatively restricted such as it is ensured that no PDCCH candidate extends outside the bandwidth-limited CORESET part.
  • the bandwidth-limited CORESET part for example expressed using a start index offset A CCE , is determined individually for each search space occasion, such as once per slot. For subsequent occasions, it may be determined according to the same method, or two or more different methods. In a related embodiment, the bandwidth-limited CORESET part is determined for one search space occasion, and the same value is used for a given number of subsequent search space occasions. This may, for example, be combined with construction of CORESETs and/or search spaces expanded in time-domain (e.g., CORESETs and/or search spaces including more than 3 OFDM symbols in the same slot or in different slots).
  • the bandwidth-limited CORESET part exhibits frequency hopping, i.e., it covers different frequency ranges in different search space occasions. In other embodiments, it covers the same frequency range, but at least some PDCCH candidates use different CCEs in different search space occasions.
  • the above embodiments for determining the bandwidth-limited CORESET part and/or the start index offset ( A CCE ) can be combined and varied in any suitable manner.
  • the start index offset ( A CCE ) is determined as a sum of two or more terms, each term determined using the start index offset using one of the embodiments above. Care must be taken in order for such combinations not to result in PDCCH candidates extending outside the legacy CORESET. This may, for example, be achieved by further modifying the expressions above for calculating the CCE start index and/or start index offset. In some embodiments, this comprises reducing the possible maximum start index offset values in one or more of terms, for example by reducing the value of N CCEp in the start index offset calculations for one term with the start index value for another term.
  • the above embodiments disclose different methods of determining a bandwidth- limited CORESET part containing PDCCH candidates. By reducing the used CCE range, there will be room for less PDCCH candidates, and the candidates are packed more tightly, which can be understood by comparing, e.g. f Figure 3 and Figure 4. For this reason, it may be considered to reduce the number of monitored PDCCH candidates
  • M s. ,red may then be used instead o n any of the above expressions.
  • M ⁇ ed is determined based on a formula, table, or similar containing at least one of the parameters N CCE , L, L max (or any other parameter that can be derived therefrom).
  • the number of PDCCH candidates is restricted according to how many PDCCH candidates of a given aggregation level that can be accommodated in a bandwidth-limited CORESET part, according to the following non-limiting example:
  • the number of PDCCH candidates is scaled according to the relation between the size of the full, unrestricted CORESET and the bandwidth-limited CORESET part, according to the following non-limiting example:
  • the maximum number of candidates for all supported ALs in a search space is set to 1 for an NR-RedCap UE. This can be particularly motivated in the case where a legacy, Rel-15, CSS in a CORESET is reused for the NR-RedCap UE.
  • Another reason for reducing the number of PDCCH candidates is for reducing the decoding complexity in an NR-RedCap UE.
  • the NR-RedCap UE receiver bandwidth may be too small to monitor PDCCH candidates both in a (legacy or new defined) CSS and a USS. If the UE is required to monitor PDCCH candidates in multiple search spaces that do not overlap in frequency, the UE may be configured to monitor different search spaces in a time- division multiplexing (TDM) manner. This may, for example, be accomplished by ensuring that the CCE index offset is zero at predefined occasions when (at least) one candidate in a CSS is to be monitored.
  • TDM time- division multiplexing
  • frequencyDomainResources Frequency domain resources for a CORESET.
  • Each bit corresponds a group of 6 RBs, with grouping starting from PRB 0, which is fully contained in the bandwidth part within which the CORESET is configured.
  • each next subsequent lower significance bit corresponds to the next lowest frequency group fully contained within the bandwidth part within which the CORESET is configured, if any.
  • Bits corresponding to a group not fully contained within the bandwidth part within which the CORESET is configured are set to zero.
  • the CORESET may be allocated to non-contiguous RBs, as indicated by the bitmap frequencyDomainResources, it is possible that the above embodiments will result in that the total frequency range spanned by the CCEs used in the bandwidth-limited CORESET part exceeds that of the NR-RedCap UE receiver bandwidth. This may, for example, happen for some of the determined values for a CCE start index offset, or any other representation of the determined bandwidth-limited CORESET part. In one embodiment, such determined bandwidth-limited CORESET parts are excluded from the allowed ones, such that PDCCH is not monitored for that particular occasion of the search space.
  • the non-allowed determined bandwidth-limited CORESET part is replaced by another one, for example a previously allowed one, an adjacent one, or some other allowed bandwidth-limited CORESET determined in some other way.
  • only a subset of the PDCCH candidates within the bandwidth-limited CORESET part are monitored by the UE, such that the resources used by these candidates are accommodated within the NR-RedCap UE receiver bandwidth.
  • this information can be used for altering also the search space determination for a non-NR-RedCap UE served by the network node in the cell.
  • an NR-RedCap UE is determining to monitor a PDCCH candidate with a given AL in a CCE set A using one of the embodiments for determining a bandwidth-reduced CORESET part rather than a CCE set f using the legacy procedure, then a non-NR-RedCap UE which determines to monitor a PDCCH candidate with a given AL in CCE set f using the legacy procedure may instead use CCE set A.
  • this information can be used for modifying the configuration of the search space determination for NR-RedCap UEs and/or non-NR-RedCap UEs in the first cell. As a non-limiting example, this may be done by modifying one or more parameters to be used in the methods presented herein based on this information.
  • the above embodiments for determining the bandwidth-limited CORESET part may be used individually per search space.
  • different embodiments may be used for different search spaces, including the possibility of using the legacy procedure as the basis for a particular search space.
  • the latter option may be particularly useful for a common search space, in that it may increase the possibility of achieving an overlap between PDCCH candidates in the common search space for legacy and NR-RedCap UEs.
  • An NR-RedCap UE may then be required to monitor only those candidates in the search space that are located inside its receiver bandwidth.
  • the determination of which embodiments to selectively use for different search spaces may be defined by RRC configuration or determined from a standards document.
  • N CCE red pi being the number of CCEs in a bandwidth- limited CORESET part, can be selected to be different than the maximum number of CCEs that can be accommodated within the receiver bandwidth of an NR-RedCap UE.
  • K may be chosen such that N CCE red p is the highest possible number determined this way, while fulfilling the condition that it is less or equal to the maximum number of CCEs that can be accommodated within the receiver bandwidth.
  • values of K may be further constrained to be multiples of, e.g., 2, 3, or 4.
  • parameters have been mentioned explicitly herein for describing the embodiments, such as the maximum supported aggregation level, L maxi the reduced number of supported CCEs, N CCE red pi and a reduced number of monitored PDCCH candidates, M ⁇ ed .
  • L maxi the reduced number of supported CCEs
  • N CCE red pi the reduced number of monitored PDCCH candidates
  • M ⁇ ed the reduced number of monitored PDCCH candidates
  • N CCE red p may be different than the maximum and/or the actual receiver bandwidth of the UE.
  • Figure 8 illustrates the operation of a network node (e.g., base station 202 such as, e.g., a gNB) and a wireless communication device 212 (e.g., a reduced bandwidth UE such as, e.g., a NR-RedCap UE) in accordance with at least some of the embodiments described above.
  • the network node sends, to the wireless communication device 212, a CORESET configuration (step 800).
  • the CORESET configuration includes information that defines a bandwidth of the CORESET, which for this discussion is referred to as a first bandwidth.
  • the network node selects a set of CCEs on which to transmit a PDCCH to the wireless communication device 212 from among a plurality of sets of CCEs that correspond to a plurality of PDCCH candidates (e.g., comprised in a search space) for the wireless communication device 212 within the CORESET (step 802).
  • Positions of the plurality of PDCCH candidates e.g., CCE indices such as the starting CCE index
  • the positions of the plurality of PDCCH candidates are defined such that the plurality of PDCCH candidates are located within a bandwidth-limited CORESET part of the CORESET, in accordance with any of the embodiments described above.
  • the positions of the plurality of PDCCH candidates are defined such that the plurality of PDCCH candidates are located within a second bandwidth that is less than, in accordance with any of the embodiments described above.
  • the large CORESET may potentially not be regarded by the wireless communication device 212 as its CORESET.
  • the wireless communication device 212 may instead use the bandwidth-limited CORESET part as its CORESET, in which case the CORESET configuration of step 800 may be a configuration of this CORESET of the wireless communication device 212.
  • this CORESET is a bandwidth-limited part of the larger CORESET having the first bandwidth.
  • the first bandwidth i.e., the bandwidth of the CORESET
  • the second bandwidth i.e., the bandwidth of the bandwidth-limited CORESET part
  • a frequency unit e.g., number of MHz
  • a number of RBs e.g., with the connection to frequency being different for different subcarrier spacings
  • a number of CCEs e.g., with the relation to number of RBs being different for CORESETs with different number of OFDM symbols.
  • the network node transmits a PDCCH to the wireless communication device 212 on the selected PDCCH candidate (step 804).
  • the wireless communication device receives the CORESET configuration in step 800.
  • the wireless communication device 212 monitors the plurality of PDCCH candidates within the CORESET that are comprised within the search space for the wireless communication device 212 (step 806). In doing so, the wireless communication device 212 attempts to detect and receive the transmitted PDCCH.
  • the wireless communication device 212 detects a DCI or PDCCH transmission in one of the monitored PDCCH candidates.
  • monitoring the plurality of PDCCH candidates comprises determining positions of the plurality of PDCCH candidates in accordance with any of the embodiments described above (e.g., based on the modified starting CCE index and, optionally, the start index offset).
  • the positions of the plurality of PDCCH candidates are defined such that the positions of the plurality of PDCCH candidates are all within the bandwidth-limited CORESET part (i.e., within the second bandwidth).
  • the plurality of PDCCH candidates is all PDCCH candidates monitored by the wireless communication device 212 within the search space within the CORESET.
  • the wireless communication device 212 is configured by the network node to monitor a set of PDCCH candidates within a search space within the CORESET.
  • the positions of all of the PDCCH candidates in this configured set of PDCCH candidates are within the bandwidth-limited CORESET part.
  • the wireless communication device 212 is not configured by the network node to monitor any PDCCH candidates in the CORESET outside the bandwidth-limited CORESET part.
  • the plurality of PDCCH candidates comprise PDCCH candidates for two or more different aggregation levels.
  • An aggregation level is the number of CCEs used for a PDCCH candidate.
  • the wireless communication device 212 supports a bandwidth that is less than the first bandwidth (i.e., less than the bandwidth of the CORESET), and the second bandwidth is less than or equal to the bandwidth supported by the wireless communication device 212.
  • monitoring the plurality of PDCCH candidates in step 806 comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function of a value (e.g., N CCE red p ) that corresponds to the bandwidth supported by the wireless communication device 212 (see step 806A).
  • determining the position of the PDCCH candidate as a function of a value (e.g., N CCE red p ) that corresponds to the bandwidth supported by the wireless communication device comprises determining an index of a CCE (e.g., a starting CCE) for the PDCCH candidate based on a modulo X operation, where X is a function of N CCE red P , where N CCE red p is a total number of CCEs in the bandwidth supported by the wireless communication device 212.
  • X is a function of N CCE red P
  • N CCE red p is a total number of CCEs in the bandwidth supported by the wireless communication device 212.
  • monitoring the plurality of PDCCH candidates in step 806 comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function of a bandwidth related value that corresponds to a bandwidth that is less than or equal to the bandwidth supported by the wireless communication device 212 (see step 806A).
  • bandwidth related value e.g., N CCE red P , L max , etc.
  • the bandwidth related value (X) is any such value or any value derived therefrom (e.g., [ N CC red p /L ⁇ , ⁇ L ma L ⁇ , etc.).
  • determining the position of the PDCCH candidate as a function of the bandwidth related value that corresponds to a bandwidth that is less than or equal to the bandwidth supported by the wireless communication device 212 comprises determining an index of a CCE (e.g., a starting CCE ) for the PDCCH candidate based on a modulo X operation, where X is the bandwidth related value or a value derived therefrom and is a function of a number of CCEs that is less than or equal to N CCE red pi where N CCE red p is a total number of CCEs in the bandwidth supported by the wireless communication device 212.
  • a CCE e.g., a starting CCE
  • monitoring the plurality of PDCCH candidates in step 806 comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function of a maximum aggregation level ( ma ) supported by the wireless communication device 212 (see step 806A).
  • determining the position of the PDCCH candidate as a function of the maximum aggregation level ( ma ) supported by the wireless communication device 212 comprises determining 806A an index of a CCE (e.g., a starting CCE) for the PDCCH candidate based on a modulo X operation, where X is a function of the maximum aggregation level ( L max ) supported by the wireless communication device 212.
  • a CCE e.g., a starting CCE
  • monitoring the plurality of PDCCH candidates in step 806 comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function of a predefined or preconfigured scaling factor (see step 806A).
  • the scaling factor is or is based on a ratio of a first value (e.g., N CCE red p ) that corresponds to the bandwidth supported by the wireless communication device 212 and a second value (e.g., N CCE p ) that corresponds to the bandwidth of the CORESET.
  • determining the position of the PDCCH candidate as a function of the predefined or preconfigured scaling factor in step 806A comprises determining an index of a CCE (e.g., a starting CCE) for the PDCCH candidate based on the predefined or preconfigured scaling factor.
  • a CCE e.g., a starting CCE
  • the wireless communication device 212 is a reduced-bandwidth UE (e.g., a NR RedCap UE).
  • the wireless communication device 212 supports the full bandwidth of the CORESET (e.g., is a legacy NR UE).
  • the wireless communication device 212 supports the first bandwidth (i.e., the bandwidth of the CORESET).
  • the second bandwidth is less than or equal to a bandwidth supported by other reduced-bandwidth wireless communication devices (e.g., one or more other NR RedCap UEs).
  • the network node also transmits PDCCH(s) to one or more other wireless communication devices, which are reduced-bandwidth devices, in the CORESET within the bandwidth-limited CORESET part.
  • the plurality of PDCCH candidates are positioned towards a lower end of the bandwidth of the CORESET.
  • the plurality of PDCCH candidates are positioned relative to a lower end of the bandwidth of the CORESET based on an offset.
  • the offset is wireless communication device specific.
  • the offset is preconfigured (e.g., via RRC signaling).
  • the offset may be preconfigured by the network node at any time prior to when the wireless communication device 212 determines the positions of the PDCCH candidates.
  • the offset is determined by a function or otherwise based on a parameter which is unique to the wireless communication device 212, or to the CORESET, or to search space, or to the bandwidth part in which the CORESET is located.
  • the offset is determined based on the location of CCE(s) used for a PDCCH candidate using a maximum supported aggregation level of the wireless communication device 212 when placed in the CORESET using the procedure that applies for a legacy, i.e., not bandwidth-reduced UE.
  • the wireless communication device 212 is a reduced- bandwidth device (e.g., a NR RedCap UE) that supports a bandwidth that is less than the full bandwidth of the CORESET but greater than or equal to the second bandwidth.
  • the network node also transmits PDCCH(s) to one or more other wireless communication devices that support the full bandwidth of the CORESET (i.e., the first bandwidth), and the offset is determined based on the location of CCEs of a PDCCH(s) transmitted to these other wireless communication device(s) using a maximum aggregation level of the CORESET.
  • monitoring the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function the offset (see step 806A). In one embodiment, determining the position of the PDCCH candidate as a function the offset comprises determining an index of a CCE (e.g., a starting CCE) of the PDCCH candidate as a function of the offset.
  • a CCE e.g., a starting CCE
  • bandwidth portions within the first bandwidth i.e., the bandwidth of the CORESET) in which PDCCH candidates for different wireless communication devices are located are uniformly distributed within the first bandwidth.
  • the plurality of PDCCH candidates comprise a number of PDCCH candidates for a particular aggregation level, wherein the number of PDCCH candidates for the particular aggregation level is a function of a value (e.g., N CCE red p ) that corresponds to the bandwidth supported by the wireless communication device 212.
  • a value e.g., N CCE red p
  • the wireless communication device 212 refrains from monitoring for PDCCH in one or more search spaces within the CORESET, the one or more search spaces comprising one or more CCEs that are mapped to at least one REG that is at least partially outside of a supported bandwidth of the wireless communication device 212.
  • the wireless communication device 212 refrains from monitoring for PDCCH in one or more PDCCH candidates that comprise one or more CCEs that are mapped to at least one REG that is at least partially outside of a supported bandwidth of the wireless communication device 212 (or outside of the second bandwidth).
  • the wireless communication device 212 is a reduced- bandwidth UE (e.g., a NR RedCap UE). See, for example, the various equations above that define the starting CCE index. However, these embodiments are also applicable to wireless communication devices 212 that support the full bandwidth of the CORESET.
  • a reduced- bandwidth UE e.g., a NR RedCap UE
  • the bandwidth related value (e.g., N CCE red PI L max , etc.) included in the equations above for determining the starting CCE index may relate to the bandwidth of other devices that do or may also monitor for PDCCH in the same CORESET or may relate to a reduced bandwidth in which the wireless communication device 212 desires to or is configured to monitor for PDCCH.
  • FIG. 9 is a schematic block diagram of a network node 900 according to some embodiments of the present disclosure.
  • the network node 900 may be, for example, a base station 202 or 206 or a network node that implements all or part of the functionality of the base station 202 or gNB described herein.
  • the network node 900 includes a control system 902 that includes one or more processors 904 (e.g., Central Processing Units (CPUs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), and/or the like), memory 906, and a network interface 908.
  • the one or more processors 904 are also referred to herein as processing circuitry.
  • the network node 900 may include one or more radio units 910 that each includes one or more transmitters 912 and one or more receivers 914 coupled to one or more antennas 916.
  • the radio units 910 may be referred to or be part of radio interface circuitry.
  • the radio unit(s) 910 is external to the control system 902 and connected to the control system 902 via, e.g., a wired connection (e.g., an optical cable).
  • the radio unit(s) 910 and potentially the antenna(s) 916 are integrated together with the control system 902.
  • the one or more processors 904 operate to provide one or more functions of a radio access node 900 as described herein.
  • the function(s) are implemented in software that is stored, e.g., in the memory 906 and executed by the one or more processors 904.
  • FIG 10 is a schematic block diagram that illustrates a virtualized embodiment of the network node 900 according to some embodiments of the present disclosure.
  • a "virtualized" network node is an implementation of the network node 900 in which at least a portion of the functionality of the network node 900 is implemented as a virtual component(s) (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)).
  • the network node 900 may include the control system 902 and/or the one or more radio units 910, as described above.
  • the control system 902 may be connected to the radio unit(s) 910 via, for example, an optical cable or the like.
  • the network node 900 includes one or more processing nodes 1000 coupled to or included as part of a network(s) 1002. If present, the control system 902 or the radio unit(s) are connected to the processing node(s) 1000 via the network 1002.
  • Each processing node 1000 includes one or more processors 1004 (e.g., CPUs, ASICs, FPGAs, and/or the like), memory 1006, and a network interface 1008.
  • functions 1010 of the network node 900 described herein are implemented at the one or more processing nodes 1000 or distributed across the one or more processing nodes 1000 and the control system 902 and/or the radio unit(s) 910 in any desired manner.
  • some or all of the functions 1010 of the network node 900 described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environment(s) hosted by the processing node(s) 1000.
  • additional signaling or communication between the processing node(s) 1000 and the control system 902 is used in order to carry out at least some of the desired functions 1010.
  • the control system 902 may not be included, in which case the radio unit(s) 910 communicate directly with the processing node(s) 1000 via an appropriate network interface(s).
  • a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the network node 900 or a node (e.g., a processing node 1000) implementing one or more of the functions 1010 of the network node 900 in a virtual environment according to any of the embodiments described herein is provided.
  • a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).
  • FIG 11 is a schematic block diagram of the network node 900 according to some other embodiments of the present disclosure.
  • the network node 900 includes one or more modules 1100, each of which is implemented in software.
  • the module(s) 1100 provide the functionality of the network node 900 described herein. This discussion is equally applicable to the processing node 1000 of Figure 10 where the modules 1100 may be implemented at one of the processing nodes 1000 or distributed across multiple processing nodes 1000 and/or distributed across the processing node(s) 1000 and the control system 902.
  • FIG. 12 is a schematic block diagram of a wireless communication device 1200 according to some embodiments of the present disclosure.
  • the wireless communication device 1200 includes one or more processors 1202 (e.g., CPUs, ASICs, FPGAs, and/or the like), memory 1204, and one or more transceivers 1206 each including one or more transmitters 1208 and one or more receivers 1210 coupled to one or more antennas 1212.
  • the transceiver(s) 1206 includes radio-front end circuitry connected to the antenna(s) 1212 that is configured to condition signals communicated between the antenna(s) 1212 and the processor(s) 1202, as will be appreciated by on of ordinary skill in the art.
  • the processors 1202 are also referred to herein as processing circuitry.
  • the transceivers 1206 are also referred to herein as radio circuitry.
  • the functionality of the wireless communication device 1200 described above may be fully or partially implemented in software that is, e.g., stored in the memory 1204 and executed by the processor(s) 1202.
  • the wireless communication device 1200 may include additional components not illustrated in Figure 12 such as, e.g., one or more user interface components (e.g., an input/output interface including a display, buttons, a touch screen, a microphone, a speaker(s), and/or the like and/or any other components for allowing input of information into the wireless communication device 1200 and/or allowing output of information from the wireless communication device 1200), a power supply (e.g., a battery and associated power circuitry), etc.
  • user interface components e.g., an input/output interface including a display, buttons, a touch screen, a microphone, a speaker(s), and/or the like and/or any other components for allowing input of information into the wireless communication device 1200 and/or allowing output of information from the wireless communication device 1200
  • a power supply e.g., a battery and associated power circuitry
  • a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the wireless communication device 1200 according to any of the embodiments described herein is provided.
  • a carrier comprising the aforementioned computer program product is provided.
  • the carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).
  • FIG. 13 is a schematic block diagram of the wireless communication device 1200 according to some other embodiments of the present disclosure.
  • the wireless communication device 1200 includes one or more modules 1300, each of which is implemented in software.
  • the module(s) 1300 provide the functionality of the wireless communication device 1200 described herein.
  • a communication system includes a telecommunication network 1400, such as a 3GPP- type cellular network, which comprises an access network 1402, such as a RAN, and a core network 1404.
  • the access network 1402 comprises a plurality of base stations 1406A, 1406B, 1406C, such as Node Bs, eNBs, gNBs, or other types of wireless Access Points (APs), each defining a corresponding coverage area 1408A, 1408B, 1408C.
  • Each base station 1406A, 1406B, 1406C is connectable to the core network 1404 over a wired or wireless connection 1410.
  • a first UE 1412 located in coverage area 1408C is configured to wirelessly connect to, or be paged by, the corresponding base station 1406C.
  • a second UE 1414 in coverage area 1408A is wirelessly connectable to the corresponding base station 1406A. While a plurality of UEs 1412, 1414 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 1406.
  • the telecommunication network 1400 is itself connected to a host computer 1416, which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server, or as processing resources in a server farm.
  • the host computer 1416 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider.
  • Connections 1418 and 1420 between the telecommunication network 1400 and the host computer 1416 may extend directly from the core network 1404 to the host computer 1416 or may go via an optional intermediate network 1422.
  • the intermediate network 1422 may be one of, or a combination of more than one of, a public, private, or hosted network; the intermediate network 1422, if any, may be a backbone network or the Internet; in particular, the intermediate network 1422 may comprise two or more sub-networks (not shown).
  • the communication system of Figure 14 as a whole enables connectivity between the connected UEs 1412, 1414 and the host computer 1416.
  • the connectivity may be described as an Over-the-Top (OTT) connection 1424.
  • the host computer 1416 and the connected UEs 1412, 1414 are configured to communicate data and/or signaling via the OTT connection 1424, using the access network 1402, the core network 1404, any intermediate network 1422, and possible further infrastructure (not shown) as intermediaries.
  • the OTT connection 1424 may be transparent in the sense that the participating communication devices through which the OTT connection 1424 passes are unaware of routing of uplink and downlink communications.
  • the base station 1406 may not or need not be informed about the past routing of an incoming downlink communication with data originating from the host computer 1416 to be forwarded (e.g., handed over) to a connected UE 1412. Similarly, the base station 1406 need not be aware of the future routing of an outgoing uplink communication originating from the UE 1412 towards the host computer 1416.
  • a host computer 1502 comprises hardware 1504 including a communication interface 1506 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 1500.
  • the host computer 1502 further comprises processing circuitry 1508, which may have storage and/or processing capabilities.
  • the processing circuitry 1508 may comprise one or more programmable processors, ASICs, FPGAs, or combinations of these (not shown) adapted to execute instructions.
  • the host computer 1502 further comprises software 1510, which is stored in or accessible by the host computer 1502 and executable by the processing circuitry 1508.
  • the software 1510 includes a host application 1512.
  • the host application 1512 may be operable to provide a service to a remote user, such as a UE 1514 connecting via an OTT connection 1516 terminating at the UE 1514 and the host computer 1502.
  • the host application 1512 may provide user data which is transmitted using the OTT connection 1516.
  • the communication system 1500 further includes a base station 1518 provided in a telecommunication system and comprising hardware 1520 enabling it to communicate with the host computer 1502 and with the UE 1514.
  • the hardware 1520 may include a communication interface 1522 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 1500, as well as a radio interface 1524 for setting up and maintaining at least a wireless connection 1526 with the UE 1514 located in a coverage area (not shown in Figure 15) served by the base station 1518.
  • the communication interface 1522 may be configured to facilitate a connection 1528 to the host computer 1502.
  • connection 1528 may be direct or it may pass through a core network (not shown in Figure 15) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system.
  • the hardware 1520 of the base station 1518 further includes processing circuitry 1530, which may comprise one or more programmable processors, ASICs, FPGAs, or combinations of these (not shown) adapted to execute instructions.
  • the base station 1518 further has software 1532 stored internally or accessible via an external connection.
  • the communication system 1500 further includes the UE 1514 already referred to.
  • the UE's 1514 hardware 1534 may include a radio interface 1536 configured to set up and maintain a wireless connection 1526 with a base station serving a coverage area in which the UE 1514 is currently located.
  • the hardware 1534 of the UE 1514 further includes processing circuitry 1538, which may comprise one or more programmable processors, ASICs, FPGAs, or combinations of these (not shown) adapted to execute instructions.
  • the UE 1514 further comprises software 1540, which is stored in or accessible by the UE 1514 and executable by the processing circuitry 1538.
  • the software 1540 includes a client application 1542.
  • the client application 1542 may be operable to provide a service to a human or non-human user via the UE 1514, with the support of the host computer 1502.
  • the executing host application 1512 may communicate with the executing client application 1542 via the OTT connection 1516 terminating at the UE 1514 and the host computer 1502.
  • the client application 1542 may receive request data from the host application 1512 and provide user data in response to the request data.
  • the OTT connection 1516 may transfer both the request data and the user data.
  • the client application 1542 may interact with the user to generate the user data that it provides.
  • the host computer 1502, the base station 1518, and the UE 1514 illustrated in Figure 15 may be similar or identical to the host computer 1416, one of the base stations 1406A, 1406B, 1406C, and one of the UEs 1412, 1414 of Figure 14, respectively.
  • the inner workings of these entities may be as shown in Figure 15 and independently, the surrounding network topology may be that of Figure 14.
  • the OTT connection 1516 has been drawn abstractly to illustrate the communication between the host computer 1502 and the UE 1514 via the base station 1518 without explicit reference to any intermediary devices and the precise routing of messages via these devices.
  • the network infrastructure may determine the routing, which may be configured to hide from the UE 1514 or from the service provider operating the host computer 1502, or both. While the OTT connection 1516 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).
  • the wireless connection 1526 between the UE 1514 and the base station 1518 is in accordance with the teachings of the embodiments described throughout this disclosure.
  • One or more of the various embodiments improve the performance of OTT services provided to the UE 1514 using the OTT connection 1516, in which the wireless connection 1526 forms the last segment.
  • a measurement procedure may be provided for the purpose of monitoring data rate, latency, and other factors on which the one or more embodiments improve.
  • the measurement procedure and/or the network functionality for reconfiguring the OTT connection 1516 may be implemented in the software 1510 and the hardware 1504 of the host computer 1502 or in the software 1540 and the hardware 1534 of the UE 1514, or both.
  • sensors may be deployed in or in association with communication devices through which the OTT connection 1516 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which the software 1510, 1540 may compute or estimate the monitored quantities.
  • the reconfiguring of the OTT connection 1516 may include message format, retransmission settings, preferred routing, etc.; the reconfiguring need not affect the base station 1518, and it may be unknown or imperceptible to the base station 1518. Such procedures and functionalities may be known and practiced in the art.
  • measurements may involve proprietary UE signaling facilitating the host computer 1502's measurements of throughput, propagation times, latency, and the like. The measurements may be implemented in that the software 1510 and 1540 causes messages to be transmitted, in particular empty or 'dummy' messages, using the OTT connection 1516 while it monitors propagation times, errors, etc.
  • FIG 16 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment.
  • the communication system includes a host computer, a base station, and a UE which may be those described with reference to Figures 14 and 15. For simplicity of the present disclosure, only drawing references to Figure 16 will be included in this section.
  • the host computer provides user data.
  • sub-step 1602 (which may be optional) of step 1600, the host computer provides the user data by executing a host application.
  • the host computer initiates a transmission carrying the user data to the UE.
  • the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure.
  • the UE executes a client application associated with the host application executed by the host computer.
  • FIG 17 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment.
  • the communication system includes a host computer, a base station, and a UE which may be those described with reference to Figures 14 and 15. For simplicity of the present disclosure, only drawing references to Figure 17 will be included in this section.
  • the host computer provides user data.
  • the host computer provides the user data by executing a host application.
  • the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure.
  • step 1704 (which may be optional), the UE receives the user data carried in the transmission.
  • FIG. 18 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment.
  • the communication system includes a host computer, a base station, and a UE which may be those described with reference to Figures 14 and 15. For simplicity of the present disclosure, only drawing references to Figure 18 will be included in this section.
  • the UE receives input data provided by the host computer. Additionally or alternatively, in step 1802, the UE provides user data.
  • sub-step 1804 (which may be optional) of step 1800, the UE provides the user data by executing a client application.
  • sub-step 1806 (which may be optional) of step 1802, the UE executes a client application which provides the user data in reaction to the received input data provided by the host computer.
  • the executed client application may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the UE initiates, in sub-step 1808 (which may be optional), transmission of the user data to the host computer. In step 1810 of the method, the host computer receives the user data transmitted from the UE, in accordance with the teachings of the embodiments described throughout this disclosure.
  • FIG 19 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment.
  • the communication system includes a host computer, a base station, and a UE which may be those described with reference to Figures 14 and 15. For simplicity of the present disclosure, only drawing references to Figure 19 will be included in this section.
  • the base station receives user data from the UE.
  • the base station initiates transmission of the received user data to the host computer.
  • step 1904 (which may be optional)
  • the host computer receives the user data carried in the transmission initiated by the base station.
  • any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses.
  • Each virtual apparatus may comprise a number of these functional units.
  • These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processor (DSPs), special-purpose digital logic, and the like.
  • the processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc.
  • Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein.
  • the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according one or more embodiments of the present disclosure.
  • Embodiment 1 The method of any of the embodiments of a method of operation of a wireless communication device disclosed herein or claimed in the following Claims section, further comprising providing user data and forwarding the user data to a host computer via the transmission to the network node.
  • Embodiment 2 The method of any of the embodiments of a method of operation of a network node disclosed herein or any of the claims in the following Claims section, further comprising obtaining user data and forwarding the user data to a host computer or a wireless communication device.
  • Embodiment 3 A wireless communication device comprising:
  • processing circuitry configured to perform any of the steps of any of the Embodiments of a method of operation of a wireless communication device disclosed herein or any of the claims in the following Claims section;
  • Embodiment 4 A network node comprising:
  • processing circuitry configured to perform any of the steps of any of the embodiments of a method performed by a network node or base station or of any of the claims in the following Claims section;
  • Embodiment 5 A wireless communication device comprising:
  • radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry;
  • processing circuitry being configured to perform any of the steps of any of the Embodiments of a method of operation of a wireless communication device disclosed herein or any of the claims in the following Claims section;
  • Embodiment 6 A communication system including a host computer comprising:
  • processing circuitry configured to provide user data
  • a communication interface configured to forward the user data to a cellular network for transmission to a wireless communication device
  • the cellular network comprises a network node having a radio interface and processing circuitry, the network node's processing circuitry configured to perform any of the steps of any of the Embodiments of a method performed by a network node or base station or of any of the claims in the following Claims section.
  • Embodiment 7 The communication system of the previous embodiment further including the network node.
  • Embodiment 8 The communication system of the previous 2 embodiments, further including the wireless communication device, wherein the wireless communication device is configured to communicate with the network node.
  • Embodiment 9 The communication system of the previous 3 embodiments, wherein:
  • the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data
  • the wireless communication device comprises processing circuitry configured to execute a client application associated with the host application.
  • Embodiment 10 A method implemented in a communication system including a host computer, a network node, and a wireless communication device, the method comprising:
  • Embodiment 11 The method of the previous embodiment, further comprising, at the network node, transmitting the user data.
  • Embodiment 12 The method of the previous 2 embodiments, wherein the user data is provided at the host computer by executing a host application, the method further comprising, at the wireless communication device, executing a client application associated with the host application.
  • Embodiment 13 A wireless communication device configured to communicate with a network node, the wireless communication device comprising a radio interface and processing circuitry configured to perform the method of the previous 3 embodiments.
  • Embodiment 14 A communication system including a host computer comprising:
  • processing circuitry configured to provide user data
  • a communication interface configured to forward user data to a cellular network for transmission to a wireless communication device; • wherein the wireless communication device comprises a radio interface and processing circuitry, the wireless communication device's components configured to perform any of the steps of any of the Embodiments of a method of operation of a wireless communication device disclosed herein or any of the claims in the following Claims section.
  • Embodiment 15 The communication system of the previous embodiment, wherein the cellular network further includes a network node configured to communicate with the wireless communication device.
  • Embodiment 16 The communication system of the previous 2 embodiments, wherein:
  • the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data
  • the wireless communication device's processing circuitry is configured to execute a client application associated with the host application.
  • Embodiment 17 A method implemented in a communication system including a host computer, a network node, and a wireless communication device, the method comprising:
  • Embodiment 18 The method of the previous embodiment, further comprising at the wireless communication device, receiving the user data from the network node.
  • Embodiment 19 A communication system including a host computer comprising:
  • communication interface configured to receive user data originating from a transmission from a wireless communication device to a network node
  • the wireless communication device comprises a radio interface and processing circuitry, the wireless communication device's processing circuitry configured to perform any of the steps of any of the Embodiments of a method of operation of a wireless communication device disclosed herein or any of the claims in the following Claims section.
  • Embodiment 20 The communication system of the previous embodiment, further including the wireless communication device.
  • Embodiment 21 The communication system of the previous 2 embodiments, further including the network node, wherein the network node comprises a radio interface configured to communicate with the wireless communication device and a communication interface configured to forward to the host computer the user data carried by a transmission from the wireless communication device to the network node.
  • the network node comprises a radio interface configured to communicate with the wireless communication device and a communication interface configured to forward to the host computer the user data carried by a transmission from the wireless communication device to the network node.
  • Embodiment 22 The communication system of the previous 3 embodiments, wherein:
  • the processing circuitry of the host computer is configured to execute a host application
  • the wireless communication device's processing circuitry is configured to execute a client application associated with the host application, thereby providing the user data.
  • Embodiment 23 The communication system of the previous 4 embodiments, wherein:
  • the processing circuitry of the host computer is configured to execute a host application, thereby providing request data
  • the wireless communication device's processing circuitry is configured to execute a client application associated with the host application, thereby providing the user data in response to the request data.
  • Embodiment 24 A method implemented in a communication system including a host computer, a network node, and a wireless communication device, the method comprising, at the host computer, receiving user data transmitted to the network node from the wireless communication device, wherein the wireless communication device performs any of the steps of any of the Embodiments of a method of operation of a wireless communication device disclosed herein or any of the claims in the following Claims section .
  • Embodiment 25 The method of the previous embodiment, further comprising, at the wireless communication device, providing the user data to the network node.
  • Embodiment 26 The method of the previous 2 embodiments, further comprising:
  • Embodiment 27 The method of the previous 3 embodiments, further comprising:
  • Embodiment 28 A communication system including a host computer comprising a communication interface configured to receive user data originating from a transmission from a wireless communication device to a network node, wherein the network node comprises a radio interface and processing circuitry, the network node's processing circuitry configured to perform any of the steps of any of the Embodiments of a method performed by a network node or base station or of any of the claims in the following Claims section.
  • Embodiment 29 The communication system of the previous embodiment further including the network node.
  • Embodiment 30 The communication system of the previous 2 embodiments, further including the wireless communication device, wherein the wireless communication device is configured to communicate with the network node.
  • Embodiment 31 The communication system of the previous 3 embodiments, wherein:
  • the processing circuitry of the host computer is configured to execute a host application
  • Embodiment 32 A method implemented in a communication system including a host computer, a network node, and a wireless communication device, the method comprising, at the host computer, receiving, from the network node, user data originating from a transmission which the network node has received from the wireless communication device, wherein the wireless communication device performs any of the steps of any of the Embodiments of a method of operation of a wireless communication device disclosed herein or any of the claims in the following Claims section .
  • Embodiment 33 The method of the previous embodiment, further comprising at the network node, receiving the user data from the wireless communication device.
  • Embodiment 34 The method of the previous 2 embodiments, further comprising at the network node, initiating a transmission of the received user data to the host computer.

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Abstract

Systems and methods are disclosed herein that relate to bandwidth limited search space partitioning. In one embodiment, a method performed by a wireless communication device comprises receiving a Control Resource Set (CORESET) configuration that defines a CORESET having a first bandwidth and monitoring a plurality of Physical Downlink Control Channel (PDCCH) candidates within the CORESET. Positions of the plurality of PDCCH candidates within the CORESET are defined such that the plurality of PDCCH candidates are located within a second bandwidth that is less than the first bandwidth. In this manner, the wireless communication device can monitor PDCCH candidates within a reduced receive bandwidth within a CORESET having a larger bandwidth.

Description

BANDWIDTH LIMITED SEARCH SPACE PARTIUONING
Related Applications
This application claims the benefit of provisional patent application serial number 63/007,651, filed April 9, 2020, the disclosure of which is hereby incorporated herein by reference in its entirety.
Technical Field
The present disclosure relates to transmission of and monitoring for Physical Downlink Control Channel (PDCCH) in PDCCH candidates in a Control Resource Set (CORESET) and bandwidth limited wireless communication devices.
Background
The next paradigm shift in processing and manufacturing is the Industry 4.0 in which factories are automated and made much more flexible and dynamic with the help of wireless connectivity. This includes real-time control of robots and machines using time-critical Machine-Type Communication (cMTC) and improved observability, control, and error detection with the help of large numbers of more simple actuators and sensors (e.g., massive Machine-Type Communication or mMTC).
For cMTC support, Ultra-Reliable Low-Latency Communication (URLLC) was introduced in Third Generation Partnership Project (3GPP) Release 15 for both Long Term Evolution (LTE) and New Radio (NR), and NR URLLC is further enhanced in Release 16 within the enhanced URLLC (eURLLC) and Industrial IoT work items.
For mMTC and Low Power Wide Area (LPWA) support, 3GPP introduced both Narrowband Internet-of-Things (NB-IoT) and Long Term Evolution for Machine-Type Communication (LTE-MTC, or LTE-M) in Release 13. These technologies have been further enhanced through all releases up until and including the ongoing Release 16 work.
NR was introduced in 3GPP Release 15 and focused mainly on the enhanced Mobile Broadband (eMBB) and cMTC. For Release 17, however, an NR User Equipment (UE) type with lower capabilities will likely be introduced since it is supported and proposed by many companies. The intention is to have an MTC version of NR, i.e. Reduced capability NR device (NR-RedCap), which is mid-end, filling the gap between eMBB NR and NB-IoT/LTE-M, e.g., to provide more efficient inband operation with URLLC in industrial use cases.
Low-cost or low-complexity UE implementation is needed for the Fifth Generation (5G) system, e.g., for massive industrial sensors deployment or wearables. Currently, NR-RedCap (Reduced capability NR device) is used as the running name for the discussion of such low-complexity UEs in 3GPP (see RP-193238 for more detail). NR- RedCap is a new feature that is currently under discussion and could be introduced as early as in 3GPP Release 17. NR-RedCap is intended for use cases that do not require a device to support full-fledged NR capability and IMT-2020 performance requirements. For example, the data rate does not need to reach above 1 Gigabits per second (Gbps), and the latency does not need to be as low as 1 millisecond (ms). By relaxing the data rate and latency targets, NR-RedCap allows low-cost or low-complexity UE implementation.
Specifically, one means of achieving complexity reduction and possibly energy consumption reduction is by reducing the requirements on UE bandwidth. In 3GPP Release 15, an NR UE is required to support 100 Megahertz (MHz) carrier bandwidth in Frequency Range 1 (from 410 MHz to 7125 MHz) and 200 MHz carrier bandwidth in Frequency Range 2 (from 24.25 GHz to 52.6 GHz). For NR-RedCap UEs, supporting 100 MHz or 200 MHz bandwidth is superfluous. For example, a UE bandwidth of 8.64 MHz might be sufficient if the use cases do not require a data rate higher than 20 Megabits per second (Mbps).
NR Physical Downlink Control Channel (PDCCH) and Control Resource Sets (CORESETs)
PDCCH carries Downlink Control Information (DCI). PDCCHs are transmitted in CORESETs which span over one, two, or three contiguous Orthogonal Frequency Division Multiplexing (OFDM) symbols over multiple Resource Blocks (RBs). In the frequency domain, a CORESET can span over one or multiple chunks of six RBs. For CORESETs other than CORESET #0, multiple chunks of six RBs can be either contiguous or non-contiguous, and CORESETs are aligned with a six-RB grid (starting from reference Point A). CORESET #0, which is configured during the initial access, can only have 24, 48, or 96 RBs. Also, CORESET #0 must be contiguous in frequency domain, and it is not necessarily aligned with the six-RB grid. A PDCCH is carried by 1, 2, 4, 8, or 16 Control Channel Elements (CCEs).
Multiple CCEs used for transmission of a DCI is referred to as an Aggregation Level (AL).
Each CCE is composed of six Resource Element Groups (REGs), and each REG is 12
Resource Elements (REs) in one OFDM symbol, as shown in Figure 1. A REG bundle consists of 2, 3, or 6 REGs. Thus, a CCE can be composed of one or multiple bundles.
Each CORESET is associated with a CCE-REG mapping, which can be an interleaved CCE-REG mapping or a non-interleaved CCE-REG mapping. In the non- interleaved case, all CCEs in an AL are mapped in consecutive REG bundles of the associated CORESET. In the interleaved case, REG bundles of CCEs are distributed in the frequency domain over the entire CORESET bandwidth. For CORESET #0, the CCE-
REG mapping is always interleaved with predefined parameters.
In order to receive DCI, a UE needs to blindly decode PDCCH candidates potentially transmitted from the network using one or more search spaces. A search space consists of a set of PDCCH candidates where each candidate can occupy multiple
CCEs. The number of CCEs used for a PDCCH candidate is referred to as AL, which in
NR can be 1, 2, 4, 8, or 16. A higher AL provides higher coverage.
Which CCEs to use for a certain PDCCH candidate is determined by a procedure, mainly described by the following excerpt from 3GPP TS 38.213, v.15.7.0.
For a search space set s associated with CORESET p, the CCE indexes for aggregation level L corresponding to PDCCH candidate ms nc/ of the search space set in slot
Figure imgf000005_0001
for an active DL BWP of a serving cell corresponding to carrier indicator field value nCI are given by 39827 for
Figure imgf000005_0002
pmod3 = 0, Ap = 39829 for pmod3 = 1, Ap = 39839 for pmod3 = 2, and D = 65537; i = 0, , L — 1;
NQQE.P is the number of CCEs, numbered from 0 to N Ep — 1, in CORESET p; nCI is the carrier indicator field value if the UE is configured with a carrier indicator field by CrossCarrierSchedulingConfig for the serving cell on which PDCCH is monitored; otherwise, including for any CSS, nCI = 0;
Figure imgf000006_0001
the number of PDCCH candidates the UE is configured to monitor for aggregation level L of a search space set s for a serving cell corresponding to nCI ; for any CSS, M®, x = M ; for a USS,
Figure imgf000006_0003
is the maximum of
Figure imgf000006_0002
over all configured nCI values for a CCE aggregation level L of search space set s ; the RNTI value used for nRNTI is the C-RNTI.
The above procedure establishes that, for each PDCCH candidate with aggregation level L, the UE is required to monitor in a search space the associated set of L CCEs, and thus the corresponding REGs and REs, to which the PDCCH candidate is mapped. When non-interleaved mapping is used, these L CCEs are confined to a localized set of RBs, where the number of RBs depends on the number of OFDM symbols configured for the CORESET.
Figure imgf000006_0004
Systems and methods are disclosed herein that relate to bandwidth limited search space partitioning. In one embodiment, a method performed by a wireless communication device comprises receiving a Control Resource Set (CORESET) configuration that defines a CORESET having a first bandwidth and monitoring a plurality of Physical Downlink Control Channel (PDCCH) candidates within the CORESET. Positions of the plurality of PDCCH candidates within the CORESET are defined such that the plurality of PDCCH candidates are located within a second bandwidth that is less than the first bandwidth. In this manner, the wireless communication can monitor PDCCH candidates within a reduced receive bandwidth within a CORESET having a larger bandwidth.
In one embodiment, the plurality of PDCCH candidates is all PDCCH candidates monitored by the wireless communication device within a search space within the CO RESET.
In one embodiment, the plurality of PDCCH candidates comprise PDCCH candidates for two or more different aggregation levels.
In one embodiment, the wireless communication device supports a bandwidth that is less than the first bandwidth, and the second bandwidth is less than or equal to the bandwidth supported by the wireless communication device. In one embodiment, monitoring the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function of a value that corresponds to the bandwidth supported by the wireless communication device. In one embodiment, determining the position of the PDCCH candidate as a function of the value that corresponds to the bandwidth supported by the wireless communication device comprises determining an index of a Control Channel Element (CCE) for the PDCCH candidate based on a modulo X operation, where X is a function of NCCE red pi where NCCE red p is a total number of CCEs in the bandwidth supported by the wireless communication device. In another embodiment, monitoring the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function of a bandwidth related value that corresponds to a bandwidth that is less than or equal to the bandwidth supported by the wireless communication device. In one embodiment, determining the position of the PDCCH candidate as a function of the bandwidth related value, X, that corresponds to a bandwidth that is less than or equal to the bandwidth supported by the wireless communication device comprises determining an index of a CCE for the PDCCH candidate based on a modulo X operation, where X is a function of a number of CCEs that is less than or equal to NCCE red pi where NCCE red p is a total number of CCEs in the bandwidth supported by the wireless communication device. In another embodiment, monitoring the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function of a maximum aggregation level ( Lmax ) supported by the wireless communication device. In one embodiment, determining the position of the PDCCH candidate as a function of the maximum aggregation level ( Lmax ) supported by the wireless communication device comprises determining an index of a CCE for the PDCCH candidate based on a modulo X operation, where X is a function of the maximum aggregation level ( ma ) supported by the wireless communication device. In another embodiment, monitoring the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function of a predefined or preconfigured scaling factor. In one embodiment, the scaling factor is or is based on a ratio of a first value that corresponds to the bandwidth supported by the wireless communication device and a second value that corresponds to the bandwidth of the CORESET. In one embodiment, determining the position of the PDCCH candidate as a function of the predefined or preconfigured scaling factor comprises determining an index of a CCE for the PDCCH candidate based on the predefined or preconfigured scaling factor.
In one embodiment, the wireless communication device supports the first bandwidth, and the second bandwidth is less than or equal to a bandwidth supported by other reduced-bandwidth wireless communication devices.
In one embodiment, the plurality of PDCCH candidates are positioned towards a lower end of the first bandwidth.
In one embodiment, the plurality of PDCCH candidates are positioned relative to a lower end of the first bandwidth based on an offset. In one embodiment, the offset is wireless communication device specific. In one embodiment, the offset is preconfigured. In another embodiment, the offset is determined by a function or otherwise based on a parameter which is unique to the wireless communication device, or to the CORESET, or to a search space, or to bandwidth part in which the CORESET is located. In another embodiment, the offset is determined based on the location of CCE(s) used for a PDCCH candidate using a maximum supported aggregation level when placed in the CORESET. In one embodiment, monitoring the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function the offset. In one embodiment, determining the position of the PDCCH candidate as a function the offset comprises determining an index of a CCE of the PDCCH candidate as a function of the offset.
In one embodiment, bandwidth portions within the first bandwidth in which PDCCH candidates for different wireless communication devices are located are uniformly distributed within the bandwidth of the CORESET.
In one embodiment, the plurality of PDCCH candidates comprise a number of PDCCH candidates for a particular aggregation level, wherein the number of PDCCH candidates for the particular aggregation level is a function of a value that corresponds to the bandwidth supported by the wireless communication device.
In one embodiment, the method further comprises refraining from monitoring for PDCCH in one or more search spaces within the CORESET, the one or more search spaces comprising one or more CCEs that are mapped to at least one Resource Element Group (REG) that is at least partially outside of a supported bandwidth of the wireless communication device.
In one embodiment, the first bandwidth and/or the second bandwidth are measured in terms of: a frequency unit, a number of Resource Blocks (RBs), or a number of CCEs.
In one embodiment, the method further comprises detecting Downlink Control Information (DCI) in one of the monitored plurality of PDCCH candidates.
In one embodiment, the method further comprises detecting a PDCCH transmission in one of the monitored plurality of PDCCH candidates.
Corresponding embodiments of a wireless communication device are also disclosed. In one embodiment, a wireless communication device is adapted to receive a CORESET configuration that defines a CORESET having a first bandwidth and monitor a plurality of PDCCH candidates within the CORESET. Positions of the plurality of PDCCH candidates within the CORESET are defined such that the plurality of PDCCH candidates are located within a second bandwidth, the second bandwidth being less than the first bandwidth.
In one embodiment, a wireless communication device comprises one or more transmitters, one or more receivers, and processing circuitry associated with the one or more transmitters and the one or more receivers. The processing circuitry is configured to cause the wireless communication device to receive a CORESET configuration that defines a CORESET having a first bandwidth and monitor a plurality of PDCCH candidates within the CORESET. Positions of the plurality of PDCCH candidates within the CORESET are defined such that the plurality of PDCCH candidates are located within a second bandwidth, the second bandwidth being less than the first bandwidth.
Embodiments of a method performed by a network node are also disclosed. In one embodiment, a method performed by a network node comprises configuring a wireless communication device with a CORESET having a first bandwidth, selecting a set of CCEs on which to transmit a PDCCH to the wireless communication device from among a plurality of sets of CCEs that correspond to a plurality of PDCCH candidates for the wireless communication device within the CORESET, wherein positions of the plurality of PDCCH candidates are defined such that the plurality of PDCCH candidates are located within a second bandwidth that is less than the first bandwidth. The method further comprises transmitting a PDCCH to the wireless communication device on the selected set of CCEs.
Corresponding embodiments of a network node are also disclosed. In one embodiment, a network node is adapted to configure a wireless communication device with a CORESET having a first bandwidth and select a set of CCEs on which to transmit a PDCCH to the wireless communication device from among a plurality of sets of CCEs that correspond to a plurality of PDCCH candidates for the wireless communication device within the CORESET, wherein positions of the plurality of PDCCH candidates are defined such that the plurality of PDCCH candidates are located within a second bandwidth that is less than the first bandwidth. The network node is further adapted to transmit a PDCCH to the wireless communication device on the selected set of CCEs.
In one embodiment, a network node comprises processing circuitry configured to cause the network node to configure a wireless communication device with a CORESET having a first bandwidth and select a set of CCEs on which to transmit a PDCCH to the wireless communication device from among a plurality of sets of CCEs that correspond to a plurality of PDCCH candidates for the wireless communication device within the CORESET, wherein positions of the plurality of PDCCH candidates are defined such that the plurality of PDCCH candidates are located within a second bandwidth that is less than the first bandwidth. The processing circuitry is further configured to cause the network node to transmit a PDCCH to the wireless communication device on the selected set of CCEs.
Figure imgf000010_0001
The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.
Figure 1 illustrates an example of a Control Resource Set (CORESET) including multiple Control Channel Elements (CCEs), where each CCE is composed of six Resource Element Groups (REGs) and each REG is twelve Resource Elements (REs) in one Orthogonal Frequency Division Multiplexing (OFMD) symbol;
Figure 2 illustrates one example of a cellular communications system in which embodiments of the present disclosure may be implemented; Figure 3 illustrates an example of Physical Downlink Control Channel (PDCCH) candidates to be monitored for an example search space in accordance with existing New Radio (NR) specifications;
Figure 4 illustrates an example of PDCCFI candidates to be monitored for an example search space wherein locations of the PDCCFI candidates are determined based on a reduced bandwidth in accordance with some embodiments of the present disclosure;
Figure 5 illustrates another example of PDCCFI candidates to be monitored for an example search space wherein locations of the PDCCFI candidates are determined based on a reduced bandwidth in accordance with some embodiments of the present disclosure;
Figure 6 illustrates another example of PDCCFI candidates to be monitored for an example search space wherein locations of the PDCCFI candidates are determined based on a reduced bandwidth in accordance with some embodiments of the present disclosure;
Figure 7 illustrates another example of PDCCFI candidates to be monitored for an example search space wherein locations of the PDCCFI candidates are determined based on a reduced bandwidth and an offset in accordance with some embodiments of the present disclosure;
Figure 8 illustrates the operation of a network node (e.g., base station such as, e.g., a gNB) and a wireless communication device (e.g., a reduced bandwidth User Equipment (UE)) in accordance with at least some embodiments of the present disclosure;
Figures 9 through 11 are schematic block diagrams of example embodiments of a network node;
Figures 12 and 13 are schematic block diagrams of example embodiments of a wireless communication device;
Figure 14 illustrates an example embodiment of a communication system in which embodiments of the present disclosure may be implemented;
Figure 15 illustrates example embodiments of the host computer, base station, and UE of Figure 14; and
Figures 16 through 19 are flow charts that illustrate example embodiments of methods implemented in a communication system such as that of Figure 14. Detailed Description
The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.
Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.
Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features, and advantages of the enclosed embodiments will be apparent from the following description.
Radio Node: As used herein, a "radio node" is either a radio access node or a wireless communication device.
Radio Access Node: As used herein, a "radio access node" or "radio network node" or "radio access network node" is any node in a Radio Access Network (RAN) of a cellular communications network that operates to wirelessly transmit and/or receive signals. Some examples of a radio access node include, but are not limited to, a base station (e.g., a New Radio (NR) base station (gNB) in a Third Generation Partnership Project (3GPP) Fifth Generation (5G) NR network or an enhanced or evolved Node B (eNB) in a 3GPP Long Term Evolution (LTE) network), a high-power or macro base station, a low-power base station (e.g., a micro base station, a pico base station, a home eNB, or the like), a relay node, a network node that implements part of the functionality of a base station (e.g., a network node that implements a gNB Central Unit (gNB-CU) or a network node that implements a gNB Distributed Unit (gNB-DU)) or a network node that implements part of the functionality of some other type of radio access node.
Core Network Node: As used herein, a "core network node" is any type of node in a core network or any node that implements a core network function. Some examples of a core network node include, e.g., a Mobility Management Entity (MME), a Packet Data Network Gateway (P-GW), a Service Capability Exposure Function (SCEF), a Home Subscriber Server (HSS), or the like. Some other examples of a core network node include a node implementing an Access and Mobility Management Function (AMF), a User Plane Function (UPF), a Session Management Function (SMF), an Authentication Server Function (AUSF), a Network Slice Selection Function (NSSF), a Network Exposure Function (NEF), a Network Function (NF) Repository Function (NRF), a Policy Control Function (PCF), a Unified Data Management (UDM), or the like.
Communication Device: As used herein, a "communication device" is any type of device that has access to an access network. Some examples of a communication device include, but are not limited to: mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or Personal Computer (PC). The communication device may be a portable, hand-held, computer-comprised, or vehicle- mounted mobile device, enabled to communicate voice and/or data via a wireless or wireline connection.
Wireless Communication Device: One type of communication device is a wireless communication device, which may be any type of wireless device that has access to (i.e., is served by) a wireless network (e.g., a cellular network). Some examples of a wireless communication device include, but are not limited to: a User Equipment device (UE) in a 3GPP network, a Machine Type Communication (MTC) device, and an Internet of Things (IoT) device. Such wireless communication devices may be, or may be integrated into, a mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or PC. The wireless communication device may be a portable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice and/or data via a wireless connection.
Network Node: As used herein, a "network node" is any node that is either part of the RAN or the core network of a cellular communications network/ system.
Note that the description given herein focuses on a 3GPP cellular communications system and, as such, 3GPP terminology or terminology similar to 3GPP terminology is oftentimes used. However, the concepts disclosed herein are not limited to a 3GPP system.
Note that, in the description herein, reference may be made to the term "cell"; however, particularly with respect to 5G NR concepts, beams may be used instead of cells and, as such, it is important to note that the concepts described herein are equally applicable to both cells and beams.
There currently exist certain challenge(s). The procedure for determining which Control Channel Elements (CCEs) to use for a Physical Downlink Control Channel (PDCCH) candidate results in the PDCCH candidate being mapped to a contiguous set of Resource Blocks (RBs) when non-interleaved mapping is used. For a bandwidth-limited UE, such as an NR Reduced Capacity (NR-RedCap) UE, this means that the UE will be able to receive PDCCH candidates up to a given maximum aggregation level (AL). If both the network and the UE are aware of this maximum AL, it is possible to schedule a PDCCH transmission such that the UE can tune its receiver frequency range such that its bandwidth covers the RBs used for this candidate. This naturally holds also for a PDCCH candidate with an AL lower than the maximum one, since fewer RBs will then be used. However, given the way the CCEs are determined, there is no guarantee that the PDCCH candidates with an AL lower than the maximum one are in fact mapped to the same set of RBs as for the maximum AL. Thus, with the current definition of the search space, an NR-RedCap UE may be restricted to use only a subset of the available ALs at any given time, namely the ones whose candidates are being mapped to the RBs coinciding with the current frequency range of the receiver. The NR-RedCap UE could potentially receive different frequency ranges at different times such that different sets of candidates/ALs are being monitored in a time-multiplexing fashion. This may, however, significantly reduce the PDCCH scheduling flexibility.
One solution to this problem would be to define all Control Resource Sets (CORESETs) to be used by NR-RedCap UEs in the system such that all RBs in the CORESET can be accommodated within the NR-RedCap UE receiver bandwidth. However, if the CORESETs for all UEs (both legacy NR and NR-RedCap UE) in the system are configured with this lower bandwidth, this may result in a control channel capacity that is too low. Another natural solution would be to configure new CORESETs specifically for NR-RedCap UEs, where these new CORESETs are different from the CORESETs used for legacy NR UEs. However, this reduces the system resource utilization.
There is thus a need for methods and apparatuses for restricting the bandwidth of a search space for different aggregation levels to a confined frequency range for reduced bandwidth UE such as, e.g., an NR-RedCap UE.
Certain aspects of the present disclosure and their embodiments may provide solutions to the aforementioned or other challenges. Systems and methods are provided for restricting CCEs used for PDCCH candidates in a CORESET such that PDCCH candidates with different aggregation levels are mapped to a portion of the bandwidth of the CORESET. For example, this restriction may be such that PDCCH candidates with different aggregation levels are mapped to a subset of one contiguous set of CCEs, where the subset of the CCEs include only CCEs that are mapped to REGs that are within the portion of the bandwidth of the CORESET. This portion of the bandwidth of the CORESET may for example be less than or equal to a bandwidth supported by a reduced bandwidth UE (e.g., a RedCap UE) to which the PDCCH is transmitted. This can be illustrated by comparing an example using the legacy Rel-15 search space definition in Figure 3 where PDCCH candidates with different aggregation levels are mapped to CCEs across the full CORESET bandwidth, and a search space definition according to one embodiment of the present disclosure in Figure 4 where PDCCH candidates with different aggregation levels are mapped to CCEs restricted to be within only a portion of the full CORESET bandwidth, which is denoted in Figure 4 as NcCE,red,p· Embodiments of the present disclosure use non-interleaved CCE-REG mapping. This implies that all PDCCH candidates are confined to REGs within a bandwidth-limited CORESET part, which extends over a smaller bandwidth than the full, unrestricted CORESET. This smaller bandwidth may, for example, correspond to the supported receiver bandwidth of a reduced bandwidth UE (e.g., an NR-RedCap UE) monitoring the search space.
In one embodiment, the restriction of the CCEs to which the PDCCH candidates are mapped is done by modifying the existing hash function (such as the hash function above from 3GPP TS 38.213, v.15.7.0) used for determining the CCEs for a PDCCH candidate such that:
1) All CCEs used are confined to within a range of CCE indices within the bandwidth of a reduced bandwidth UE (e.g., an NR REDCAP UE), and
2) (optionally) a CCE start index offset is added in order to allow for frequency multiplexing within the large CORESET.
Some embodiments of the present disclosure apply both to CORESETS used for common search space and UE-specific search space, whereas others primarily target the latter.
In one embodiment, a bandwidth-limited part of a larger CORESET can be defined such that all PDCCH candidates monitored by a bandwidth-reduced wireless device will be located inside its receiver bandwidth, even if the search space is associated with the larger CORESET. The solutions presented herein include different ways of restricting the range of the CCEs used for the monitored PDCCH candidates.
Certain embodiments may provide one or more of the following technical advantage(s). The proposed solutions ensure that a UE (e.g., an NR-RedCap UE) with reduced receive bandwidth can monitor PDCCH candidates with different aggregation levels within a CORESET having a bandwidth which is larger than the UE receiver bandwidth. Therefore, it is more efficient if the reduced bandwidth UE (e.g., an NR- RedCap UE) can utilize the resource in the larger CORESETs that are also used by the legacy NR UEs. Another advantage with using a part of a larger CORESET, rather than a separate smaller CORESET for a reduced bandwidth UE, is that it may result in better frequency diversity in that different PDCCH transmissions may be mapped to different frequency regions at different times. This would alleviate the risk that a smaller CORESET may be located in a frequency region with worse radio channel conditions. Furthermore, given the same total number of UEs, having more UEs sharing the same set of resources in a larger CORESET may be beneficial from improved statistical multiplexing point of view compared to having more sets of resources in smaller CORESETs, each CORESET shared by fewer UEs.
Figure 2 illustrates one example of a cellular communications system 200 in which embodiments of the present disclosure may be implemented. In the embodiments described herein, the cellular communications system 200 is a 5G System (5GS) including a Next Generation RAN (NG-RAN) and a 5G Core (5GC). In this example, the RAN includes base stations 202-1 and 202-2, which in the 5GS include NR base stations (gNBs) and optionally next generation eNBs (ng-eNBs) (i.e., LTE RAN nodes connected to the 5GC), controlling corresponding (macro) cells 204-1 and 204-2. The base stations 202-1 and 202-2 are generally referred to herein collectively as base stations 202 and individually as base station 202. Likewise, the (macro) cells 204-1 and 204-2 are generally referred to herein collectively as (macro) cells 204 and individually as (macro) cell 204. The RAN may also include a number of low power nodes 206-1 through 206-4 controlling corresponding small cells 208-1 through 208-4. The low power nodes 206-1 through 206-4 can be small base stations (such as pico or femto base stations) or Remote Radio Heads (RRHs), or the like. Notably, while not illustrated, one or more of the small cells 208-1 through 208-4 may alternatively be provided by the base stations 202. The low power nodes 206-1 through 206-4 are generally referred to herein collectively as low power nodes 206 and individually as low power node 206. Likewise, the small cells 208-1 through 208-4 are generally referred to herein collectively as small cells 208 and individually as small cell 208. The cellular communications system 200 also includes a core network 210, which in the 5GS is referred to as the 5GC. The base stations 202 (and optionally the low power nodes 206) are connected to the core network 210.
The base stations 202 and the low power nodes 206 provide service to wireless communication devices 212-1 through 212-5 in the corresponding cells 204 and 208. The wireless communication devices 212-1 through 212-5 are generally referred to herein collectively as wireless communication devices 212 and individually as wireless communication device 212. In the following description, the wireless communication devices 212 are oftentimes UEs and as such sometimes referred to as UEs 212, but the present disclosure is not limited thereto. In the embodiments described herein, at least some of the wireless communication devices 212 are reduced bandwidth devices such as, e.g., NR-RedCap UEs. Note, however that the embodiments described here are not limited to NR-RedCap UEs, but instead can be used for any type of wireless communication device 212 that supports a reduced bandwidth (i.e., supports a receive bandwidth that is less than a full bandwidth of a CORESET). This may, for example, refer to a situation where the wireless communication device 212 in fact is capable of supporting the full bandwidth of a CORESET, but for some reason is configured to follow procedures that apply to reduced bandwidth devices, such as a NR-RedCap UE, for example in order to be able to utilize some other functionality which are supported only for NR-RedCap UEs.
Now a detailed description of some example embodiments will be described. The solutions presented herein are focused on new ways of determining which CCEs to use for the monitored PDCCH candidates. Since there is a predetermined mapping between CCEs and REGs in an NR CORESET, and therefore also between CCEs and RBs, the proposed solutions will also directly influence which REGs and RBs in the CORESET that are used for the PDCCH candidates. Hence, it would be possible to formulate the same, or similar, methods operating on REGs or PRBs in a CORESET. For example, by using the embodiments for selecting CCEs listed below, and then mapping to corresponding REGs and/or RBs, equivalent formulations of the embodiments can be derived.
In some embodiments, one or more modifications to the hash function for determining CCEs for a PDCCH candidate are provided. Using the notation from 3GPP TS 38.213, iVccE,P is the number of CCEs, numbered from 0 to /VCCEp - 1, in CORESET p. These CCEs are located across the full bandwidth of the CORESET which, here, is assumed to be larger than the bandwidth of the NR-RedCap UE, which is reduced compared to a legacy NR UE. Herein, NCCE red p denotes the number of CCEs in a bandwidth-limited part of a CORESET p. Typically, but not necessarily, this corresponds to the maximum number of CCEs that can be accommodated within the receiver bandwidth of an NR-RedCap UE. Further, Lmax denotes the maximum aggregation level supported by the UE, i.e., received within the UE receiver bandwidth assuming non- interleaved CCE-REG mapping. It can be noted that Lmax £ NCCE red pi such that PDCCH candidates with the maximum supported aggregation level always lie within the UE receiver bandwidth, but does not necessarily cover the full UE receiver bandwidth. It can further be noted that there is no restriction here on whether all aggregation levels defined for Rel-15 NR, {1,2,4,8,16}, are supported or only a subset of them are supported. That is, Lmax may be 16 but may also be 8 or lower. Moreover, the description herein also covers the case when new (maximum or other) aggregation levels are introduced, possibly with L being a non-power of two integer (i.e., L can adopt values other than {1,2,4,8,16}). The two modifications to the search space definition can readily be combined.
The main problem when using a CORESET larger than the UE bandwidth is that the CCE indices for different candidates may vary such that not all (or none) of the CCEs (for all monitored PDCCH candidates of all aggregation levels) are confined within NCCE, red, p CCEs. Below, different solutions are presented to overcome this problem.
First, a function is introduced for describing the index of the first CCE for a given PDCCH candidate in a search space, which is obtained by setting the index i = 0 in the hash function from 3GPP TS 38.213, where this hash function is described above. For simplicity, the discussion herein is restricted to the case without cross-carrier scheduling, i.e., nCI = 0. The embodiments can be readily modified to also cover the case with cross-carrier scheduling, for example by considering nCI as an offset value added to in the embodiments described below. However, since the main purpose of the description herein is to provide solutions for UEs with reduced capabilities, carrier aggregation in general and cross carrier scheduling in particular are not considered a main scenario.
Then, the index of the first CCE for a legacy PDCCH candidate with aggregation level L, as defined by 3GPP TS 38.213 in Rel-15 is herein denoted CCE0 Ll and given by the following expression: ms NCCE,p mod[NCCEP/L\ ,
Figure imgf000019_0001
L - M ft) where the different parameters included in the expression are the same as disclosed above, except that the dependencies on the Carrier Indicator (Cl) field has been removed (i.e., nCI = 0) since cross-carrier scheduling is not currently considered. The index of a first CCE used for a PDCCH candidate will herein be denoted a CCE start index or simply a start index, and thus CCE0 L represents the CCE start index for legacy PDCCH candidates. The indices for all of the CCEs in the legacy PDCCH candidates are found by adding the index /to the Equation for CCE0 L. First, an illustrative example is considered for the purpose of showing how CCEs for different PDCCH candidates may be distributed for a legacy mapping, i.e., without using the bandwidth-limited CORESET part disclosed herein. In the example, a CORESET containing NCCE P = 18 CCEs is used, and an example search space containing
Ms (i) = {3, 2, 1, 1} PDCCH candidates for aggregation levels L = {1, 2, 4, 8} is considered. Note that this is just an example used for illustrative purposes. In a real NR deployment, the CORESET size is typically much larger, and also AL 16 may be supported by an NR-RedCap UE. For each of the candidates, the expression CCEQ L above is used for determining the CCE start index. According to the CCE index determination procedure according to TS 38.213 included earlier, the parameter is
Figure imgf000020_0001
0 for any common search space, and will vary in a pseudo-random manner for a UE specific search space, based on the slot number as well as the Cell Radio Network Temporary Identifier (C-RNTI) of the UE. Figure 3 depicts an example of the PDCCH candidates to monitor for the example search space when = 5 {i.e., a UE-specific
Figure imgf000020_0002
search space). For each monitored aggregation level, the parameter determines
Figure imgf000020_0003
the lowest CCE index for the first PDCCH candidate (for which ms = 0), and if more candidates are to be monitored for that aggregation level, these are spread essentially uniformly among the available CCEs.
As seen from Figure 3, using the legacy procedure for mapping PDCCH candidates to CCEs can result in the CCEs used covering essentially all the available CCEs in the full bandwidth of the CORESET, and therefore the UE is required to be able to receive the full CORESET bandwidth. It can be noted that this will happen for more or less any configuration of CORESETs and search spaces and is not a property of an isolated example as the one in Figure 3.
The above legacy expression for CCE0 L will now be modified in various embodiments in order to make the search space located to within a limited bandwidth, lower than the full CORESET bandwidth. These embodiments will apply both to a network node, such as base station 202 (e.g., a gNB), and a wireless communication device 212, such as NR-RedCap (or other) UE, in that both nodes need to have the same knowledge of possible CCE allocation for the monitored PDCCH candidates. This applies both to PDCCH candidates in a Common Search Space (CSS) and a UE Specific Search Space (USS). In a first set of embodiments, the total number of CCEs iVCcE,P in the CORESET is replaced in the formula with a lower number (e.g., NCCE red p ) determined based on the UE reduced bandwidth. In particular, the divisor |NCCE,p J applied to the modulo operator in the expression for CCE0 L plays the role of limiting the CCE start index of all PDCCFI candidates in the search space to within an allowable range in the NR CORESET. Thus, by replacing JVCCE,P with a lower number therein, a bandwidth reduced mapping can be achieved.
In one embodiment, the legacy CCE0 L for representing the CCE start index is replaced by CCEX L, where the number of CCEs within the bandwidth-limited CORESET part, typically coinciding with the receiver bandwidth, is used instead of the total number of CCEs in the CORESET, i.e.:
Figure imgf000021_0001
This ensures that, for all aggregation levels supported by an NR-RedCap UE with reduced bandwidth, the CCEs used for all PDCCH candidates are confined within the lowest Ncc E,red,P indices. This is illustrated with an example for NCCE red p = 10 in Figure 4, which can be compared with the legacy mapping used in Figure 3, where the CCEs are distributed across the whole CORESET.
In a variant of this embodiment, NCCE red p is replaced by Lmax in the expression for CCE1 L, as shown below:
Figure imgf000021_0002
This may result in the bandwidth-limited CORESET part being smaller than the UE receiver bandwidth (thus not utilizing the entire UE bandwidth), but it may be advantageous for other reasons, e.g. to better align the bandwidth-limited CORESET part with PDCCFI candidates used for legacy UEs which use the full size of the CORESET. Using the same example search space as above, the CCEs used for different PDCCFI candidates are shown in Figure 5.
In another embodiment, the start index CCE2 L can be defined as a function of the legacy CCE0 L and a scaling factor nr. In one example of this embodiment, the scaling factor nr is a ratio between the number of CCEs supported by the NR-RedCap UE and the total number of CCEs in the CORESET, i.e., nr =
NCCE,p
Figure imgf000022_0001
The function / can be selected in such a way that the search space is shrunk by the scaling factor nr\
Figure imgf000022_0002
For the above-mentioned example, CCE2 L can be defined as,
Figure imgf000022_0003
Figure 6 illustrates an example of CCEs used for different PDCCFI candidates in the example search space when NCCE red p = 10 and the start index is given by the expression above for CCE2 L.
By scaling down the search space and using CCE2 L to find the start index, it may happen that the new obtained PDCCFI candidate collide, i.e., they are mapped to the same set of CCEs. In such cases, one of the candidates can simply be discarded.
It can be noted that by only replacing the NCCE p with a lower number in the expressions above, the CCEs used will always be placed towards the lower end of the total range of available CCEs in the full, unrestricted CORESET. For example, if it's possible to fit only one PDCCFI candidate with the maximum supported AL within the bandwidth-limited CORESET part, i.e., Lmax > NCCE red p/2, its lowest CCE index will always be zero. This may, in some cases, be a desired property. For example, for a legacy CSS, there will be (at least) one candidate for each monitored AL that start with
CCE index 0, due to the fact that Ur^{ = 0. Thus, it would often be possible for an NR-
RedCap UE to monitor PDCCH candidates both within the CSS and a USS in a bandwidth-limited CORESET part defined according to the above embodiments, assuming non-interleaved CCE-REG mapping is used (which excludes the application to CORESET #0). The PDCCH candidates in the CSS may refer to, e.g. scheduling of paging messages, System Information Blocks (SIBs) and Random Access Response (RAR), which may be common to both legacy UEs and NR-RedCap UEs. There is, however, the drawback that many candidates may overlap between the USS and the CSS, and also between the USS for different NR-RedCap UEs. Thus, solutions that reduce the risk of having overlapping PDCCH candidates may be desirable.
In one embodiment, a start index offset (ACCE) is added such that, with a start index offset larger than zero, none of the PDCCH candidates within the bandwidth- limited CORESET part may start at CCE index 0. This may, for example, be expressed as a modified start index expression CCE3 L. If CCE1 L above is used as a baseline, a modified start index expression can be defined as:
Figure imgf000023_0001
where ACCE represents the CCE start index offset for the bandwidth-limited CORESET part. Similarly, a modified start index expression can instead be based on CCE2 L defined above with a CCE start index offset added. The start index offset may be a fixed constant value. In one embodiment, in order to avoid the CORESET partitioning being overlapping for different UEs, the offset is UE-specific. However, if new common search spaces are to be defined for NR-RedCap UEs, the start index offset may instead be common between the UEs for such search spaces.
Herein, this start index offset is described to be applied directly to the CCE index in the CORESET, but an offset can equivalently be expressed in terms of an offset to REGs or RBs, given the present mapping between the entities. For example, in a CORESET consisting of 1, 2, or 3 OFDM symbols, a CCE index offset of 8 would correspond to an RB index offset of 48, 24, or 16, respectively.
In one embodiment, the start index offset (ACCE) is determined via higher layer signaling (e.g., via Radio Resource Control (RRC) configuration). The configured value may be set using UE-specific configuration (e.g., UE-specific RRC configuration). The start index offset may be configured per UE, per CORESET, per search space, per bandwidth part, per carrier, or for any other appropriate entity.
In one embodiment, the start index offset
Figure imgf000023_0002
is determined from a function, or otherwise based on a parameter which is unique to the UE, CORESET, search space, bandwidth part, or similar. The determination may result in a constant start index offset value, or a varying value, for example between slots, and for example in a pseudo-random manner. Without limitation, the start index offset (ACC£) may be a function of one or more of:
• A UE identity, such as an International Mobile Subscriber Identity (IMSI), a Temporary Mobile Subscriber Identity (TMSI) or 5G S-TMSI, or any other physical or higher layer UE-specific identity,
• A Radio Network Temporary Identifier (RNTI), such as a C-RNTI, SI-RNTI, RA- RNTI, P-RNTI, etc. • A search space identity, such as given by the searchSpaceld field comprised in an RRC configuration message,
• A CORESET identity, such as given by the control ResourceSetld field comprised in an RRC configuration message,
• A time index, such a slot number or a System Frame Number (SFN).
• Cell specific parameters, such as a Physical Cell Id.
• Other mechanisms, such as a defined frequency hopping scheme or a fixed offset, that control the covered frequency range by the NR-RedCap UE.
In one embodiment, the start index offset ( ACCE ) is determined based on the location of the CCEs used for a PDCCH candidate using the maximum supported aggregation level Lmax, when placed in the full, unrestricted CORESET. This can, for example, be accomplished by using the following expression for ACCE \
Figure imgf000024_0001
By using this expression, the bandwidth-limited CORESET part for different NR-RedCap UEs will be distributed essentially uniformly across the whole bandwidth of the full, unrestricted CORESET, according to where a legacy UE would have its first PDCCH candidate located. Using the same example search space as above, an illustration of the CCEs used for all PDCCH candidates is shown in Figure 7. It is noted that the PDCCH candidate with AL 8 uses the same CCEs for the legacy mapping (c.f. Figure 3), whereas the relative placement of the CCEs follows that of when expression CCE L is used (c.f. Figure 4).
In a variant of this embodiment, NCCE red p is replaced by Lmax in the expression for CCE3 L such that:
Figure imgf000024_0002
In another variant of this embodiment, in the above formula for calculating ACCEf the maximum supported AL Lmax is replaced by another (typically larger) number, for example the highest defined AL in the NR system.
In one embodiment, the start index offset (ACCE) is determined as the maximum AL used in another search space, such as a common search space. This has the effect that the bandwidth-limited CORESET part does not overlap with at least one PDCCH candidate for each AL in the common search space. The common search space may be a legacy, Rel-15, common search space, or a new defined common search space applicable for an NR-RedCap UE.
The primary motivation for introducing the start index offset ACCE above was to move the whole bandwidth-limited CORESET part inside the full, unrestricted CORESET. It is also possible to move the PDCCH candidates within the UE receiver bandwidth. In one embodiment, this is accomplished by adding a start index offset, e.g., fulfilling ACCE < 1 - 1· In a related embodiment, the start index offset is additionally or alternatively restricted such as it is ensured that no PDCCH candidate extends outside the bandwidth-limited CORESET part.
In one embodiment, the bandwidth-limited CORESET part, for example expressed using a start index offset ACCE, is determined individually for each search space occasion, such as once per slot. For subsequent occasions, it may be determined according to the same method, or two or more different methods. In a related embodiment, the bandwidth-limited CORESET part is determined for one search space occasion, and the same value is used for a given number of subsequent search space occasions. This may, for example, be combined with construction of CORESETs and/or search spaces expanded in time-domain (e.g., CORESETs and/or search spaces including more than 3 OFDM symbols in the same slot or in different slots). Some of the above embodiments will result in that the bandwidth-limited CORESET part exhibits frequency hopping, i.e., it covers different frequency ranges in different search space occasions. In other embodiments, it covers the same frequency range, but at least some PDCCH candidates use different CCEs in different search space occasions.
The above embodiments for determining the bandwidth-limited CORESET part and/or the start index offset ( ACCE ) can be combined and varied in any suitable manner. In a non-limiting example, the start index offset ( ACCE ) is determined as a sum of two or more terms, each term determined using the start index offset using one of the embodiments above. Care must be taken in order for such combinations not to result in PDCCH candidates extending outside the legacy CORESET. This may, for example, be achieved by further modifying the expressions above for calculating the CCE start index and/or start index offset. In some embodiments, this comprises reducing the possible maximum start index offset values in one or more of terms, for example by reducing the value of NCCEp in the start index offset calculations for one term with the start index value for another term.
The above embodiments disclose different methods of determining a bandwidth- limited CORESET part containing PDCCH candidates. By reducing the used CCE range, there will be room for less PDCCH candidates, and the candidates are packed more tightly, which can be understood by comparing, e.g.f Figure 3 and Figure 4. For this reason, it may be considered to reduce the number of monitored PDCCH candidates
(L)
M for an aggregation level L to a lower value, say M^ed, for a search space in a bandwidth-limited CORESET part. When determining the CCEs used for the candidates,
(L)
M s. ,red may then be used instead o
Figure imgf000026_0001
n any of the above expressions.
In some embodiments, M^ed is determined based on a formula, table, or similar containing at least one of the parameters NCCE
Figure imgf000026_0002
, L, Lmax (or any other parameter that can be derived therefrom). In one such embodiment, the number of PDCCH candidates is restricted according to how many PDCCH candidates of a given aggregation level that can be accommodated in a bandwidth-limited CORESET part, according to the following non-limiting example:
Figure imgf000026_0003
In another embodiment, the number of PDCCH candidates is scaled according to the relation between the size of the full, unrestricted CORESET and the bandwidth- limited CORESET part, according to the following non-limiting example:
Figure imgf000026_0004
In yet another embodiment, the maximum number of candidates for all supported ALs in a search space is set to 1 for an NR-RedCap UE. This can be particularly motivated in the case where a legacy, Rel-15, CSS in a CORESET is reused for the NR-RedCap UE.
Another reason for reducing the number of PDCCH candidates is for reducing the decoding complexity in an NR-RedCap UE.
As was noted above, the NR-RedCap UE receiver bandwidth may be too small to monitor PDCCH candidates both in a (legacy or new defined) CSS and a USS. If the UE is required to monitor PDCCH candidates in multiple search spaces that do not overlap in frequency, the UE may be configured to monitor different search spaces in a time- division multiplexing (TDM) manner. This may, for example, be accomplished by ensuring that the CCE index offset is zero at predefined occasions when (at least) one candidate in a CSS is to be monitored.
Currently in NR, the CORESET configuration in frequency domain is indicated by using a bitmap, i.e., frequencyDomainResources, as part of the Control ResourceSet information element defined in TS 38.331. To be more specific, frequencyDomainResources: Frequency domain resources for a CORESET.
• Each bit corresponds a group of 6 RBs, with grouping starting from PRB 0, which is fully contained in the bandwidth part within which the CORESET is configured.
• The most significant bit corresponds to the group of lowest frequency which is fully contained in the bandwidth part within which the CORESET is configured, each next subsequent lower significance bit corresponds to the next lowest frequency group fully contained within the bandwidth part within which the CORESET is configured, if any. Bits corresponding to a group not fully contained within the bandwidth part within which the CORESET is configured are set to zero.
Since the CORESET may be allocated to non-contiguous RBs, as indicated by the bitmap frequencyDomainResources, it is possible that the above embodiments will result in that the total frequency range spanned by the CCEs used in the bandwidth-limited CORESET part exceeds that of the NR-RedCap UE receiver bandwidth. This may, for example, happen for some of the determined values for a CCE start index offset, or any other representation of the determined bandwidth-limited CORESET part. In one embodiment, such determined bandwidth-limited CORESET parts are excluded from the allowed ones, such that PDCCH is not monitored for that particular occasion of the search space. In a related embodiment, the non-allowed determined bandwidth-limited CORESET part is replaced by another one, for example a previously allowed one, an adjacent one, or some other allowed bandwidth-limited CORESET determined in some other way. In another related embodiment, only a subset of the PDCCH candidates within the bandwidth-limited CORESET part are monitored by the UE, such that the resources used by these candidates are accommodated within the NR-RedCap UE receiver bandwidth.
The procedure for monitoring PDCCH candidates in NR CORESETs by using different sets of CCEs for different UEs was defined in Rel-15, and a built-in property is that it occasionally results in overlapping CCEs to be used for PDCCH candidates for different UEs. This will be true also with the introduction of the new mechanisms presented herein, both between NR-RedCap UEs, but also between NR-RedCap UEs and other UEs following the Rel-15 procedure. When any of the new mechanisms are used in a cell served by a gNB (or similar), information about this may be signaled to other network nodes, e.g. over an NG or an Xn interface, and/or to non-NR-RedCap UEs, e.g. as part of system information.
In some embodiments, when a network node indicates if, and potentially how, any of the embodiments herein for determining a bandwidth-reduced CORESET part is used in a cell, this information can be used for altering also the search space determination for a non-NR-RedCap UE served by the network node in the cell. As a non-limiting example, if an NR-RedCap UE is determining to monitor a PDCCH candidate with a given AL in a CCE set A using one of the embodiments for determining a bandwidth-reduced CORESET part rather than a CCE set f using the legacy procedure, then a non-NR-RedCap UE which determines to monitor a PDCCH candidate with a given AL in CCE set f using the legacy procedure may instead use CCE set A.
In some network node embodiments, when the network node serving a first cell is notified about if, and potentially how, any of the embodiments herein for determining a bandwidth-reduced CORESET part is used in a second cell served by the same or a different network node, this information can be used for modifying the configuration of the search space determination for NR-RedCap UEs and/or non-NR-RedCap UEs in the first cell. As a non-limiting example, this may be done by modifying one or more parameters to be used in the methods presented herein based on this information.
The above embodiments for determining the bandwidth-limited CORESET part may be used individually per search space. For example, different embodiments may be used for different search spaces, including the possibility of using the legacy procedure as the basis for a particular search space. The latter option may be particularly useful for a common search space, in that it may increase the possibility of achieving an overlap between PDCCH candidates in the common search space for legacy and NR-RedCap UEs. An NR-RedCap UE may then be required to monitor only those candidates in the search space that are located inside its receiver bandwidth. The determination of which embodiments to selectively use for different search spaces may be defined by RRC configuration or determined from a standards document.
There are other means of increasing the number of PDCCH candidates that overlap between when using the legacy Rel-15 procedure and the embodiments herein. It was mentioned above that NCCE red pi being the number of CCEs in a bandwidth- limited CORESET part, can be selected to be different than the maximum number of CCEs that can be accommodated within the receiver bandwidth of an NR-RedCap UE.
In one particular embodiment, NCCE red p is determined as an integer divisor of the number of the total number of CCEs in the CORESET, i.e., NCCE red p = NCCE p/K , where K is an integer > 1. As a non-limiting example, K may be chosen such that NCCE red p is the highest possible number determined this way, while fulfilling the condition that it is less or equal to the maximum number of CCEs that can be accommodated within the receiver bandwidth. Alternatively, or additionally, values of K may be further constrained to be multiples of, e.g., 2, 3, or 4. It may further be based on the number of monitored candidates Ms (i) for an aggregation level L in the search space for the search space of a legacy UE and/or an NR-RedCap UE. By selections according to such embodiments, there is an increasing probability that PDCCH candidates overlap when using the legacy Rel-15 procedure and the embodiments herein. This, again, can be particularly useful when applied to a common search space. It may, additionally, be suitably combined with embodiments mentioned above for determining a reduced number of monitored candidates, M ^ed.
The above embodiments for determining the bandwidth-limited CORESET part and the CCEs used for the PDCCH candidates therein have been described using examples of expressions for start indices and start index offsets. There are several alternative ways of achieving the same technical effect, and these alternatives are also covered by the description above.
Different parameters have been mentioned explicitly herein for describing the embodiments, such as the maximum supported aggregation level, Lmaxi the reduced number of supported CCEs, NCCE red pi and a reduced number of monitored PDCCH candidates, M^ed. Furthermore, one or more parameters may be used to, explicitly or implicitly, capture other configuration options regarding how different embodiments herein are employed. The parameters may be defined according to one or more of the following alternatives:
• Given by constant values, defined in a standard,
• Given by a formula, table, or similar, defined in a standard,
• Defined based on a UE class, a UE device type, a UE category, or similar, • Configured by the network, e.g. via broadcast or UE-specific RRC signaling,
• Indicated by the UE, e.g., as part of a UE capability signaling
It can further be noted that NCCE red p may be different than the maximum and/or the actual receiver bandwidth of the UE.
Figure 8 illustrates the operation of a network node (e.g., base station 202 such as, e.g., a gNB) and a wireless communication device 212 (e.g., a reduced bandwidth UE such as, e.g., a NR-RedCap UE) in accordance with at least some of the embodiments described above. As illustrated, the network node sends, to the wireless communication device 212, a CORESET configuration (step 800). The CORESET configuration includes information that defines a bandwidth of the CORESET, which for this discussion is referred to as a first bandwidth. The network node selects a set of CCEs on which to transmit a PDCCH to the wireless communication device 212 from among a plurality of sets of CCEs that correspond to a plurality of PDCCH candidates (e.g., comprised in a search space) for the wireless communication device 212 within the CORESET (step 802). Positions of the plurality of PDCCH candidates (e.g., CCE indices such as the starting CCE index) are defined such that the plurality of PDCCH candidates are located within a bandwidth-limited CORESET part of the CORESET, in accordance with any of the embodiments described above. In other words, within the CORESET, the positions of the plurality of PDCCH candidates are defined such that the plurality of PDCCH candidates are located within a second bandwidth that is less than, in accordance with any of the embodiments described above.
It should be noted that, in embodiments in which the wireless communication device 212 is a reduced-bandwidth UE (e.g., a NR RedCap UE), the large CORESET may potentially not be regarded by the wireless communication device 212 as its CORESET. The wireless communication device 212 may instead use the bandwidth-limited CORESET part as its CORESET, in which case the CORESET configuration of step 800 may be a configuration of this CORESET of the wireless communication device 212. However, at the network level, this CORESET is a bandwidth-limited part of the larger CORESET having the first bandwidth.
It should also be noted that the first bandwidth (i.e., the bandwidth of the CORESET) and the second bandwidth (i.e., the bandwidth of the bandwidth-limited CORESET part) may each be defined in terms of a frequency unit (e.g., number of MHz), a number of RBs (e.g., with the connection to frequency being different for different subcarrier spacings), or a number of CCEs (e.g., with the relation to number of RBs being different for CORESETs with different number of OFDM symbols).
The network node transmits a PDCCH to the wireless communication device 212 on the selected PDCCH candidate (step 804).
At the wireless communication device 212, the wireless communication device receives the CORESET configuration in step 800. The wireless communication device 212 monitors the plurality of PDCCH candidates within the CORESET that are comprised within the search space for the wireless communication device 212 (step 806). In doing so, the wireless communication device 212 attempts to detect and receive the transmitted PDCCH. Thus, in one embodiment, the wireless communication device 212 detects a DCI or PDCCH transmission in one of the monitored PDCCH candidates. In some embodiments, monitoring the plurality of PDCCH candidates comprises determining positions of the plurality of PDCCH candidates in accordance with any of the embodiments described above (e.g., based on the modified starting CCE index and, optionally, the start index offset). As discussed above, the positions of the plurality of PDCCH candidates are defined such that the positions of the plurality of PDCCH candidates are all within the bandwidth-limited CORESET part (i.e., within the second bandwidth).
In one embodiment, the plurality of PDCCH candidates is all PDCCH candidates monitored by the wireless communication device 212 within the search space within the CORESET. In other words, the wireless communication device 212 is configured by the network node to monitor a set of PDCCH candidates within a search space within the CORESET. The positions of all of the PDCCH candidates in this configured set of PDCCH candidates are within the bandwidth-limited CORESET part. In other words, the wireless communication device 212 is not configured by the network node to monitor any PDCCH candidates in the CORESET outside the bandwidth-limited CORESET part.
In one embodiment, the plurality of PDCCH candidates comprise PDCCH candidates for two or more different aggregation levels. An aggregation level is the number of CCEs used for a PDCCH candidate.
In one embodiment, the wireless communication device 212 supports a bandwidth that is less than the first bandwidth (i.e., less than the bandwidth of the CORESET), and the second bandwidth is less than or equal to the bandwidth supported by the wireless communication device 212. In one embodiment, monitoring the plurality of PDCCH candidates in step 806 comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function of a value (e.g., NCCE red p) that corresponds to the bandwidth supported by the wireless communication device 212 (see step 806A). In one embodiment, determining the position of the PDCCH candidate as a function of a value (e.g., NCCE red p) that corresponds to the bandwidth supported by the wireless communication device comprises determining an index of a CCE (e.g., a starting CCE) for the PDCCH candidate based on a modulo X operation, where X is a function of NCCE red P, where NCCE red p is a total number of CCEs in the bandwidth supported by the wireless communication device 212. Note that the description above for how the starting CCE index is determined are generally applicable to any and all CCEs in the PDCCH candidate by adding the index "i", as will be appreciated by one of skill in the art.
In one embodiment, monitoring the plurality of PDCCH candidates in step 806 comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function of a bandwidth related value that corresponds to a bandwidth that is less than or equal to the bandwidth supported by the wireless communication device 212 (see step 806A). Note that, in the description above, several different bandwidth related values are described (e.g., NCCE red P, Lmax, etc.). However, other similar values may be used. Here, the bandwidth related value (X) is any such value or any value derived therefrom (e.g., [ NCC red p/L\ , \Lma L\, etc.). In one embodiment, determining the position of the PDCCH candidate as a function of the bandwidth related value that corresponds to a bandwidth that is less than or equal to the bandwidth supported by the wireless communication device 212 comprises determining an index of a CCE (e.g., a starting CCE ) for the PDCCH candidate based on a modulo X operation, where X is the bandwidth related value or a value derived therefrom and is a function of a number of CCEs that is less than or equal to NCCE red pi where NCCE red p is a total number of CCEs in the bandwidth supported by the wireless communication device 212.
In one embodiment monitoring the plurality of PDCCH candidates in step 806 comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function of a maximum aggregation level ( ma ) supported by the wireless communication device 212 (see step 806A). In one embodiment, determining the position of the PDCCH candidate as a function of the maximum aggregation level ( ma ) supported by the wireless communication device 212 comprises determining 806A an index of a CCE (e.g., a starting CCE) for the PDCCH candidate based on a modulo X operation, where X is a function of the maximum aggregation level ( Lmax ) supported by the wireless communication device 212.
In one embodiment, monitoring the plurality of PDCCH candidates in step 806 comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function of a predefined or preconfigured scaling factor (see step 806A). In one embodiment, the scaling factor is or is based on a ratio of a first value (e.g., NCCE red p) that corresponds to the bandwidth supported by the wireless communication device 212 and a second value (e.g., NCCE p ) that corresponds to the bandwidth of the CORESET. In one embodiment, determining the position of the PDCCH candidate as a function of the predefined or preconfigured scaling factor in step 806A comprises determining an index of a CCE (e.g., a starting CCE) for the PDCCH candidate based on the predefined or preconfigured scaling factor.
Note that, in many of the embodiments described herein, the wireless communication device 212 is a reduced-bandwidth UE (e.g., a NR RedCap UE). However, the present disclosure is not limited thereto. For example, in some embodiments, the wireless communication device 212 supports the full bandwidth of the CORESET (e.g., is a legacy NR UE). Thus, in one embodiment, the wireless communication device 212 supports the first bandwidth (i.e., the bandwidth of the CORESET). Further, in one embodiment, the second bandwidth is less than or equal to a bandwidth supported by other reduced-bandwidth wireless communication devices (e.g., one or more other NR RedCap UEs). In one embodiment, the network node also transmits PDCCH(s) to one or more other wireless communication devices, which are reduced-bandwidth devices, in the CORESET within the bandwidth-limited CORESET part.
In one embodiment, the plurality of PDCCH candidates are positioned towards a lower end of the bandwidth of the CORESET.
In one embodiment, the plurality of PDCCH candidates are positioned relative to a lower end of the bandwidth of the CORESET based on an offset. In one embodiment, the offset is wireless communication device specific. In one embodiment, the offset is preconfigured (e.g., via RRC signaling). For example, the offset may be preconfigured by the network node at any time prior to when the wireless communication device 212 determines the positions of the PDCCH candidates. In one embodiment, the offset is determined by a function or otherwise based on a parameter which is unique to the wireless communication device 212, or to the CORESET, or to search space, or to the bandwidth part in which the CORESET is located.
In one embodiment, the offset is determined based on the location of CCE(s) used for a PDCCH candidate using a maximum supported aggregation level of the wireless communication device 212 when placed in the CORESET using the procedure that applies for a legacy, i.e., not bandwidth-reduced UE. In some embodiments, the wireless communication device 212 is a reduced- bandwidth device (e.g., a NR RedCap UE) that supports a bandwidth that is less than the full bandwidth of the CORESET but greater than or equal to the second bandwidth. In one embodiment, the network node also transmits PDCCH(s) to one or more other wireless communication devices that support the full bandwidth of the CORESET (i.e., the first bandwidth), and the offset is determined based on the location of CCEs of a PDCCH(s) transmitted to these other wireless communication device(s) using a maximum aggregation level of the CORESET.
In one embodiment, monitoring the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining a position of the PDCCH candidate as a function the offset (see step 806A). In one embodiment, determining the position of the PDCCH candidate as a function the offset comprises determining an index of a CCE (e.g., a starting CCE) of the PDCCH candidate as a function of the offset.
In one embodiment, bandwidth portions within the first bandwidth (i.e., the bandwidth of the CORESET) in which PDCCH candidates for different wireless communication devices are located are uniformly distributed within the first bandwidth.
In one embodiment, the plurality of PDCCH candidates comprise a number of PDCCH candidates for a particular aggregation level, wherein the number of PDCCH candidates for the particular aggregation level is a function of a value (e.g., NCCE red p) that corresponds to the bandwidth supported by the wireless communication device 212.
In one embodiment, the wireless communication device 212 refrains from monitoring for PDCCH in one or more search spaces within the CORESET, the one or more search spaces comprising one or more CCEs that are mapped to at least one REG that is at least partially outside of a supported bandwidth of the wireless communication device 212.
In another embodiment, the wireless communication device 212 refrains from monitoring for PDCCH in one or more PDCCH candidates that comprise one or more CCEs that are mapped to at least one REG that is at least partially outside of a supported bandwidth of the wireless communication device 212 (or outside of the second bandwidth).
It should be noted that many of the embodiments described herein for how to determine the positions of the PDCCH candidates focus on a scenario in which the wireless communication device 212 is a reduced- bandwidth UE (e.g., a NR RedCap UE). See, for example, the various equations above that define the starting CCE index. However, these embodiments are also applicable to wireless communication devices 212 that support the full bandwidth of the CORESET. In this case, the bandwidth related value (e.g., NCCE red PI Lmax, etc.) included in the equations above for determining the starting CCE index may relate to the bandwidth of other devices that do or may also monitor for PDCCH in the same CORESET or may relate to a reduced bandwidth in which the wireless communication device 212 desires to or is configured to monitor for PDCCH.
Figure 9 is a schematic block diagram of a network node 900 according to some embodiments of the present disclosure. Optional features are represented by dashed boxes. The network node 900 may be, for example, a base station 202 or 206 or a network node that implements all or part of the functionality of the base station 202 or gNB described herein. As illustrated, the network node 900 includes a control system 902 that includes one or more processors 904 (e.g., Central Processing Units (CPUs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), and/or the like), memory 906, and a network interface 908. The one or more processors 904 are also referred to herein as processing circuitry. In addition, the network node 900 may include one or more radio units 910 that each includes one or more transmitters 912 and one or more receivers 914 coupled to one or more antennas 916. The radio units 910 may be referred to or be part of radio interface circuitry. In some embodiments, the radio unit(s) 910 is external to the control system 902 and connected to the control system 902 via, e.g., a wired connection (e.g., an optical cable). However, in some other embodiments, the radio unit(s) 910 and potentially the antenna(s) 916 are integrated together with the control system 902. The one or more processors 904 operate to provide one or more functions of a radio access node 900 as described herein. In some embodiments, the function(s) are implemented in software that is stored, e.g., in the memory 906 and executed by the one or more processors 904.
Figure 10 is a schematic block diagram that illustrates a virtualized embodiment of the network node 900 according to some embodiments of the present disclosure. As used herein, a "virtualized" network node is an implementation of the network node 900 in which at least a portion of the functionality of the network node 900 is implemented as a virtual component(s) (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)). As illustrated, in this example, the network node 900 may include the control system 902 and/or the one or more radio units 910, as described above. The control system 902 may be connected to the radio unit(s) 910 via, for example, an optical cable or the like. The network node 900 includes one or more processing nodes 1000 coupled to or included as part of a network(s) 1002. If present, the control system 902 or the radio unit(s) are connected to the processing node(s) 1000 via the network 1002. Each processing node 1000 includes one or more processors 1004 (e.g., CPUs, ASICs, FPGAs, and/or the like), memory 1006, and a network interface 1008.
In this example, functions 1010 of the network node 900 described herein are implemented at the one or more processing nodes 1000 or distributed across the one or more processing nodes 1000 and the control system 902 and/or the radio unit(s) 910 in any desired manner. In some particular embodiments, some or all of the functions 1010 of the network node 900 described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environment(s) hosted by the processing node(s) 1000. As will be appreciated by one of ordinary skill in the art, additional signaling or communication between the processing node(s) 1000 and the control system 902 is used in order to carry out at least some of the desired functions 1010. Notably, in some embodiments, the control system 902 may not be included, in which case the radio unit(s) 910 communicate directly with the processing node(s) 1000 via an appropriate network interface(s).
In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the network node 900 or a node (e.g., a processing node 1000) implementing one or more of the functions 1010 of the network node 900 in a virtual environment according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).
Figure 11 is a schematic block diagram of the network node 900 according to some other embodiments of the present disclosure. The network node 900 includes one or more modules 1100, each of which is implemented in software. The module(s) 1100 provide the functionality of the network node 900 described herein. This discussion is equally applicable to the processing node 1000 of Figure 10 where the modules 1100 may be implemented at one of the processing nodes 1000 or distributed across multiple processing nodes 1000 and/or distributed across the processing node(s) 1000 and the control system 902.
Figure 12 is a schematic block diagram of a wireless communication device 1200 according to some embodiments of the present disclosure. As illustrated, the wireless communication device 1200 includes one or more processors 1202 (e.g., CPUs, ASICs, FPGAs, and/or the like), memory 1204, and one or more transceivers 1206 each including one or more transmitters 1208 and one or more receivers 1210 coupled to one or more antennas 1212. The transceiver(s) 1206 includes radio-front end circuitry connected to the antenna(s) 1212 that is configured to condition signals communicated between the antenna(s) 1212 and the processor(s) 1202, as will be appreciated by on of ordinary skill in the art. The processors 1202 are also referred to herein as processing circuitry. The transceivers 1206 are also referred to herein as radio circuitry. In some embodiments, the functionality of the wireless communication device 1200 described above may be fully or partially implemented in software that is, e.g., stored in the memory 1204 and executed by the processor(s) 1202. Note that the wireless communication device 1200 may include additional components not illustrated in Figure 12 such as, e.g., one or more user interface components (e.g., an input/output interface including a display, buttons, a touch screen, a microphone, a speaker(s), and/or the like and/or any other components for allowing input of information into the wireless communication device 1200 and/or allowing output of information from the wireless communication device 1200), a power supply (e.g., a battery and associated power circuitry), etc.
In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the wireless communication device 1200 according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).
Figure 13 is a schematic block diagram of the wireless communication device 1200 according to some other embodiments of the present disclosure. The wireless communication device 1200 includes one or more modules 1300, each of which is implemented in software. The module(s) 1300 provide the functionality of the wireless communication device 1200 described herein.
With reference to Figure 14, in accordance with an embodiment, a communication system includes a telecommunication network 1400, such as a 3GPP- type cellular network, which comprises an access network 1402, such as a RAN, and a core network 1404. The access network 1402 comprises a plurality of base stations 1406A, 1406B, 1406C, such as Node Bs, eNBs, gNBs, or other types of wireless Access Points (APs), each defining a corresponding coverage area 1408A, 1408B, 1408C. Each base station 1406A, 1406B, 1406C is connectable to the core network 1404 over a wired or wireless connection 1410. A first UE 1412 located in coverage area 1408C is configured to wirelessly connect to, or be paged by, the corresponding base station 1406C. A second UE 1414 in coverage area 1408A is wirelessly connectable to the corresponding base station 1406A. While a plurality of UEs 1412, 1414 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 1406.
The telecommunication network 1400 is itself connected to a host computer 1416, which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server, or as processing resources in a server farm. The host computer 1416 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. Connections 1418 and 1420 between the telecommunication network 1400 and the host computer 1416 may extend directly from the core network 1404 to the host computer 1416 or may go via an optional intermediate network 1422. The intermediate network 1422 may be one of, or a combination of more than one of, a public, private, or hosted network; the intermediate network 1422, if any, may be a backbone network or the Internet; in particular, the intermediate network 1422 may comprise two or more sub-networks (not shown).
The communication system of Figure 14 as a whole enables connectivity between the connected UEs 1412, 1414 and the host computer 1416. The connectivity may be described as an Over-the-Top (OTT) connection 1424. The host computer 1416 and the connected UEs 1412, 1414 are configured to communicate data and/or signaling via the OTT connection 1424, using the access network 1402, the core network 1404, any intermediate network 1422, and possible further infrastructure (not shown) as intermediaries. The OTT connection 1424 may be transparent in the sense that the participating communication devices through which the OTT connection 1424 passes are unaware of routing of uplink and downlink communications. For example, the base station 1406 may not or need not be informed about the past routing of an incoming downlink communication with data originating from the host computer 1416 to be forwarded (e.g., handed over) to a connected UE 1412. Similarly, the base station 1406 need not be aware of the future routing of an outgoing uplink communication originating from the UE 1412 towards the host computer 1416.
Example implementations, in accordance with an embodiment, of the UE, base station, and host computer discussed in the preceding paragraphs will now be described with reference to Figure 15. In a communication system 1500, a host computer 1502 comprises hardware 1504 including a communication interface 1506 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 1500. The host computer 1502 further comprises processing circuitry 1508, which may have storage and/or processing capabilities. In particular, the processing circuitry 1508 may comprise one or more programmable processors, ASICs, FPGAs, or combinations of these (not shown) adapted to execute instructions. The host computer 1502 further comprises software 1510, which is stored in or accessible by the host computer 1502 and executable by the processing circuitry 1508. The software 1510 includes a host application 1512. The host application 1512 may be operable to provide a service to a remote user, such as a UE 1514 connecting via an OTT connection 1516 terminating at the UE 1514 and the host computer 1502. In providing the service to the remote user, the host application 1512 may provide user data which is transmitted using the OTT connection 1516.
The communication system 1500 further includes a base station 1518 provided in a telecommunication system and comprising hardware 1520 enabling it to communicate with the host computer 1502 and with the UE 1514. The hardware 1520 may include a communication interface 1522 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 1500, as well as a radio interface 1524 for setting up and maintaining at least a wireless connection 1526 with the UE 1514 located in a coverage area (not shown in Figure 15) served by the base station 1518. The communication interface 1522 may be configured to facilitate a connection 1528 to the host computer 1502. The connection 1528 may be direct or it may pass through a core network (not shown in Figure 15) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, the hardware 1520 of the base station 1518 further includes processing circuitry 1530, which may comprise one or more programmable processors, ASICs, FPGAs, or combinations of these (not shown) adapted to execute instructions. The base station 1518 further has software 1532 stored internally or accessible via an external connection.
The communication system 1500 further includes the UE 1514 already referred to. The UE's 1514 hardware 1534 may include a radio interface 1536 configured to set up and maintain a wireless connection 1526 with a base station serving a coverage area in which the UE 1514 is currently located. The hardware 1534 of the UE 1514 further includes processing circuitry 1538, which may comprise one or more programmable processors, ASICs, FPGAs, or combinations of these (not shown) adapted to execute instructions. The UE 1514 further comprises software 1540, which is stored in or accessible by the UE 1514 and executable by the processing circuitry 1538. The software 1540 includes a client application 1542. The client application 1542 may be operable to provide a service to a human or non-human user via the UE 1514, with the support of the host computer 1502. In the host computer 1502, the executing host application 1512 may communicate with the executing client application 1542 via the OTT connection 1516 terminating at the UE 1514 and the host computer 1502. In providing the service to the user, the client application 1542 may receive request data from the host application 1512 and provide user data in response to the request data. The OTT connection 1516 may transfer both the request data and the user data. The client application 1542 may interact with the user to generate the user data that it provides.
It is noted that the host computer 1502, the base station 1518, and the UE 1514 illustrated in Figure 15 may be similar or identical to the host computer 1416, one of the base stations 1406A, 1406B, 1406C, and one of the UEs 1412, 1414 of Figure 14, respectively. This is to say, the inner workings of these entities may be as shown in Figure 15 and independently, the surrounding network topology may be that of Figure 14.
In Figure 15, the OTT connection 1516 has been drawn abstractly to illustrate the communication between the host computer 1502 and the UE 1514 via the base station 1518 without explicit reference to any intermediary devices and the precise routing of messages via these devices. The network infrastructure may determine the routing, which may be configured to hide from the UE 1514 or from the service provider operating the host computer 1502, or both. While the OTT connection 1516 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).
The wireless connection 1526 between the UE 1514 and the base station 1518 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the UE 1514 using the OTT connection 1516, in which the wireless connection 1526 forms the last segment.
A measurement procedure may be provided for the purpose of monitoring data rate, latency, and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 1516 between the host computer 1502 and the UE 1514, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 1516 may be implemented in the software 1510 and the hardware 1504 of the host computer 1502 or in the software 1540 and the hardware 1534 of the UE 1514, or both. In some embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 1516 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which the software 1510, 1540 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 1516 may include message format, retransmission settings, preferred routing, etc.; the reconfiguring need not affect the base station 1518, and it may be unknown or imperceptible to the base station 1518. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating the host computer 1502's measurements of throughput, propagation times, latency, and the like. The measurements may be implemented in that the software 1510 and 1540 causes messages to be transmitted, in particular empty or 'dummy' messages, using the OTT connection 1516 while it monitors propagation times, errors, etc.
Figure 16 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station, and a UE which may be those described with reference to Figures 14 and 15. For simplicity of the present disclosure, only drawing references to Figure 16 will be included in this section. In step 1600, the host computer provides user data. In sub-step 1602 (which may be optional) of step 1600, the host computer provides the user data by executing a host application. In step 1604, the host computer initiates a transmission carrying the user data to the UE. In step 1606 (which may be optional), the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 1608 (which may also be optional), the UE executes a client application associated with the host application executed by the host computer.
Figure 17 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station, and a UE which may be those described with reference to Figures 14 and 15. For simplicity of the present disclosure, only drawing references to Figure 17 will be included in this section. In step 1700 of the method, the host computer provides user data. In an optional sub-step (not shown) the host computer provides the user data by executing a host application. In step 1702, the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure. In step 1704 (which may be optional), the UE receives the user data carried in the transmission.
Figure 18 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station, and a UE which may be those described with reference to Figures 14 and 15. For simplicity of the present disclosure, only drawing references to Figure 18 will be included in this section. In step 1800 (which may be optional), the UE receives input data provided by the host computer. Additionally or alternatively, in step 1802, the UE provides user data. In sub-step 1804 (which may be optional) of step 1800, the UE provides the user data by executing a client application. In sub-step 1806 (which may be optional) of step 1802, the UE executes a client application which provides the user data in reaction to the received input data provided by the host computer. In providing the user data, the executed client application may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the UE initiates, in sub-step 1808 (which may be optional), transmission of the user data to the host computer. In step 1810 of the method, the host computer receives the user data transmitted from the UE, in accordance with the teachings of the embodiments described throughout this disclosure.
Figure 19 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station, and a UE which may be those described with reference to Figures 14 and 15. For simplicity of the present disclosure, only drawing references to Figure 19 will be included in this section. In step 1900 (which may be optional), in accordance with the teachings of the embodiments described throughout this disclosure, the base station receives user data from the UE. In step 1902 (which may be optional), the base station initiates transmission of the received user data to the host computer. In step 1904 (which may be optional), the host computer receives the user data carried in the transmission initiated by the base station.
Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processor (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according one or more embodiments of the present disclosure.
While processes in the figures may show a particular order of operations performed by certain embodiments of the present disclosure, it should be understood that such order is exemplary (e.g., alternative embodiments may perform the operations in a different order, combine certain operations, overlap certain operations, etc.).
Some example embodiments of the present disclosure are as follows:
Embodiment 1: The method of any of the embodiments of a method of operation of a wireless communication device disclosed herein or claimed in the following Claims section, further comprising providing user data and forwarding the user data to a host computer via the transmission to the network node.
Embodiment 2: The method of any of the embodiments of a method of operation of a network node disclosed herein or any of the claims in the following Claims section, further comprising obtaining user data and forwarding the user data to a host computer or a wireless communication device.
Embodiment 3: A wireless communication device comprising:
• processing circuitry configured to perform any of the steps of any of the Embodiments of a method of operation of a wireless communication device disclosed herein or any of the claims in the following Claims section; and
• power supply circuitry configured to supply power to the wireless communication device. Embodiment 4: A network node comprising:
• processing circuitry configured to perform any of the steps of any of the embodiments of a method performed by a network node or base station or of any of the claims in the following Claims section; and
• power supply circuitry configured to supply power to the network node.
Embodiment 5: A wireless communication device comprising:
• an antenna configured to send and receive wireless signals;
• radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry;
• the processing circuitry being configured to perform any of the steps of any of the Embodiments of a method of operation of a wireless communication device disclosed herein or any of the claims in the following Claims section;
• an input interface connected to the processing circuitry and configured to allow input of information into the wireless communication device to be processed by the processing circuitry;
• an output interface connected to the processing circuitry and configured to output information from the wireless communication device that has been processed by the processing circuitry; and
• a battery connected to the processing circuitry and configured to supply power to the wireless communication device.
Embodiment 6: A communication system including a host computer comprising:
• processing circuitry configured to provide user data; and
• a communication interface configured to forward the user data to a cellular network for transmission to a wireless communication device;
• wherein the cellular network comprises a network node having a radio interface and processing circuitry, the network node's processing circuitry configured to perform any of the steps of any of the Embodiments of a method performed by a network node or base station or of any of the claims in the following Claims section.
Embodiment 7: The communication system of the previous embodiment further including the network node. Embodiment 8: The communication system of the previous 2 embodiments, further including the wireless communication device, wherein the wireless communication device is configured to communicate with the network node.
Embodiment 9: The communication system of the previous 3 embodiments, wherein:
• the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; and
• the wireless communication device comprises processing circuitry configured to execute a client application associated with the host application.
Embodiment 10: A method implemented in a communication system including a host computer, a network node, and a wireless communication device, the method comprising:
• at the host computer, providing user data; and
• at the host computer, initiating a transmission carrying the user data to the wireless communication device via a cellular network comprising the network node, wherein the network node performs any of the steps of any of the Embodiments of a method performed by a network node or base station or of any of the claims in the following Claims section.
Embodiment 11: The method of the previous embodiment, further comprising, at the network node, transmitting the user data.
Embodiment 12: The method of the previous 2 embodiments, wherein the user data is provided at the host computer by executing a host application, the method further comprising, at the wireless communication device, executing a client application associated with the host application.
Embodiment 13: A wireless communication device configured to communicate with a network node, the wireless communication device comprising a radio interface and processing circuitry configured to perform the method of the previous 3 embodiments.
Embodiment 14: A communication system including a host computer comprising:
• processing circuitry configured to provide user data; and
• a communication interface configured to forward user data to a cellular network for transmission to a wireless communication device; • wherein the wireless communication device comprises a radio interface and processing circuitry, the wireless communication device's components configured to perform any of the steps of any of the Embodiments of a method of operation of a wireless communication device disclosed herein or any of the claims in the following Claims section.
Embodiment 15: The communication system of the previous embodiment, wherein the cellular network further includes a network node configured to communicate with the wireless communication device.
Embodiment 16: The communication system of the previous 2 embodiments, wherein:
• the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; and
• the wireless communication device's processing circuitry is configured to execute a client application associated with the host application.
Embodiment 17: A method implemented in a communication system including a host computer, a network node, and a wireless communication device, the method comprising:
• at the host computer, providing user data; and
• at the host computer, initiating a transmission carrying the user data to the wireless communication device via a cellular network comprising the network node, wherein the wireless communication device performs any of the steps of any of the Embodiments of a method of operation of a wireless communication device disclosed herein or any of the claims in the following Claims section.
Embodiment 18: The method of the previous embodiment, further comprising at the wireless communication device, receiving the user data from the network node.
Embodiment 19: A communication system including a host computer comprising:
• communication interface configured to receive user data originating from a transmission from a wireless communication device to a network node;
• wherein the wireless communication device comprises a radio interface and processing circuitry, the wireless communication device's processing circuitry configured to perform any of the steps of any of the Embodiments of a method of operation of a wireless communication device disclosed herein or any of the claims in the following Claims section.
Embodiment 20: The communication system of the previous embodiment, further including the wireless communication device.
Embodiment 21: The communication system of the previous 2 embodiments, further including the network node, wherein the network node comprises a radio interface configured to communicate with the wireless communication device and a communication interface configured to forward to the host computer the user data carried by a transmission from the wireless communication device to the network node.
Embodiment 22: The communication system of the previous 3 embodiments, wherein:
• the processing circuitry of the host computer is configured to execute a host application; and
• the wireless communication device's processing circuitry is configured to execute a client application associated with the host application, thereby providing the user data.
Embodiment 23: The communication system of the previous 4 embodiments, wherein:
• the processing circuitry of the host computer is configured to execute a host application, thereby providing request data; and
• the wireless communication device's processing circuitry is configured to execute a client application associated with the host application, thereby providing the user data in response to the request data.
Embodiment 24: A method implemented in a communication system including a host computer, a network node, and a wireless communication device, the method comprising, at the host computer, receiving user data transmitted to the network node from the wireless communication device, wherein the wireless communication device performs any of the steps of any of the Embodiments of a method of operation of a wireless communication device disclosed herein or any of the claims in the following Claims section .
Embodiment 25: The method of the previous embodiment, further comprising, at the wireless communication device, providing the user data to the network node. Embodiment 26: The method of the previous 2 embodiments, further comprising:
• at the wireless communication device, executing a client application, thereby providing the user data to be transmitted; and
• at the host computer, executing a host application associated with the client application.
Embodiment 27: The method of the previous 3 embodiments, further comprising:
• at the wireless communication device, executing a client application; and
• at the wireless communication device, receiving input data to the client application, the input data being provided at the host computer by executing a host application associated with the client application;
• wherein the user data to be transmitted is provided by the client application in response to the input data.
Embodiment 28: A communication system including a host computer comprising a communication interface configured to receive user data originating from a transmission from a wireless communication device to a network node, wherein the network node comprises a radio interface and processing circuitry, the network node's processing circuitry configured to perform any of the steps of any of the Embodiments of a method performed by a network node or base station or of any of the claims in the following Claims section.
Embodiment 29: The communication system of the previous embodiment further including the network node.
Embodiment 30: The communication system of the previous 2 embodiments, further including the wireless communication device, wherein the wireless communication device is configured to communicate with the network node.
Embodiment 31: The communication system of the previous 3 embodiments, wherein:
• the processing circuitry of the host computer is configured to execute a host application; and
• the wireless communication device is configured to execute a client application associated with the host application, thereby providing the user data to be received by the host computer. Embodiment 32: A method implemented in a communication system including a host computer, a network node, and a wireless communication device, the method comprising, at the host computer, receiving, from the network node, user data originating from a transmission which the network node has received from the wireless communication device, wherein the wireless communication device performs any of the steps of any of the Embodiments of a method of operation of a wireless communication device disclosed herein or any of the claims in the following Claims section .
Embodiment 33: The method of the previous embodiment, further comprising at the network node, receiving the user data from the wireless communication device. Embodiment 34: The method of the previous 2 embodiments, further comprising at the network node, initiating a transmission of the received user data to the host computer.
Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein.

Claims

Claims
1. A method performed by a wireless communication device (212), the method comprising: receiving (800) a Control Resource Set, CORESET, configuration that defines a CORESET having a first bandwidth; and monitoring (806) a plurality of Physical Downlink Control Channel, PDCCH, candidates within the CORESET; wherein positions of the plurality of PDCCH candidates within the CORESET are defined such that the plurality of PDCCH candidates are located within a second bandwidth, the second bandwidth being less than the first bandwidth.
2. The method of claim 1, wherein the plurality of PDCCH candidates is all PDCCH candidates monitored by the wireless communication device (212) within a search space within the CORESET.
3. The method of claim 1 or 2, wherein the plurality of PDCCH candidates comprise PDCCH candidates for two or more different aggregation levels.
4. The method of any one of claims 1 to 3, wherein the wireless communication device (212) supports a bandwidth that is less than the first bandwidth, and the second bandwidth is less than or equal to the bandwidth supported by the wireless communication device (212).
5. The method of claim 4, wherein monitoring (806) the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining (806A) a position of the PDCCH candidate as a function of a value that corresponds to the bandwidth supported by the wireless communication device (212).
6. The method of claim 5, wherein determining (806A) the position of the PDCCH candidate as a function of the value that corresponds to the bandwidth supported by the wireless communication device (212) comprises determining (806A) an index of a Control Channel Element, CCE, for the PDCCH candidate based on a modulo X operation, where X is a function of NCCE red pi where NCCE red p is a total number of CCEs in the bandwidth supported by the wireless communication device (212).
7. The method of claim 4, wherein monitoring (806) the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining (806A) a position of the PDCCH candidate as a function of a bandwidth related value that corresponds to a bandwidth that is less than or equal to the bandwidth supported by the wireless communication device (212).
8. The method of claim 7, wherein determining (806A) the position of the PDCCH candidate as a function of the bandwidth related value, X, that corresponds to a bandwidth that is less than or equal to the bandwidth supported by the wireless communication device (212) comprises determining (806A) an index of a CCE for the PDCCH candidate based on a modulo X operation, where X is a function of a number of CCEs that is less than or equal to NCCE red pi where NCCE red p is a total number of CCEs in the bandwidth supported by the wireless communication device (212).
9. The method of claim 4, wherein monitoring (806) the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining (806A) a position of the PDCCH candidate as a function of a maximum aggregation level ( Lmax ) supported by the wireless communication device (212).
10. The method of claim 9, wherein determining (806A) the position of the PDCCH candidate as a function of the maximum aggregation level ( Lmax ) supported by the wireless communication device (212) comprises determining (806A) an index of a CCE for the PDCCH candidate based on a modulo X operation, where X is a function of the maximum aggregation level ( ma ) supported by the wireless communication device (212).
11. The method of claim 4, wherein monitoring (806) the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining (806A) a position of the PDCCH candidate as a function of a predefined or preconfigured scaling factor.
12. The method of claim 11, wherein the scaling factor is or is based on a ratio of a first value that corresponds to the bandwidth supported by the wireless communication device (212) and a second value that corresponds to the bandwidth of the CORESET.
13. The method of claim 11 or 12, wherein determining (806A) the position of the PDCCH candidate as a function of the predefined or preconfigured scaling factor comprises determining (806A) an index of a CCE for the PDCCH candidate based on the predefined or preconfigured scaling factor.
14. The method of any one of claims 1 to 3, wherein the wireless communication device (212) supports the first bandwidth, and the second bandwidth is less than or equal to a bandwidth supported by other reduced-bandwidth wireless communication devices.
15. The method of any one of claims 1 to 14, wherein the plurality of PDCCH candidates are positioned towards a lower end of the first bandwidth.
16. The method of any one of claims 1 to 14, wherein the plurality of PDCCH candidates are positioned relative to a lower end of the first bandwidth based on an offset.
17. The method of claim 16, wherein the offset is wireless communication device specific.
18. The method of claim 16 or 17, wherein the offset is preconfigured.
19. The method of claim 16 or 17, wherein the offset is determined by a function or otherwise based on a parameter which is unique to the wireless communication device (212), or to the CORESET, or to a search space, or to bandwidth part in which the
CO RESET is located.
20. The method of claim 16 or 17, wherein the offset is determined based on the location of CCE(s) used for a PDCCH candidate using a maximum supported aggregation level when placed in the CORESET.
21. The method of any one of claims 16 to 20, wherein monitoring (806) the plurality of PDCCH candidates comprises, for each PDCCH candidate of the plurality of PDCCH candidates, determining (806A) a position of the PDCCH candidate as a function the offset.
22. The method of claim 21, wherein determining (806A) the position of the PDCCH candidate as a function the offset comprises determining (806A) an index of a CCE of the PDCCH candidate as a function of the offset.
23. The method of any one of claims 1 to 22, wherein bandwidth portions within the first bandwidth in which PDCCH candidates for different wireless communication devices are located are uniformly distributed within the bandwidth of the CORESET.
24. The method of any one of claims 1 to 23, wherein the plurality of PDCCH candidates comprise a number of PDCCH candidates for a particular aggregation level, wherein the number of PDCCH candidates for the particular aggregation level is a function of a value that corresponds to the bandwidth supported by the wireless communication device (212).
25. The method of any one of claims 1 to 24, further comprising refraining from monitoring for PDCCH in one or more search spaces within the CORESET, the one or more search spaces comprising one or more CCEs that are mapped to at least one Resource Element Group, REG, that is at least partially outside of a supported bandwidth of the wireless communication device (212).
26. The method of any one of claims 1 to 25, wherein the first bandwidth and/or the second bandwidth are measured in terms of: a frequency unit; a number of Resource Blocks, RBs; or a number of CCEs.
27. The method of any one of claims 1 to 26, further comprising: detecting Downlink Control Information, DCI, in one of the monitored plurality of PDCCH candidates.
28. The method of any one of claims 1 to 26, further comprising: detecting a PDCCH transmission in one of the monitored plurality of PDCCH candidates.
29. A wireless communication device (212) adapted to: receive (800) a Control Resource Set, CORESET, configuration that defines a CORESET having a first bandwidth; and monitor (806) a plurality of Physical Downlink Control Channel, PDCCH, candidates within the CORESET; wherein positions of the plurality of PDCCH candidates within the CORESET are defined such that the plurality of PDCCH candidates are located within a second bandwidth, the second bandwidth being less than the first bandwidth.
30. The wireless communication device (212) of claim 29, wherein the wireless communication device (212) is further adapted to perform the method of any of claims 2 to 28.
31. A wireless communication device (212; 1200) comprising: one or more transmitters (1208); one or more receivers (1210); and processing circuitry (1202) associated with the one or more transmitters (1208) and the one or more receivers (1210), the processing circuitry (1202) configured to cause the wireless communication device (212; 1200) to: receive (800) a Control Resource Set, CORESET, configuration that defines a CORESET having a first bandwidth; and monitor (806) a plurality of Physical Downlink Control Channel, PDCCH, candidates within the CORESET; wherein positions of the plurality of PDCCH candidates within the CORESET are defined such that the plurality of PDCCH candidates are located within a second bandwidth, the second bandwidth being less than the first bandwidth.
32. The wireless communication device (212; 1200) of claim 31, wherein the processing circuitry (1202) is further configured to cause the wireless communication device (212; 1200) to perform the method of any of claims 2 to 28.
33. A method performed by a network node (202; 900), the method comprising: configuring (800) a wireless communication device (212) with a Control Resource
Set, CORESET, the CORESET having a first bandwidth; selecting (802) a set of Control Channel Elements, CCEs, on which to transmit a Physical Downlink Control Channel, PDCCH, to the wireless communication device (212) from among a plurality of sets of CCEs that correspond to a plurality of PDCCH candidates for the wireless communication device (212) within the CORESET, wherein positions of the plurality of PDCCH candidates are defined such that the plurality of PDCCH candidates are located within a second bandwidth that is less than the first bandwidth; and transmitting (804) a PDCCH to the wireless communication device (212) on the selected set of CCEs.
34. The method of claim 33, wherein the plurality of PDCCH candidates is all PDCCH candidates within a search space for the wireless communication device (212) within the CO RESET.
35. The method of claim 33 or 34, wherein the plurality of PDCCH candidates comprise PDCCH candidates for two or more different aggregation levels.
36. The method of any one of claims 33 to 35, wherein the second bandwidth is less than or equal to a bandwidth supported by the wireless communication device (212).
37. The method of claim 36, wherein, for each PDCCH candidate of the plurality of PDCCH candidates, a position of the PDCCH candidate is a function of a value that corresponds to the bandwidth supported by the wireless communication device (212).
38. The method of claim 36, wherein, for each PDCCH candidate of the plurality of PDCCH candidates, an index of a CCE for the PDCCH candidate is based on a modulo X operation, where X is a function of NCCE red pi where NCCE red p is a total number of CCEs in the bandwidth supported by the wireless communication device (212).
39. The method of claim 36, wherein, for each PDCCH candidate of the plurality of PDCCH candidates, a position of the PDCCH candidate is a function of a bandwidth related value, X, that corresponds to a bandwidth that is less than or equal to the bandwidth supported by the wireless communication device (212).
40. The method of claim 36, wherein, for each PDCCH candidate of the plurality of PDCCH candidates, an index of a CCE for the PDCCH candidate is based on a modulo X operation, where X is a function of a number of CCEs value that is less than or equal to NCCE, red, p, where NCCE red'P is a total number of CCEs in the bandwidth supported by the wireless communication device (212).
41. The method of claim 36, wherein, for each PDCCH candidate of the plurality of PDCCH candidates, a position of the PDCCH candidate as a function of a maximum aggregation level ( Lmax ) supported by the wireless communication device (212).
42. The method of claim 36, wherein, for each PDCCH candidate of the plurality of PDCCH candidates, an index of a CCE for the PDCCH candidate is based on a modulo X operation, where X is a function of a maximum aggregation level ( Lmax ) supported by the wireless communication device (212).
43. The method of claim 36, wherein, for each PDCCH candidate of the plurality of PDCCH candidates, a position of the PDCCH candidate is a function of a predefined or preconfigured scaling factor.
44. The method of claim 43, wherein the scaling factor is or is based on a ratio of a first value that corresponds to the bandwidth supported by the wireless communication device (212) and a second value that corresponds to the bandwidth of the CORESET.
45. The method of claim 43 or 44, wherein, for each PDCCH candidate of the plurality of PDCCH candidates, an index of a CCE for the PDCCH candidate is based on the predefined or preconfigured scaling factor.
46. The method of any one of claims 33 to 35, wherein the wireless communication device (212) supports the first bandwidth, and the second bandwidth is less than or equal to a bandwidth supported by other reduced-bandwidth wireless communication devices.
47. The method of any one of claims 33 to 46, wherein the plurality of PDCCH candidates are positioned towards a lower end of the first bandwidth.
48. The method of any one of claims 33 to 46, wherein the plurality of PDCCH candidates are positioned relative to a lower end of the first bandwidth on an offset.
49. The method of claim 48, wherein the offset is wireless communication device specific.
50. The method of claim 48 or 49, wherein the offset is preconfigured.
51. The method of claim 48 or 49, wherein the offset is determined by a function or otherwise based on a parameter which is unique to the wireless communication device (212), or to the CORESET, or to search space, or to bandwidth part in which the
CO RESET is located.
52. The method of claim 48 or 49, wherein the offset is determined based on the location of CCE(s) used for a PDCCH candidate using a maximum supported aggregation level when placed in the CORESET.
53. The method of claim 48 or 49, further comprising: transmitting a PDCCH transmission to a second wireless communication device within the CORESET on CCEs that correspond to a PDCCH candidate using a maximum supported aggregation level of the CORESET, the second wireless communication device supporting the first bandwidth; wherein the offset is determined based on the location of the CCEs used for the PDCCH candidate using the maximum supported aggregation level of the CORESET.
54. The method of any one of claims 48 to 53, wherein, for each PDCCH candidate of the plurality of PDCCH candidates, a position of the PDCCH candidate is a function the offset.
55. The method of claim 54, wherein, for each PDCCH candidate of the plurality of PDCCH candidates, an index of a CCE of the PDCCH candidate is a function of the offset.
56. The method of any one of claims 33 to 55, wherein bandwidth portions within the first bandwidth in which PDCCH candidates for different wireless communication devices are located are uniformly distributed within the bandwidth of the CORESET.
57. The method of any one of claims 33 to 56, wherein the plurality of PDCCH candidates comprise a number of PDCCH candidates for a particular aggregation level, wherein the number of PDCCH candidates for the particular aggregation level is a function of a value that corresponds to the bandwidth supported by the wireless communication device (212).
58. A network node (202; 900) adapted to: configure (800) a wireless communication device (212) with a Control Resource Set, CORESET, the CORESET having a first bandwidth; select (802) a set of Control Channel Elements, CCEs, on which to transmit a Physical Downlink Control Channel, PDCCH, to the wireless communication device (212) from among a plurality of sets of CCEs that correspond to a plurality of PDCCH candidates for the wireless communication device (212) within the CORESET, wherein positions of the plurality of PDCCH candidates are defined such that the plurality of PDCCH candidates are located within a second bandwidth that is less than the first bandwidth; and transmit (804) a PDCCH to the wireless communication device (212) on the selected set of CCEs.
59. The network node (202; 900) of claim 58, wherein the network node (202; 900) is further adapted to perform the method of any of claims 34 to 57.
60. A network node (202; 900) comprising processing circuity (904; 1004) configured to cause the network node (202; 900) to: configure (800) a wireless communication device (212) with a Control Resource Set, CORESET, the CORESET having a first bandwidth; select (802) a set of Control Channel Elements, CCEs, on which to transmit a Physical Downlink Control Channel, PDCCH, to the wireless communication device (212) from among a plurality of sets of CCEs that correspond to a plurality of PDCCH candidates for the wireless communication device (212) within the CORESET, wherein positions of the plurality of PDCCH candidates are defined such that the plurality of PDCCH candidates are located within a second bandwidth that is less than the first bandwidth; and transmit (804) a PDCCH to the wireless communication device (212) on the selected set of CCEs.
61. The network node (202; 900) of claim 58, wherein the processing circuity (904; 1004) is further configured to cause the network node (202; 900) to perform the method of any of claims 34 to 57.
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