WO2025126195A1

WO2025126195A1 - Techniques for indicating a downlink transmission with a discrete fourier transform spread orthogonal frequency domain multiplexing waveform

Info

Publication number: WO2025126195A1
Application number: PCT/IB2025/050675
Authority: WO
Inventors: Ali Ramadan ALI; Karthikeyan Ganesan; Sher Ali CHEEMA
Original assignee: Lenovo Singapore Pte Ltd
Current assignee: Lenovo Singapore Pte Ltd
Priority date: 2024-01-22
Filing date: 2025-01-22
Publication date: 2025-06-19
Anticipated expiration: 2026-07-22

Abstract

Various aspects of the present disclosure relate to receiving (1102) a configuration that indicates a waveform associated with a downlink control channel transmission, wherein the waveform comprises a discrete Fourier transform spread orthogonal frequency domain multiplexing (DFT-s-OFDM) waveform. Aspects of the present disclosure may relate to receiving (1104) an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending downlink control channel transmission. Aspects of the present disclosure may further relate to transmitting (1106) a request to switch the waveform for a next downlink control channel transmission in response to receiving a downlink transmission and based at least in part on a signal quality measurement.

Description

TECHNIQUES FOR INDICATING A DOWNLINK TRANSMISSION WITH A DISCRETE FOURIER TRANSFORM SPREAD ORTHOGONAL FREQUENCY DOMAIN MULTIPLEXING WAVEFORM

TECHNICAL FIELD

[0001] The present disclosure relates to wireless communications, and more specifically to techniques for indicating whether a discrete Fourier transform spread orthogonal frequency domain multiplexing (DFT-s-OFDM) waveform is enabled for a physical downlink control channel (PDCCH) transmission.

BACKGROUND

[0002] A wireless communications system may include one or multiple network communication devices, which may be known as a network equipment (NE), supporting wireless communications for one or multiple user communication devices, which may be otherwise known as user equipment (UE), or other suitable terminology. The wireless communications system may support wireless communications with one or multiple user communication devices by utilizing resources of the wireless communication system (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers, or the like)). Additionally, the wireless communications system may support wireless communications across various radio access technologies (RATs) including third generation (3G) radio access technology, fourth generation (4G) radio access technology, fifth generation (5G) radio access technology, among other suitable radio access technologies beyond 5G (e.g., 5G- Advanced (5G-A), sixth generation (6G)).

SUMMARY

[0003] An article “a” before an element is unrestricted and understood to refer to “at least one” of those elements or “one or more” of those elements. The terms “a,” “at least one,” “one or more,” and “at least one of one or more” may be interchangeable. As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of’ or “one or more of’ or “one or both of) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on.” Further, as used herein, including in the claims, a “set” may include one or more elements.

[0004] A UE for wireless communication is described. The UE may be configured to, capable of, or operable to receive a configuration that indicates a waveform associated with a PDCCH transmission, where the waveform comprises a DFT-s-OFDM waveform; receive an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending PDCCH transmission; and transmit a request to switch the waveform for a next PDCCH transmission in response to receiving a DL transmission and based at least in part on a downlink (DL) signal quality measurement.

[0005] A processor for wireless communication is described. The processor may be configured to, capable of, or operable to receive a configuration that indicates a waveform associated with a PDCCH transmission, where the waveform comprises a DFT-s-OFDM waveform; receive an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending PDCCH transmission; and transmit a request to switch the waveform for a next PDCCH transmission in response to receiving a DL transmission and based at least in part on a signal quality measurement.

[0006] A method performed or performable by a UE for wireless communication is described. The method may include receiving a configuration that indicates a waveform associated with a PDCCH transmission, where the waveform comprises a DFT-s-OFDM waveform; receiving an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending PDCCH transmission; and transmitting a request to switch the waveform for a next PDCCH transmission in response to receiving a DL transmission and based at least in part on a signal quality measurement.

[0007] A base station for wireless communication is described. The base station may be configured to, capable of, or operable to transmit a configuration that indicates a waveform associated with a PDCCH transmission, where the waveform comprises a DFT-s-OFDM waveform; transmit an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending PDCCH transmission; and receive a request to switch the waveform for the PDCCH transmission in response to transmitting a DL transmission and based at least in part on a signal quality measurement.

[0008] A processor for wireless communication by a base station is described. The processor may be configured to, capable of, or operable to transmit a configuration that indicates a waveform associated with a PDCCH transmission, where the waveform comprises a DFT-s-OFDM waveform; transmit an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending PDCCH transmission; and receive a request to switch the waveform for the PDCCH transmission in response to transmitting a DL transmission and based at least in part on a signal quality measurement.

[0009] A method performed or performable by an anchor base station for wireless communication is described. The method may include transmitting a configuration that indicates a waveform associated with a PDCCH transmission, where the waveform comprises a DFT-s-OFDM waveform; transmitting an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending PDCCH transmission; and receiving a request to switch the waveform for a next PDCCH transmission in response to transmitting a DL transmission and based at least in part on a signal quality measurement.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 illustrates an example of a wireless communications system in accordance with aspects of the present disclosure.

[0011] Figure 2 illustrates an example of a protocol stack in accordance with aspects of the present disclosure.

[0012] Figure 3A illustrates an example of a cyclic prefix orthogonal frequency division multiplexing (CP -OFDM) based control resource set (CORESET) transmission, in accordance with aspects of the present disclosure.

[0013] Figure 3B illustrates an example of a DFT-s-OFDM based CORESET transmission, in accordance with aspects of the present disclosure.

[0014] Figure 4 illustrates a comparison of peak to average power ratio (PAPR) of DFT-s-OFDM based physical downlink control channel (PDCCH) transmission with different aggregation levels (ALs) compared to CP -OFDM based PDCCH transmission, in accordance with aspects of the present disclosure. [0015] Figure 5 illustrates a CORESET configuration indicating the enabling or disabling and length of transform precoding, in accordance with aspects of the present disclosure.

[0016] Figure 6 illustrates a CORESET configuration indicating the enabling or disabling and length of transform precoding and the demodulation reference signal (DMRS) location, in accordance with aspects of the present disclosure.

[0017] Figure 7 illustrates a CORESET configuration indicating the enabling or disabling of transform precoding, in accordance with aspects of the present disclosure.

[0018] Figure 8 illustrates an example of a UE in accordance with aspects of the present disclosure.

[0019] Figure 9 illustrates an example of a processor in accordance with aspects of the present disclosure.

[0020] Figure 10 illustrates an example of a NE in accordance with aspects of the present disclosure.

[0021] Figure 11 illustrates a flowchart of a method performed by a UE in accordance with aspects of the present disclosure.

[0022] Figure 12 illustrates a flowchart of a method performed by an NE in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

[0023] Some wireless communication systems may support DFT-s-OFDM waveforms for uplink (UL) transmission. For instance, a UE at a cell-edge or with one or more of a reduced capacity (RedCap) or low power condition may use DFT-s-OFDM waveforms for an UL transmission. Due to its low PAPR, the DFT-s-OFDM waveform enables improved coverage and reduced power consumption at the UE. As the downlink (DL) coverage and the requirements for low-energy consumption on the network side also emerge as significant considerations for future networks, waveforms with low PAPR — such as DFT-s-OFDM — can be considered for DL data and/or control channels. This consideration aims to enhance coverage and decrease energy consumption on the network side. However, there are several aspects related to the design, configuration, and signaling of parameters for data and control channels that should be considered when adopting DFT-s-OFDM waveform in the DL. To address the shortcomings with DL coverage and the low-energy consumption requirements discussed herein, the present disclosure describes techniques for enabling and/or disabling of configurations associated with a DFT-s-OFDM waveform for DL transmissions (e.g., PDCCH), and signaling of these configurations associated with DFT-s-OFDM waveforms.

[0024] According to one aspect of the present disclosure, one or more of a UE or NE (e.g., a base station) may support a CORESET design of a PDCCH transmission associated with a DFT-s-OFDM waveform. The CORESET design may include one or more methods of applying transform precoding on a control channel (e.g., PDCCH). Beneficially, the DFT-s-OFDM waveform enables improved coverage and reduced power consumption at the UE.

[0025] According to another aspect of the present disclosure, a NE (e.g., a base station) may support transmission of an indication for enabling or disabling transform precoding on control channel (e.g., PDCCH). Beneficially, the indication allows the UE to efficiently determine when to use transform de-precoding when decoding a received signal.

[0026] According to yet another aspect of the present disclosure, one or more of a UE or NE (e.g., a base station) may support a configuration and signaling of the configuration, which may include one or more methods of applying a transform precoding. Additionally, or alternatively, the configuration may indicate one or more DMRS locations of a control channel (e.g., a PDCCH) during an initial access and a connected mode. Beneficially, the indication allows the UE to efficiently determine the location of data symbols in a received signal.

[0027] According to yet another aspect of the present disclosure, one or more of a UE or NE (e.g., a base station) may support indicating switching (i.e., changing) a waveform type based on a request (e.g., a UE request). Beneficially, the indication allows the UE to adapt the downlink waveform, e.g., based on a downlink signal quality.

[0028] Aspects of the present disclosure are described in the context of a wireless communications system.

[0029] Figure 1 illustrates an example of a wireless communications system 100 in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more NE 102, one or more UE 104, and a core network (CN) 106. The wireless communications system 100 may support various radio access technologies. In some implementations, the wireless communications system 100 may be a 4G network, such as a long-term evolution (LTE) network or an LTE-advanced (LTE- A) network. In some other implementations, the wireless communications system 100 may be a new radio (NR) network, such as a 5G network, a 5G-advanced (5G-A) network, or a 5G ultrawideband (5G-UWB) network. In other implementations, the wireless communications system 100 may be a combination of a 4G network and a 5G network, or other suitable radio access technology including institute of electrical and electronics engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20. The wireless communications system 100 may support radio access technologies beyond 5G, for example, 6G. Additionally, the wireless communications system 100 may support technologies, such as time division multiple access (TDMA), frequency division multiple access (FDMA), or code division multiple access (CDMA), etc.

[0030] The one or more NE 102 may be dispersed throughout a geographic region to form the wireless communications system 100. One or more of the NE 102 described herein may be or include or may be referred to as a network node, a base station, a network element, a network function, a network entity, a radio access network (RAN), a NodeB, an eNodeB (eNB), a next-generation NodeB (gNB), or other suitable terminology. An NE 102 and a UE 104 may communicate via a communication link, which may be a wireless or wired connection. For example, an NE 102 and a UE 104 may perform wireless communication (e.g., receive signaling, transmit signaling) over a Uu interface.

[0031] An NE 102 may provide a geographic coverage area for which the NE 102 may support services for one or more UEs 104 within the geographic coverage area. For example, an NE 102 and a UE 104 may support wireless communication of signals related to services (e.g., voice, video, packet data, messaging, broadcast, etc.) according to one or multiple radio access technologies. In some implementations, an NE 102 may be moveable, for example, a satellite associated with a non-terrestrial network (NTN). In some implementations, different geographic coverage areas associated with the same or different radio access technologies may overlap, but the different geographic coverage areas may be associated with different NE 102. [0032] The one or more UE 104 may be dispersed throughout a geographic region of the wireless communications system 100. A UE 104 may include or may be referred to as a remote unit, a mobile device, a wireless device, a remote device, a subscriber device, a transmitter device, a receiver device, or some other suitable terminology. In some implementations, the UE 104 may be referred to as a unit, a station, a terminal, or a client, among other examples. Additionally, or alternatively, the UE 104 may be referred to as an intemet-of-things (loT) device, an intemet-of-everything (loE) device, or machinetype communication (MTC) device, among other examples.

[0033] A UE 104 may be able to support wireless communication directly with other UEs 104 over a communication link. For example, a UE 104 may support wireless communication directly with another UE 104 over a device-to-d evice (D2D) communication link. In some implementations, such as vehicle-to-vehicle (V2V) deployments, vehicle-to-everything (V2X) deployments, or cellular-V2X deployments, the communication link may be referred to as a sidelink. For example, a UE 104 may support wireless communication directly with another UE 104 over a PC5 interface.

[0034] An NE 102 may support communications with the CN 106, or with another NE 102, or both. For example, an NE 102 may interface with other NE 102 or the CN 106 through one or more backhaul links (e.g., SI, N2, N2, or network interface). In some implementations, the NE 102 may communicate with each other directly. In some other implementations, the NE 102 may communicate with each other or indirectly (e.g., via the CN 106). In some implementations, one or more NE 102 may include subcomponents, such as an access network entity, which may be an example of an access node controller (ANC). An ANC may communicate with the one or more UEs 104 through one or more other access network transmission entities, which may be referred to as a radio heads, smart radio heads, or transmission-reception points (TRPs).

[0035] The CN 106 may support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The CN 106 may be an evolved packet core (EPC), or a 5G core (5GC), which may include a control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management functions (AMF)) and a user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)). In some implementations, the control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management (e.g., data bearers, signal bearers, etc.) for the one or more UEs 104 served by the one or more NE 102 associated with the CN 106.

[0036] The CN 106 may communicate with a packet data network over one or more backhaul links (e.g., via an SI, N2, N2, or another network interface). The packet data network may include an application server. In some implementations, one or more UEs 104 may communicate with the application server. A UE 104 may establish a session (e.g., a protocol data unit (PDU) session, or a PDN connection, or the like) with the CN 106 via an NE 102. The CN 106 may route traffic (e.g., control information, data, and the like) between the UE 104 and the application server using the established session (e.g., the established PDU session). The PDU session may be an example of a logical connection between the UE 104 and the CN 106 (e.g., one or more network functions of the CN 106).

[0037] In the wireless communications system 100, the NEs 102 and the UEs 104 may use resources of the wireless communications system 100 (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers)) to perform various operations (e.g., wireless communications). In some implementations, the NEs 102 and the UEs 104 may support different resource structures. For example, the NEs 102 and the UEs 104 may support different frame structures. In some implementations, such as in 4G, the NEs 102 and the UEs 104 may support a single frame structure. In some other implementations, such as in 5 G and among other suitable radio access technologies, the NEs 102 and the UEs 104 may support various frame structures (i.e., multiple frame structures). The NEs 102 and the UEs 104 may support various frame structures based on one or more numerologies.

[0038] One or more numerologies may be supported in the wireless communications system 100, and a numerology may include a subcarrier spacing and a cyclic prefix. A first numerology (e.g., i=0) may be associated with a first subcarrier spacing (e.g., 15 kHz) and a normal cyclic prefix. In some implementations, the first numerology (e.g., =0) associated with the first subcarrier spacing (e.g., 15 kHz) may utilize one slot per subframe. A second numerology (e.g., ^=1) may be associated with a second subcarrier spacing (e.g., 30 kHz) and a normal cyclic prefix. A third numerology (e.g., i=2) may be associated with a third subcarrier spacing (e.g., 60 kHz) and a normal cyclic prefix or an extended cyclic prefix. A fourth numerology (e.g., ju=3) may be associated with a fourth subcarrier spacing (e.g., 120 kHz) and a normal cyclic prefix. A fifth numerology (e.g., [1=4) may be associated with a fifth subcarrier spacing (e.g., 240 kHz) and a normal cyclic prefix.

[0039] A time interval of a resource (e.g., a communication resource) may be organized according to frames (also referred to as radio frames). Each frame may have a duration, for example, a 10 millisecond (ms) duration. In some implementations, each frame may include multiple subframes. For example, each frame may include 10 subframes, and each subframe may have a duration, for example, a 1 ms duration. In some implementations, each frame may have the same duration. In some implementations, each subframe of a frame may have the same duration.

[0040] Additionally, or alternatively, a time interval of a resource (e.g., a communication resource) may be organized according to slots. For example, a subframe may include a number (e.g., quantity) of slots. The number of slots in each subframe may also depend on the one or more numerologies supported in the wireless communications system 100. For instance, the first, second, third, fourth, and fifth numerologies (i.e., [1=0, [1=1, [1=2, [1=3, [1=4) associated with respective subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz may utilize a single slot per subframe, two slots per subframe, four slots per subframe, eight slots per subframe, and 16 slots per subframe, respectively. Each slot may include a number (e.g., quantity) of symbols (e.g., orthogonal frequency domain multiplexing (OFDM) symbols). In some implementations, the number (e.g., quantity) of slots for a subframe may depend on a numerology. For a normal cyclic prefix, a slot may include 14 symbols. For an extended cyclic prefix (e.g., applicable for 60 kHz subcarrier spacing), a slot may include 12 symbols. The relationship between the number of symbols per slot, the number of slots per subframe, and the number of slots per frame for a normal cyclic prefix and an extended cyclic prefix may depend on a numerology. It should be understood that reference to a first numerology (e.g., [1=0) associated with a first subcarrier spacing (e.g., 15 kHz) may be used interchangeably between subframes and slots.

[0041] In the wireless communications system 100, an electromagnetic (EM) spectrum may be split, based on frequency or wavelength, into various classes, frequency bands, frequency channels, etc. By way of example, the wireless communications system 100 may support one or multiple operating frequency bands, such as frequency range designations FR1 (410 MHz - 7.125 GHz), FR2 (24.25 GHz - 52.6 GHz), FR3 (7.125 GHz - 24.25 GHz), FR4 (52.6 GHz - 114.25 GHz), FR4a or FR4-1 (52.6 GHz - 71 GHz), and FR5 (114.25 GHz - 300 GHz). In some implementations, the NEs 102 and the UEs 104 may perform wireless communications over one or more of the operating frequency bands. In some implementations, FR1 may be used by the NEs 102 and the UEs 104, among other equipment or devices for cellular communications traffic (e.g., control information, data). In some implementations, FR2 may be used by the NEs 102 and the UEs 104, among other equipment or devices for short-range, high data rate capabilities.

[0042] FR1 may be associated with one or multiple numerologies (e.g., at least three numeral ogies). For example, FR1 may be associated with a first numerology (e.g., jU=O), which includes 15 kHz subcarrier spacing; a second numerology (e.g., ^=1), which includes 30 kHz subcarrier spacing; and a third numerology (e.g., jU=2), which includes 60 kHz subcarrier spacing. FR2 may be associated with one or multiple numerologies (e.g., at least 2 numerologies). For example, FR2 may be associated with a third numerology (e.g., jU=2), which includes 60 kHz subcarrier spacing; and a fourth numerology (e.g., jU=3), which includes 120 kHz subcarrier spacing.

[0043] The wireless communications system 100 may support wireless communication in one or more of an unlicensed spectrum (also referred to as “shared spectrum”) or a licensed spectrum. In some implementations, wireless communication over the unlicensed spectrum may provide cost advantages, enabling wireless communication to avoid overlaying the operator’s licensed spectrum. Instead, it can utilize license-free spectrum according to local regulations in specific geographic areas. Unlicensed operation may occur on a Uu interface (referred to as NR-U) and/or a sidelink interface (e.g., SL-U).

[0044] During initial access, a UE 104 may detect a candidate cell and perform downlink (DL) synchronization. For example, a NE 102 (e.g., a gNB) may transmit a synchronization signal and broadcast channel (SS/PBCH) transmission, referred to as a synchronization signal block (SSB). The synchronization signal may be a predefined data sequence known to the UE 104 (or derivable using information stored at the UE 104) and a predefined location in time relative to frame/subframe boundaries, etc. The UE 104 may receive the SSB and, based on the received SSB, obtain DL timing information (e.g., symbol timing) for the DL synchronization. The UE 104 may also decode system information (SI) based on the SSB. In beam -based communication, each DL beam may be associated with a respective SSB.

[0045] Based on performing DL synchronization and acquiring SI, such as a master information block (MIB) and a system information block type 1 (SIB1), the UE 104 may perform uplink (UL) synchronization and resource request by performing a random access procedure, referred to as “RACH procedure” by selecting and transmitting a preamble on a physical random access channel (PRACH). In some implementations, the NE 102 (e.g., gNB) may transmit a maximum of 64 SSBs and a maximum of 64 corresponding copies of physical downlink control channel (PDCCH) and/or physical downlink shared channel (PDSCH) for delivery of SIB 1 over one or more high frequency bands (e.g., 28 GHz). This may cause significant network energy consumption even under conditions of very low traffic load.

[0046] The preamble may be transmitted during a random access channel (RACH) occasion, i.e., a predetermined set of time-frequency resources available for reception of the preamble. In beam -based communication, the UE 104 may select a certain DL beam and transmit the preamble on a corresponding UL beam. In these examples, there may be a mapping between SSB and RACH occasion, allowing the NE 102 to determine which beam the UE 104 has selected. To complete the RACH procedure, after transmitting the preamble (also referred to as “Msgl”), the UE 104 may monitor for a random-access response (RAR) message (also referred to as “Msg2”). The NE 102 (e.g., gNB) may transmit UL timing adjustment information in the RAR and may also schedule an UL resource, referred to as an initial uplink grant.

[0047] Figure 2 illustrates an example of a protocol stack 200 in accordance with aspects of the present disclosure. While Figure 2 shows a UE 206, a RAN node 208, and a 5G core network (5GC) 210 (e.g., comprising at least an AMF), these are representative of a set of UEs 104 interacting with an NE 102 (e.g., base station) and a CN 106. As depicted, the protocol stack 200 comprises a User Plane protocol stack 202 and a Control Plane protocol stack 204. The User Plane protocol stack 202 includes a physical (PHY) layer 212, a medium access control (MAC) sublayer 214, a radio link control (RLC) sublayer 216, a packet data convergence protocol (PDCP) sublayer 218, and a service data adaptation protocol (SDAP) layer 220. The Control Plane protocol stack 204 includes a PHY layer 212, a MAC sublayer 214, a RLC sublayer 216, and a PDCP sublayer 218. The Control Plane protocol stack 204 also includes a radio resource control (RRC) layer 222 and a non- access stratum (NAS) layer 224.

[0048] The access stratum (AS) layer 226 (also referred to as “AS protocol stack”) for the User Plane protocol stack 202 consists of at least SDAP, PDCP, RLC and MAC sublayers, and the physical layer. The AS layer 228 for the Control Plane protocol stack 204 consists of at least RRC, PDCP, RLC and MAC sublayers, and the physical layer. The layer-1 (LI) includes the PHY layer 212. The layer-2 (L2) is split into the SDAP sublayer 220, PDCP sublayer 218, RLC sublayer 216, and MAC sublayer 214. The layer-3 (L3) includes the RRC layer 222 and the NAS layer 224 for the control plane and includes, e.g., an internet protocol (IP) layer and/or PDU Layer (not depicted) for the user plane. LI and L2 are referred to as “lower layers,” while L3 and above (e.g., transport layer, application layer) are referred to as “higher layers” or “upper layers.”

[0049] The PHY layer 212 offers transport channels to the MAC sublayer 214. The PHY layer 212 may perform a beam failure detection procedure using energy detection thresholds, as described herein. In certain embodiments, the PHY layer 212 may send an indication of beam failure to a MAC entity at the MAC sublayer 214. The MAC sublayer 214 offers logical channels to the RLC sublayer 216. The RLC sublayer 216 offers RLC channels to the PDCP sublayer 218. The PDCP sublayer 218 offers radio bearers to the SDAP sublayer 220 and/or RRC layer 222. The SDAP sublayer 220 offers QoS flows to the core network (e.g., 5GC). The RRC layer 222 provides for the addition, modification, and release of carrier aggregation and/or dual connectivity. The RRC layer 222 also manages the establishment, configuration, maintenance, and release of signaling radio bearers (SRBs) and data radio bearers (DRBs).

[0050] The NAS layer 224 is between the UE 206 and an AMF in the 5GC 210. NAS messages are passed transparently through the RAN. The NAS layer 224 is used to manage the establishment of communication sessions and for maintaining continuous communications with the UE 206 as it moves between different cells of the RAN. In contrast, the AS layers 226 and 228 are between the UE 206 and the RAN (i.e., RAN node 208) and carry information over the wireless portion of the network. While not depicted in Figure 2, the IP layer exists above the NAS layer 224, a transport layer exists above the IP layer, and an application layer exists above the transport layer.

[0051] The MAC sublayer 214 is the lowest sublayer in the L2 architecture of the NR protocol stack. Its connection to the PHY layer 212 below is through transport channels, and the connection to the RLC sublayer 216 above is through logical channels. The MAC sublayer 214 therefore performs multiplexing and demultiplexing between logical channels and transport channels: the MAC sublayer 214 in the transmitting side constructs MAC PDUs (also known as transport blocks (TBs)) from MAC service data units (SDUs) received through logical channels, and the MAC sublayer 214 in the receiving side recovers MAC SDUs from MAC PDUs received through transport channels.

[0052] The MAC sublayer 214 provides a data transfer service for the RLC sublayer 216 through logical channels, which are either control logical channels which carry control data (e.g., RRC signaling) or traffic logical channels which carry user plane data. On the other hand, the data from the MAC sublayer 214 is exchanged with the PHY layer 212 through transport channels, which are classified as UL or downlink (DL). Data is multiplexed into transport channels depending on how it is transmitted over the air.

[0053] The PHY layer 212 is responsible for the actual transmission of data and control information via the air interface, i.e., the PHY layer 212 carries all information from the MAC transport channels over the air interface on the transmission side. Some of the important functions performed by the PHY layer 212 include coding and modulation, link adaptation (e.g., adaptive modulation and coding (AMC)), power control, cell search and random access (for initial synchronization and handover purposes) and other measurements (inside the 3rd Generation Partnership Project (“3GPP”) system (i.e., NR and/or LTE system) and between systems) for the RRC layer 222. The PHY layer 212 performs transmissions based on transmission parameters, such as the modulation scheme, the coding rate (i.e., the modulation and coding scheme (MCS)), the number of physical resource blocks (PRBs), etc.

[0054] In some embodiments, the protocol stack may be a NR protocol stack used in a 5G NR system. Note that an LTE protocol stack comprises similar structure to the protocol stack 200, with the differences that the LTE protocol stack lacks the SDAP sublayer 220 in the AS layer 226, that an EPC replaces the 5GC 510, and that the NAS layer 224 is between the UE 206 and an MME in the EPC. Also note that the present disclosure distinguishes between a protocol layer (such as the aforementioned PHY layer 212, MAC sublayer 214, RLC sublayer 216, PDCP sublayer 218, SDAP sublayer 220, RRC layer 222 and NAS layer 224) and a transmission layer in multiple-input multiple-output (MIMO) communication (also referred to as a “MIMO layer” or a “data stream”).

[0055] Regarding the UE procedure for determining a PDCCH assignment, a set of PDCCH candidates for a UE to monitor is defined in terms of PDCCH search space sets. A search space set can be a common search space (CSS) set or a UE-specific search space (USS) set. A respective UE may monitor PDCCH candidates in one or more of the following nine search spaces sets:

[0056] First, a TypeO-PDCCH CSS set on the primary cell of the master cell group (MCG) configured by A) parameter pdcch-ConfigSIBl in the master information block (MIB) or by parameter s earchSpace SIB 1 in the Information Element (IE) PDCCH- ConfigCommon or by parameter searchSpaceZero in the IE PDCCH-ConfigCommon for a downlink control information (DCI) format 1 0 with cyclic redundancy check (CRC) scrambled by a SI radio network temporary identifier (RNTI), or B) parameter searchSpaceZero by providing searchSpaceID=O for parameter searchSpaceMCCH or parameter searchSpaceMTCH for a DCI format 4_0 with CRC scrambled by a multimedia broadcast/multicast service (MBMS) control channel (MCCH) RNTI (MCCH-RNTI) or a group RNTI (G-RNTI) for broadcast.

[0057] Second, a TypeOA-PDCCH CSS set configured by parameter searchSpaceOtherSystemlnformation in the IE PDCCH-ConfigCommon for a DCI format 1 0 with CRC scrambled by a SI-RNTI on the primary cell of the MCG.

[0058] Third, a TypeOB-PDCCH CSS set configured by the parameters searchSpaceMCCH and searchSpaceMTCH for a DCI format 4_0 with CRC scrambled by a MCCH-RNTI or a G-RNTI for broadcast, on the primary cell of the MCG.

[0059] Fourth, a Type 1 -PDCCH CSS set configured by parameter ra-SearchSpace in the IE PDCCH-ConfigCommon for a DCI format with CRC scrambled by a randomaccess RNTI (RA-RNTI), a Message B RNTI (MsgB-RNTI), or a temporary cell RNTI (TC-RNTI) on the primary cell. [0060] Fifth, a TypelA-PDCCH CSS set configured by parameter sdt-SearchSpace in the IE PDCCH-ConfigCommon for a DCI format with CRC scrambled by a cell RNTI (C-RNTI) or a Configured Scheduling RNTI (CS-RNTI) on the primary cell.

[0061] Sixth, a Type2-PDCCH CSS set configured by the parameter pagingSearchSpace in the IE PDCCH-ConfigCommon for a DCI format 1 0 with CRC scrambled by a Paging RNTI (P-RNTI) on the primary cell of the MCG.

[0062] Seventh, a Type2A-PDCCH CSS set configured by the parameter pei- SecirchSpace in the IE pei-ConfigBWP for a DCI format 2_7 with CRC scrambled by a Paging Early Indication RNTI (PEI -RNTI) on the primary cell of the MCG.

[0063] Eighth, a Type3-PDCCH CSS set configured by A) the parameter SecirchSpace in the IE PDCCH-Config with the value searchSpaceType = ‘common’ for DCI formats with CRC scrambled by an interruption RNTI (INT-RNTI), slot format indication RNTI (SFI-RNTI), transmit power control physical uplink shared channel RNTI (TPC-PUSCH-RNTI), transmit power control physical uplink control channel RNTI (TPC-PUCCH-RNTI), transmit power control sounding reference signal RNTI (TPC-SRS-RNTI), cancellation indication RNTI (CI-RNTI), or network energy saving RNTI (NES-RNTI) and, only for the primary cell, C-RNTI, modulation and coding scheme-cell RNTI (MCS-C-RNTI), CS-RNTI(s), or power saving RNTI (PS-RNTI), or B) the parameter SecirchSpace in the IE pdcch-ConfigMulticast for DCI formats with CRC scrambled by G-RNTI, or group configured scheduling RNTI (G-CS-RNTI), or C) the parameters searchSpaceMCCH and searchSpaceMTCH on a secondary cell for a DCI format 4 0 with CRC scrambled by a MCCH-RNTI or a G-RNTI for broadcast.

[0064] Nineth, a USS set configured by the parameter SearchSpace in the IE PDCCH-Config with the value searchSpaceType = ‘ue-Specific’ for DCI formats with CRC scrambled by C-RNTI, MCS-C-RNTI, semi persistent channel state information RNTI (SP-CSI-RNTI), CS-RNTI(s), sidelink RNTI (SL-RNTI), sidelink configured scheduling (SL-CS-RNTI), sidelink (SL) Semi-Persistent Scheduling (SPS) vehicle RNTI (V-RNTI), or network controlled repeater RNTI (NCR-RNTI).

[0065] If a UE is provided a zero value for the parameter searchSpacelD in the IE

PDCCH-ConfigCommon for a Type0/0A/2-PDCCH CSS set, or is provided a zero value for the parameters searchSpaceMCCH or searchSpaceMTCH, then the UE determines monitoring occasions for PDCCH candidates of the Type0/0A/2-PDCCH CSS set, and if the UE is provided a C-RNTI, then the UE monitors PDCCH candidates only at monitoring occasions associated with a SS/PBCH block, where the SS/PBCH block is determined by the most recent of: A) a MAC control element (CE) activation command indicating a transmission configuration indicator (TCI) state of the active bandwidth part (BWP) that includes a CORESET with index 0 (e.g., as described in 3GPP technical specification (TS) 38.214), where the TCI-state includes a channel state information reference signal (CSI-RS) which is quasi-co-located with the SS/PBCH block, or B) a random access procedure that is not initiated by a PDCCH order that triggers a contention -free random access procedure.

[0066] If a UE monitors PDCCH candidates for DCI formats with CRC scrambled by a C-RNTI and if the UE is provided a non-zero value for searchSpacelD in PDCCH- ConfigCommon for a Type0/0A/2-PDCCH CSS set, or monitors PDCCH candidates for DCI formats with CRC scrambled by a MCCH-RNTI or a G-RNTI for broadcast and the UE is provided a non-zero value for searchSpaceMCCH and searchSpaceMTCH in PDCCH-ConfigCommon for a TypeO/OB-PDCCH CSS set, then the UE determines monitoring occasions for PDCCH candidates of the TypeO/OA/2 -PDCCH CSS set, or of the TypeO/OB-PDCCH set, respectively, based on the search space set associated with the value of searchSpacelD.

[0067] The UE may assume that the DMRS antenna port associated with PDCCH receptions in the CORESET configured by pdcch-ConfigSIBl in MIB, the DMRS antenna port associated with corresponding PDSCH receptions, and the corresponding SS/PBCH block are quasi co-located with respect to average gain, quasi co-location (QCL) 'typeA' and 'typeD' properties, when applicable, if the UE is not provided a TCI state indicating QCL information of the DMRS antenna port for PDCCH reception in the CORESET. Note that each TCI state contains parameters for configuring a QCL relationship between one or two DL reference signals (RSs) and the DMRS ports of the PDSCH, the DMRS port of the PDCCH, or the CSI-RS port(s) of a CSI-RS resource.

[0068] The value for the DMRS scrambling sequence initialization is the cell ID. For operation without shared spectrum channel access in FR1 and FR2-1, a subcarrier spacing (SCS) is provided by the parameter subCarrierSpacingCommon in the MIB. For operation with shared spectrum channel access in FR1 and for operation in FR2-2, a SCS is same as the SCS of a corresponding SS/PBCH block.

[0069] For single cell operation or for operation with carrier aggregation in a same frequency band, a UE does not expect to monitor a PDCCH in a Type0/0A/0B/2/3- PDCCH CSS set or in a USS set if a DMRS for monitoring a PDCCH in a Typel- PDCCH CSS set is not configured with same qcl-Type parameter set to 'typeD' properties (e.g., as described in 3GPP TS 38.214) with a DMRS for monitoring the PDCCH in the Type0/0A/0B/2/3-PDCCH CSS set or in the USS set, and if the PDCCH or an associated PDSCH overlaps in at least one symbol with a PDCCH the UE monitors in a Typel- PDCCH CSS set or with an associated PDSCH.

[0070] If a UE is provided with both: A) one or more search space sets by corresponding one or more of searchSpaceZero, searchSpaceSIBl, searchSpaceOtherSystemlnformation, pagingSearchSpace, ra-SearchSpace, and B) a C- RNTI, an MCS-C-RNTI, or a CS-RNTI, then the UE monitors PDCCH candidates for DCI format 0 0 and DCI format 1 0 with CRC scrambled by the C-RNTI, the MCS-C- RNTI, or the CS-RNTI in the one or more search space sets in a slot where the UE monitors PDCCH candidates for at least a DCI format 0 0 or a DCI format 1 0 with CRC scrambled by SI-RNTI, RA-RNTI, MsgB-RNTI, or P-RNTI.

[0071] If a UE is provided with both A) one or more search space sets by corresponding one or more of searchSpaceZero, searchSpaceSIBl, searchSpaceOtherSystemlnformation, pagingSearchSpace, pei-SearchSpace, ra- SearchSpace, or a CSS set by PDCCH-Config, and B) a SI-RNTI, a P-RNTI, a PEI- RNTI, a RA-RNTI, a MsgB-RNTI, a SFI-RNTI, an INT-RNTI, a TPC-PUSCH-RNTI, a TPC-PUCCH-RNTI, or a TPC-SRS-RNTI, then, for a RNTI from any of these RNTIs, the UE does not expect to process information from more than one DCI format with CRC scrambled with the RNTI per slot.

[0072] Table 1 describes control channel element (CCE) aggregation levels (ALs) and maximum number of PDCCH candidates per CCE AL for CSS sets configured by searchSpaceSIBl .

Table 1

[0073] For each DL BWP configured to a UE in a serving cell, the UE can be provided by higher layer signaling with A) P < 3 CORESETs if the parameter coresetPoolIndex is not provided, or if a value of the parameter coresetPoolIndex is same for all CORESETs if the parameter coresetPoolIndex is provided; or B) P < 5 CORESETs if the parameter coresetPoolIndex is not provided for a first CORESET, or is provided and has a value 0 for a first CORESET, and is provided and has a value 1 for a second CORESET.

[0074] For each CORESET, the UE is provided the following by ControlResourceSet: A) a CORESET index p. by the parameter controlResourceSetld or by the parameter controlResourceSetId-v!610, where i) 0 < p < 12 if the parameter coresetPoolIndex is not provided, or if a value of the parameter coresetPoolIndex is same for all CORESETs if the parameter coresetPoolIndex is provided, or ii) 0 < p < 16 if the parameter coresetPoolIndex is not provided for a first CORESET, or is provided and has a value 0 for a first CORESET, and is provided and has a value 1 for a second CORESET; B) a DMRS scrambling sequence initialization value by the parameter pdcch- DMRS-ScramblinglD,' C) a precoder granularity for a number of resource element groups (REGs) in the frequency domain where the UE can assume use of a same DMRS precoder by the parameter precoderGranularity, D) a number of consecutive symbols provided by duration; E) a set of resource blocks provided by the parameter frequencyDomainResources,' F) CCE-to-REG mapping parameters provided by the parameter cce-REG-MappingType,- G) an antenna port quasi co-location, from a set of antenna port quasi co-locations provided by TCI-State, indicating quasi co-location information of the DMRS antenna port for PDCCH reception; and H) an indication for a presence or absence of a transmission configuration indication (TCI) field for a DCI format, other than DCI format 1 0, that schedules PDSCH receptions or has associated HARQ-ACK information without scheduling PDSCH and is provided by a PDCCH in CORESET p. by the parameter tci-PresentlnDCI or tci-PresentDCI-1-2. [0075] For each CORESET in a DL BWP of a serving cell, a respective parameter frequencyDomainResources provides a bitmap. If a CORESET is not associated with any search space set configured with the parameter freqMonitorLocations , the bits of the bitmap have a one-to-one mapping with non-overlapping groups of 6 consecutive PRBs, in ascending order of the PRB index in the DL BWP bandwidth of N^Pp^/P PRBs with starting common resource block (RB) position Ng^p^t, where the first common RB of the first group of 6 PRBs has common RB index 6 • [iVg^^/ 6] if rb-Offset is not provided, or the first common RB of the first group of 6 PRBs has common RB index

+

provided by rb-Offset.

[0076] Otherwise, if a CORESET is associated with at least one search space set configured with the parameter freqMonitorLocations, the first Npf^seto bits of the bitmap have a one-to-one mapping with non-overlapping groups of 6 consecutive PRBs, in ascending order of the PRB index in each RB set k in the DL BWP bandwidth of Np ^p PRBs with starting common RB position RBso+kDL ’ where the first common RB of the first group of 6 PRBs has common RB index RB^f^p^_L + N°^^seL and k is indicated by the parameter freqMonitorLocations if provided for a search space set; otherwise,

number of available PRBs in the RB set 0 for the DL BWP, and Np^^set is provided by rb-Offset or Np^^set = 0 if rb-Offset is not provided. If a UE is provided RB sets in the DL BWP, the UE expects that the RBs of the CORESET are within the union of the PRBs in the RB sets of the DL BWP.

[0077] For each CORESET provided by the parameters cfr-ConfigMCCH-MTCH or cfr-ConfigMulticast in a common frequency resource (CFR) of a serving cell, the quantities N^pp^/p and Njfwp¹' in this clause are replaced by the size of CFR Npf^p and starting common RB position.

[0078] Described herein are structures of CORESET based on DFT-s-OFDM waveform and the related signaling to the UE. For a physical downlink control channel (PDCCH) transmission, a downlink control information (DCI) payload is rate matched and encoded, e.g., with polar coding, then modulated with quadrature phase shift keying (QPSK) modulation. [0079] The QPSK symbols are mapped to control channel elements (CCEs), and each CCE may be comprised of one or multiple REGs. For example, a CCE can have 6 REGs, where each REG contains 12 resource elements (REs). The CCE REGs can be mapped to one or more OFDM symbols (i.e., in the time domain). For 5G NR, cyclic prefix OFDM (CP-OFDM) was chosen as the main candidate for both DL and UL with DFT-s-OFDM being used for UL in some areas.

[0080] When using the CP-OFDM waveform, the last part of data of an OFDM frame is appended at the beginning of the OFDM frame, and length of cyclic prefix is chosen to be greater than a channel delay spread. This overcomes the inter-symbol interference that can result from delays and reflections. Additionally, the cyclic prefix length is adaptive according to the link conditions.

[0081] DFT-s-OFDM, is a single carrier-like transmission scheme that can be combined with OFDM. For each user, the encoded bit sequence is mapped to a complex constellation of symbols (e.g., QPSK modulation), and the different users (i.e., different transmitters) are assigned different Fourier coefficients. This assignment is carried out in the mapping and de-mapping blocks. The receiver side includes one de-mapping block, one inverse discrete Fourier transform (IDFT) block (for de-spreading), and one detection block for each user signal to be received. As in CP-OFDM, guard intervals (e.g., cyclic prefixes) with cyclic repetition are introduced between blocks of symbols in view to eliminate inter-symbol interference from time spreading (e.g., caused by multi-path propagation) among the blocks.

[0082] Figure 3A illustrates an exemplary resource grid 300 of a CP-OFDM based CORESET transmission 302, in accordance with aspects of the present disclosure. The CP-OFDM based CORESET transmission 302 may be transmitted by a gNB (e.g., an embodiment of the RAN node 208) and is received by a UE (e.g., the UE 206).

[0083] For the CP-OFDM waveform, the DMRS symbols 304 are interleaved between the 12 REs of the REG 306. Note that the DMRS comprises a scrambled sequence of bits generated based on pseudo-random sequences. The DMRS is a physical reference signal used for downlink (DL) radio channel estimation notably for decoding a received signal. [0084] Figure 3B illustrates an exemplary resource grid 320 of DFT-s-OFDM based CORESET 322, in accordance with aspects of the present disclosure. The DFT-s-OFDM based CORESET transmission 322 may be transmitted by a gNB (e.g., an embodiment of the RAN node 208) and is received by a UE (e.g., the UE 206).

[0085] In various embodiments, the DFT-s-OFDM based CORESET 322 comprises the DMRS symbols 324 in the first OFDM symbol. Here, the DMRS comprises multiple REGs and may span the bandwidth of the CORE SET 322. Unlike CP-OFDM based mapping of REs in the REGs, for the DFT-s-OFDM based CORESET 322, the 12 REs of the REG 326 are mapped in contiguous manner without DMRS symbols interleaved between the REs. This allows for the gNB to apply the transform precoding on the data symbols.

[0086] For the DFT-s-OFDM based CORESET 322, the DMRS symbols may be allocated in separate OFDM symbols, either in the beginning, the end, or in the middle of the CORESET 322. The DMRS symbols may be based on OFDM waveform or may be generated by applying DFT-s-OFDM on the generated sequence. The transform precoding can be applied on the REG level, the CCE level, or the aggregation level (AL) level as shown in Figure 3B. Note that transform precoding is based on the discrete Fourier transform (DFT) and is a step to create the DFT-s-OFDM waveform. Transform precoding spreads the data to reduce the peak to average power ratio (PAPR) of the waveform.

[0087] The PAPR is one aspect of performance that needs to be considered as the PAPR has a major impact on the efficiency of the power amplifiers. Different options of applying the transform precoding can lead to different gains in terms of PAPR reduction as shown in Figure 4.

[0088] Figure 4 illustrates a complementary cumulative distribution function (CCDF) graph 400 showing the PAPR of DFT-s-OFDM based PDCCH with different AL compared to CP-OFDM. The CCDF graph shows the reduction of the PAPR when DFT- s-OFDM is applied (i.e., comparing to CP-OFDM), and also shows that applying the spreading over the total length of AL gives better reduction of PAPR. However, this also leads to the UE applying DFT with variable lengths during the blind search of the different ALs. [0089] According to aspects of a first solution, a gNB indicates to the UE the use of DFT-s-OFDM for CORESET#0, e.g., of a pending PDCCH transmission, by signaling information in a physical broadcast channel (PBCH) transmission. In various embodiments, the gNB implicitly indicates the use of the DFT-s-OFDM waveform by indicating that a transform precoding is enabled. In some implementations of the first solution, the UE decodes a bit field in PBCH that indicates the application of transform precoding of CORESET#0 during its initial access after detecting primary synchronization signal (PSS) and secondary synchronization signal (SSS).

[0090] In one implementation, a single bit is transmitted in PBCH that indicates whether transform precoding is applied (i.e., enabled) for CORESET#0 or not. The UE may assume, e.g., based on a pre -configuration, that the DMRS symbol of the PDCCH transmission is located in the first symbol within the search space. Alternatively, the UE may assume, e.g., based on a pre-configuration, that the DMRS symbol is located in the last symbol of the search space. During its PDCCH detection, the UE applies transform de- precoding on the frequency domain symbols before decoding the control data.

[0091] In another implementation of the first solution, the gNB may indicate to the UE the configuration of CORESET#0 using a bit field with multiple bits in a PBCH transmission. Here, different values of the multiple bits may be used to indicate whether transform precoding is applied (i.e., enabled) and a location of the DMRS symbol. In one example, the value ‘00’ indicates that transform precoder is not applied (thus, the CP- OFDM waveform is used), the value ‘01’ indicates that transform precoding is applied and DMRS symbol is the first OFDM symbol, the value ‘ 10’ indicates that the transform precoding is applied and DMRS symbol is the second OFDM symbol, etc.

[0092] In an alternative implementation of the first solution, the gNB may indicate the way the transform precoding is applied on the PDCCH, e.g., using one or more bits in a PBCH transmission. In one example, a bit field indicates whether the transform precoding is applied on REG level, CCE level, or AL level. Note that this bit field in PBCH may be combined with or separate from the bit field used to indicate whether the transform precoding is enabled/disabled and/or the DMRS location.

[0093] For REG level transform precoding, the spreading (DFT) is applied on each 12 REs that represent the REG. For CCE level transform precoding, the spreading (DFT) is applied on the total number of REs in a symbol for one CCE (i.e., corresponding to multiple REGs).

[0094] For AL-based spreading, the spreading (DFT) is applied on all CCEs within the AL, e.g., as shown in Figure 3B. For example, for AL=4, the length of the applied DFT is 4 times the length of the CCE. At the UE side, the UE performs a blind search for different PDCCH candidates with different Als. For each AL trial, the UE applies the despreading either on each REG, CCE or on the whole AL length, i.e., depending on the indication from the gNB.

[0095] According to aspects of a second solution, the gNB indicates to the UE the use of DFT-s-OFDM for UE dedicated CORESET(s), e.g., of a pending PDCCH transmission. In one implementation, the UE may determine whether transform precoding is enabled or not for the dedicated CORESET based on the indication of CORESET#0. In one example, if CORESET#0 is transmitted with DFT-s-OFDM, UE assumes that the dedicated CORESET is transmitted with DFT-s-OFDM. In another implementation, the gNB indicates the transform precoding information to the UE using RRC message as part of ControlResourceSet configuration. In one implementation, a parameter in ControlResourceSet configuration is added to indicate the transform precoding of the CORESET.

[0096] Figure 5 illustrates an abstract syntax notation one (ASN.1) representation of a CORESET configuration 500 for indicating the enabling/disabling of a DFT-s-OFDM waveform. In one embodiment, the UE receives the CORESET configuration 500 from the gNB in an RRC message. As depicted, the CORESET configuration 500 includes the parameter 502 “transform? re coder” with the enumerated values being either “enabled” or “disabled.”

[0097] Upon decoding the RRC message, the UE starts the search for the PDCCH candidate with or without applying transform de-precoding on the frequency domain symbols depending on whether transform precoding is enabled or not. After performing the transform de-precoding, the UE then de-maps the equalized time domain PDCCH symbols for further decoding. The UE does this for each blind search iteration.

[0098] In another implementation, the gNB indicates to the UE, along with enabling the transform precoding, the length of DFT used for spreading the PDCCH. In one example, transform precoding (DFT spreading) is applied on every REG (e.g., 12 REs) in each symbol. In another example, the transform precoding is applied on every CCE (multiple REGs, e.g., 2 REGs) for each symbol.

[0099] In alternative example, transform precoding is applied on all CCEs within an AL. Here, during its blind search for PDCCH candidates, the UE starts with performing the DFT de-spreading on the AL1 (e.g., 2 REGs length in case of 3 symbols PDCCH) on the equalized frequency domain symbols. If unsuccessful, then the UE applies DFT despreading on AL2 (e.g., 2 CCEs length (e.g., 4 REGs length) in case of 3 symbols PDCCH), and then AL4, etc. until the PDCCH candidate is found. As used herein, DFT “de-spreading” refers to the inverse operation of the DFT-based spreading performed by the transmitting device (e.g., the gNB).

[0100] Figure 6 illustrates an ASN. 1 representation of a CORESET configuration 600 for indicating the enabling/disabling of a DFT-s-OFDM waveform with an indication of the length of transform precoding. In one embodiment, the UE receives the CORESET configuration 600 from the gNB in an RRC message.

[0101] As depicted, the CORESET configuration 600 includes the parameter 602 “transform? recoder” with the enumerated values being “disabled,” “ enabledOverREG” (i.e., indicating that the transform precoding is applied at the REG level), “enabledOverCCE” (i.e., indicating that the transform precoding is applied at the CCE level), and “enabledOverAL” (i.e., indicating that the transform precoding is applied at the AL level).

[0102] In one implementation, based on pre-configuration, the UE assumes that the DMRS symbol for channel estimation is the first symbol in the search space. In another example, the UE assumes that the DMRS symbol of PDCCH is the last symbol in the search space.

[0103] In alternative implementation, the gNB sends DMRS location information to the UE along with the transform precoding information. In various embodiments, the DMRS location information indicates whether the DMRS symbol is located as the first symbol of the CORESET, the second symbol, or the last symbol.

[0104] Figure 7 illustrates an ASN. 1 representation of a CORESET configuration 700 for indicating the enabling/disabling of a DFT-s-OFDM waveform (with a length indication) and further indicating the location of PDCCH DMRS symbol. In one embodiment, the UE receives the CORESET configuration 700 from the gNB in an RRC message.

[0105] As depicted, the CORESET configuration 700 includes the parameter 602 "iransforml^> recoder" , described above. Additionally, the CORESET configuration 700 includes the parameter 702 "DMRS-location" with the enumerated values being “nl” (i.e., indicating that the DMRS is located in the first OFDM symbol), “n2” (i.e., indicating that the DMRS is located in the second OFDM symbol), and “n3” (i.e., indicating that the DMRS is located in the third OFDM symbol).

[0106] According to aspects of a third solution, the UE indicates to the network (i.e., the gNB) a request to change the waveform used for transmitting PDCCH. Upon measuring the quality of one or more DL channels, the UE may request to switch the waveform (i.e., change the waveform type) for the next PDCCH transmission.

[0107] In some embodiments, the UE is preconfigured with threshold(s) for DL quality, e.g., the value of a reference signal received power (RSRP) (or a received signal strength indicator (RSSI), or a reference signal received quality (RSRQ), or a combination thereof) of the DMRS used for transmitting the previous PDCCH (or SSB, or PDSCH, or CSI-RS, etc.) to the UE. Alternatively, the DL signal quality may be measured based on the signal- to-noise ratio (SNR) (or signal-to-interference-plus-noise ratio (SINR)) of the CSI-RS. When the threshold is met, the UE sends a request, to enable or disable transform precoding of the next PDCCH, on Uplink Control Information (UCI) over the physical uplink control channel (PUCCH) and/or the physical uplink shared channel (PUSCH).

[0108] In one implementation, for receiving the next PDCCH, the UE may assume that the next PDCCH will be transmitted, according to its request, i.e., with transform precoding enabled/disabled.

[0109] In another implementation, the UE assumes that next PDCCH is transmitted with the same configuration of the previously transmitted PDCCH, and in the DCI field, the UE expects acknowledgement from gNB for accepting the request of the waveform change for the following PDCCH. Within the DCI, gNB indicates accepting UE request and indicates the configuration of next PDCCH with or without transform precoding and the related details of the application of transform precoding in case the request is to switch the waveform from CP-OFDM to DFT-s-OFDM.

[0110] In an alternative implementation, the UE may request the way the transform precoding (DFT spreading length) needs to be applied (i.e., over REG, over CCE, or over AL). In this implementation, the gNB may transmit an acknowledgement for accepting the request of the way the transform precoding needs to be applied for the following PDCCH.

[0111] Note that various aspects of the above solutions may be combined. For example, one or more solutions may be implemented together in a UE and/or network. Therefore, the above numbering of solutions is for organization of similar concepts and the aspects described therein are assumed to be implementable jointly, unless explicitly described otherwise.

[0112] Figure 8 illustrates an example of a UE 800 in accordance with aspects of the present disclosure. The UE 800 may include a processor 802, a memory 804, a controller 806, and a transceiver 808. The processor 802, the memory 804, the controller 806, or the transceiver 808, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

[0113] The processor 802, the memory 804, the controller 806, or the transceiver 808, or various combinations or components thereof may be implemented in hardware (e.g., circuitry). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure.

[0114] The processor 802 may include an intelligent hardware device (e.g., a general- purpose processor, a DSP, a central processing unit (CPU), an ASIC, a field programmable gate array (FPGA), or any combination thereof). In some implementations, the processor 802 may be configured to operate the memory 804. In some other implementations, the memory 804 may be integrated into the processor 802. The processor 802 may be configured to execute computer-readable instructions stored in the memory 804 to cause the UE 800 to perform various functions of the present disclosure.

[0115] The memory 804 may include volatile or non-volatile memory. The memory 804 may store computer-readable, computer-executable code including instructions that, when executed by the processor 802, cause the UE 800 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such the memory 804 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non- transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

[0116] In some implementations, the processor 802 and the memory 804 coupled with the processor 802 may be configured to cause the UE 800 to perform various functions (e.g., operations, signaling) described herein (e.g., executing, by the processor 802, instructions stored in the memory 804). In some implementations, the processor 802 may include multiple processors and the memory 804 may include multiple memories. One or more of the multiple processors may be coupled with one or more of the multiple memories, which may be individually or collectively, configured to perform various functions (e.g., operations, signaling) of the UE 800 as disclosed herein.

[UE claim support]

[0117] The processor 802 coupled with the memory 804 may be configured to, capable of, or operable to cause the UE 800 to receive (e.g., from the network) a configuration that indicates a waveform associated with a DL control channel transmission, where the waveform comprises a DFT-s-OFDM waveform; receive (e.g., from the network) an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending DL control channel transmission; and transmit (e.g., to the network) a request to switch the waveform for a next DL control channel transmission in response to receiving a DL transmission and based at least in part on a signal quality measurement (e.g., corresponding to the DL transmission). In some examples, the DL control channel transmission comprises a PDCCH transmission. [0118] In some implementations, the DL transmission comprises one or more of the pending DL control channel transmission (e.g., PDCCH transmission), a DMRS, a downlink data channel transmission (e.g., PDSCH transmission), or a CSI-RS. In some embodiments, the signal quality measurement comprises one or more of a RSRP, a RSSI, a RSRQ, or a SNR.

[0119] In some implementations, the processor 802 coupled with the memory 804 may be configured to, capable of, or operable to cause the UE 800 to receive (e.g., from the network) a second configuration that indicates a DFT size, and to perform a DFT despreading of a received DL control channel transmission (e.g., the pending PDCCH transmission) based at least in part on the DFT size. In certain implementations, the DFT size corresponds to one or more REG size (i.e., comprising 12 REs), a CCE size (i.e., comprising multiple REGs), or an AL size.

[0120] In some implementations, the processor 802 coupled with the memory 804 may be configured to, capable of, or operable to cause the UE 800 to receive (e.g., from the network) a second indication that a transform precoding is enabled or disabled for a common CORESET (e.g., CORESET#0). In certain implementations, the second indication comprises one or more bits in a MIB. In one implementation, the second indication is a single bit in the MIB. In certain implementations, the transform precoding is applied at one or more of an REG level, a CCE level, or an AL level.

[0121] In some implementations, the processor 802 coupled with the memory 804 may be configured to, capable of, or operable to cause the UE 800 to receive (e.g., from the network) a second configuration for channel estimation of a respective DL control channel transmission (e.g., PDCCH) corresponding to a common CORESET (e.g., CORESET#0), where the second configuration indicates a symbol location of a DMRS. In some examples, the indicated symbol location is for when a transform precoding is enabled.

[0122] In certain implementations, the symbol location of the DMRS corresponds to a first symbol of the CORESET, a second symbol of the CORESET, or a third symbol of the CORESET. In certain implementations, the second configuration comprises a bit field in a broadcast channel transmission (e.g., a PBCH transmission), said bit field indicating a symbol location of the DMRS. [0123] In some implementations, the processor 802 coupled with the memory 804 may be configured to, capable of, or operable to cause the UE 800 to receive (e.g., from the network) a second configuration for applying a DFT for transform de-precoding of a common CORESET (e.g., CORESET#0), where the second configuration indicates a symbol location of a DMRS. In some examples, the indicated symbol location is for when a transform precoding is enabled.

[0124] In certain implementations, the length of the DFT corresponds to one or more of a REG size (i.e., comprising 12 REs), a CCE size (i.e., comprising multiple REGs), or an AL size to be applied during a blind search for a candidate DL control channel transmission (e.g., PDCCH). In certain implementations, the second configuration comprises a bit field in a broadcast channel transmission (e.g., PBCH transmission).

[0125] In some implementations, the processor 802 coupled with the memory 804 may be configured to, capable of, or operable to cause the UE 800 to receive (e.g., from the network) a second configuration for receiving a UE-dedicated CORESET using the DFT-s-OFDM waveform. In certain implementations, the processor 802 coupled with the memory 804 may be configured to, capable of, or operable to cause the UE 800 to receive an RRC message comprising a DL control channel configuration (e.g., PDCCH configuration), where the DL control channel configuration comprises the second configuration.

[0126] In certain implementations, the second configuration further comprises a second indication that a transform precoding is enabled or disabled. In certain implementations, the transform precoding of the UE-dedicated CORESET is enabled whenever the transform precoding is also enabled for a common CORESET (e.g., CORESET#0).

[0127] In some implementations, the processor 802 coupled with the memory 804 may be configured to, capable of, or operable to cause the UE 800 to receive (e.g., from the network) a second configuration for performing a DFT de-spreading of a received DL control channel transmission (e.g., the pending PDCCH transmission). In certain implementations, the processor 802 coupled with the memory 804 to, capable of, or operable to cause the UE 800 to perform the DFT de-spreading on one or more of a REG level, a CCE level, or an AL level. [0128] In some implementations, the processor 802 coupled with the memory 804 may be configured to, capable of, or operable to cause the UE 800 to receive (e.g., from the network) a second configuration for the location of a set of DMRS symbols for estimating a channel on a CORESET during a connected mode associated with the UE. In such embodiments, the CORESET may comprise one or more of a UE-dedicated CORESET or a common CORESET (e.g., not CORESET#0). In certain implementations, the second configuration is sent in a SIB (e.g., SIB1).

[0129] In some implementations, the processor 802 coupled with the memory 804 may be configured to, capable of, or operable to cause the UE 800 to transmit (e.g., to the network) a second request that a transform precoding is enabled or disabled for the next DL control channel transmission (e.g., PDCCH transmission). In certain implementations, the second request is based at least in part on a DL measurement of at least one previously received DL control channel or DL data channel, i.e., according to a defined (or predefined) threshold of the DL quality.

[0130] In certain implementations, the second request further indicates a requested level of the transform precoding, where the requested level corresponds to one or more of a REG level, a CCE level, or an AL level.

[0131] In certain implementations, the processor 802 coupled with the memory 804 may be configured to, capable of, or operable to cause the UE 800 to enable or disable a transform de-precoding for a next CORESET transmission, in accordance with the second request. In other words, the UE expects the next transmitted CORESET to be based on the requested waveform and start decoding the CORESET based on whether the request is for enabling or disabling the transform precoding.

[0132] In certain implementations, the processor 802 coupled with the memory 804 may be configured to, capable of, or operable to cause the UE 800 to: A) decode a next CORESET transmission is accordance with a current transform precoding configuration;

B) receive (e.g., from the network) an acknowledgement of the second request, or an updated transform precoding configuration, or both; and C) decode a subsequent CORESET in accordance with the updated transform precoding configuration.

[0133] The controller 806 may manage input and output signals for the UE 800. The controller 806 may also manage peripherals not integrated into the UE 800. In some implementations, the controller 806 may utilize an operating system (OS) such as iOS®, ANDROID®, WINDOWS®, or other operating systems. In some implementations, the controller 806 may be implemented as part of the processor 802.

[0134] In some implementations, the UE 800 may include at least one transceiver 808. In some other implementations, the UE 800 may have more than one transceiver 808. The transceiver 808 may represent a wireless transceiver. The transceiver 808 may include one or more receiver chains 810, one or more transmitter chains 812, or a combination thereof.

[0135] A receiver chain 810 may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, the receiver chain 810 may include one or more antennas for receiving the signal over the air or wireless medium. The receiver chain 810 may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. The receiver chain 810 may include at least one demodulator configured to demodulate the received signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 810 may include at least one decoder for decoding/ processing the demodulated signal to receive the transmitted data.

[0136] A transmitter chain 812 may be configured to generate and transmit signals (e.g., control information, data, packets). The transmitter chain 812 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes like phase-shift keying (PSK) or quadrature amplitude modulation (QAM). The transmitter chain 812 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 812 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

[0137] Figure 9 illustrates an example of a processor 900 in accordance with aspects of the present disclosure. The processor 900 may be an example of a processor configured to perform various operations in accordance with examples as described herein. The processor 900 may include a controller 902 configured to perform various operations in accordance with examples as described herein. The processor 900 may optionally include at least one memory 904, which may be, for example, an L1/L2/L3 cache. Additionally, or alternatively, the processor 900 may optionally include one or more arithmetic -logic units (ALUs) 906. One or more of these components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses).

[0138] The processor 900 may be a processor chipset and include a protocol stack (e.g., a software stack) executed by the processor chipset to perform various operations (e.g., receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) in accordance with examples as described herein. The processor chipset may include one or more cores, one or more caches (e.g., memory local to or included in the processor chipset (e.g., the processor 900) or other memory (e.g., random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), static RAM (SRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase change memory (PCM), and others).

[0139] The controller 902 may be configured to manage and coordinate various operations (e.g., signaling, receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) of the processor 900 to cause the processor 900 to support various operations in accordance with examples as described herein. For example, the controller 902 may operate as a control unit of the processor 900, generating control signals that manage the operation of various components of the processor 900. These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating timing of operations.

[0140] The controller 902 may be configured to fetch (e.g., obtain, retrieve, receive) instructions from the memory 904 and determine subsequent instruction(s) to be executed to cause the processor 900 to support various operations in accordance with examples as described herein. The controller 902 may be configured to track memory address of instructions associated with the memory 904. The controller 902 may be configured to decode instructions to determine the operation to be performed and the operands involved. For example, the controller 902 may be configured to interpret the instruction and determine control signals to be output to other components of the processor 900 to cause the processor 900 to support various operations in accordance with examples as described herein. Additionally, or alternatively, the controller 902 may be configured to manage flow of data within the processor 900. The controller 902 may be configured to control transfer of data between registers, arithmetic logic units (ALUs), and other functional units of the processor 900.

[0141] The memory 904 may include one or more caches (e.g., memory local to or included in the processor 900 or other memory, such RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc. In some implementations, the memory 904 may reside within or on a processor chipset (e.g., local to the processor 900). In some other implementations, the memory 904 may reside external to the processor chipset (e.g., remote to the processor 900).

[0142] The memory 904 may store computer-readable, computer-executable code including instructions that, when executed by the processor 900, cause the processor 900 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. The controller 902 and/or the processor 900 may be configured to execute computer-readable instructions stored in the memory 904 to cause the processor 900 to perform various functions. For example, the processor 900 and/or the controller 902 may be coupled with or to the memory 904, the processor 900, the controller 902, and the memory 904 may be configured to perform various functions described herein. In some examples, the processor 900 may include multiple processors and the memory 904 may include multiple memories. One or more of the multiple processors may be coupled with one or more of the multiple memories, which may, individually or collectively, be configured to perform various functions herein.

[0143] The one or more ALUs 906 may be configured to support various operations in accordance with examples as described herein. In some implementations, the one or more ALUs 906 may reside within or on a processor chipset (e.g., the processor 900). In some other implementations, the one or more ALUs 906 may reside external to the processor chipset (e.g., the processor 900). One or more ALUs 906 may perform one or more computations such as addition, subtraction, multiplication, and division on data. For example, one or more ALUs 906 may receive input operands and an operation code, which determines an operation to be executed. One or more ALUs 906 be configured with a variety of logical and arithmetic circuits, including adders, subtractors, shifters, and logic gates, to process and manipulate the data according to the operation. Additionally, or alternatively, the one or more ALUs 906 may support logical operations such as AND, OR, exclusive-OR (XOR), not-OR (NOR), and not-AND (NAND), enabling the one or more ALUs 906 to handle conditional operations, comparisons, and bitwise operations.

[Processor claim support]

[0144] In some implementations, the processor 900 may support various functions (e.g., operations, signaling) of a UE, in accordance with examples as disclosed herein. For example, the controller 902 coupled with the memory 904 may be configured to, capable of, or operable to cause the processor 900 to receive (e.g., from the network) a configuration that indicates a waveform associated with a DL control channel transmission, where the waveform comprises a DFT-s-OFDM waveform; receive (e.g., from the network) an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending DL control channel transmission; and transmit (e.g., to the network) a request to switch the waveform for a next DL control channel transmission in response to receiving a DL transmission and based at least in part on a signal quality measurement (e.g., corresponding to the DL transmission). In some examples, the DL control channel transmission comprises a PDCCH transmission. Additionally, the controller 902 coupled with the memory 904 may be configured to, capable of, or operable to cause the processor 900 to perform one or more functions (e.g., operations, signaling) of the UE as described herein.

[0145] Additionally, or alternatively, in some other implementations, the processor 900 may support various functions (e.g., operations, signaling) of a NE (e.g., base station), in accordance with examples as disclosed herein. For example, the controller 902 coupled with the memory 904 may be configured to, capable of, or operable to cause the processor 900 to transmit (e.g., to a UE) a configuration that indicates a waveform associated with a DL control channel transmission, where the waveform comprises a DFT-s-OFDM waveform; transmit (e.g., to the UE) an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending DL control channel transmission; and receive (e.g., from the UE) a request to switch the waveform for the DL control channel transmission in response to transmitting a DL transmission and based at least in part on a signal quality measurement (e.g., corresponding to the DL transmission). In some examples, the DL control channel transmission comprises a PDCCH transmission. Additionally, the controller 902 coupled with the memory 904 may be configured to, capable of, or operable to cause the processor 900 to perform one or more functions (e.g., operations, signaling) of the NE as described herein.

[0146] Figure 10 illustrates an example of a NE 1000 in accordance with aspects of the present disclosure. The NE 1000 may include a processor 1002, a memory 1004, a controller 1006, and a transceiver 1008. The processor 1002, the memory 1004, the controller 1006, or the transceiver 1008, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

[0147] The processor 1002, the memory 1004, the controller 1006, or the transceiver 1008, or various combinations or components thereof may be implemented in hardware (e.g., circuitry). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure.

[0148] The processor 1002 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof). In some implementations, the processor 1002 may be configured to operate the memory 1004. In some other implementations, the memory 1004 may be integrated into the processor 1002. The processor 1002 may be configured to execute computer-readable instructions stored in the memory 1004 to cause the NE 1000 to perform various functions of the present disclosure.

[0149] The memory 1004 may include volatile or non-volatile memory. The memory 1004 may store computer-readable, computer-executable code including instructions when executed by the processor 1002 cause the NE 1000 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such the memory 1004 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non- transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

[0150] In some implementations, the processor 1002 and the memory 1004 coupled with the processor 1002 may be configured to cause the NE 1000 to perform various functions (e.g., operations, signaling) described herein (e.g., executing, by the processor 1002, instructions stored in the memory 1004). In some implementations, the processor 1002 may include multiple processors and the memory 1004 may include multiple memories. One or more of the multiple processors may be coupled with one or more of the multiple memories, which may be individually or collectively, configured to perform various functions (e.g., operations, signaling) of the NE 1000 as disclosed herein.

[NE claim support]

[0151] The processor 1002 coupled with the memory 1004 may be configured to, capable of, or operable to cause the NE 1000 to transmit (e.g., to a UE) a configuration for receiving a DL control channel transmission (e.g., PDCCH transmission), where the waveform comprises a DFT-s-OFDM waveform; transmit (e.g., to the UE) an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending DL control channel transmission (e.g., PDCCH transmission); and receive (e.g., from the UE) a request to switch the waveform for the DL control channel transmission (e.g., PDCCH transmission) in response to transmitting a DL transmission and based at least in part on a signal quality measurement (e.g., corresponding to the DL transmission).

[0152] In some implementations, the DL transmission comprises one or more of the pending DL control channel transmission (e.g., PDCCH transmission), a DMRS, a downlink data channel transmission (e.g., PDSCH transmission), or a CSI-RS.

[0153] In some implementations, the processor 1002 coupled with the memory 1004 may be configured to, capable of, or operable to cause the NE 1000 to transmit (e.g., to the UE) a second configuration that indicates a DFT size, and to perform a DFT spreading of a respective DL control channel transmission (e.g., PDCCH transmission) based at least in part on the DFT size. In certain implementations, the DFT size corresponds to one or more REG size (i.e., comprising 12 REs), a CCE size (i.e., comprising multiple REGs), or an AL size. [0154] In some implementations, the processor 1002 coupled with the memory 1004 may be configured to, capable of, or operable to cause the NE 1000 to apply/perform a transform precoding on one or more of an REG level, a CCE level, or an AL level. In some implementations, the processor 1002 coupled with the memory 1004 may be configured to, capable of, or operable to cause the NE 1000 to transmit (e.g., to the UE) a second indication that a transform precoding is enabled or disabled for a common CORESET (e.g., CORESET#0). In certain implementations, the second indication comprises at least one bit in a MIB.

[0155] In some implementations, the processor 1002 coupled with the memory 1004 may be configured to, capable of, or operable to cause the NE 1000 to transmit (e.g., to the UE) a second configuration for channel estimation of a respective DL control channel transmission (e.g., PDCCH) corresponding to a common CORESET (e.g., CORESET#0), where the second configuration indicates a symbol location (i.e., in the time domain) of a DMRS. In some examples, the indicated symbol location is for when a transform precoding is enabled.

[0156] In certain implementations, the symbol location of the DMRS corresponds to a first symbol of the CORESET, a second symbol of the CORESET, or a third symbol of the CORESET. In certain implementations, the second configuration comprises a bit field in the PBCH transmission, said bit field indicating the symbol location of the DMRS.

[0157] In some implementations, the processor 1002 coupled with the memory 1004 may be configured to, capable of, or operable to cause the NE 1000 to transmit (e.g., to the UE) a second configuration for applying a DFT for transform de-precoding of a common CORESET (e.g., CORESET#0), where the second configuration indicates a symbol location (i.e., in the time domain) of a DMRS. In some examples, the indicated symbol location is for when a transform precoding is enabled.

[0158] In certain implementations, the length of the DFT corresponds to one or more REG size (i.e., comprising 12 REs), a CCE size (i.e., comprising multiple REGs), or a size of an AL to be applied during a blind search for a candidate DL control channel transmission (e.g., PDCCH). In certain implementations, the second configuration comprises a bit field in a PBCH transmission.

[0159] In some implementations, the processor 1002 coupled with the memory 1004 may be configured to, capable of, or operable to cause the NE 1000 to transmit (e.g., to the UE) a second configuration for receiving a UE-dedicated CORESET using the DFT-s- OFDM waveform. In certain implementations, the processor 1002 coupled with the memory 1004 may be configured to, capable of, or operable to cause the NE 1000 to transmit a RRC message comprising a DL control channel configuration (e.g., PDCCH configuration), where the DL control channel configuration comprises the second configuration.

[0160] In certain implementations, the second configuration further comprises a second indication that a transform precoding is enabled or disabled. In certain implementations, the second configuration further comprises a second indication that a transform precoding of the UE-dedicated CORESET is enabled whenever the transform precoding is also enabled for a common CORESET (e.g., CORESET#0).

[0161] In some implementations, the processor 1002 coupled with the memory 1004 may be configured to, capable of, or operable to cause the NE 1000 to transmit (e.g., to the UE) a second configuration for applying/performing a DFT de-spreading of a received DL control channel transmission (e.g., the pending PDCCH transmission). In certain implementations, the second configuration indicates that the DFT de-spreading is to be applied at a REG level, a CCE level, or an AL level.

[0162] In some implementations, the processor 1002 coupled with the memory 1004 may be configured to, capable of, or operable to cause the NE 1000 to transmit (e.g., to the UE) a second configuration for the location of a set of DMRS symbols for estimating a channel on a CORESET during a connected mode associated with the UE. In such embodiments, the CORESET may comprise one or more of a UE-dedicated CORESET or a common CORESET (e.g., not CORESET#0). In certain implementations, the second configuration is sent in a SIB (e.g., SIB1).

[0163] In some implementations, the processor 1002 coupled with the memory 1004 may be configured to, capable of, or operable to cause the NE 1000 to receive (e.g., from the UE) a second request that a transform precoding is enabled or disabled for the next DL control channel transmission (e.g., PDCCH transmission). In certain implementations, the processor 1002 coupled with the memory 1004 may be configured to, capable of, or operable to cause the NE 1000 to enable or disable the transform precoding for a next CORESET transmission. In certain implementations, the second request further indicates a requested level of the transform precoding, where the requested level corresponds to one or more of an REG level, a CCE level, or an AL level.

[0164] In certain implementations, the processor 1002 coupled with the memory 1004 may be configured to, capable of, or operable to cause the NE 1000 to: A) transmit a next CORESET transmission is accordance with a current transform precoding configuration;

B) transmit (e.g., to the UE) an acknowledgement of the second request, or an updated transform precoding configuration, or both; and C) transmit a subsequent CORESET in accordance with the updated transform precoding configuration.

[0165] The controller 1006 may manage input and output signals for the NE 1000. The controller 1006 may also manage peripherals not integrated into the NE 1000. In some implementations, the controller 1006 may utilize an operating system such as iOS®, ANDROID®, WINDOWS®, or other operating systems. In some implementations, the controller 1006 may be implemented as part of the processor 1002.

[0166] In some implementations, the NE 1000 may include at least one transceiver 1008. In some other implementations, the NE 1000 may have more than one transceiver 1008. The transceiver 1008 may represent a wireless transceiver. The transceiver 1008 may include one or more receiver chains 1010, one or more transmitter chains 1012, or a combination thereof.

[0167] A receiver chain 1010 may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, the receiver chain 1010 may include one or more antennas for receiving the signal over the air or wireless medium. The receiver chain 1010 may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. The receiver chain 1010 may include at least one demodulator configured to demodulate the received signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 1010 may include at least one decoder for decoding/ processing the demodulated signal to receive the transmitted data.

[0168] A transmitter chain 1012 may be configured to generate and transmit signals (e.g., control information, data, packets). The transmitter chain 1012 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes like phase-shift keying (PSK) or quadrature amplitude modulation (QAM). The transmitter chain 1012 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 1012 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

[0169] Figure 11 depicts one embodiment of a method 1100 in accordance with aspects of the present disclosure. The operations of the method 1100 may be implemented by a UE as described herein. In some implementations, the UE may execute a set of instructions to control the function elements of the UE to perform the described functions.

[0170] At step 1102, the method 1100 may include receiving a configuration that indicates a waveform associated with a downlink control channel transmission, where the waveform comprises a DFT-s-OFDM waveform. The operations of step 1102 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of step 1102 may be performed by a UE, as described with reference to Figure 8.

[0171] At step 1104, the method 1100 may include receiving an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending downlink control channel transmission. The operations of step 1104 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of step 1104 may be performed by a UE, as described with reference to Figure 8.

[0172] At step 1106, the method 1100 may include transmitting a request to switch the waveform for a next downlink control channel transmission in response to receiving a downlink transmission and based at least in part on a signal quality measurement. The operations of step 1106 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of step 1106 may be performed by a UE, as described with reference to Figure 8.

[0173] It should be noted that the method 1100 described herein describes one possible implementation, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. [0174] Figure 12 depicts one embodiment of a method 1200 in accordance with aspects of the present disclosure. In various embodiments, the operations of the method 1200 may be implemented by aNE as described herein. In some implementations, the NE may execute a set of instructions to control the function elements of the NE to perform the described functions.

[0175] At step 1202, the method 1200 may include transmitting a configuration that indicates a waveform associated with a downlink control channel transmission, where the waveform comprises a DFT-s-OFDM waveform. The operations of step 1202 may be performed in accordance with examples as described herein. In some implementations, aspects of the operation of step 1202 may be performed by aNE, as described with reference to Figure 10.

[0176] At step 1204, the method 1200 may include transmitting an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending downlink control channel transmission. The operations of step 1204 may be performed in accordance with examples as described herein. In some implementations, aspects of the operation of step 1204 may be performed by a NE, as described with reference to Figure 10.

[0177] At step 1206, the method 1200 may include receiving a request to switch the waveform for a next downlink control channel in response to transmitting a downlink transmission and based at least in part on a signal quality measurement. The operations of step 1206 may be performed in accordance with examples as described herein. In some implementations, aspects of the operation of step 1206 may be performed by a NE, as described with reference to Figure 10.

[0178] It should be noted that the method 1200 described herein describes one possible implementation, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible.

[0179] The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

CLAIMS What is claimed is:

1. A user equipment (UE) for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the UE to: receive a configuration that indicates a waveform associated with a downlink control channel transmission, wherein the waveform comprises a discrete Fourier transform spread orthogonal frequency domain multiplexing (DFT-s-OFDM) waveform; receive an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending downlink control channel transmission; and transmit a request to switch the waveform for a next downlink control channel transmission in response to receiving a downlink transmission and based at least in part on a signal quality measurement.

2. The UE of claim 1, wherein the at least one processor is configured to cause the UE to: receive a second configuration that indicates a discrete Fourier transform (DFT) size; and perform a DFT de-spreading of the pending downlink control channel transmission based at least in part on the DFT size.

3. The UE of claim 1, wherein the at least one processor is configured to cause the UE to receive a second indication that a transform precoding is enabled or disabled for a common control resource set (CORESET).

4. The UE of claim 1, wherein the at least one processor is configured to cause the UE to receive a second configuration for channel estimation of a respective downlink control channel corresponding to a common control resource set (CORESET), wherein the second configuration indicates a symbol location of a demodulation reference signal (DMRS).

5. The UE of claim 1, wherein the at least one processor is configured to cause the UE to receive a second configuration for applying a discrete Fourier transform (DFT) for transform de-precoding of a common control resource set (CORESET), and wherein the second configuration indicates a symbol location of a demodulation reference signal (DMRS).

6. The UE of claim 1, wherein the at least one processor is configured to cause the UE to receive a second configuration for receiving a UE-dedicated control resource set (CORESET) using the DFT-s-OFDM waveform.

7. The UE of claim 1, wherein the at least one processor is configured to cause the UE to receive a second configuration for performing a discrete Fourier transform (DFT) de-spreading of the pending downlink control channel transmission.

8. The UE of claim 1, wherein the at least one processor is configured to cause the UE to receive a second configuration for a location of a set of DMRS symbols for estimating a channel on a control resource set (CORESET) during a connected mode associated with the UE, and wherein the CORESET comprises one or more of a UE-dedicated CORESET or a common CORESET.

9. The UE of claim 1, wherein the at least one processor is configured to cause the UE to transmit a second request that a transform precoding is enabled or disabled for the next downlink control channel transmission.

10. The UE of claim 1, wherein the received downlink transmission comprises one or more of the pending downlink control channel transmission, a demodulation reference signal (DMRS), a downlink data channel transmission, or a channel state information reference signal (CSI-RS), and wherein the signal quality measurement comprises one or more of a reference signal received power (RSRP), a received signal strength indicator (RSSI), a reference signal received quality (RSRQ), or a signal-to-noise ratio (SNR).

11. A method performed by a user equipment (UE), the method comprising: receiving a configuration that indicates a waveform associated with a downlink control channel transmission, wherein the waveform comprises a discrete Fourier transform spread orthogonal frequency domain multiplexing (DFT-s-OFDM) waveform; receiving an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending downlink control channel transmission; and transmitting a request to switch the waveform for a next downlink control channel transmission in response to receiving a downlink transmission and based at least in part on a signal quality measurement.

12. A base station for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the base station to: transmit a configuration that indicates a waveform associated with a downlink control channel transmission, wherein the waveform comprises a discrete Fourier transform spread orthogonal frequency domain multiplexing (DFT-s-OFDM) waveform; transmit an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending downlink control channel transmission; and receive a request to switch the waveform for a next downlink control channel transmission in response to transmitting a downlink transmission and based at least in part on a signal quality measurement.

13. The base station of claim 12, wherein the at least one processor is configured to cause the base station to: transmit a second configuration that indicates a discrete Fourier transform (DFT) size; and perform a DFT spreading of a respective downlink control channel transmission based at least in part on the DFT size.

14. The base station of claim 12, wherein the at least one processor is configured to cause the base station to perform a transform precoding on one or more of a resource element group (REG) level, a control channel element (CCE) level, or an aggregation level (AL) level.

15. The base station of claim 12, wherein the at least one processor is configured to cause the base station to transmit a second indication that a transform precoding is enabled or disabled for a common control resource set (CORESET).

16. The base station of claim 12, wherein the at least one processor is configured to cause the base station to transmit a second configuration for channel estimation of a respective downlink control channel corresponding to a common control resource set (CORESET), wherein the second configuration indicates a symbol location of a demodulation reference signal (DMRS) when a transform precoding is enabled.

17. The base station of claim 12, wherein the at least one processor is configured to cause the base station to transmit a second configuration for applying a discrete Fourier transform (DFT) for transform de-precoding of a common control resource set (CORESET), wherein the second configuration indicates a symbol location of a demodulation reference signal (DMRS) when a transform precoding is enabled.

18. The base station of claim 12, wherein the at least one processor is configured to cause the base station to transmit a second configuration for receiving a user equipment (UE) -dedicated control resource set (CORESET) using the DFT-s- OFDM waveform.

19. The base station of claim 12, wherein the at least one processor is configured to cause the base station to transmit a second configuration for performing a discrete Fourier transform (DFT) de-spreading of a the pending downlink control channel transmission.

20. A method performed by a base station, the method comprising: transmitting a configuration that indicates a waveform associated with a downlink control channel transmission, wherein the waveform comprises a discrete Fourier transform spread orthogonal frequency domain multiplexing (DFT-s-OFDM) waveform; transmitting an indication that the DFT-s-OFDM waveform is enabled or disabled for a pending downlink control channel transmission; and receiving a request to switch the waveform for a next downlink control channel transmission in response to transmitting a downlink transmission and based at least in part on a signal quality measurement.