WO2025020120A1

WO2025020120A1 - Enhanced type-ii channel state information (csi) with a larger number of antenna ports

Info

Publication number: WO2025020120A1
Application number: PCT/CN2023/109283
Authority: WO
Inventors: Jing Dai; Liangming WU; Hao Xu
Original assignee: Qualcomm Inc
Current assignee: Qualcomm Inc
Priority date: 2023-07-26
Filing date: 2023-07-26
Publication date: 2025-01-30
Anticipated expiration: 2026-01-26

Abstract

Certain aspects of the present disclosure provide a method for wireless communications at a user equipment (UE). The UE may select a first number of spatial domain (SD) grids from a plurality of SD grids where each SD grid of the plurality of SD grids comprises multiple SD bases. The UE may then transmit an indication of the selected first number of SD grids to a network entity in a channel state information (CSI) report.

Description

ENHANCED TYPE-II CHANNEL STATE INFORMATION (CSI) WITH A LARGER NUMBER OF ANTENNA PORTS

BACKGROUND

Field of the Disclosure

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for grid-based spatial domain (SD) bases selection.

Description of Related Art

Wireless communications systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, or other similar types of services. These wireless communications systems may employ multiple-access technologies capable of supporting communications with multiple users by sharing available wireless communications system resources with those users.

Although wireless communications systems have made great technological advancements over many years, challenges still exist. For example, complex and dynamic environments can still attenuate or block signals between wireless transmitters and wireless receivers. Accordingly, there is a continuous desire to improve the technical performance of wireless communications systems, including, for example: improving speed and data carrying capacity of communications, improving efficiency of the use of shared communications mediums, reducing power used by transmitters and receivers while performing communications, improving reliability of wireless communications, avoiding redundant transmissions and/or receptions and related processing, improving the coverage area of wireless communications, increasing the number and types of devices that can access wireless communications systems, increasing the ability for different types of devices to intercommunicate, increasing the number and type of wireless communications mediums available for use, and the like. Consequently, there exists a need for further improvements in wireless communications systems to overcome the aforementioned technical challenges and others.

SUMMARY

One aspect provides a method for wireless communications at a user equipment (UE) . The method includes selecting a first number of spatial domain (SD) grids from a plurality of SD grids, wherein each SD grid of the plurality of SD grids comprises multiple SD bases; and transmitting an indication of the selected first number of SD grids to a network entity in a channel state information (CSI) report.

Another aspect provides a method for wireless communications at a network entity. The method includes transmitting at least one CSI-reference signal (RS) to a UE; and receiving a CSI report from the UE, in response to the at least one CSI-RS, indicating a selection of a first number of SD grids from a plurality of SD grids, wherein each SD grid of the plurality of SD grids comprises multiple SD bases.

Other aspects provide: an apparatus operable, configured, or otherwise adapted to perform the aforementioned methods as well as those described elsewhere herein; a non-transitory, computer-readable media comprising instructions that, when executed by a processor of an apparatus, cause the apparatus to perform the aforementioned methods as well as those described elsewhere herein; a computer program product embodied on a computer-readable storage medium comprising code for performing the aforementioned methods as well as those described elsewhere herein; and an apparatus comprising means for performing the aforementioned methods as well as those described elsewhere herein. By way of example, an apparatus may comprise a processing system, a device with a processing system, or processing systems cooperating over one or more networks.

The following description and the appended figures set forth certain features for purposes of illustration.

BRIEF DESCRIPTION OF DRAWINGS

The appended figures depict certain features of the various aspects described herein and are not to be considered limiting of the scope of this disclosure.

FIG. 1 depicts an example wireless communications network.

FIG. 2 depicts an example disaggregated base station (BS) architecture.

FIG. 3 depicts aspects of an example BS and an example user equipment (UE) .

FIG. 4A, FIG. 4B, FIG. 4C, and FIG. 4D depict various example aspects of data structures for a wireless communications network.

FIG. 5 depicts example frequency ranges and middle frequency bands.

FIG. 6A depicts example precoder matrices.

FIG. 6B depicts example content of enhanced type-II (eType-II) channel state information (CSI) .

FIG. 7 depicts example eType-II CSI.

FIG. 8 depicts example combinatorial coefficients.

FIG. 9 depicts a call flow diagram illustrating example communication among a UE and a network entity.

FIG. 10 depicts example scatters.

FIG. 11 depicts example spatial domain (SD) grids.

FIG. 12 depicts example SD basis indexes.

FIG. 13 depicts different SD grids.

FIG. 14 depicts example hybrid beamforming using digital and analog beams.

FIG. 15 depicts example amplitude and delay for a beam for a first subcarrier spacing (SCS) and a first bandwidth part (BWP) .

FIG. 16 depicts example amplitude and delay for a beam for a first SCS and a second BWP.

FIG. 17 depicts example amplitude and delay for a beam for a first SCS and a third BWP.

FIG. 18 depicts a method for wireless communications at a UE.

FIG. 19 depicts a method for wireless communications at a network entity.

FIG. 20 and FIG. 21 depict example communications devices.

DETAILED DESCRIPTION

Channel state information (CSI) indicates channel properties of a communication link. The CSI represents combined effects of, for example, scattering, fading, and power decay with a distance between a transmitter and a receiver. Channel estimation using pilots, such as CSI reference signals (CSI-RS) , may be performed to determine these effects on a channel. The CSI may be used to adapt transmissions based on current channel conditions, which is useful for achieving reliable communication, in particular, with high data rates in multi-antenna systems. The CSI is measured at the receiver, quantized, and fed back to the transmitter.

The CSI may include various parameters or metrics, such as a channel quality indicator (CQI) , precoding matrix indicator (PMI) , CSI reference signal (RS) resource indicator (CRI) , and rank indicator (RI) . The CSI may also include information associated with spatial domain (SD) beam selection (i.e., a subset of SD bases (beams) out of a total number of SD bases) . The total number of SD bases may be based on a number of antennas in horizontal and vertical directions of a panel. A value of the subset of SD bases may be determined based on combinatorial coefficients in a standards-defined table.

The combinatorial coefficients in the standards-defined table are applicable for devices with a limited number of antennas (i.e., the number of antennas in horizontal and vertical directions of a panel can at most be 16) . However, for the devices with a large number of antennas, the combinatorial coefficients in the standards-defined table may not be applicable.

Updating the current standard-defined table to support larger values of the number of antennas in the horizontal and vertical directions will make the standard-defined table too big. Since the current standard-defined table is firmware-based, which is embedded into a hardware of a chipset of a device, any increase in the size of the standard-defined table will require more memory and as a result larger chipset in the device.

Rather than conventional selection of the subset of SD bases, aspects of the present disclosure provide apparatuses, methods, processing systems, and computer-readable mediums for grid-based SD bases selection in a panel. For example, SD bases with consecutive indices in the panel may be aggregated as SD grids. That is, each SD grid may include multiple SD bases with the consecutive indices. A user equipment (UE) may select a subset of SD grids (as opposed to the subset of SD bases) from a set of SD grids. Since there is less number of SD grids than SD bases, the UE may still be able to use the combinatorial coefficients in the current standards-defined table to determine a value of the subset of SD grids. In some cases, within each SD grid of the subset of SD grids, the UE may also select one or more SD bases. The UE may generate and transmit a CSI report, which indicates the subset of SD grids and/or the one or more SD bases in each SD grid of the subset of SD grids.

Particular aspects of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. In some examples, the described techniques can be used to provide enhanced CSI report by devices with a larger number of antennas, without changing any hardware of the devices in order to provide information (e.g., SD beam selection information) in the CSI report.

Introduction to Wireless Communications Networks

The techniques and methods described herein may be used for various wireless communications networks. While aspects may be described herein using terminology commonly associated with 3G, 4G, and/or 5G wireless technologies, aspects of the present disclosure may likewise be applicable to other communications systems and standards not explicitly mentioned herein.

FIG. 1 depicts an example of a wireless communications network 100, in which aspects described herein may be implemented.

Generally, wireless communications network 100 includes various network entities (alternatively, network elements or network nodes) . A network entity is generally a communications device and/or a communications function performed by a communications device (e.g., a user equipment (UE) , a base station (BS) , a component of a BS, a server, etc. ) . For example, various functions of a network as well as various devices associated with and interacting with a network may be considered network entities. Further, wireless communications network 100 includes terrestrial aspects, such as ground-based network entities (e.g., BSs 102) , and non-terrestrial aspects, such as satellite 140 and aircraft 145, which may include network entities on-board (e.g., one or more BSs) capable of communicating with other network elements (e.g., terrestrial BSs) and UEs.

In the depicted example, wireless communications network 100 includes BSs 102, UEs 104, and one or more core networks, such as an Evolved Packet Core (EPC) 160 and 5G Core (5GC) network 190, which interoperate to provide communications services over various communications links, including wired and wireless links.

FIG. 1 depicts various example UEs 104, which may more generally include: a cellular phone, smart phone, session initiation protocol (SIP) phone, laptop, personal digital assistant (PDA) , satellite radio, global positioning system, multimedia device, video device, digital audio player, camera, game console, tablet, smart device, wearable device, vehicle, electric meter, gas pump, large or small kitchen appliance, healthcare device, implant, sensor/actuator, display, internet of things (IoT) devices, always on (AON) devices, edge processing devices, or other similar devices. UEs 104 may also be referred to more generally as a mobile device, a wireless device, a wireless communications device, a station, a mobile station, a subscriber station, a mobile subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a remote device, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, and others.

BSs 102 wirelessly communicate with (e.g., transmit signals to or receive signals from) UEs 104 via communications links 120. The communications links 120 between BSs 102 and UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a BS 102 and/or downlink (DL) (also referred to as forward link) transmissions from a BS 102 to a UE 104. The communications links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity in various aspects.

BSs 102 may generally include: a NodeB, enhanced NodeB (eNB) , next generation enhanced NodeB (ng-eNB) , next generation NodeB (gNB or gNodeB) , access point, base transceiver station, radio BS, radio transceiver, transceiver function, transmission reception point, and/or others. Each of BSs 102 may provide communications coverage for a respective geographic coverage area 110, which may sometimes be referred to as a cell, and which may overlap in some cases (e.g., small cell 102’ may have a coverage area 110’ that overlaps the coverage area 110 of a macro cell) . A BS may, for example, provide communications coverage for a macro cell (covering relatively large geographic area) , a pico cell (covering relatively smaller geographic area, such as a sports stadium) , a femto cell (relatively smaller geographic area (e.g., a home) ) , and/or other types of cells.

While BSs 102 are depicted in various aspects as unitary communications devices, BSs 102 may be implemented in various configurations. For example, one or more components of a BS 102 may be disaggregated, including a central unit (CU) , one or more distributed units (DUs) , one or more radio units (RUs) , a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC) , or a Non-Real Time (Non-RT) RIC, to name a few examples. In another example, various aspects of a BS 102 may be virtualized. More generally, a BS (e.g., BS 102) may include components that are located at a single physical location or components located at various physical locations. In examples in which a BS 102 includes components that are located at various physical locations, the various components may each perform functions such that, collectively, the various components achieve functionality that is similar to a BS 102 that is located at a single physical location. In some aspects, a BS 102 including components that are located at various physical locations may be referred to as a disaggregated radio access network (RAN) architecture, such as an Open RAN (O-RAN) or Virtualized RAN (VRAN) architecture. FIG. 2 depicts and describes an example disaggregated BS architecture.

Different BSs 102 within wireless communications network 100 may also be configured to support different radio access technologies, such as 3G, 4G, and/or 5G. For example, BSs 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) ) may interface with the EPC 160 through first backhaul links 132 (e.g., an S1 interface) . BSs 102 configured for 5G (e.g., 5G NR or Next Generation RAN (NG-RAN) ) may interface with 5GC 190 through second backhaul links 184. BSs 102 may communicate directly or indirectly (e.g., through the EPC 160 or 5GC 190) with each other over third backhaul links 134 (e.g., X2 interface) , which may be wired or wireless.

Wireless communications network 100 may subdivide the electromagnetic spectrum into various classes, bands, channels, or other features. In some aspects, the subdivision is provided based on wavelength and frequency, where frequency may also be referred to as a carrier, a subcarrier, a frequency channel, a tone, or a subband. For example, 3GPP currently defines Frequency Range 1 (FR1) as including 600 MHz –6 GHz, which is often referred to (interchangeably) as “Sub-6 GHz” . Similarly, 3GPP currently defines Frequency Range 2 (FR2) as including 26 –41 GHz, which is sometimes referred to (interchangeably) as a “millimeter wave” ( “mmW” or “mmWave” ) . A BS configured to communicate using mmWave/near mmWave radio frequency bands (e.g., a mmWave BS such as BS 180) may utilize beamforming (e.g., 182) with a UE (e.g., 104) to improve path loss and range.

The communications links 120 between BSs 102 and, for example, UEs 104, may be through one or more carriers, which may have different bandwidths (e.g., 5, 10, 15, 20, 100, 400, and/or other MHz) , and which may be aggregated in various aspects. Carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL than for UL) .

Communications using higher frequency bands may have higher path loss and a shorter range compared to lower frequency communications. Accordingly, certain BSs (e.g., 180 in FIG. 1) may utilize beamforming 182 with a UE 104 to improve path loss and range. For example, BS 180 and the UE 104 may each include a plurality of antennas, such as antenna elements, antenna panels, and/or antenna arrays to facilitate the beamforming. In some cases, BS 180 may transmit a beamformed signal to UE 104 in one or more transmit directions 182’. UE 104 may receive the beamformed signal from the BS 180 in one or more receive directions 182”. UE 104 may also transmit a beamformed signal to the BS 180 in one or more transmit directions 182”. BS 180 may also receive the beamformed signal from UE 104 in one or more receive directions 182’. BS 180 and UE 104 may then perform beam training to determine the best receive and transmit directions for each of BS 180 and UE 104. Notably, the transmit and receive directions for BS 180 may or may not be the same. Similarly, the transmit and receive directions for UE 104 may or may not be the same.

Wireless communications network 100 further includes a Wi-Fi AP 150 in communication with Wi-Fi stations (STAs) 152 via communications links 154 in, for example, a 2.4 GHz and/or 5 GHz unlicensed frequency spectrum.

Certain UEs 104 may communicate with each other using device-to-device (D2D) communications link 158. D2D communications link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , a physical sidelink control channel (PSCCH) , and/or a physical sidelink feedback channel (PSFCH) .

EPC 160 may include various functional components, including: a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and/or a Packet Data Network (PDN) Gateway 172, such as in the depicted example. MME 162 may be in communication with a Home Subscriber Server (HSS) 174. MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, MME 162 provides bearer and connection management.

Generally, user Internet protocol (IP) packets are transferred through Serving Gateway 166, which itself is connected to PDN Gateway 172. PDN Gateway 172 provides UE IP address allocation as well as other functions. PDN Gateway 172 and the BM-SC 170 are connected to IP Services 176, which may include, for example, the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a Packet Switched (PS) streaming service, and/or other IP services.

BM-SC 170 may provide functions for MBMS user service provisioning and delivery. BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and/or may be used to schedule MBMS transmissions. MBMS Gateway 168 may be used to distribute MBMS traffic to the BSs 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and/or may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

5GC 190 may include various functional components, including: an Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. AMF 192 may be in communication with Unified Data Management (UDM) 196.

AMF 192 is a control node that processes signaling between UEs 104 and 5GC 190. AMF 192 provides, for example, quality of service (QoS) flow and session management.

Internet protocol (IP) packets are transferred through UPF 195, which is connected to the IP Services 197, and which provides UE IP address allocation as well as other functions for 5GC 190. IP Services 197 may include, for example, the Internet, an intranet, an IMS, a PS streaming service, and/or other IP services.

Wireless communication network 100 further includes spatial domain (SD) component 198, which may be configured to perform method 1800 of FIG. 18. Wireless communication network 100 further includes SD component 199, which may be configured to perform method 1900 of FIG. 19.

In various aspects, a network entity or network node can be implemented as an aggregated BS, as a disaggregated BS, a component of a BS, an integrated access and backhaul (IAB) node, a relay node, a sidelink node, to name a few examples.

FIG. 2 depicts an example disaggregated BS 200 architecture. The disaggregated BS 200 architecture may include one or more central units (CUs) 210 that can communicate directly with a core network 220 via a backhaul link, or indirectly with the core network 220 through one or more disaggregated BS units (such as a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC) 225 via an E2 link, or a Non-Real Time (Non-RT) RIC 215 associated with a Service Management and Orchestration (SMO) Framework 205, or both) . A CU 210 may communicate with one or more distributed units (DUs) 230 via respective midhaul links, such as an F1 interface. The DUs 230 may communicate with one or more radio units (RUs) 240 via respective fronthaul links. The RUs 240 may communicate with respective UEs 104 via one or more radio frequency (RF) access links. In some implementations, the UE 104 may be simultaneously served by multiple RUs 240.

Each of the units, e.g., the CUs 210, the DUs 230, the RUs 240, as well as the Near-RT RICs 225, the Non-RT RICs 215 and the SMO Framework 205, may include one or more interfaces or be coupled to one or more interfaces configured to receive or transmit signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of the units, or an associated processor or controller providing instructions to the communications interfaces of the units, can be configured to communicate with one or more of the other units via the transmission medium. For example, the units can include a wired interface configured to receive or transmit signals over a wired transmission medium to one or more of the other units. Additionally or alternatively, the units can include a wireless interface, which may include a receiver, a transmitter or transceiver (such as a radio frequency (RF) transceiver) , configured to receive or transmit signals, or both, over a wireless transmission medium to one or more of the other units.

In some aspects, the CU 210 may host one or more higher layer control functions. Such control functions can include radio resource control (RRC) , packet data convergence protocol (PDCP) , service data adaptation protocol (SDAP) , or the like. Each control function can be implemented with an interface configured to communicate signals with other control functions hosted by the CU 210. The CU 210 may be configured to handle user plane functionality (e.g., Central Unit –User Plane (CU-UP) ) , control plane functionality (e.g., Central Unit –Control Plane (CU-CP) ) , or a combination thereof. In some implementations, the CU 210 can be logically split into one or more CU-UP units and one or more CU-CP units. The CU-UP unit can communicate bidirectionally with the CU-CP unit via an interface, such as the E1 interface when implemented in an O-RAN configuration. The CU 210 can be implemented to communicate with the DU 230, as necessary, for network control and signaling.

The DU 230 may correspond to a logical unit that includes one or more BS functions to control the operation of one or more RUs 240. In some aspects, the DU 230 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, or the like) depending, at least in part, on a functional split, such as those defined by the 3^rd Generation Partnership Project (3GPP) . In some aspects, the DU 230 may further host one or more low PHY layers. Each layer (or module) can be implemented with an interface configured to communicate signals with other layers (and modules) hosted by the DU 230, or with the control functions hosted by the CU 210.

Lower-layer functionality can be implemented by one or more RUs 240. In some deployments, an RU 240, controlled by a DU 230, may correspond to a logical node that hosts RF processing functions, or low-PHY layer functions (such as performing fast Fourier transform (FFT) , inverse FFT (iFFT) , digital beamforming, physical random access channel (PRACH) extraction and filtering, or the like) , or both, based at least in part on the functional split, such as a lower layer functional split. In such an architecture, the RU (s) 240 can be implemented to handle over the air (OTA) communications with one or more UEs 104. In some implementations, real-time and non-real-time aspects of control and user plane communications with the RU (s) 240 can be controlled by the corresponding DU 230. In some scenarios, this configuration can enable the DU (s) 230 and the CU 210 to be implemented in a cloud-based RAN architecture, such as a vRAN architecture.

The SMO Framework 205 may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements. For non-virtualized network elements, the SMO Framework 205 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements which may be managed via an operations and maintenance interface (such as an O1 interface) . For virtualized network elements, the SMO Framework 205 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 290) to perform network element life cycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an O2 interface) . Such virtualized network elements can include, but are not limited to, CUs 210, DUs 230, RUs 240 and Near-RT RICs 225. In some implementations, the SMO Framework 205 can communicate with a hardware aspect of a 4G RAN, such as an open eNB (O-eNB) 211, via an O1 interface. Additionally, in some implementations, the SMO Framework 205 can communicate directly with one or more RUs 240 via an O1 interface. The SMO Framework 205 also may include a Non-RT RIC 215 configured to support functionality of the SMO Framework 205.

The Non-RT RIC 215 may be configured to include a logical function that enables non-real-time control and optimization of RAN elements and resources, Artificial Intelligence/Machine Learning (AI/ML) workflows including model training and updates, or policy-based guidance of applications/features in the Near-RT RIC 225. The Non-RT RIC 215 may be coupled to or communicate with (such as via an A1 interface) the Near-RT RIC 225. The Near-RT RIC 225 may be configured to include a logical function that enables near-real-time control and optimization of RAN elements and resources via data collection and actions over an interface (such as via an E2 interface) connecting one or more CUs 210, one or more DUs 230, or both, as well as an O-eNB, with the Near-RT RIC 225.

In some implementations, to generate AI/ML models to be deployed in the Near-RT RIC 225, the Non-RT RIC 215 may receive parameters or external enrichment information from external servers. Such information may be utilized by the Near-RT RIC 225 and may be received at the SMO Framework 205 or the Non-RT RIC 215 from non-network data sources or from network functions. In some examples, the Non-RT RIC 215 or the Near-RT RIC 225 may be configured to tune RAN behavior or performance. For example, the Non-RT RIC 215 may monitor long-term trends and patterns for performance and employ AI/ML models to perform corrective actions through the SMO Framework 205 (such as reconfiguration via O1) or via creation of RAN management policies (such as A1 policies) .

FIG. 3 depicts aspects of an example BS 102 and a UE 104.

Generally, BS 102 includes various processors (e.g., 320, 330, 338, and 340) , antennas 334a-t (collectively 334) , transceivers 332a-t (collectively 332) , which include modulators and demodulators, and other aspects, which enable wireless transmission of data (e.g., data source 312) and wireless reception of data (e.g., data sink 339) . For example, BS 102 may send and receive data between BS 102 and UE 104. BS 102 includes controller/processor 340, which may be configured to implement various functions described herein related to wireless communications.

BS 102 includes controller/processor 340, which may be configured to implement various functions related to wireless communications. In the depicted example, controller/processor 340 includes SD component 341, which may be representative of SD component 199 of FIG. 1. Notably, while depicted as an aspect of controller/processor 340, SD component 341 may be implemented additionally or alternatively in various other aspects of BS 102 in other implementations.

Generally, UE 104 includes various processors (e.g., 358, 364, 366, and 380) , antennas 352a-r (collectively 352) , transceivers 354a-r (collectively 354) , which include modulators and demodulators, and other aspects, which enable wireless transmission of data (e.g., retrieved from data source 362) and wireless reception of data (e.g., provided to data sink 360) . UE 104 includes controller/processor 380, which may be configured to implement various functions described herein related to wireless communications.

UE 104 includes controller/processor 380, which may be configured to implement various functions related to wireless communications. In the depicted example, controller/processor 380 includes SD component 381, which may be representative of SD component 198 of FIG. 1. Notably, while depicted as an aspect of controller/processor 380, SD component 381 may be implemented additionally or alternatively in various other aspects of UE 104 in other implementations.

In regards to an example downlink transmission, BS 102 includes a transmit processor 320 that may receive data from a data source 312 and control information from a controller/processor 340. The control information may be for the physical broadcast channel (PBCH) , physical control format indicator channel (PCFICH) , physical HARQ indicator channel (PHICH) , physical downlink control channel (PDCCH) , group common PDCCH (GC PDCCH) , and/or others. The data may be for the physical downlink shared channel (PDSCH) , in some examples.

Transmit processor 320 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. Transmit processor 320 may also generate reference symbols, such as for the primary synchronization signal (PSS) , secondary synchronization signal (SSS) , PBCH demodulation reference signal (DMRS) , and channel state information reference signal (CSI-RS) .

Transmit (TX) multiple-input multiple-output (MIMO) processor 330 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs) in transceivers 332a-332t. Each modulator in transceivers 332a-332t may process a respective output symbol stream to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from the modulators in transceivers 332a-332t may be transmitted via the antennas 334a-334t, respectively.

In order to receive the downlink transmission, UE 104 includes antennas 352a-352r that may receive the downlink signals from the BS 102 and may provide received signals to the demodulators (DEMODs) in transceivers 354a-354r, respectively. Each demodulator in transceivers 354a-354r may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator may further process the input samples to obtain received symbols.

MIMO detector 356 may obtain received symbols from all the demodulators in transceivers 354a-354r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. Receive processor 358 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 104 to a data sink 360, and provide decoded control information to a controller/processor 380.

In regards to an example uplink transmission, UE 104 further includes a transmit processor 364 that may receive and process data (e.g., for the PUSCH) from a data source 362 and control information (e.g., for the physical uplink control channel (PUCCH) ) from the controller/processor 380. Transmit processor 364 may also generate reference symbols for a reference signal (e.g., for the sounding reference signal (SRS) ) . The symbols from the transmit processor 364 may be precoded by a TX MIMO processor 366 if applicable, further processed by the modulators in transceivers 354a-354r (e.g., for SC-FDM) , and transmitted to BS 102.

At BS 102, the uplink signals from UE 104 may be received by antennas 334a-t, processed by the demodulators in transceivers 332a-332t, detected by a MIMO detector 336 if applicable, and further processed by a receive processor 338 to obtain decoded data and control information sent by UE 104. Receive processor 338 may provide the decoded data to a data sink 339 and the decoded control information to the controller/processor 340.

Memories 342 and 382 may store data and program codes for BS 102 and UE 104, respectively.

Scheduler 344 may schedule UEs for data transmission on the downlink and/or uplink.

In various aspects, BS 102 may be described as transmitting and receiving various types of data associated with the methods described herein. In these contexts, “transmitting” may refer to various mechanisms of outputting data, such as outputting data from data source 312, scheduler 344, memory 342, transmit processor 320, controller/processor 340, TX MIMO processor 330, transceivers 332a-t, antenna 334a-t, and/or other aspects described herein. Similarly, “receiving” may refer to various mechanisms of obtaining data, such as obtaining data from antennas 334a-t, transceivers 332a-t, RX MIMO detector 336, controller/processor 340, receive processor 338, scheduler 344, memory 342, and/or other aspects described herein.

In various aspects, UE 104 may likewise be described as transmitting and receiving various types of data associated with the methods described herein. In these contexts, “transmitting” may refer to various mechanisms of outputting data, such as outputting data from data source 362, memory 382, transmit processor 364, controller/processor 380, TX MIMO processor 366, transceivers 354a-t, antenna 352a-t, and/or other aspects described herein. Similarly, “receiving” may refer to various mechanisms of obtaining data, such as obtaining data from antennas 352a-t, transceivers 354a-t, RX MIMO detector 356, controller/processor 380, receive processor 358, memory 382, and/or other aspects described herein.

In some aspects, a processor may be configured to perform various operations, such as those associated with the methods described herein, and transmit (output) to or receive (obtain) data from another interface that is configured to transmit or receive, respectively, the data.

FIG. 4A, FIG. 4B, FIG. 4C, and FIG. 4D depict aspects of data structures for a wireless communications network, such as wireless communications network 100 of FIG. 1.

In particular, FIG. 4A is a diagram 400 illustrating an example of a first subframe within a 5G (e.g., 5G NR) frame structure, FIG. 4B is a diagram 430 illustrating an example of DL channels within a 5G subframe, FIG. 4C is a diagram 450 illustrating an example of a second subframe within a 5G frame structure, and FIG. 4D is a diagram 480 illustrating an example of UL channels within a 5G subframe.

Wireless communications systems may utilize orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) on the uplink and downlink. Such systems may also support half-duplex operation using time division duplexing (TDD) . OFDM and single-carrier frequency division multiplexing (SC-FDM) partition the system bandwidth (e.g., as depicted in FIG. 4B and FIG. 4D) into multiple orthogonal subcarriers. Each subcarrier may be modulated with data. Modulation symbols may be sent in the frequency domain with OFDM and/or in the time domain with SC-FDM.

A wireless communications frame structure may be frequency division duplex (FDD) , in which, for a particular set of subcarriers, subframes within the set of subcarriers are dedicated for either DL or UL. Wireless communications frame structures may also be time division duplex (TDD) , in which, for a particular set of subcarriers, subframes within the set of subcarriers are dedicated for both DL and UL.

In FIG. 4A and 4C, the wireless communications frame structure is TDD where D is DL, U is UL, and X is flexible for use between DL/UL. UEs may be configured with a slot format through a received slot format indicator (SFI) (dynamically through DL control information (DCI) , or semi-statically/statically through radio resource control (RRC) signaling) . In the depicted examples, a 10 ms frame is divided into 10 equally sized 1 ms subframes. Each subframe may include one or more time slots. In some examples, each slot may include 7 or 14 symbols, depending on the slot format. Subframes may also include mini-slots, which generally have fewer symbols than an entire slot. Other wireless communications technologies may have a different frame structure and/or different channels.

In certain aspects, the number of slots within a subframe is based on a slot configuration and a numerology. For example, for slot configuration 0, different numerologies (μ) 0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots, respectively, per subframe. For slot configuration 1, different numerologies 0 to 2 allow for 2, 4, and 8 slots, respectively, per subframe. Accordingly, for slot configuration 0 and numerology μ, there are 14 symbols/slot and 2μ slots/subframe. The subcarrier spacing and symbol length/duration are a function of the numerology. The subcarrier spacing may be equal to 2^μ×15 kHz, where μ is the numerology 0 to 5. As such, the numerology μ=0 has a subcarrier spacing of 15 kHz and the numerology μ=5 has a subcarrier spacing of 480 kHz. The symbol length/duration is inversely related to the subcarrier spacing. FIG. 4A, FIG. 4B, FIG. 4C, and FIG. 4D provide an example of slot configuration 0 with 14 symbols per slot and numerology μ=2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs.

As depicted in FIG. 4A, FIG. 4B, FIG. 4C, and FIG. 4D, a resource grid may be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as physical RBs (PRBs) ) that extends, for example, 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs) . The number of bits carried by each RE depends on the modulation scheme.

As illustrated in FIG. 4A, some of the REs carry reference (pilot) signals (RS) for a UE (e.g., UE 104 of FIG. 1 and FIG. 3) . The RS may include demodulation RS (DMRS) and/or channel state information reference signals (CSI-RS) for channel estimation at the UE. The RS may also include beam measurement RS (BRS) , beam refinement RS (BRRS) , and/or phase tracking RS (PT-RS) .

FIG. 4B illustrates an example of various DL channels within a subframe of a frame. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) , each CCE including, for example, nine RE groups (REGs) , each REG including, for example, four consecutive REs in an OFDM symbol.

A primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE (e.g., 104 of FIG. 1 and FIG. 3) to determine subframe/symbol timing and a physical layer identity.

A secondary synchronization signal (SSS) may be within symbol 4 of particular subframes of a frame. The SSS is used by a UE to determine a physical layer cell identity group number and radio frame timing.

Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI) . Based on the PCI, the UE can determine the locations of the aforementioned DMRS. The physical broadcast channel (PBCH) , which carries a master information block (MIB) , may be logically grouped with the PSS and SSS to form a synchronization signal (SS) /PBCH block. The MIB provides a number of RBs in the system bandwidth and a system frame number (SFN) . The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs) , and/or paging messages.

As illustrated in FIG. 4C, some of the REs carry DMRS (indicated as R for one particular configuration, but other DMRS configurations are possible) for channel estimation at the BS. The UE may transmit DMRS for the PUCCH and DMRS for the PUSCH. The PUSCH DMRS may be transmitted, for example, in the first one or two symbols of the PUSCH. The PUCCH DMRS may be transmitted in different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used. UE 104 may transmit sounding reference signals (SRS) . The SRS may be transmitted, for example, in the last symbol of a subframe. The SRS may have a comb structure, and a UE may transmit SRS on one of the combs. The SRS may be used by a BS for channel quality estimation to enable frequency-dependent scheduling on the UL.

FIG. 4D illustrates an example of various UL channels within a subframe of a frame. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI) , such as scheduling requests, a channel quality indicator (CQI) , a precoding matrix indicator (PMI) , a rank indicator (RI) , and HARQ ACK/NACK feedback. The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR) , a power headroom report (PHR) , and/or UCI.

Introduction to mmWave Wireless Communications

In wireless communications, an electromagnetic spectrum is often subdivided into various classes, bands, channels, or other features. The subdivision is often provided based on wavelength and frequency, where frequency may also be referred to as a carrier, a subcarrier, a frequency channel, a tone, or a subband.

5^th generation (5G) networks may utilize several frequency ranges, which in some cases are defined by a standard, such as 3rd generation partnership project (3GPP) standards. For example, 3GPP technical standard TS 38.101 currently defines Frequency Range 1 (FR1) as including 600 MHz –6 GHz, though specific uplink and downlink allocations may fall outside of this general range. Thus, FR1 is often referred to (interchangeably) as a “Sub-6 GHz” band.

Similarly, TS 38.101 currently defines Frequency Range 2 (FR2) as including 26 –41 GHz, though again specific uplink and downlink allocations may fall outside of this general range. FR2, is sometimes referred to (interchangeably) as a “millimeter wave” ( “mmW” or “mmWave” ) band, despite being different from the extremely high frequency (EHF) band (30 GHz –300 GHz) that is identified by the International Telecommunications Union (ITU) as a “millimeter wave” band because wavelengths at these frequencies are between 1 millimeter and 10 millimeters.

Communications using mmWave/near mmWave radio frequency band (e.g., 3 GHz –300 GHz) may have higher path loss and a shorter range compared to lower frequency communications. As described above with respect to FIG. 1, a base station (BS) (e.g., 180) configured to communicate using mmWave/near mmWave radio frequency bands may utilize beamforming (e.g., 182) with a user equipment (UE) (e.g., 104) to improve path loss and range.

Overview of Massive Multiple Input Multiple Output (MIMO)

Multiple input multiple output (MIMO) is an antenna technology that focuses energy of a signal at a receiver. The technology involves mathematical algorithms that combine a strength of a radiation from multiple antennas. With the MIMO, the multiple antennas carry multiple data streams over a same frequency, and a transmission band subdivides into several different channels, or spaces, to carry data.

Massive MIMO extends capabilities of the MIMO and has to do with a number of antennas involved with signal transmission and reception. For example, the massive MIMO essentially groups together a larger number of antennas at a transmitter and the receiver to provide better throughput and better spectrum efficiency. To achieve the massive MIMO capacity gain, multiple user equipments (UEs) may generate downlink traffic simultaneously. Many variables may impact an actual gain provided by the massive MIMO.

Overview of Channel State Information (CSI)

Time and frequency resources that can be used by a user equipment (UE) to report the CSI are controlled by a base station (BS) (e.g., gNB) . The CSI may include channel quality indicator (CQI) , precoding matrix indicator (PMI) , CSI-RS resource indicator (CRI) , SS/PBCH Block Resource indicator (SSBRI) , layer indicator (LI) , rank indicator (RI) and/or L1 reference signal received power (RSRP) . However, as described below, additional or other information may be included in the CSI.

The UE may be configured by the BS for CSI reporting. For example, the BS configures the UE with a CSI report configuration or with multiple CSI report configurations. The CSI report configuration may be provided to the UE via higher layer signaling, such as radio resource control (RRC) signaling (e.g., CSI-ReportConfig) . The CSI report configuration may be associated with CSI-RS resources for channel measurement (CM) , interference measurement (IM) , or both. The CSI report configuration configures the CSI-RS resources for the CSI measurement (e.g., CSI-ResourceConfig) . The CSI-RS resources provide the UE with the configuration of CSI-RS ports, or CSI-RS port groups, mapped to time and frequency resources (e.g., resource elements (REs) ) . The CSI-RS resources can be zero power (ZP) or non-zero power (NZP) resources. At least one NZP CSI-RS resource may be configured for the CM.

The CSI report configuration may configure the UE for aperiodic, periodic, or semi-persistent CSI reporting. For periodic CSI, the UE may be configured with periodic CSI-RS resources. Periodic CSI on a physical uplink control channel (PUCCH) may be triggered via an RRC. Semi-persistent CSI reporting on the PUCCH may be activated via a medium access control (MAC) control element (CE) . For aperiodic and semi-persistent CSI on a physical uplink shared channel (PUSCH) , the BS may signal the UE a CSI report trigger indicating for the UE to send a CSI report for one or more CSI-RS resources, or configuring the CSI-RS report trigger state (e.g., CSI-AperiodicTriggerStateList and CSI-SemiPersistentOnPUSCH-TriggerStateList) . The CSI report trigger for aperiodic CSI and semi-persistent CSI on PUSCH may be provided via downlink control information (DCI) .

The UE may report a CSI feedback (CSF) based on the CSI report configuration and the CSI report trigger. For example, the UE may measure the channel on which the triggered CSI-RS resources (e.g., associated with the CSI report configuration) is conveyed. Based on the measurements, the UE may select a preferred CSI-RS resource. The UE reports the CSF for the selected CSI-RS resource.

Each CSI report configuration may be associated with a single downlink (DL) bandwidth part (BWP) . The CSI report setting configuration may define a CSI reporting band as a subset of subbands of the BWP. The associated DL BWP may indicated by a higher layer parameter (e.g., bwp-Id) in the CSI report configuration for the CM and contains parameter (s) for one CSI reporting band, such as codebook configuration, time-domain behavior, frequency granularity for the CSI, measurement restriction configurations, and the CSI-related quantities to be reported by the UE. Each CSI resource setting may be located in the DL BWP identified by the higher layer parameter, and all CSI resource settings may be linked to a CSI report setting have the same DL BWP.

In certain systems, the UE can be configured via a higher layer signaling (e.g., in the CSI report configuration) with one out of two possible subband sizes (e.g., reportFreqConfiguration contained in a CSI-ReportConfig) which indicates a frequency granularity of the CSI report, where a subband may be defined as contiguous physical resource blocks (PRBs) and depends on a total number of PRBs in the BWP. The UE may further receive an indication of the subbands for which the CSI feedback is requested. In some examples, a subband mask is configured for the requested subbands for CSI reporting. The UE computes precoders for each requested subband and finds a precoding matrix indicator (PMI) that matches a computed precoder on each of the subbands.

In 5G new radio (NR) massive multiple input multiple output (MIMO) , CSI (i.e., digital beamforming) supports at most 32 antenna ports. In (a low-band) Frequency Range 1 (FR1) , only small number of antenna ports may be used (e.g., due to some limitation is an antenna array size (e.g., based on a form factor) ) . In Frequency Range 2 (FR2) too, a small number of antenna ports (e.g. 2 or 4-ports) may be used to limit the antenna hardware cost. In some cases, the small number of antenna ports are used since the small number of antenna ports work fine under narrow analog beams implemented with a large phased antenna array (e.g., with 1024 antenna elements) .

In some middle frequency bands (e.g., higher FR1 (e.g. 3 –6GHz) or Frequency Range 3 (FR2) (7 –24GHz) ) as depicted in a diagram 500 of FIG. 5, a large number of antenna ports may be used. In some cases, the middle frequency bands may support much a larger number of antenna ports (e.g., more than 32 antenna ports) . For example, a 128-TXRU with 64-port or 128-port CSI-RS may be supported. In some cases, the middle frequency bands may be deployed with more than one analog beam (e.g., four or more beams) for hybrid beamforming.

Overview of Channel State Information (CSI) Feedback Coefficient Reporting

A user equipment (UE) may be configured for channel state information (CSI) reporting, for example, by receiving a CSI configuration message from a base station (BS) . In some cases, the UE may be configured to report at least a Type II precoder across configured frequency domain (FD) units. For example, a precoder matrix W_r for layer r includes W₁ matrix, reporting a subest of selected beams using spatial compression and W_2, r matrix, reporting (for cross-polarization) linear combination coefficients for selected beams (2L) across configured FD units:

where

where b_i is a selected beam, c_i is a set of linear combination coefficients (i.e., entries of W_2, r matrix) , L is a number of selected spatial beams, and N₃ corresponds to a number of frequency units (e.g., subbands, resource blocks (RBs) , etc. ) . In certain configurations, L is radio resource control (RRC) configured. The precoder is based on a linear combination of digital fourier transform (DFT) beams. The Type II codebook may improve multi-user (MU) multiple input multiple output (MIMO) performance. In some configurations considering there are two polarizations, the W_2, r matrix has size 2L X N₃.

In some cases, the UE may be configured to report FD compressed precoder feedback to reduce overhead of a CSI report. As depicted in FIG. 6A, a precoder matrix (W_2, i) for layer i with i=0, 1 may use an FD compressionmatrix to compress the precoder matrix intomatrix size to 2L X M (where M is network configured and communicated in a CSI configuration message via an RRC or downlink control information (DCI) , and M < N₃) given as:

Where the precoder matrix W_i (not shown) has P = 2N₁N₂ rows (spatial domain, number of ports) and N₃ columns (frequency-domain compression unit containing RBs or reporting sub-bands) , and where M bases are selected for each of layer 0 and layer 1 independently. Thematrix 620 consists of linear combination coefficients (amplitude and co-phasing) , where each element represents a coefficient of a tap for a beam. Thematrix 620 is defined by size 2L X M, where one row corresponds to one spatial beam in W₁ (not shown) of size P X 2L (where L is network entity configured via an RRC) , and one entry therein represents a coefficient of one tap for this spatial beam. The UE may be configured to report (e.g., CSI report) a subset K₀ < 2LM of the linear combination coefficients of thematrix 620. For example, the UE may report K_NZ, i <K₀ coefficients (e.g., where K_NZ, i corresponds to a maximum number of non-zero coefficients for layer-i with i=0 or 1, and K₀ is network configured via RRC) illustrated as shaded squares (e.g., unreported coefficients are set to zero) . In some configurations, an entry in thematrix 620 corresponds to a row ofmatrix 630. In the example shown, both thematrix 620 at layer 0 and thematrix 640 at layer 1 are 2L X M.

Thematrix 630 is composed of the basis vectors (e.g., each row is a basis vector) used to perform compression in FD. In the example shown, both thematrix 630 at layer 0 and thematrix 660 at layer 1 include M=4 FD basis (e.g., illustrated as shaded rows) from N₃ candidate DFT basis. In some configurations, the UE may report a subset of selected basis of thematrix via the CSI report. The M bases specifically selected at layer 0 and layer 1. That is, the M bases selected at layer 0 can be same/partially-overlapped/non-overlapped with the M bases selected at layer 1.

Overview of User Equipment (UE) Precoding Matrix Indicator (PMI) Codebook-based Channel State Feedback (CSF)

A precoding matrix indicator (PMI) codebook refers to a dictionary of PMI entries. In this way, using a PMI codebook, each PMI component from a pre-defined set can be mapped to bit-sequences reported by a user equipment (UE) . A base station (BS) receiving a bit-sequence (e.g., as a channel state feedback (CSF) ) can then obtain a corresponding PMI from the reported bit-sequence.

How the UE calculates the PMI may be left to the UE implementation. However, how the UE reports the PMI should follow a format defined in the codebook, so the UE and the BS each know how to map PMI components to reported bit-sequences.

FIG. 6B depicts an example 670 for enhanced Type-II (eType-II) channel state information (CSI) . In this example 670, for each layer, a precoder across a number of N₃ (PMI-) subbands is a N_t×N₃ matrix:

where spatial domain (SD) bases W₁ (e.g., direct fourier transform (DFT) bases) is a N_t×2L matrix, W₁ is layer-common, N_t=2N₁O₁N₂O₂ (e.g., a number of Tx antennas –with O₁ and O₂ DFT oversampling) is radio resource control (RRC) configured, L= {2, 4, 6} (e.g., a number of beams) is RRC-configured, frequency domain (FD) bases W_f (e.g., DFT bases) is a M×N₃ matrix, W_f is layer-specific, M (e.g., a number of FD bases) is rank-pair specific, i.e. M₁=M₂ for rank= {1, 2} , and M₃=M₄ for rank= {3, 4} , M₁ or M₃ is RRC-configured. Coefficients matrixis a 2L×M matrix and is layer-specific. For each layer, a UE may report up to K₀ non-zero coefficients, where K₀ is RRC-configured. Across all layers, the UE may report up to 2K₀ non-zero coefficients, where unreported coefficients may be set to zeros.

Overview of Channel State Information (CSI) Content

Channel state information (CSI) report configuration can also configure CSI parameters (sometimes referred to as quantities) to be reported. Codebooks may include Type I single panel, Type I multi-panel, and Type II single panel. Regardless which codebook is used, a CSI report may include at least channel quality indicator (CQI) , precoding matrix indicator (PMI) , CSI reference signal (RS) resource indicator (CRI) , and rank indicator (RI) . The structure of the PMI may vary based on the codebook.

In some cases, the CSI report is divided into two parts due to a large payload size. For example, the CRI, the RI, and the CQI may be in a first part (Part I) of the CSI report and the PMI may be in a second part (Part II) of the CSI report.

For the Type I single panel codebook, the PMI may include a W1 matrix (e.g., a subest of beams) and a W2 matrix (e.g., a phase for cross polarization combination and beam selection) . For the Type I multi-panel codebook, compared to type I single panel codebook, the PMI further comprises a phase for cross panel combination. A base station (BS) may have a plurality of transmit (TX) beams. A user equipment (UE) can feed back to the BS an index of a preferred beam, or beams, of the candidate beams. For example, the UE may feed back a precoding vector w for l-th layer:

, where b represents the oversampled beam (e.g., discrete Fourier transform (DFT) beam) , for both polarizations, andis the co-phasing.

For the Type II codebook (e.g., which may be designed for a single panel) , the PMI is a linear combination of beams; it has a subset of orthogonal beams to be used for linear combination and has per layer, per polarization, amplitude and phase for each beam. The preferred precoder for a layer can be a combination of beams and associated quantized coefficients, and the UE can feedback the selected beams and the coefficients to the BS.

The UE may report a CSI feedback based on the CSI report configuration and a CSI report trigger. For example, the UE may measure a channel associated with the CSI for triggered CSI-RS resources. Based on the measurements, the UE may select a preferred CSI-RS resource. The UE reports the CSI feedback for the selected CSI-RS resource. The CQI may be calculated conditioned on the reported PMI, RI and CRI; the PMI may be calculated conditioned on the reported RI and CRI; and the RI may be calculated conditioned on the reported CRI.

FIG. 7 depicts content of a CSI report 700. The CSI report 700 includes a first part and a second part. The first part of the CSI report may have a fixed payload size (e.g., which may be smaller than the second part of the CSI report) and is transmitted with a higher reliability. A BS is able to determine a larger payload size of the second part of the CSI report, based on decoding of the first part of the CSI report.

The first part of the CSI report indicates RI, CQI, and a number of non-zero coefficients (NZCs) (e.g., indicating a total number of NZCs across all layers) . The RI and the NZCs may be used to determine the payload size of the second part of the CSI report.

The second part of the CSI report includes one or more fields to indicate spatial domain (SD) beam selection, frequency domain (FD) basis selection for different layers, strongest coefficient indication (SCI) for the different layers, coefficient bitmap selection for the different layers, and quantization of NZCs for the different layers. For example, the second part of the CSI report may include a field indicating the SD beam selection. The field indicates L number of SD bases (beams) out of N₁N₂ O₁O₂ total SD bases. N₁, N₂ is determined by a number of antennas in horizontal and vertical directions of a panel. O1, O2 indicates direct fourier transform (DFT) oversampling. O1 determines a sweeping step in a horizontal direction and O2 determines a sweeping step in a vertical direction. In some cases, the higher O1, O2 is, a beam can be sweeped in smaller step (i.e., a finer angle) .

In some cases, a process of combinatorial selection of the L number of SD bases/beams (e.g., out of total N₁N₂ SD bases) is hard-coded based on a standard-defined combinatorial coefficients table (e.g., as depicted in a diagram 800 of FIG. 8) for SD bases. As depicted in the table of FIG. 8, a value of N₁N₂ can be at most 16 and a value of L can be at most 6.

In massive multiple input multiple output (MIMO) systems with a large number of antenna ports (e.g., 128 port) , a value of N₁N₂ may also be higher (e.g., 64) . This high value of N₁N₂ is not supported in a current standard-defined table where the value of the N₁N₂ is at most 16. Also, in such cases, the L number of SD bases/beams being selected may also need to be larger (e.g., than at most 6 supported in the current standard-defined table) , since every beam may be narrower due to a larger number of antenna ports, and thus every beam is associated with fewer propagation paths.

In some cases, updating the current standard-defined table to support larger values of the N₁N₂ and the L will make the standard-defined table too big. Since the current standard-defined table is firmware-based, which is embedded into a hardware of a chipset of the UE, any increase in the size of the standard-defined table will require more memory and as a result larger chipset in the UE.

Aspects Related To Grid-based Spatial Domain (SD) selection

Aspects of the present disclosure provide apparatuses, methods, processing systems, and computer-readable mediums for grid-based SD bases selection in a panel (e.g., an antenna panel) . For example, SD bases with consecutive indices in the panel may be aggregated as SD grids. That is, each SD grid may include multiple SD bases with the consecutive indices. A user equipment (UE) may select a subset of SD grids (as opposed to the SD bases) from a set of SD grids. Within each SD grid of the subset of SD grids, the UE may select one or more SD bases. The UE may generate and transmit a channel state information (CSI) report, which indicates the subset of SD grids and/or the one or more SD bases in each SD grid of the subset of SD grids.

The techniques proposed herein for the grid-based SD bases selection may be understood with reference to FIG. 9 to FIG. 21.

FIG. 9 depicts a call flow diagram 900 illustrating example communication among a UE and a network entity (e.g., a base station (BS) ) for a grid-based SD bases selection in a panel. The UE shown in FIG. 9 may be an example of the UE 104 depicted and described with respect to FIG. 1 and FIG. 3, and/or a UE depicted in FIG. 10. The network entity depicted in FIG. 9 may be an example of the BS 102 depicted and described with respect to FIG. 1 and FIG. 3, the disaggregated BS depicted and described with respect to FIG. 2, and/or a BS depicted in FIG. 10.

As indicated at 905, the UE selects a first number of SD grids from a plurality of SD grids. Each SD grid of the plurality of SD grids includes or is associated with multiple SD bases (e.g., corresponding to multiple SD beams) . The SD bases with consecutive indices may be aggregated as SD grids. In one example, a first set of SD bases with consecutive indices may be aggregated as a first SD grid. In another example, a second set of SD bases with consecutive indices may be aggregated as a second SD grid. Each SD grid may include different SD bases.

In certain aspects, the SD bases with the consecutive indices may correspond to a same scatter. For example, nearby SD beams corresponding to nearby SD bases may have a similar propagation path and correspond to a same scatter. As depicted in a diagram 1000 of FIG. 10, a first set of SD beams (e.g., from a BS) with consecutive indices and associated with a first propagation path may correspond to a first scatter, and a second set of SD beams (e.g., from the BS) with consecutive indices and associated with a second propagation path may correspond to a second scatter.

In one example panel depicted in a diagram 1100 of FIG. 11, N₁ and N₂ indicates a number of antennas in horizontal and vertical directions of the panel. For example, when values of N₁ and N₂ is equal to 8, there are 64 ports (e.g., corresponding to SD bases) in the panel. In this example, the panel may be divided into 16 SG grids where each 2 x 2 SD grid may include 4 ports (or SD bases) . Accordingly, in this example panelexisting standard-defined combinatorial coefficients table (as noted above) can be used for selection of L number of SD grids. For example, the UE selects L_grid SD grids out ofbynumber of bits. The L_grid SD grids may include a first SD grid and a second SD grid.

In another example, a value of N₁ is equal to 8 and a value of N₂ is equal to 4. In this example panel, there are 32 ports (e.g., corresponding to SD bases) in the panel. The panel may be divided into 16 SG grids where each 2 x 1 SD grid may include 2 ports or SD bases.

Referring back to FIG. 9, as indicated at 910, the UE selects one or more SD bases within each SD grid of the first number of SD grids. For example, for SD bases selection within each selected SD grid, the UE may use bitmaps to indicate selected SD bases within the selected SD grids. For example, SD grid (b_grid) = 2x2 = 4 bitmaps each sized e.g., 2x2 or 2x1. In this example, the UE may select bitmaps in each selected SD grid to indicate selection of corresponding SD bases within the selected SD grid.

As indicated at 915, the UE transmits a CSI report to the BS. The CSI report indicates the first number of SD grids, and one or more SD bases within each SD grid of the first number of SD grids.

In one example, a first field or part of the CSI report may indicate the first number of SD grids, and a second field or part of the CSI report may indicate the one or more SD bases within each SD grid of the first number of SD grids.

In another example, the first field or part of the CSI report may indicate the first number of SD grids and the one or more SD bases within each SD grid of the first number of SD grids.

In certain aspects, at least one of the plurality of SD grids includes a plurality of consecutive SD bases. The plurality of consecutive SD bases may include circulant consecutive SD bases (i.e., an SD basis index may wrap around (i.e., is circulant) ) .

As depicted in a diagram 1200 of FIG. 12, for one direction uniform linear array (ULA) with N₁=8, SD basis#7 and #0 may have neighbor directions. In this example, the SD basis#7 and #0 may be treated as consecutive SD bases and put into a same SD grid.

In certain aspects, the UE transmits an indication of an SD grid offset (e.g., corresponding to a split in the plurality of SD grids) to the BS in the CSI report. For example, a diagram 1300 of FIG. 13 depicts different SD grids 1310, 1320, 1330, and 1340. In such cases, the UE may indicate the SD grid offset corresponding to the split in the different SD grids 1310, 1320, 1330, and 1340 in a third field or part of the CSI report. For example, the CSI report may indicate a two bit SD grid offset for 2x2 SD grid (1-bit for N₁ and N₂ respectively) . In some cases, the differences in the SD grids 1310, 1320, 1330, and 1340 in accordance with the SD grid offset, may allow more flexibility for the SD grids 1310, 1320, 1330, and 1340 to accommodate certain scatter (s) ) .

In certain aspects, the UE reports a value of the first number of SD grids in the CSI report. In one example, the value of the first number of SD grids may be equal to a configured maximum value. In another example, the value of the first number of SD grids may be less than the configured maximum value. The BS may determine the configured maximum value and then provide the UE with the configured maximum value.

In certain aspects, the UE reports the value of the first number of SD grids in the first part of the CSI report. For example, L_grid value (e.g., corresponding to the first number of SD grids) may be included in the first part of the CSI report, since a payload size of SD beam selection may variate with the L_grid. Other information associated with the SD beam selection is in the second part of the CSI report. In one example, the L_grid value may be equal tobits, where L_grid, max may be a maximum value of a number of SD grids, while L_grid, min may be a minimum value of a number of SD gridsand b_grid corresponds to SD grid size.

In one aspect, the L_grid, max may be equal to L (e.g., a number of SD bases (beams) ) . In another aspect, the L_grid, max may be standard-defined. In another aspect, the L_grid, max may be a network-configured and the value of L_grid, max may be less than L.

In certain aspects, the UE receives a configured value of the first number of SD grids from the BS. For example, a linkage between a value of L_grid and L may be defined by standard or configured by the BS. In one example, L is equal to 2 L_grid for SD grid size b_grid=4 (2x2) . In another example, L is equal to 1.5 L_grid for SD grid size b_grid=2 (2x1) .

FIG. 14 depicts example diagram 1400 on a narrowness of SD basis (e.g., a digital beam) together with an analog beam (i.e., hybrid beamforming) for middle frequency bands (e.g., higher Frequency Range 1 (e.g. 3 –6GHz) or Frequency Range 3 (FR2) (7 –24GHz) ) . The digital beams for eight port ULA and the analog beams of three element dipole pair per port may be used to perform the hybrid beamforming.

Beamforming is a technique for engineering the emission distribution from an antenna such that electromagnetic energy is directed along a specific path or angle. The structure needed to perform beamforming is an antenna array, or a regularly spaced group of antennas in two dimensions. By controlling the relative phases and amplitudes of the signals sent to the phased array, the direction of the emitted beam can be controlled. The number of possible beams that can be emitted can be further doubled by exploiting polarization, or by only emitting electromagnetic radiation along one direction from each emitter in the array.

Analog beamforming operates by sending a signal to multiple antennas in an antenna array. The signals sent to each antenna are delayed by a specific time window, which applies a phase difference to the emission emitted from each antenna in the array. These antenna arrays are better known as phased arrays, and this application of phase difference has historically been the dominant method for beamforming in radio frequency (RF) systems.

In digital beamforming, multiple modulated signals are sent to the antenna array, and the phases and amplitudes of the signals sent to the array are combined to produce the desired beam pattern. The most basic case uses a single input data stream sent to multiple antennas, and the amplitudes are combined to produce the desired emission pattern.

The hybrid beamforming (also known as hybrid precoding) is a method that enables the use of massive multiple input multiple output (MIMO) antenna arrays in a lower power. In a traditional antenna array, each antenna requires a dedicated RF chain to transmit and receive each data stream; with hybrid precoding, each stream requires a dedicated RF chain. This greatly reduces the number of RF chains, thus reducing cost and power. The analog outputs of each chain are combined into a network of analog RF gains and phase shifters (the analog RF beamformer) that are connected to a large antenna array, where the number of antennas is more than a number of streams. These analog units cannot change weights quickly; however the computed RF weights change slowly over time since they are primarily determined by spatial positions of receivers. The digital baseband precoding weights may change from symbol to symbol due to smaller-scale multipath effects, and may also be different from subcarrier to subcarrier to account for frequency-selective fading.

In certain aspects, the UE selects a first number of frequency domain (FD) bases with consecutive indices for at least one SD basis associated with the first number of SD grids. For example, for a certain selected SD basis (e.g., a digital beam) , a set of M_per-beam FD bases with consecutive indices may be selected.

In certain aspects, per-beam M_per-beam consecutive (e.g., single-delay) FD selection is layer-specific (e.g., for a same beam and scatter) . The first number of FD bases may be different for different layers, since different layers may have each own FD phase rotation.

In certain aspects, a value of the first number of FD bases is per at least one of a beam, a polarization, and/or a layer. For example, the value of M_per-beam may be per beam and/or polarization, and layer. The UE may report the value of M_per-beam in a first FD selection field in the second part of the CSI report. In one example, M_per-beam equal to zero for a certain layer can be possible for a certain beam. In another example, for M_per- _beam greater than zero, the UE may select more than one FD basis. In one aspect, the UE may select one or two FD bases since these FD bases can be located within the a main delay lobe. In another aspect, the UE may select three or four FD bases with one or two strongest side lobes.

FIG. 15 depicts a diagram 1500 of example amplitude and delay for a beam for a first subcarrier spacing (SCS) and a first bandwidth part (BWP) . In this example, the first SCS is equal to 30 kilohertz (KHz) and the first BWP is equal to 52 resource blocks (RBs) .

FIG. 16 depicts a diagram 1600 of example amplitude and delay for a beam for a first SCS and a second BWP. In this example, the first SCS is equal to 30 KHz and the second BWP is equal to 128 RBs.

FIG. 17 depicts a diagram 1700 of example amplitude and delay for a beam for a first SCS and a third BWP. In this example, the first SCS is equal to 30 KHz and the third BWP is equal to 272 RBs. As depicted in FIGs 15-17, there is a higher value of the delay for a higher BWP with a same SCS.

In certain aspects, the UE reports an index of at least one of a beam, a polarization, or a layer corresponding to the value of the first number of FD bases to the BS.For example, the first FD selection field (e.g., in the second part of the CSI report) may be used by the UE to report value of M_per-beam (i, p, l) where index {i, p, l} is for the beam, the polarization, and the layer respectively.

In certain aspects, the UE reports a starting index of the selected first number of FD bases in a second FD selection field in the second part of the CSI report to the BS. For example, the second FD selection field (e.g., also in the second part of the CSI report) may be used by the UE to report the starting index of the selected consecutive FD bases (e.g., based on M_per-beam (i, p, l) > 0 in the first FD selection field) . For example, the UE may report bits for each non-zero M_per-beam (i, p, l) where N₃ denotes FD basis length, a number of subbands. In some cases, the first FD selection field and the second FD selection field may be a same field (e.g., by using start and length indicator value (SLIV) representation) .

In certain aspects, the UE reports a total number of non-zero first number of FD bases in the first part of the CSI report to the BS. For example, the UE may report a total number of non-zero M_per-beam (i, p, l) in the first part of the CSI report, so that the BS may know a payload size of the second FD selection field after decoding the first part of the CSI report.

In certain aspects, each of the selected first number of FD bases is associated with a quantization of one non-zero coefficient (NZC) . For example, for each one of M_per- _beam (i, p, l) > 0 FD basis selected, it is associated with a reported quantization (e.g., 3-bit amplitude and 4-bit 16 phase shift key (PSK) phase) of one NZC (e.g., of) .

In certain aspects, the UE may report a summation in the first part of the CSI report, so that the BS may know a payload size ofcoefficient quantization after decoding the first part of the CSI report. In certain aspects, a threshold (e.g., a maximum value) summation value may be configured by the BS. In one example, the threshold summation value may be configured per-layer. In another example, the threshold summation value may be configured across all-layers.

Example Method for Wireless Communications at a User Equipment (UE)

FIG. 18 shows an example of a method 1800 for wireless communications at a user equipment (UE) , such as the UE 104 of FIG. 1 and FIG. 3.

Method 1800 begins at step 1810 with selecting a first number of spatial domain (SD) grids from a plurality of SD grids where each SD grid of the plurality of SD grids comprises multiple SD bases. In some cases, the operations of this step refer to, or may be performed by, circuitry for selecting and/or code for selecting as described with reference to FIG. 20.

Method 1800 then proceeds to step 1820 with transmitting an indication of the selected first number of SD grids to a network entity in a channel state information (CSI) report. In some cases, the operations of this step refer to, or may be performed by, circuitry for transmitting and/or code for transmitting as described with reference to FIG. 20.

In certain aspects, the selecting includes selecting one or more SD bases within each SD grid of the first number of SD grids; and the transmitting comprises transmitting the indication of the selected one or more SD bases within each SD grid of the first number of SD grids to the network entity in the CSI report.

In certain aspects, at least one of the plurality of SD grids includes a plurality of consecutive SD bases.

In certain aspects, the plurality of consecutive SD bases include circulant consecutive SD bases.

In certain aspects, the transmitting includes transmitting another indication of an SD grid offset corresponding to a split in the plurality of SD grids to the network entity in the CSI report.

In certain aspects, the method 1800 further includes reporting a value of the first number of SD grids in a first part of the CSI report.

In certain aspects, a value of the first number of SD grids is equal to or less than a configured maximum value.

In certain aspects, the method 1800 further includes receiving a configured value of the first number of SD grids from the network entity.

In certain aspects, the method 1800 further includes selecting a first number of frequency domain (FD) bases with consecutive indices for at least one SD basis associated with the first number of SD grids.

In certain aspects, a value of the first number of FD bases is per at least one of a beam, a polarization, or a layer.

In certain aspects, the method 1800 further includes reporting the value of the first number of FD bases in a first FD selection field in a second part of the CSI report to the network entity.

In certain aspects, the reporting includes reporting an index of at least one of the beam, the polarization, or the layer corresponding to the value of the first number of FD bases to the network entity.

In certain aspects, the reporting includes reporting a starting index of the selected first number of FD bases in a second FD selection field in the second part of the CSI report to the network entity.

In certain aspects, the method 1800 further includes reporting a total number of non-zero first number of FD bases in a first part of the CSI report to the network entity.

In certain aspects, each of the selected first number of FD bases is associated with a quantization of one non-zero coefficient (NZC) .

In one aspect, the method 1800, or any aspect related to it, may be performed by an apparatus, such as a communications device 2000 of FIG. 20, which includes various components operable, configured, or adapted to perform the method 1800. The communications device 2000 is described below in further detail.

Note that FIG. 18 is just one example of a method, and other methods including fewer, additional, or alternative steps are possible consistent with this disclosure.

Example Method for Wireless Communications at a Network Entity

FIG. 19 shows an example of a method 1900 for wireless communications at a network entity, such as the BS 102 of FIG. 1 and FIG. 3.

Method 1900 begins at step 1910 with transmitting at least one channel state information (CSI) reference signal (RS) to a user equipment (UE) . In some cases, the operations of this step refer to, or may be performed by, circuitry for transmitting and/or code for transmitting as described with reference to FIG. 21.

Method 1900 then proceeds to step 1920 with receiving a CSI report from the UE, in response to the at least one CSI-RS, indicating a selection of a first number of spatial domain (SD) grids from a plurality of SD grids where each SD grid of the plurality of SD grids includes multiple SD bases. In some cases, the operations of this step refer to, or may be performed by, circuitry for receiving and/or code for receiving as described with reference to FIG. 21.

In certain aspects, the method 1900 further includes receiving a value of the first number of SD grids in a first part of the CSI report.

In certain aspects, the method 1900 further includes transmitting a configured value of the first number of SD grids to the UE.

In one aspect, the method 1900, or any aspect related to it, may be performed by an apparatus, such as a communications device 2100 of FIG. 21, which includes various components operable, configured, or adapted to perform the method 1900. The communications device 2100 is described below in further detail.

Note that FIG. 19 is just one example of a method, and other methods including fewer, additional, or alternative steps are possible consistent with this disclosure.

Example Communications Devices

FIG. 20 depicts aspects of an example communications device 2000. In some aspects, communications device 2000 is a user equipment (UE) , such as UE 104 described above with respect to FIG. 1 and FIG. 3.

The communications device 2000 includes a processing system 2005 coupled to the transceiver 2045 (e.g., a transmitter and/or a receiver) . The transceiver 2045 is configured to transmit and receive signals for the communications device 2000 via the antenna 2050, such as the various signals as described herein. The processing system 2005 may be configured to perform processing functions for the communications device 2000, including processing signals received and/or to be transmitted by the communications device 2000.

The processing system 2005 includes one or more processors 2010. In various aspects, the one or more processors 2010 may be representative of one or more of receive processor 358, transmit processor 364, TX MIMO processor 366, and/or controller/processor 380, as described with respect to FIG. 3. The one or more processors 2010 are coupled to a computer-readable medium/memory 2025 via a bus 2040. In certain aspects, the computer-readable medium/memory 2025 is configured to store instructions (e.g., computer-executable code) that when executed by the one or more processors 2010, cause the one or more processors 2010 to perform the method 1800 described with respect to FIG. 18, and/or any aspect related to it. Note that reference to a processor performing a function of communications device 2000 may include one or more processors 2010 performing that function of communications device 2000.

In the depicted example, computer-readable medium/memory 2025 stores code (e.g., executable instructions) , such as code for selecting 2030 and code for transmitting 2035. Processing of the code for selecting 2030 and code for transmitting 2035 may cause the communications device 2000 to perform the method 1800 described with respect to FIG. 18, and/or any aspect related to it.

The one or more processors 2010 include circuitry configured to implement (e.g., execute) the code stored in the computer-readable medium/memory 2025, including circuitry such as circuitry for selecting 2015 and circuitry for transmitting 2020. Processing with circuitry for selecting 2015 and circuitry for transmitting 2020 may cause the communications device 2000 to perform the method 1800 described with respect to FIG. 18, and/or any aspect related to it.

Various components of the communications device 2000 may provide means for performing the method 1800 described with respect to FIG. 18, and/or any aspect related to it. For example, means for transmitting, sending or outputting for transmission may include transceivers 354 and/or antenna (s) 352 of the UE 104 illustrated in FIG. 3 and/or the circuitry for transmitting 2020, code for transmitting 2035, the transceiver 2045 and the antenna 2050 of the communications device 2000 in FIG. 17. Means for receiving or obtaining may include transceivers 354 and/or antenna (s) 352 of the UE 104 illustrated in FIG. 3 and/or the transceiver 2045 and the antenna 2050 of the communications device 2000 in FIG. 20.

In some cases, rather than actually transmitting, for example, signals and/or data, a device may have an interface to output signals and/or data for transmission (ameans for outputting) . For example, a processor may output signals and/or data, via a bus interface, to a radio frequency (RF) front end for transmission. In various aspects, an RF front end may include various components, including transmit and receive processors, transmit and receive MIMO processors, modulators, demodulators, and the like, such as depicted in the examples in FIG. 3.

In some cases, rather than actually receiving signals and/or data, a device may have an interface to obtain the signals and/or data received from another device (a means for obtaining) . For example, a processor may obtain (or receive) the signals and/or data, via a bus interface, from an RF front end for reception. In various aspects, an RF front end may include various components, including transmit and receive processors, transmit and receive MIMO processors, modulators, demodulators, and the like, such as depicted in the examples in FIG. 3. Notably, FIG. 20 is an example, and many other examples and configurations of communication device 2000 are possible.

FIG. 21 depicts aspects of an example communications device 2100. In some aspects, communications device 2100 is a network entity, such as BS 102 of FIG. 1 and FIG. 3, or a disaggregated base station as discussed with respect to FIG. 2.

The communications device 2100 includes a processing system 2105 coupled to the transceiver 2155 (e.g., a transmitter and/or a receiver) and/or a network interface 2165. The transceiver 2155 is configured to transmit and receive signals for the communications device 2100 via the antenna 2160, such as the various signals as described herein. The network interface 2165 is configured to obtain and send signals for the communications device 2100 via communication link (s) , such as a backhaul link, midhaul link, and/or fronthaul link as described herein, such as with respect to FIG. 2. The processing system 2105 may be configured to perform processing functions for the communications device 2100, including processing signals received and/or to be transmitted by the communications device 2100.

The processing system 2105 includes one or more processors 2110. In various aspects, one or more processors 2110 may be representative of one or more of receive processor 338, transmit processor 320, TX MIMO processor 330, and/or controller/processor 340, as described with respect to FIG. 3. The one or more processors 2110 are coupled to a computer-readable medium/memory 2130 via a bus 2150. In certain aspects, the computer-readable medium/memory 2130 is configured to store instructions (e.g., computer-executable code) that when executed by the one or more processors 2110, cause the one or more processors 2110 to perform the method 1900 described with respect to FIG. 19, or any aspect related to it. Note that reference to a processor of communications device 2100 performing a function may include one or more processors 2110 of communications device 2100 performing that function.

In the depicted example, the computer-readable medium/memory 2130 stores code (e.g., executable instructions) , such as code for transmitting 2135 and code for receiving 2140. Processing of the code for transmitting 2135 and code for receiving 2140 may cause the communications device 2100 to perform the method 1900 described with respect to FIG. 19, or any aspect related to it.

The one or more processors 2110 include circuitry configured to implement (e.g., execute) the code stored in the computer-readable medium/memory 2130, including circuitry such as circuitry for transmitting 2115 and circuitry for receiving 2120. Processing with circuitry for transmitting 2115 and circuitry for receiving 2120 may cause the communications device 2100 to perform the method 1900 described with respect to FIG. 19, or any aspect related to it.

Various components of the communications device 2100 may provide means for performing the method 1900 described with respect to FIG. 19, or any aspect related to it. Means for transmitting, sending or outputting for transmission may include transceivers 332 and/or antenna (s) 334 of the BS 102 illustrated in FIG. 3 and/or the circuitry for transmitting 2115, the code for transmitting 2135, the transceiver 2155 and the antenna 2160 of the communications device 2100 in FIG. 21. Means for receiving or obtaining may include transceivers 332 and/or antenna (s) 334 of the BS 102 illustrated in FIG. 3 and/or the circuitry for receiving 2120, the code for receiving 2140, the transceiver 2155 and the antenna 2160 of the communications device 2100 in FIG. 21.

In some cases, rather than actually transmitting, for example, signals and/or data, a device may have an interface to output signals and/or data for transmission (ameans for outputting) . For example, a processor may output signals and/or data, via a bus interface, to an RF front end for transmission. In various aspects, an RF front end may include various components, including transmit and receive processors, transmit and receive MIMO processors, modulators, demodulators, and the like, such as depicted in the examples in FIG. 3.

In some cases, rather than actually receiving signals and/or data, a device may have an interface to obtain the signals and/or data received from another device (a means for obtaining) . For example, a processor may obtain (or receive) the signals and/or data, via a bus interface, from an RF front end for reception. In various aspects, an RF front end may include various components, including transmit and receive processors, transmit and receive MIMO processors, modulators, demodulators, and the like, such as depicted in the examples in FIG. 3. Notably, FIG. 21 is an example, and many other examples and configurations of communication device 2100 are possible.

Example Clauses

Implementation examples are described in the following numbered clauses:

Clause 1: A method for wireless communication at a user equipment (UE) , comprising: selecting a first number of spatial domain (SD) grids from a plurality of SD grids, wherein each SD grid of the plurality of SD grids comprises multiple SD bases; and transmitting an indication of the selected first number of SD grids to a network entity in a channel state information (CSI) report.

Clause 2: The method of clause 1, wherein: the selecting comprises selecting one or more SD bases within each SD grid of the first number of SD grids; and the transmitting comprises transmitting the indication of the selected one or more SD bases within each SD grid of the first number of SD grids to the network entity in the CSI report.

Clause 3: The method of any one of clauses 1-2, wherein at least one of the plurality of SD grids comprises a plurality of consecutive SD bases.

Clause 4: The method of clause 3, wherein the plurality of consecutive SD bases comprise circulant consecutive SD bases.

Clause 5: The method of any one of clauses 1-4, wherein the transmitting comprises transmitting another indication of an SD grid offset corresponding to a split in the plurality of SD grids to the network entity in the CSI report.

Clause 6: The method of any one of clauses 1-5, further comprising reporting a value of the first number of SD grids in a first part of the CSI report.

Clause 7: The method of any one of clauses 1-6, wherein a value of the first number of SD grids is equal to or less than a configured maximum value.

Clause 8: The method of any one of clauses 1-7, further comprising receiving a configured value of the first number of SD grids from the network entity.

Clause 9: The method of any one of clauses 1-8, further comprising selecting a first number of frequency domain (FD) bases with consecutive indices for at least one SD basis associated with the first number of SD grids.

Clause 10: The method of clause 9, wherein a value of the first number of FD bases is per at least one of a beam, a polarization, or a layer.

Clause 11: The method of clause 10, further comprising reporting the value of the first number of FD bases in a first FD selection field in a second part of the CSI report to the network entity.

Clause 12: The method of clause 11, wherein the reporting comprises reporting an index of at least one of the beam, the polarization, or the layer corresponding to the value of the first number of FD bases to the network entity.

Clause 13: The method of clause 11, wherein the reporting comprises reporting a starting index of the selected first number of FD bases in a second FD selection field in the second part of the CSI report to the network entity.

Clause 14: The method of clause 9, further comprising reporting a total number of non-zero first number of FD bases in a first part of the CSI report to the network entity.

Clause 15: The method of clause 9, wherein each of the selected first number of FD bases is associated with a quantization of one non-zero coefficient (NZC) .

Clause 16: A method for wireless communication at a network entity, comprising: transmitting at least one channel state information (CSI) reference signal (RS) to a user equipment (UE) ; and receiving a CSI report from the UE, in response to the at least one CSI-RS, indicating a selection of a first number of spatial domain (SD) grids from a plurality of SD grids, wherein each SD grid of the plurality of SD grids comprises multiple SD bases.

Clause 17: The method of clause 16, wherein at least one of the plurality of SD grids comprises a plurality of consecutive SD bases.

Clause 18: The method of clause 17, wherein the plurality of consecutive SD bases comprise circulant consecutive SD bases.

Clause 19: The method of any one of clauses 16-18, further comprising receiving a value of the first number of SD grids in a first part of the CSI report.

Clause 20: The method of any one of clauses 16-19, wherein a value of the first number of SD grids is equal to or less than a configured maximum value.

Clause 21: The method of any one of clauses 16-20, further comprising transmitting a configured value of the first number of SD grids to the UE.

Clause 22: An apparatus, comprising: a memory comprising executable instructions; and a processor configured to execute the executable instructions and cause the apparatus to perform a method in accordance with any one of Clauses 1-21.

Clause 23: An apparatus, comprising means for performing a method in accordance with any one of Clauses 1-21.

Clause 24: A non-transitory computer-readable medium comprising executable instructions that, when executed by a processor of an apparatus, cause the apparatus to perform a method in accordance with any one of Clauses 1-21.

Clause 25: A computer program product embodied on a computer-readable storage medium comprising code for performing a method in accordance with any one of Clauses 1-21.

Additional Considerations

The preceding description is provided to enable any person skilled in the art to practice the various aspects described herein. The examples discussed herein are not limiting of the scope, applicability, or aspects set forth in the claims. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. For example, changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various actions may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method that is practiced using other structure, functionality, or structure and functionality in addition to, or other than, the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.

The various illustrative logical blocks, modules and circuits described in connection with the present disclosure may be implemented or performed with a general purpose processor, a digital signal processor (DSP) , an ASIC, a field programmable gate array (FPGA) or other programmable logic device (PLD) , discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, a system on a chip (SoC) , or any other such configuration.

As used herein, “a processor, ” “at least one processor” or “one or more processors” generally refers to a single processor configured to perform one or multiple operations or multiple processors configured to collectively perform one or more operations. In the case of multiple processors, performance the one or more operations could be divided amongst different processors, though one processor may perform multiple operations, and multiple processors could collectively perform a single operation. Similarly, “a memory, ” “at least one memory” or “one or more memories” generally refers to a single memory configured to store data and/or instructions, multiple memories configured to collectively store data and/or instructions.

As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c) .

As used herein, the term “determining” encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure) , ascertaining and the like. Also, “determining” may include receiving (e.g., receiving information) , accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, selecting, choosing, establishing and the like.

The methods disclosed herein comprise one or more actions for achieving the methods. The method actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of actions is specified, the order and/or use of specific actions may be modified without departing from the scope of the claims. Further, the various operations of methods described above may be performed by any suitable means capable of performing the corresponding functions. The means may include various hardware and/or software component (s) and/or module (s) , including, but not limited to a circuit, an application specific integrated circuit (ASIC) , or processor.

The following claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims. Within a claim, reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” Unless specifically stated otherwise, the term “some” refers to one or more. No claim element is to be construed under the provisions of 35 U.S.C. §112 (f) unless the element is expressly recited using the phrase “means for” . All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.

Claims

An apparatus for wireless communications at a user equipment (UE) , comprising:

a memory comprising instructions; and

one or more processors configured, individually or in any combination, to execute the instructions and cause the apparatus to:

select a first number of spatial domain (SD) grids from a plurality of SD grids, wherein each SD grid of the plurality of SD grids comprises multiple SD bases; and

transmit an indication of the selected first number of SD grids to a network entity in a channel state information (CSI) report.
The apparatus of claim 1, wherein:

the select comprises select one or more SD bases within each SD grid of the first number of SD grids; and

the transmit comprises transmit the indication of the selected one or more SD bases within each SD grid of the first number of SD grids to the network entity in the CSI report.
The apparatus of claim 1, wherein at least one of the plurality of SD grids comprises a plurality of consecutive SD bases.
The apparatus of claim 3, wherein the plurality of consecutive SD bases comprise circulant consecutive SD bases.
The apparatus of claim 1, wherein the transmit comprises transmit another indication of an SD grid offset corresponding to a split in the plurality of SD grids to the network entity in the CSI report.
The apparatus of claim 1, wherein the one or more processors are further configured to execute the instructions and cause the apparatus to report a value of the first number of SD grids in a first part of the CSI report.
The apparatus of claim 1, wherein a value of the first number of SD grids is equal to or less than a configured maximum value.
The apparatus of claim 1, wherein the one or more processors are further configured to execute the instructions and cause the apparatus to receive a configured value of the first number of SD grids from the network entity.
The apparatus of claim 1, wherein the one or more processors are further configured to execute the instructions and cause the apparatus to select a first number of frequency domain (FD) bases with consecutive indices for at least one SD basis associated with the first number of SD grids.
The apparatus of claim 9, wherein a value of the first number of FD bases is per at least one of a beam, a polarization, or a layer.
The apparatus of claim 10, wherein the one or more processors are further configured to execute the instructions and cause the apparatus to report the value of the first number of FD bases in a first FD selection field in a second part of the CSI report to the network entity.
The apparatus of claim 11, wherein the report comprises report an index of at least one of the beam, the polarization, or the layer corresponding to the value of the first number of FD bases to the network entity.
The apparatus of claim 11, wherein the report comprises report a starting index of the selected first number of FD bases in a second FD selection field in the second part of the CSI report to the network entity.
The apparatus of claim 9, wherein the one or more processors are further configured to execute the instructions and cause the apparatus to report a total number of non-zero first number of FD bases in a first part of the CSI report to the network entity.
The apparatus of claim 9, wherein each of the selected first number of FD bases is associated with a quantization of one non-zero coefficient (NZC) .
An apparatus for wireless communications at a network entity, comprising:

a memory comprising instructions; and

one or more processors configured, individually or in any combination, to execute the instructions and cause the apparatus to:

transmit at least one channel state information (CSI) reference signal (RS) to a user equipment (UE) ; and

receive a CSI report from the UE, in response to the at least one CSI-RS, indicating a selection of a first number of spatial domain (SD) grids from a plurality of SD grids, wherein each SD grid of the plurality of SD grids comprises multiple SD bases.
The apparatus of claim 16, wherein at least one of the plurality of SD grids comprises a plurality of consecutive SD bases.
The apparatus of claim 17, wherein the plurality of consecutive SD bases comprise circulant consecutive SD bases.
The apparatus of claim 16, wherein the one or more processors are further configured to execute the instructions and cause the apparatus to receive a value of the first number of SD grids in a first part of the CSI report.
The apparatus of claim 16, wherein a value of the first number of SD grids is equal to or less than a configured maximum value.
The apparatus of claim 16, wherein the one or more processors are further configured to execute the instructions and cause the apparatus to transmit a configured value of the first number of SD grids to the UE.
A method for wireless communication at a user equipment (UE) , comprising:

selecting a first number of spatial domain (SD) grids from a plurality of SD grids, wherein each SD grid of the plurality of SD grids comprises multiple SD bases; and

transmitting an indication of the selected first number of SD grids to a network entity in a channel state information (CSI) report.
The method of claim 22, wherein:

the selecting comprises selecting one or more SD bases within each SD grid of the first number of SD grids; and

the transmitting comprises transmitting the indication of the selected one or more SD bases within each SD grid of the first number of SD grids to the network entity in the CSI report.
The method of claim 22, wherein at least one of the plurality of SD grids comprises a plurality of consecutive SD bases.
The method of claim 24, wherein the plurality of consecutive SD bases comprise circulant consecutive SD bases.
The method of claim 22, wherein the transmitting comprises transmitting another indication of an SD grid offset corresponding to a split in the plurality of SD grids to the network entity in the CSI report.
The method of claim 22, further comprising reporting a value of the first number of SD grids in a first part of the CSI report.
A method for wireless communication at a network entity, comprising:

transmitting at least one channel state information (CSI) reference signal (RS) to a user equipment (UE) ; and

receiving a CSI report from the UE, in response to the at least one CSI-RS, indicating a selection of a first number of spatial domain (SD) grids from a plurality of SD grids, wherein each SD grid of the plurality of SD grids comprises multiple SD bases.
The method of claim 28, wherein at least one of the plurality of SD grids comprises a plurality of consecutive SD bases.
The method of claim 29, wherein the plurality of consecutive SD bases comprise circulant consecutive SD bases.