WO2023206404A1

WO2023206404A1 - Retransmission of channel state information report for machine learning based prediction

Info

Publication number: WO2023206404A1
Application number: PCT/CN2022/090414
Authority: WO
Inventors: Qiaoyu Li; Arumugam Chendamarai Kannan; Mahmoud Taherzadeh Boroujeni; Tao Luo; Hamed Pezeshki
Original assignee: Qualcomm Incorporated
Priority date: 2022-04-29
Filing date: 2022-04-29
Publication date: 2023-11-02

Abstract

Certain aspects of the present disclosure provide a method of wireless communication by a user equipment (UE), generally including receiving a configuration for periodic or aperiodic channel state information (CSI) reporting, transmitting a first CSI report, in accordance with the configuration for periodic or aperiodic CSI reporting, and transmitting an aperiodic second CSI report containing one or more channel characteristic measurements associated with the first CSI report, if one or more conditions are met.

Description

RETRANSMISSION OF CHANNEL STATE INFORMATION REPORT FOR MACHINE LEARNING BASED PREDICTION

BACKGROUND

Field of the Disclosure

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for enhancing the delivery of channel state information (CSI) .

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 of wireless communications by a user equipment (UE) . The method includes receiving a configuration for periodic or aperiodic channel state information (CSI) reporting; transmitting a first CSI report, in accordance with the configuration for periodic or aperiodic CSI reporting; and transmitting an aperiodic second CSI report containing one or more channel characteristic measurements associated with the first CSI report, if one or more conditions are met.

Another aspect provides a method of wireless communications by a network entity. The method includes transmitting a configuration to configure a UE for periodic or aperiodic CSI reporting; receiving a first CSI report, generated by the UE in accordance with the configuration for periodic or aperiodic CSI reporting; and receiving an aperiodic second CSI report generated by the UE if one or more conditions are met, the second CSI report containing one or more channel characteristic measurements associated with the first CSI report.

Other aspects provide: an apparatus operable, configured, or otherwise adapted to perform any one or more of the aforementioned methods and/or 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/or 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 architecture.

FIG. 3 depicts aspects of an example base station and an example user equipment.

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

FIG. 5 illustrates example beam refinement procedures, in accordance with certain aspects of the present disclosure

FIG. 6 is a diagram illustrating example operations where beam management may be performed.

FIG. 7 illustrates a general functional framework applied for AI-enabled RAN intelligence.

FIG. 8 is a diagram illustrating an example of ML-based beam prediction.

FIG. 9 depicts a diagram illustrating missing channel state information (CSI) reports.

FIG. 10 depicts a call flow diagram for retransmitting CSI information, in accordance with aspects of the present disclosure.

FIG. 11 depicts a diagram illustrating buffering and retransmission of L1-reports for ML based TD beam prediction, in accordance with aspects of the present disclosure.

FIGs. 12A and 12B depict tables describing explicitly reported UE capabilities, in accordance with aspects of the present disclosure.

FIG. 13 depicts a timeline associated with implicit UE capability reporting via CPUs, in accordance with aspects of the present disclosure.

FIGs. 14A and 14B depict diagrams illustrating options for buffer release and replacement, in accordance with aspects of the present disclosure.

FIG. 15 depicts a diagram illustrating triggering of a second AP CSI report.

FIG. 16 depicts a diagram illustrating MAC-CE based UCI retransmission, in accordance with aspects of the present disclosure.

FIG. 17 depicts a diagram illustrating extensions to reporting additional CSI information, in accordance with aspects of the present disclosure.

FIG. 18 depicts a method for wireless communications.

FIG. 19 depicts a method for wireless communications.

FIG. 20 depicts aspects of an example communications device.

FIG. 21 depicts aspects of an example communications device.

DETAILED DESCRIPTION

Aspects of the present disclosure provide apparatuses, methods, processing systems, and computer-readable mediums for retransmitting certain channel state information (CSI) .

Understanding the channel state between devices communicating in a wireless communications system is an important aspect of improving the performance of wireless communications. Conventionally, many techniques have been employed for measuring the channel state and reporting feedback so that performance can be improved. However, such conventional techniques are often relatively slow, power hungry, and static in approach.

Machine learning (ML) represents an opportunity to improve upon many conventional techniques for measuring channel state and reporting feedback. For example, machine learning models may reduce the number of resource elements needed for estimating a channel state, and improve the estimates of values used in reporting the channel state. However, ML-based beam prediction typically relies on user equipment (UE) reported measurement values. An ML-based beam prediction algorithm may take a time series of such reported measurements and output a prediction for a future time window, such as a predicted beam change.

Unfortunately, missing one or more of the UE measurements may be unavoidable under certain conditions. Missing measurement reports may cause error propagation which could result in inaccurate time domain (TD) beam prediction. As an example, input samples associated with the missing reporting occasions may have to be replaced by the most recently available reported samples (which may no longer accurately reflect current channel conditions) . Thus, such replacement may lead to beam prediction errors.

To help address such missing measurement reporting problems, aspects of the present disclosure propose techniques whereby certain information may be retransmitted, for example, when the occurrence of a missing measurement report is detected. As will be described in greater detail below, a UE may be configured to buffer certain measurement information associated with periodic measurement reports so that, in the event a measurement report is missed, it may retransmit the information. As a result, missing measurement information may be provided to an ML-based beam prediction model, which may lead to more accurate prediction results.

Thus, aspects described herein, which enable robust use of machine learning models for channel state measuring and feedback procedures, enhance wireless communications performance generally, and more specifically through reduced power use, increased battery life, improved spectral efficiency, reduced latency, and decreased network overhead, to name a few technical improvements.

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 user equipments.

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 base station, 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 base station 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 base station may be virtualized. More generally, a base station (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 base station 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 base station that is located at a single physical location. In some aspects, a base station including components that are located at various physical locations may be referred to as a disaggregated radio access network architecture, such as an Open RAN (O-RAN) or Virtualized RAN (VRAN) architecture. FIG. 2 depicts and describes an example disaggregated base station 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 410 MHz –C 7125 MHz, which is often referred to (interchangeably) as “Sub-6 GHz” . Similarly, 3GPP currently defines Frequency Range 2 (FR2) as including 24,250 MHz –C 52,600 MHz, which is sometimes referred to (interchangeably) as a “millimeter wave” ( “mmW” or “mmWave” ) . A base station configured to communicate using mmWave/near mmWave radio frequency bands (e.g., a mmWave base station 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 base stations (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.

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

FIG. 2 depicts an example disaggregated base station 200 architecture. The disaggregated base station 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 base station 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 –C 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 base station 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.

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.

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.

FIGS. 4A, 4B, 4C, and 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 FIGS. 4B and 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. FIGS. 4A, 4B, 4C, and 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 FIGS. 4A, 4B, 4C, and 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 FIGS. 1 and 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 FIGS. 1 and 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 base station. 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 base station 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.

Example Beam Refinement Procedures

In mmWave systems, beam forming may be needed to overcome high path-losses. As described herein, beamforming may refer to establishing a link between a BS and UE, wherein both of the devices form a beam corresponding to each other. Both the BS and the UE find at least one adequate beam to form a communication link. BS-beam and UE-beam form what is known as a beam pair link (BPL) . As an example, on the DL, a BS may use a transmit beam and a UE may use a receive beam corresponding to the transmit beam to receive the transmission. The combination of a transmit beam and corresponding receive beam may be a BPL.

As a part of beam management, beams which are used by BS and UE have to be refined from time to time because of changing channel conditions, for example, due to movement of the UE or other objects. Additionally, the performance of a BPL may be subject to fading due to Doppler spread. Because of changing channel conditions over time, the BPL should be periodically updated or refined. Accordingly, it may be beneficial if the BS and the UE monitor beams and new BPLs.

At least one BPL has to be established for network access. As described above, new BPLs may need to be discovered later for different purposes. The network may decide to use different BPLs for different channels, or for communicating with different BSs (TRPs) or as fallback BPLs in case an existing BPL fails.

The UE typically monitors the quality of a BPL and the network may refine a BPL from time to time.

FIG. 5 illustrates example 500 for BPL discovery and refinement. In 5G-NR, the P1, P2, and P3 procedures are used for BPL discovery and refinement. The network uses a P1 procedure to enable the discovery of new BPLs. In the P1 procedure, as illustrated in FIG. 5, the BS transmits different symbols of a reference signal, each beam formed in a different spatial direction such that several (most, all) relevant places of the cell are reached. Stated otherwise, the BS transmits beams using different transmit beams over time in different directions.

For successful reception of at least a symbol of this “P1-signal” , the UE has to find an appropriate receive beam. It searches using available receive beams and applying a different UE-beam during each occurrence of the periodic P1-signal.

Once the UE has succeeded in receiving a symbol of the P1-signal it has discovered a BPL. The UE may not want to wait until it has found the best UE receive beam, since this may delay further actions. The UE may measure the reference signal receive power (RSRP) and report the symbol index together with the RSRP to the BS. Such a report will typically contain the findings of one or more BPLs.

In an example, the UE may determine a received signal having a high RSRP. The UE may not know which beam the BS used to transmit; however, the UE may report to the BS the time at which it observed the signal having a high RSRP. The BS may receive this report and may determine which BS beam the BS used at the given time.

The BS may then offer P2 and P3 procedures to refine an individual BPL. The P2 procedure refines the BS-beam of a BPL. The BS may transmit a few symbols of a reference signal with different BS-beams that are spatially close to the BS-beam of the BPL (the BS performs a sweep using neighboring beams around the selected beam) . In P2, the UE keeps its beam constant. Thus, while the UE uses the same beam as in the BPL (as illustrated in P2 procedure in FIG. 5) . The BS-beams used for P2 may be different from those for P1 in that they may be spaced closer together or they may be more focused. The UE may measure the RSRP for the various BS-beams and indicate the best one to the BS.

The P3 procedure refines the UE-beam of a BPL (see P3 procedure in FIG. 5) . While the BS-beam stays constant, the UE scans using different receive beams (the UE performs a sweep using neighboring beams) . The UE may measure the RSRP of each beam and identify the best UE-beam. Afterwards, the UE may use the best UE-beam for the BPL and report the RSRP to the BS.

Overtime, the BS and UE establish several BPLs. When the BS transmits a certain channel or signal, it lets the UE know which BPL will be involved, such that the UE may tune in the direction of the correct UE receive beam before the signal starts. In this manner, every sample of that signal or channel may be received by the UE using the correct receive beam. In an example, the BS may indicate for a scheduled signal (SRS, CSI-RS) or channel (PDSCH, PDCCH, PUSCH, PUCCH) which BPL is involved. In NR this information is called QCL indication.

Two antenna ports are QCL if properties of the channel over which a symbol on one antenna port is conveyed may be inferred from the channel over which a symbol on the other antenna port is conveyed. QCL supports, at least, beam management functionality, frequency/timing offset estimation functionality, and RRM management functionality.

The BS may use a BPL which the UE has received in the past. The transmit beam for the signal to be transmitted and the previously-received signal both point in a same direction or are QCL. The QCL indication may be needed by the UE (in advance of signal to be received) such that the UE may use a correct receive beam for each signal or channel. Some QCL indications may be needed from time to time when the BPL for a signal or channel changes and some QCL indications are needed for each scheduled instance. The QCL indication may be transmitted in the downlink control information (DCI) which may be part of the PDCCH channel. Because DCI is needed to control the information, it may be desirable that the number of bits needed to indicate the QCL is not too big. The QCL may be transmitted in a medium access control-control element (MAC-CE) or radio resource control (RRC) message.

According to one example, whenever the UE reports a BS beam that it has received with sufficient RSRP, and the BS decides to use this BPL in the future, the BS assigns it a BPL tag. Accordingly, two BPLs having different BS beams may be associated with different BPL tags. BPLs that are based on the same BS beams may be associated with the same BPL tag. Thus, according to this example, the tag is a function of the BS beam of the BPL.

As noted above, wireless systems, such as millimeter wave (mmW) systems, bring gigabit speeds to cellular networks, due to availability of large amounts of bandwidth. However, the unique challenges of heavy path-loss faced by such wireless systems necessitate new techniques such as hybrid beamforming (analog and digital) , which are not present in 3G and 4G systems. Hybrid beamforming may enhance link budget/signal to noise ratio (SNR) that may be exploited during the RACH.

In such systems, the node B (NB) and the user equipment (UE) may communicate over active beam-formed transmission beams. Active beams may be considered paired transmission (Tx) and reception (Rx) beams between the NB and UE that carry data and control channels such as PDSCH, PDCCH, PUSCH, and PUCCH. As noted above, a transmit beam used by a NB and corresponding receive beam used by a UE for downlink transmissions may be referred to as a beam pair link (BPL) . Similarly, a transmit beam used by a UE and corresponding receive beam used by a NB for uplink transmissions may also be referred to as a BPL.

Since the direction of a reference signal is unknown to the UE, the UE may need to evaluate several beams to obtain the best Rx beam for a given NB Tx beam. However, if the UE has to “sweep” through all of its Rx beams to perform the measurements (e.g., to determine the best Rx beam for a given NB Tx beam) , the UE may incur significant delay in measurement and battery life impact. Moreover, having to sweep through all Rx beams is highly resource inefficient. Thus, aspects of the present disclosure provide techniques to assist a UE when performing measurements of serving and neighbor cells when using Rx beamforming.

Example Beam Management

In wireless communications, various procedures may be performed for beam management. FIG. 6 is a diagram illustrating example operations where beam management may be performed. In initial access 602, the network may sweep through several beams, for example, via synchronization signal blocks (SSBs) , as further described herein with respect to FIG. 4B. The network may configure the UE with random access channel (RACH) resources associated with the beamformed SSBs to facilitate the initial access via the RACH resources. In certain aspects, an SSB may have a wider beam shape compared to other reference signals, such as a channel state information reference signal (CSI-RS) . A UE may use SSB detection to identify a RACH occasion (RO) for sending a RACH preamble (e.g., as part of a contention CBRA procedure) .

In connected mode 604, the network and UE may perform hierarchical beam refinement including beam selection (e.g., a process referred to as P1) , beam refinement for the transmitter (e.g., a process referred to as P2) , and beam refinement for the receiver (e.g., a process referred to as P3) . In beam selection (P1) , the network may sweep through beams, and the UE may report the beam with the best channel properties, for example. In beam refinement for the transmitter (P2) , the network may sweep through narrower beams, and the UE may report the beam with the best channel properties among the narrow beams. In beam refinement for the receiver (P3) , the network may transmit using the same beam repeatedly, and the UE may refine spatial reception parameters (e.g., a spatial filter) for receiving signals from the network via the beam. In certain aspects, the network and UE may perform complementary procedures (e.g., U1, U2, and U3) for uplink beam management.

In certain cases where a beam failure occurs (e.g., due to beam misalignment and/or blockage) , the UE may perform a beam failure recovery (BFR) procedure 606, which may allow a UE to return to connected mode 604 without performing a radio link failure procedure 608. For example, the UE may be configured with candidate beams for beam failure recovery. In response to detecting a beam failure, the UE may request the network to perform beam failure recovery via one of the candidate beams (e.g., one of the candidate beams with a reference signal received power (RSRP) above a certain threshold) . In certain cases where radio link failure (RLF) occurs, the UE may perform an RLF procedure 608 to recover from the radio link failure, such as a RACH procedure.

AI/ML Functional Framework for RAN intelligence

FIG. 7 depicts an example of AI/ML functional framework 700 for RAN intelligence, in which aspects described herein may be implemented.

The AI/ML functional framework includes a data collection function 702, a model training function 704, a model inference function 706, and an actor function 708, which interoperate to provide a platform for collaboratively applying AI/ML to various procedures in RAN.

The data collection function 702 generally provides input data to the model training function 704 and the model inference function 706. AI/ML algorithm specific data preparation (e.g., data pre-processing and cleaning, formatting, and transformation) may not be carried out in the data collection function 702.

Examples of input data to the data collection function 702 (or other functions) may include measurements from UEs or different network entities, feedback from the actor function, and output from an AI/ML model. In some cases, analysis of data needed at the model training function 704 and the model inference function 706 may be performed at the data collection function 702. As illustrated, the data collection function 702 may deliver training data to the model training function 704 and inference data to the model inference function 706.

The model training function 704 may perform AI/ML model training, validation, and testing, which may generate model performance metrics as part of the model testing procedure. The model training function 704 may also be responsible for data preparation (e.g., data pre-processing and cleaning, formatting, and transformation) based on the training data delivered by the data collection function 702, if required.

The model training function 704 may provide model deployment/update data to the Model interface function 706. The model deployment/update data may be used to initially deploy a trained, validated, and tested AI/ML model to the model inference function 706 or to deliver an updated model to the model inference function 706.

As illustrated, the model inference function 706 may provide AI/ML model inference output (e.g., predictions or decisions) to the actor function 708 and may also provide model performance feedback to the model training function 704, at times. The model inference function 706 may also be responsible for data preparation (e.g., data pre-processing and cleaning, formatting, and transformation) based on inference data delivered by the data collection function 702, at times.

The inference output of the AI/ML model may be produced by the model inference function 706. Specific details of this output may be specific in terms of use cases. The model performance feedback may be used for monitoring the performance of the AI/ML model, at times. In some cases, the model performance feedback may be delivered to the model training function 704, for example, if certain information derived from the model inference function is suitable for improvement of the AI/ML model trained in the model training function 704.

The model inference function 706 may signal the outputs of the model to nodes that have requested them (e.g., via subscription) , or nodes that take actions based on the output from the model inference function. An AI/ML model used in a model inference function 706 may need to be initially trained, validated and tested by a model training function before deployment. The model training function 704 and model inference function 706 may be able to request specific information to be used to train or execute the AI/ML algorithm and to avoid reception of unnecessary information. The nature of such information may depend on the use case and on the AI/ML algorithm.

The actor function 708 may receive the output from the model inference function 706, which may trigger or perform corresponding actions. The actor function 708 may trigger actions directed to other entities or to itself. The feedback generated by the actor function 708 may provide information used to derive training data, inference data or to monitor the performance of the AI/ML Model. As noted above, input data for a data collection function 702 may include this feedback from the actor function 708. The feedback from the actor function 708 or other network entities (via Data Collection function) may also be used at the model inference function 706.

The AI/ML functional framework 700 may be deployed in various RAN intelligence-based use cases. Such use cases may include CSI feedback enhancement, enhanced beam management (BM) , positioning and location (Pos-Loc) accuracy enhancement, and various other use cases.

AI/ML based Time Domain Beam Prediction

In certain aspects, a UE or a BS may perform ML-based beam prediction using continuous measured or reported L1-RSRP in time domain. In some cases, a pre-trained deep neural network (DNN) model may be used for such ML-based predictive beam management.

Traditionally, beam qualities and failures are identified through measurement reports carried by relevant downlink (DL) and uplink (UL) reference signals (e.g., SSB, CSI-RS, RSRP) , which increase beam selection latency and beam management overhead, while at the same beam selection accuracy may be limited due to restrictions on power and overhead that may cause poor system performance.

Instead, the AI/ML based predictive beam management may reduce the amount of reference signal transmissions used to predict non-measured beam qualities and future possibility of beam blockage/failure. In predictive beam management, beam prediction may be a highly non-linear problem, which may be efficiently solved by the pre-trained DNN model that may predict future beam qualities, for example, based on a UE moving speed and trajectory that is difficult to be modeled through conventional statistical processing methods.

FIG. 8 is a diagram illustrating an example AI/ML based time domain beam prediction that achieves three predictive targets including: (1) future L1-RSRPs for current used beams, (2) candidate selected beams with strong power in the future, and (3) possibility of failure/blockage for current used beams.

The pre-trained DNN models with different the targets may be implemented both in the UE or the BS. A time series of L1-RSRPs may be measured by the UE and then reported to the BS as input by the pre-trained DNN models to infer future beam activities in order to enable beam prediction. The inference results compared with ground truth data as training data may be used to further train the pre-trained DNN models to improve accuracy. Without repeatedly monitoring reference signals, the AI/ML based time domain beam prediction may significantly reduce the UE power consumption and the UE-specific reference signal overhead, while at the same time improving network throughput and decreasing beam management latency.

The ML model may run at the UE or network entity (e.g., a BS such as a gNB) . The data collection function noted above may be used to provide training data for the BS and the UE, in which the training data for the UE may be collected through enhanced air interface or application layer approaches, and additional the UE computation may be required by the DNN models training and necessary data storage.

AI/ML based spatial diversity (SD) beam prediction may be used for uplink or downlink beam management. ML models, deployed at the UE or gNB, for such use cases may provide explicit or implicit SD beam prediction.

Aspects Related to Retransmission of CSI for ML-Based Beam Prediction

As noted above, ML-based beam prediction typically relies on user equipment (UE) reported measurement values. For example, as illustrated in FIG. 9, an ML-based algorithm may perform beam prediction based on periodically reported (e.g., every 160ms) reference signal received power (RSRP) measurements. In the illustrated example, the ML model may predict RSRPs (e.g., for the next 20ms instance) based on the series of RSRP measurements reports.

In RSRP reports are missing, the ML-based algorithm may use previous predicted (or previously reported) RSRPs to fill in the missing report information. Unfortunately, using the predicted RSRP to replace the missing RSRP reported values may lead to inaccurate beam prediction.

To help address such missing measurement reporting problems, aspects of the present disclosure propose techniques whereby certain information may be retransmitted, for example, when the occurrence of a missing measurement report is detected. Aspects of the present disclosure provide detailed UE capability definitions and signaling enhancements, that may help support retransmission of L1-reports, for gNB based and ML-assisted time domain beam prediction As will be described in greater detail below, a UE may be configured to buffer certain measurement information associated with periodic measurement reports so that, in the event a measurement report is missed, it may retransmit the information.

The measurement report retransmission proposed herein may be understood with reference to the call flow diagram 1000 of FIG. 10.

As illustrated, a UE may first be configured (by a network entity) for periodic (P) or semi-persistent (SP) CSI reporting. For example, the UE may be configured to report SSB rank indicator (SSBRI) , CSI resource indicator (CRI) and L1-RSRP/L1-Signal to Interference & Noise Ratio (L1-SINR) information, via CSI-Reports.

As illustrated, the UE may then periodically transmit a first CSI report, based on the configuration. In response to detecting a trigger condition, the UE may transmit an aperiodic (AP) second CSI report. For example, the condition may be receipt of a request for AP reporting from the network or the condition may be based on a triggering event associated with a CSI-RS resource configuration.

As illustrated in FIG. 11, in some cases, in order to support retransmission of certain information, the UE may buffers one or more components of report quantities (e.g., one or more channel characteristic measurements associated with the first P/SP CSI report) associated with a most recently reported first Channel State Information (CSI) report, until a certain first time instance after transmitting the first CSI report. After transmitting the first CSI report and until the first time instance, the UE can be further triggered with a second AP CSI report, or requested to report via uplink (UL) media access control (MAC) control element (MAC-CE) , a retransmission of the buffered report quantities.

Possible report quantities (that may be part of the AP reporting) may include L1-RSRPs/SINRs and their associated Connection-Management-Request (CMR) IDs and other report quantities like rank indication (RI) /pre-coding matrix indicator (PMI) /channel quality indicator (CQI) /layer interception (LI) . In some cases, a priority of the second (AP) reporting may be lower than other types of CSI reports e.g., (as the other ones impact more instantaneous communication performance) .

In some cases, the UE may only buffer measurement information after the UE reported its capability to perform such buffering. The UE may indicate such capabilities explicitly or implicitly.

For explicit UE capability reporting, the UE may report according to one or more options. For example, according to a first option, the UE may report a maximum number of L1-RSRPs/SINRs (together w/their associated CMR IDs) that can be buffered from the first CSI report. The table in FIG. 12A illustrates example of how a UE may report capabilities by indicating a row in a configuration table.

The reported maximum number may be further dependent on the maximum total number of CSI measurement resources (CMRs) included in the CMR set associated with the first CSI report, since a greater number of bits are needed to report CRI/SSBRI for greater number of CSI-RS/SSB resources. In some cases, the UE may further report multiple combinations of such capabilities, each combination indicating that the buffer can be simultaneously shared among the associated multiple active first CSI reports.

According to a second option, the UE may report one or multiple options of maximum number of buffered UCI payload bits. For example, as shown in FIG. 12B, the UE may indicate the maximum number of UCI payload bits the UE may buffer, for certain types of reports or combination of report types. In some cases, the buffered UCI payload bits are shared among multiple active first CSI reports.

One example of implicit UE capability reporting is via a reported number of CPUs the UE supports. For example, the UE may implicitly indicate the number of UCI bits it can buffer via a UE capability report that indicates a maximum number of CPUs the UE supports. In some cases, a certain number of maximum UCI payload bits that can be buffered at a certain time, is standard predefined to be associated with a single CPU. For example, a single CPU can be defined as buffering up2 45 UCI bits at a given time.

UE reports a certain number of CPUs, representing its capability to buffer UCI payloads, wherein reporting multiple number of CPUs represents extended number of UCI payload bits for the same duration. For example, as illustrated in FIG. 13, suppose a single CPU can be defined to occupy 45 payload bits to buffer at a certain time, UE reporting 2 CPUs represents that it can buffer up-to 90 UCI payload bits at a given time. In some cases, the number of UCI bits may be rounded up to the applicable number matching integer number of CPUs is considered when calculating occupied number of CPUs.

According to a first option, as illustrated in FIG. 13, the UE may be considered as occupying an additional number of CPUs after the first CSI Report. Such a number of CPUs may only occupied after the UE reported the first CSI report. According to a second option, the additional number of CPUs may be occupied with a TD offset before the slot transmitting the first CSI report. This may make sense because the UE may need to buffer the UCI payload bits before transmitting them for the first time. The offset can be standard predefined, or further reported as UE capability.

According to certain aspects, when to maintain or clear buffered UCI bits may depend on priorities between multiple first CSI reports (e.g., wither first-in-first-out) . If the simultaneously required number of bits (to buffer) is greater than the UE reported capability, the UE may clear the earliest buffered ones (e.g., effectively prioritizing the most recent first CSI report when buffering) .

In some cases, these two types of capability reporting may be combined. For example, instead of predefining the number of UCI payload bits by standard, the number of UCI payload bits associated with a single CPU may be UE reported. Based on this association, the buffering capability may be implicitly indicated by indicating the number of CSI processing units (CPUs) the UE supports, assuming each CPU is associated with a number of UCI bits.

The UE may apply various buffer release and/or replacement rules when determining what UCI bits to buffer or clear. Buffered UCI payload bits regarding a certain first CSI report can be released, based on various techniques.

For example, as illustrated in FIG. 14A, using a timer-based technique, the buffered UCI payload bits can be released, after a time starting after the associated first CSI report is initially transmitted, has expired. The timer length can be standard predefined, or further gNB configured together with the triggering state configurations associated with the first (AP) CSI report, or dynamically indicated when triggering the first (AP) CSI report. For example, when the first CSI report is an AP CSI report, the buffered UCI payload bits can be released after 5 slots.

According to a second option, as illustrated in FIG. 14B, buffered bits may be replaced by a new CSI report’s payload in a series of P/SP CSI reports. For example, the first CSI report may be associated with a P/SP CSI report setting, such that the buffered UCI payload bits are replaced by the UCI payload bits of the same series of P/SP CSI reports, after a next applicable first CSI report is transmitted.

FIG. 15 shows how the second AP CSI report may be triggered and may include information from a previous P/SP CSI report. There are various options for triggering the second AP CSI Report, as shown in FIG. 15. For example, in some cases, the UE may be further configured with an AP CSI report triggering state configuration associated with the second AP CSI report, comprising at least one of the following enhancement information: an ID of the CSI report setting associated with the first CSI report and a number of L1-RSRPs/SINRs that should be buffered. For example, to reduce buffering efforts, although the first CSI report may need to report 4 L1-RSRPs together with the CMR-IDs, the second AP CSI report may only need to report the strongest one/two. A buffer release timer, as described above, may also be used. Such configurations may be via the CSI-AssociatedReportConfigInfo IE associated with the triggering state configuration of the second AP CSI report.

In some cases, upon receiving a UL-grant DCI triggering the second AP CSI report, the UE may report the UCI payloads most recently reported by the first CSI report. The network may try and make sure that the second AP CSI report should not be reported at a time where the associated UCI payloads are already released. In some cases, if the UE receives the UL-grant before the associated timer expires, the UE may reset the timer after the second CSI report is successfully transmitted. In this manner, if the second CSI report is also missed, the gNB can further trigger another second CSI report.

As illustrated in FIG. 16, in some cases, buffered measurements may be transmitted via a MAC-CE based UCI Retransmission. Such buffered UCI payloads can be alternatively reported via UL MAC-CE. This can be further based on, for example, the buffering configurations described above, which may be configured alternatively by the CSI report setting associated with the first CSI report. In some cases, an UL MAC-CE can be requested by the gNB via MAC-CE/DCI. The request may include the first CSI Report’s report setting ID.

If the UE receives the gNB commands on transmitting such UL MAC-CE before the associated Timer expires, the UE may reset the timer after the MAC-CE is successfully transmitted. Such that if the MAC-CE is also missed, the gNB can further trigger another second CSI report or request another MAC-CE.

As illustrated in FIG. 17, in some cases, the techniques described herein may be extended to reporting additional L1-RSRPs/SINRs (e.g., measurement for different CMRs than associated with the first P/SP CSI report transmissions. In such cases, the report quantities in the second CSI report may alternatively be additional L1-RSRPs that have not been reported in the first CSI report. This approach may help remove prediction uncertainty with marginal additional reporting efforts. Similar buffering capabilities and buffer release rules, as described above, may be extended to such use cases.

In some cases, the UE capabilities reported, as described above, may be reported for any activated ServCell. For example, this may imply that different component carriers (CCs) may have their own buffer memory (allocation at the UE) . In other cases, the UE capabilities reported, as described above, may be reported as a shared capability among multiple ServCells (e.g., FR1 and FR2 CCs may need to share a common buffer memory) .

Example Operations of a User Equipment

FIG. 18 shows an example of a method 1800 for wireless communications by a UE, such as UE 104 of FIGS. 1 and 3.

Method 1800 begins at step 1805 with receiving a configuration for periodic or aperiodic CSI reporting. 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. 20.

Method 1800 then proceeds to step 1810 with transmitting a first CSI report, in accordance with the configuration for periodic or aperiodic CSI reporting. 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.

Method 1800 then proceeds to step 1815 with transmitting an aperiodic second CSI report containing one or more channel characteristic measurements associated with the first CSI report, if one or more conditions are met. 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 some aspects, the one or more conditions are met if the UE receives a request to transmit the second CSI report.

In some aspects, the UE buffers the channel characteristic measurements associated with the first CSI report for a time duration after transmitting the first CSI report; and the UE expects to receive the request within the time duration.

In some aspects, the channel characteristic measurements associated with the first CSI report comprise at least one of: RSRP, SINR, RI, PMI, CQI, or LI values.

In some aspects, the channel characteristic measurements associated with the first CSI report comprise one or more values not previously reported.

In some aspects, the aperiodic second CSI report has a lower priority than the one or more other types of CSI reports.

In some aspects, the method 1800 further includes reporting a capability of the UE to buffer the channel characteristic measurements associated with the first CSI report. In some cases, the operations of this step refer to, or may be performed by, circuitry for reporting and/or code for reporting as described with reference to FIG. 20.

In some aspects, the capability is indicated as a number of UCI bits the UE can buffer at a given time.

In some aspects, the UE indicates one or more capability indexes, wherein each capability index maps to a number of UCI bits.

In some aspects, the capability is implicitly indicated by a number of CPUs the UE supports, each CPU associated with a number of UCI bits.

In some aspects, the UE occupies additional CPUs after transmitting the first CSI report while buffering the one or more report quantities.

In some aspects, the method 1800 further includes clearing bits of the buffered one or more report quantities in order to avoid exceeding the number of UCI bits the UE indicated it can support, wherein the bits are cleared based on how long they have been buffered. In some cases, the operations of this step refer to, or may be performed by, circuitry for clearing and/or code for clearing as described with reference to FIG. 20.

In some aspects, the capability is indicated by reporting: a number of CPUs the UE supports; and a number of UCI bits the UE supports per CPU.

In some aspects, the capability of the UE to buffer the channel characteristic measurements associated with the first CSI report is reported for activated serving cells.

In some aspects, the capability of the UE to buffer the channel characteristic measurements associated with the first CSI report is reported as a shared capability among multiple serving cells.

In some aspects, the method 1800 further includes releasing buffered bits of the channel characteristic measurements associated with the first CSI report a time period after transmission of the first CSI report. In some cases, the operations of this step refer to, or may be performed by, circuitry for releasing and/or code for releasing as described with reference to FIG. 20.

In some aspects, the first report is associated with a periodic or SP CSI report setting; and the UE released buffered bits of the channel characteristic measurements associated with the first CSI report, such that buffered UCI payload bits are replaced by UCI payload bits of a same series of periodic or SP, after a subsequent CSI report is.

In some aspects, the one or more conditions involve a report triggering state associated with a configuration of the second CSI report.

In some aspects, the configuration of the second CSI report indicates an AP CSI triggering state association with the second CSI report.

In some aspects, the second CSI report is transmitted via an uplink MAC-CE.

In some aspects, the method 1800 further includes receiving a request for the second CSI report, wherein the second CSI report is transmitted via the uplink MAC CE in response to the request. 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. 20.

In some aspects, the channel characteristic measurements associated with the first CSI report comprise one or more channel characteristic measurements not previously reported in the first CSI report.

In one aspect, method 1800, or any aspect related to it, may be performed by an apparatus, such as communications device 2000 of FIG. 20, which includes various components operable, configured, or adapted to perform the method 1800. 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 Operations of a Network Entity

FIG. 19 shows an example of a method 1900 for wireless communications by a network entity, such as BS 102 of FIGS. 1 and 3, or a disaggregated base station as discussed with respect to FIG. 2.

Method 1900 begins at step 1905 with transmitting a configuration to configure a UE for periodic or aperiodic CSI reporting. 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 1910 with receiving a first CSI report, generated by the UE in accordance with the configuration for periodic or aperiodic CSI reporting. 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.

Method 1900 then proceeds to step 1915 with receiving an aperiodic second CSI report generated by the UE if one or more conditions are met, the second CSI report containing one or more channel characteristic measurements associated with the first CSI report. 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 some aspects, the one or more conditions are met if the network entity transmits a request for the UE to transmit the second CSI report is received.

In some aspects, the request is transmitted in response to determining a first CSI report transmission was missed.

In some aspects, the method 1900 further includes receiving a report of a capability of the UE to buffer the channel characteristic measurements associated with the first CSI report. 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 some aspects, the UE is considered as occupying additional CPUs after transmitting the first CSI report while buffering the one or more report quantities.

In some aspects, the second CSI report is received via an uplink MAC-CE.

In some aspects, the method 1900 further includes receiving a request for the second CSI report, wherein the second CSI report is received via the uplink MAC CE in response to the request. 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 one aspect, method 1900, or any aspect related to it, may be performed by an apparatus, such as communications device 2100 of FIG. 21, which includes various components operable, configured, or adapted to perform the method 1900. 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, such as UE 104 described above with respect to FIGS. 1 and 3.

The communications device 2000 includes a processing system 2005 coupled to the transceiver 2075 (e.g., a transmitter and/or a receiver) . The transceiver 2075 is configured to transmit and receive signals for the communications device 2000 via the antenna 2080, 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 2040 via a bus 2070. In certain aspects, the computer-readable medium/memory 2040 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, 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 2040 stores code (e.g., executable instructions) , such as code for receiving 2045, code for transmitting 2050, code for reporting 2055, code for clearing 2060, and code for releasing 2065. Processing of the code for receiving 2045, code for transmitting 2050, code for reporting 2055, code for clearing 2060, and code for releasing 2065 may cause the communications device 2000 to perform the method 1800 described with respect to FIG. 18, 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 2040, including circuitry such as circuitry for receiving 2015, circuitry for transmitting 2020, circuitry for reporting 2025, circuitry for clearing 2030, and circuitry for releasing 2035. Processing with circuitry for receiving 2015, circuitry for transmitting 2020, circuitry for reporting 2025, circuitry for clearing 2030, and circuitry for releasing 2035 may cause the communications device 2000 to perform the method 1800 described with respect to FIG. 18, 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, 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 transceiver 2075 and the antenna 2080 of the communications device 2000 in FIG. 20. 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 2075 and the antenna 2080 of the communications device 2000 in FIG. 20.

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 FIGS. 1 and 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 2145 (e.g., a transmitter and/or a receiver) and/or a network interface 2155. The transceiver 2145 is configured to transmit and receive signals for the communications device 2100 via the antenna 2150, such as the various signals as described herein. The network interface 2155 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 2125 via a bus 2140. In certain aspects, the computer-readable medium/memory 2125 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 2125 stores code (e.g., executable instructions) , such as code for transmitting 2130 and code for receiving 2135. Processing of the code for transmitting 2130 and code for receiving 2135 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 2125, 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 as 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 as 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 transceiver 2145 and the antenna 2150 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 transceiver 2145 and the antenna 2150 of the communications device 2100 in FIG. 21.

Example Clauses

Implementation examples are described in the following numbered clauses:

Clause 1: A method of wireless communication by a UE, comprising: receiving a configuration for periodic or aperiodic CSI reporting; transmitting a first CSI report, in accordance with the configuration for periodic or aperiodic CSI reporting; and transmitting an aperiodic second CSI report containing one or more channel characteristic measurements associated with the first CSI report, if one or more conditions are met.

Clause 2: The method of Clause 1, wherein the one or more conditions are met if the UE receives a request to transmit the second CSI report.

Clause 3: The method of Clause 2, wherein: the UE buffers the channel characteristic measurements associated with the first CSI report for a time duration after transmitting the first CSI report; and the UE expects to receive the request within the time duration.

Clause 4: The method of any one of Clauses 1-3, wherein the channel characteristic measurements associated with the first CSI report comprise at least one of: RSRP, SINR, RI, PMI, CQI, or LI values.

Clause 5: The method of any one of Clauses 1-4, wherein the channel characteristic measurements associated with the first CSI report comprise one or more values not previously reported.

Clause 6: The method of any one of Clauses 1-5, wherein the aperiodic second CSI report has a lower priority than the one or more other types of CSI reports.

Clause 7: The method of any one of Clauses 1-6, further comprising: reporting a capability of the UE to buffer the channel characteristic measurements associated with the first CSI report.

Clause 8: The method of Clause 7, wherein the capability is indicated as a number of UCI bits the UE can buffer at a given time.

Clause 9: The method of Clause 8, wherein the UE indicates one or more capability indexes, wherein each capability index maps to a number of UCI bits.

Clause 10: The method of Clause 8, wherein the capability is implicitly indicated by a number of CPUs the UE supports, each CPU associated with a number of UCI bits.

Clause 11: The method of Clause 10, wherein the UE occupies additional CPUs after transmitting the first CSI report while buffering the one or more report quantities.

Clause 12: The method of Clause 7, further comprising: clearing bits of the buffered one or more report quantities in order to avoid exceeding the number of UCI bits the UE indicated it can support, wherein the bits are cleared based on how long they have been buffered.

Clause 13: The method of Clause 7, wherein the capability is indicated by reporting: a number of CPUs the UE supports; and a number of UCI bits the UE supports per CPU.

Clause 14: The method of Clause 7, wherein the capability of the UE to buffer the channel characteristic measurements associated with the first CSI report is reported for activated serving cells.

Clause 15: The method of Clause 7, wherein the capability of the UE to buffer the channel characteristic measurements associated with the first CSI report is reported as a shared capability among multiple serving cells.

Clause 16: The method of any one of Clauses 1-15, further comprising: releasing buffered bits of the channel characteristic measurements associated with the first CSI report a time period after transmission of the first CSI report.

Clause 17: The method of any one of Clauses 1-16, wherein: the first report is associated with a periodic or SP CSI report setting; and the UE released buffered bits of the channel characteristic measurements associated with the first CSI report, such that buffered UCI payload bits are replaced by UCI payload bits of a same series of periodic or SP, after a subsequent CSI report is.

Clause 18: The method of any one of Clauses 1-17, wherein the one or more conditions involve a report triggering state associated with a configuration of the second CSI report.

Clause 19: The method of Clause 18, wherein: the configuration of the second CSI report indicates an AP CSI triggering state association with the second CSI report.

Clause 20: The method of any one of Clauses 1-19, wherein the second CSI report is transmitted via an uplink MAC-CE.

Clause 21: The method of Clause 20, further comprising: receiving a request for the second CSI report, wherein the second CSI report is transmitted via the uplink MAC CE in response to the request.

Clause 22: The method of any one of Clauses 1-21, wherein the channel characteristic measurements associated with the first CSI report comprise one or more channel characteristic measurements not previously reported in the first CSI report.

Clause 23: A method of wireless communication by a network entity, comprising: transmitting a configuration to configure a UE for periodic or aperiodic CSI reporting; receiving a first CSI report, generated by the UE in accordance with the configuration for periodic or aperiodic CSI reporting; and receiving an aperiodic second CSI report generated by the UE if one or more conditions are met, the second CSI report containing one or more channel characteristic measurements associated with the first CSI report.

Clause 24: The method of Clause 23, wherein the one or more conditions are met if the network entity transmits a request for the UE to transmit the second CSI report is received.

Clause 25: The method of Clause 24, wherein the request is transmitted in response to determining a first CSI report transmission was missed.

Clause 26: The method of any one of Clauses 23-25, wherein the channel characteristic measurements associated with the first CSI report comprise at least one of: RSRP, SINR, RI, PMI, CQI, or LI values.

Clause 27: The method of any one of Clauses 23-26, wherein the channel characteristic measurements associated with the first CSI report comprise one or more values not previously reported.

Clause 28: The method of any one of Clauses 23-27, wherein the aperiodic second CSI report has a lower priority than the one or more other types of CSI reports.

Clause 29: The method of any one of Clauses 23-28, further comprising: receiving a report of a capability of the UE to buffer the channel characteristic measurements associated with the first CSI report.

Clause 30: The method of Clause 29, wherein the capability is indicated as a number of UCI bits the UE can buffer at a given time.

Clause 31: The method of Clause 30, wherein the UE indicates one or more capability indexes, wherein each capability index maps to a number of UCI bits.

Clause 32: The method of Clause 30, wherein the capability is implicitly indicated by a number of CPUs the UE supports, each CPU associated with a number of UCI bits.

Clause 33: The method of Clause 32, wherein the UE is considered as occupying additional CPUs after transmitting the first CSI report while buffering the one or more report quantities.

Clause 34: The method of Clause 29, wherein the capability is indicated by reporting: a number of CPUs the UE supports; and a number of UCI bits the UE supports per CPU.

Clause 35: The method of Clause 29, wherein the capability of the UE to buffer the channel characteristic measurements associated with the first CSI report is reported for activated serving cells.

Clause 36: The method of Clause 29, wherein the capability of the UE to buffer the channel characteristic measurements associated with the first CSI report is reported as a shared capability among multiple serving cells.

Clause 37: The method of any one of Clauses 23-36, wherein the one or more conditions involve a report triggering state associated with a configuration of the second CSI report.

Clause 38: The method of Clause 37, wherein: the configuration of the second CSI report indicates an AP CSI triggering state association with the second CSI report.

Clause 39: The method of any one of Clauses 23-38, wherein the second CSI report is received via an uplink MAC-CE.

Clause 40: The method of Clause 39, further comprising: receiving a request for the second CSI report, wherein the second CSI report is received via the uplink MAC CE in response to the request.

Clause 41: The method of any one of Clauses 23-40, wherein the channel characteristic measurements associated with the first CSI report comprise one or more channel characteristic measurements not previously reported in the first CSI report.

Clause 42: 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 1-41.

Clause 43: An apparatus, comprising means for performing a method in accordance with any one of Clauses 1-41.

Clause 44: 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 1-41.

Clause 45: A computer program product embodied on a computer-readable storage medium comprising code for performing a method in accordance with any one of Clauses 1-41.

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 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.., 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

A method of wireless communication by a user equipment (UE) , comprising:

receiving a configuration for periodic or aperiodic channel state information (CSI) reporting;

transmitting a first CSI report, in accordance with the configuration for periodic or aperiodic CSI reporting; and

transmitting an aperiodic second CSI report containing one or more channel characteristic measurements associated with the first CSI report, if one or more conditions are met.
The method of claim 1, wherein the one or more conditions are met if the UE receives a request to transmit the second CSI report.
The method of claim 2, wherein:

the UE buffers the channel characteristic measurements associated with the first CSI report for a time duration after transmitting the first CSI report; and

the UE expects to receive the request within the time duration.
The method of claim 1, wherein the channel characteristic measurements associated with the first CSI report comprise at least one of: reference signal received power (RSRP) , signal to interference and noise ratio (SINR) , rank indicator (RI) , precoding matrix indicator (PMI) , channel quality indicator CQI) , or layer indicator (LI) values.
The method of claim 1, wherein the channel characteristic measurements associated with the first CSI report comprise one or more values not previously reported.
The method of claim 1, wherein the aperiodic second CSI report has a lower priority than the one or more other types of CSI reports.
The method of claim 1, further comprising reporting a capability of the UE to buffer the channel characteristic measurements associated with the first CSI report.
The method of claim 7, wherein the capability is indicated as a number of uplink control information (UCI) bits the UE can buffer at a given time.
The method of claim 8, wherein the UE indicates one or more capability indexes, wherein each capability index maps to a number of UCI bits.
The method of claim 8, wherein the capability is implicitly indicated by a number of CSI processing units (CPUs) the UE supports, each CPU associated with a number of UCI bits.
The method of claim 10, wherein the UE occupies additional CPUs after transmitting the first CSI report while buffering the one or more report quantities.
The method of claim 7, further comprising:

clearing bits of the buffered one or more report quantities in order to avoid exceeding the number of UCI bits the UE indicated it can support, wherein the bits are cleared based on how long they have been buffered.
The method of claim 7, wherein the capability is indicated by reporting:

a number of CSI processing units (CPUs) the UE supports; and

a number of UCI bits the UE supports per CPU.
The method of claim 7, wherein the capability of the UE to buffer the channel characteristic measurements associated with the first CSI report is reported for activated serving cells.
The method of claim 7, wherein the capability of the UE to buffer the channel characteristic measurements associated with the first CSI report is reported as a shared capability among multiple serving cells.
The method of claim 1, further comprising releasing buffered bits of the channel characteristic measurements associated with the first CSI report a time period after transmission of the first CSI report.
The method of claim 1, wherein:

the first report is associated with a periodic or semi-persistent (SP) CSI report setting; and

the UE released buffered bits of the channel characteristic measurements associated with the first CSI report, such that buffered UCI payload bits are replaced by UCI payload bits of a same series of periodic or SP, after a subsequent CSI report is.
The method of claim 1, wherein the one or more conditions involve a report triggering state associated with a configuration of the second CSI report.
The method of claim 18, wherein:

the configuration of the second CSI report indicates an aperiodic (AP) CSI triggering state association with the second CSI report.
The method of claim 1, wherein the second CSI report is transmitted via an uplink medium access control (MAC) control element (CE) .
The method of claim 20, further comprising:

receiving a request for the second CSI report, wherein the second CSI report is transmitted via the uplink MAC CE in response to the request.
The method of claim 1, wherein the channel characteristic measurements associated with the first CSI report comprise one or more channel characteristic measurements not previously reported in the first CSI report.
A method of wireless communication by a network entity, comprising:

transmitting a configuration to configure a user equipment (UE) for periodic or aperiodic channel state information (CSI) reporting;

receiving a first CSI report, generated by the UE in accordance with the configuration for periodic or aperiodic CSI reporting; and

receiving an aperiodic second CSI report generated by the UE if one or more conditions are met, the second CSI report containing one or more channel characteristic measurements associated with the first CSI report.
The method of claim 23, wherein the one or more conditions are met if the network entity transmits a request for the UE to transmit the second CSI report is received.
The method of claim 24, wherein the request is transmitted in response to determining a first CSI report transmission was missed.
The method of claim 23, wherein the channel characteristic measurements associated with the first CSI report comprise at least one of: reference signal received power (RSRP) , signal to interference and noise ratio (SINR) , rank indicator (RI) , precoding matrix indicator (PMI) , channel quality indicator CQI) , or layer indicator (LI) values.
The method of claim 23, wherein the channel characteristic measurements associated with the first CSI report comprise one or more values not previously reported.
The method of claim 23, wherein the aperiodic second CSI report has a lower priority than the one or more other types of CSI reports.
The method of claim 23, further comprising receiving a report of a capability of the UE to buffer the channel characteristic measurements associated with the first CSI report.
The method of claim 29, wherein the capability is indicated as a number of uplink control information (UCI) bits the UE can buffer at a given time.
The method of claim 30, wherein the UE indicates one or more capability indexes, wherein each capability index maps to a number of UCI bits.
The method of claim 30, wherein the capability is implicitly indicated by a number of CSI processing units (CPUs) the UE supports, each CPU associated with a number of UCI bits.
The method of claim 32, wherein the UE is considered as occupying additional CPUs after transmitting the first CSI report while buffering the one or more report quantities.
The method of claim 29, wherein the capability is indicated by reporting:

a number of CSI processing units (CPUs) the UE supports; and

a number of UCI bits the UE supports per CPU.
The method of claim 29, wherein the capability of the UE to buffer the channel characteristic measurements associated with the first CSI report is reported for activated serving cells.
The method of claim 29, wherein the capability of the UE to buffer the channel characteristic measurements associated with the first CSI report is reported as a shared capability among multiple serving cells.
The method of claim 23, wherein the one or more conditions involve a report triggering state associated with a configuration of the second CSI report.
The method of claim 37, wherein:

the configuration of the second CSI report indicates an aperiodic (AP) CSI triggering state association with the second CSI report.
The method of claim 23, wherein the second CSI report is received via an uplink medium access control (MAC) control element (CE) .
The method of claim 39, further comprising:

receiving a request for the second CSI report, wherein the second CSI report is received via the uplink MAC CE in response to the request.
The method of claim 23, wherein the channel characteristic measurements associated with the first CSI report comprise one or more channel characteristic measurements not previously reported in the first CSI report.
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 Claims 1-41.
An apparatus, comprising means for performing a method in accordance with any one of Claims 1-41.
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 Claims 1-41.
A computer program product embodied on a computer-readable storage medium comprising code for performing a method in accordance with any one of Claims 1-41.