Network data collection for machine learning-based channel state information compression and prediction
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- GOOGLE LLC
- Filing Date
- 2023-07-13
- Publication Date
- 2026-04-22
AI Technical Summary
The accuracy of channel state information (CSI) reports in wireless communication systems is affected by various factors, including control signaling mechanisms, CSI report content, and UE complexity-related aspects such as CPU occupancy rules and minimum processing delays, which impact the quality of training data for machine learning (ML) systems used for CSI compression and prediction.
A configuration procedure is implemented for network entities to communicate with user equipment (UEs), where UEs receive specific report content configurations for CSI reports and transmit CSI reports based on predefined conditions such as CPU occupancy rules and minimum processing delays. This configuration enhances the accuracy of CSI reports sent to network entities.
The proposed solution improves the accuracy of CSI reports, which is critical for the performance of ML systems used for CSI compression and prediction, thereby enhancing the overall system performance by reducing the need for quantized codebooks.
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Figure CN2023107273_16012025_PF_FP_ABST
Abstract
Description
NETWORK DATA COLLECTION FOR MACHINE LEARNING-BASED CHANNEL STATE INFORMATION COMPRESSION AND PREDICTIONTECHNICAL FIELD
[0001] The present disclosure relates generally to wireless communication, and more particularly, to network data collection for machine learning (ML) -based channel state information (CSI) compression and prediction.BACKGROUND
[0002] The Third Generation Partnership Project (3GPP) specifies a radio interface referred to as fifth generation (5G) new radio (NR) (5G NR) . An architecture for a 5G NR wireless communication system includes a 5G core (5GC) network, a 5G radio access network (5G-RAN) , a user equipment (UE) , etc. The 5G NR architecture seeks to provide increased data rates, decreased latency, and / or increased capacity compared to prior generation cellular communication systems.
[0003] Wireless communication systems, in general, provide various telecommunication services (e.g., telephony, video, data, messaging, broadcasts, etc. ) based on multiple-access technologies, such as orthogonal frequency division multiple access (OFDMA) technologies, that support communication with multiple UEs. Improvements in mobile broadband continue the progression of such wireless communication technologies. For example, the accuracy of a channel state information (CSI) report is associated with the data collection process, which can affect the quality of the training data used for the machine learning (ML) system. The accuracy of the CSI report depends on several factors including a control signaling mechanism and CSI report content. Furthermore, UE complexity-related aspects including CSI processing unit (CPU) occupancy rules and a minimum processing delay for the CSI report may affect the accuracy of the CSI report.
[0004] BRIEF SUMMARY
[0005] The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects. This summary neither identifies key or critical elements of all aspects nor delineates the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.
[0006] To reduce the size of a channel state information (CSI) report, a user equipment (UE) can compress a channel estimate array using a machine learning (ML) model and feed the compressed estimate back to a network entity. The network entity then decompresses, using another ML model, the channel estimate array and uses the decompressed estimate to determine downlink transmission parameters. This compression and decompression using the ML system eliminates the need for a quantized codebook and can improve overall system performance. The performance of the ML system depends on the performance of an ML model trained by the training data collected during a data collection process. Additionally, the performance may depend on the data collected for refining the ML model as well as for monitoring the ML model.
[0007] The accuracy of a CSI report is associated with the data collection process, which can affect the quality of the training data used for the ML system. The accuracy of the CSI report depends on several factors including a control signaling mechanism and CSI report content. Furthermore, UE complexity-related aspects including CSI processing unit (CPU) occupancy rules and a minimum processing delay for the CSI report may affect the accuracy of the CSI report.
[0008] Aspects of the present disclosure address the above-noted and other deficiencies by implementing a configuration procedure for a network entity to communicate with UEs. In one example, the UE may receive, from the network entity, a configuration that indicates a specific report content for the CSI report. In another example, the UE transmits, to the network entity, the CSI report based on UE predefined conditions, such as a CPU occupancy rule for calculation of the CSI report, or a minimum processing delay for the CSI report. The configuration procedure may provide improved accuracy for the CSI report to the network entity.
[0009] According to some aspects, the UE receives, from a network entity, a channel state information-reference signal (CSI-RS) on a channel measurement resource (CMR) configured for collection of data associated with at least one of CSI compression or CSI prediction. The UE transmits, to the network entity, a CSI report including precoder information for the data based on the receiving the CSI-RS on the CMR.
[0010] According to some aspects, the network entity transmits, to a UE, a CSI-RS on a CMR configured for collection of data associated with at least one of CSI compression or CSI prediction. The network entity receives, from the UE, a CSI report including precoder information for the data based on the receiving of the CSI-RS on the CMR.BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 illustrates a diagram of a wireless communications system that includes a plurality of user equipments (UEs) and network entities in communication over one or more cells according to an embodiment.
[0012] FIG. 2 is a channel state information (CSI) compression according to an embodiment.
[0013] FIG. 3 illustrates an example of a CSI prediction according to an embodiment.
[0014] FIG. 4 is a signaling diagram illustrating communications between a UE and a network entity for performing report content configuration and report procedure according to an embodiment.
[0015] FIG. 5 illustrates an example for the channel quality indictor (CQI) report for multiple number of layers according to an embodiment.
[0016] FIG. 6A illustrates one example for the CSI report for X=3 channel measurement resource (CMR) instances based on a reference time according to an embodiment.
[0017] FIG. 6B illustrates one example for the CSI report for X report instances and Y averaging instances based on a reference time according to an embodiment.
[0018] FIG. 6C illustrates one example for the CSI report based on multiple aperiodic channel state information-reference signal (CSI-RS) instances according to an embodiment.
[0019] FIG. 7 is a flowchart of a method of wireless communication at a UE according to an embodiment.
[0020] FIG. 8 is a flowchart of a method of wireless communication at a network entity according to an embodiment.
[0021] FIG. 9 is a diagram illustrating a hardware implementation for an example UE apparatus according to some embodiments.
[0022] FIG. 10 is a diagram illustrating a hardware implementation for one or more example network entities according to some embodiments.DETAILED DESCRIPTION
[0023] FIG. 1 illustrates a diagram 100 of a wireless communications system associated with a plurality of cells 190. The wireless communications system includes user equipments (UEs) 102 and base stations / network entities 104. Some base stations may include an aggregated base station architecture and other base stations may include a disaggregated base station architecture. The aggregated base station architecture utilizes a radio protocol stack that is physically or logically integrated within a single radio access network (RAN) node. A disaggregated base station architecture utilizes a protocol stack that is physically or logically distributed among two or more units (e.g., radio unit (RU) 106, distributed unit (DU) 108, central unit (CU) 110) . For example, a CU 110 is implemented within a RAN node, and one or more DUs 108 may be co-located with the CU 110, or alternatively, may be geographically or virtually distributed throughout one or multiple other RAN nodes. The DUs 108 may be implemented to communicate with one or more RUs 106. Any of the RU 106, the DU 108 and the CU 110 can be implemented as virtual units, such as a virtual radio unit (VRU) , a virtual distributed unit (VDU) , or a virtual central unit (VCU) . The base station / network entity 104 (e.g., an aggregated base station or disaggregated units of the base station, such as the RU 106 or the DU 108) , may be referred to as a transmission reception point (TRP) .
[0024] Operations of the base station 104 and / or network designs may be based on aggregation characteristics of base station functionality. For example, disaggregated base station architectures are utilized in an integrated access backhaul (IAB) network, an open-radio access network (O-RAN) network, or a virtualized radio access network (vRAN) , which may also be referred to a cloud radio access network (C-RAN) . Disaggregation may include distributing functionality across the two or more units at various physical locations, as well as distributing functionality for at least one unit virtually, which can enable flexibility in network designs. The various units of the disaggregated base station architecture, or the disaggregated RAN architecture, can be configured for wired or wireless communication with at least one other unit. For example, the base stations 104d, 104e and / or the RUs 106a, 106b, 106c, 106d may communicate with the UEs 102a, 102b, 102c, 102d, and / or 102s via one or more radio frequency (RF) access links based on a Uu interface. In examples, multiple RUs 106 and / or base stations 104 may simultaneously serve the UEs 102, such as by intra-cell and / or inter-cell access links between the UEs 102 and the RUs 106 / base stations 104.
[0025] The RU 106, the DU 108, and the CU 110 may include (or may be coupled to) one or more interfaces configured to transmit or receive information / signals via a wired or wireless transmission medium. For example, a wired interface can be configured to transmit or receive the information / signals over a wired transmission medium, such as via the fronthaul link 160 between the RU 106d and the baseband unit (BBU) 112 of the base station 104d associated with the cell 190d. The BBU 112 includes a DU 108 and a CU 110, which may also have a wired interface (e.g., midhaul link) configured between the DU 108 and the CU 110 to transmit or receive the information / signals between the DU 108 and the CU 110. In further examples, a wireless interface, which may include a receiver, a transmitter, or a transceiver, such as an RF transceiver, configured to transmit and / or receive the information / signals via the wireless transmission medium, such as for information communicated between the RU 106a of the cell 190a and the base station 104e of the cell 190e via cross-cell communication beams 136-138 of the RU 106a and the base station 104e.
[0026] The RUs 106 may be configured to implement lower layer functionality. For example, the RU 106 is controlled by the DU 108 and may correspond to a logical node that hosts RF processing functions, or lower layer PHY functionality, such as execution of fast Fourier transform (FFT) , inverse FFT (iFFT) , digital beamforming, physical random access channel (PRACH) extraction and filtering, etc. The functionality of the RU 106 may be based on the functional split, such as a functional split of lower layers.
[0027] The RUs 106 may transmit or receive over-the-air (OTA) communication with one or more UEs 102. For example, the RU 106b of the cell 190b communicates with the UE 102b of the cell 190b via a first set of communication beams 132 of the RU 106b and a second set of communication beams 134b of the UE 102b, which may correspond to inter-cell communication beams or, in some examples, cross-cell communication beams. For instance, the UE 102b of the cell 190b may communicate with the RU 106a of the cell 190a via a third set of communication beams 134a of the UE 102b and a fourth set of communication beams 136 of the RU 106a. DUs 108 can control both real-time and non-real-time features of control plane and user plane communications of the RUs 106.
[0028] Any combination of the RU 106, the DU 108, and the CU 110, or reference thereto individually, may correspond to a base station 104. Thus, the base station 104 may include at least one of the RU 106, the DU 108, or the CU 110. The base stations 104 provide the UEs 102 with access to a core network. The base stations 104 may relay communications between the UEs 102 and the core network (not shown) . The base stations 104 may be associated with macrocells for higher-power cellular base stations and / or small cells for lower-power cellular base stations. For example, the cell 190e may correspond to a macrocell, whereas the cells 190a-190d may correspond to small cells. Small cells include femtocells, picocells, microcells, etc. A network that includes at least one macrocell and at least one small cell may be referred to as a “heterogeneous network. ”
[0029] Transmissions from a UE 102 to a base station 104 / RU 106 are referred to as uplink (UL) transmissions, whereas transmissions from the base station 104 / RU 106 to the UE 102 are referred to as downlink (DL) transmissions. Uplink transmissions may also be referred to as reverse link transmissions and downlink transmissions may also be referred to as forward link transmissions. For example, the RU 106d utilizes antennas of the base station 104d of cell 190d to transmit a downlink / forward link communication to the UE 102d or receive an uplink / reverse link communication from the UE 102d based on the Uu interface associated with the access link between the UE 102d and the base station 104d / RU 106d.
[0030] Communication links between the UEs 102 and the base stations 104 / RUs 106 may be based on multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication links may be associated with one or more carriers. The UEs 102 and the base stations 104 / RUs 106 may utilize a spectrum bandwidth of Y MHz (e.g., 5, 10, 15, 20, 100, 400, 800, 1600, 2000, etc. MHz) per carrier allocated in a carrier aggregation of up to a total of Yx MHz, where x component carriers (CCs) are used for communication in each of the uplink and downlink directions. The carriers may or may not be adjacent to each other along a frequency spectrum. In examples, uplink and downlink carriers may be allocated in an asymmetric manner, with more or fewer carriers allocated to either the uplink or the downlink. A primary component carrier and one or more secondary component carriers may be included in the component carriers. The primary component carrier may be associated with a primary cell (PCell) and a secondary component carrier may be associated with a secondary cell (SCell) .
[0031] Some UEs 102, such as the UEs 102a and 102s, may perform device-to-device (D2D) communications over sidelink. For example, a sidelink communication / D2D link utilizes a spectrum for a wireless wide area network (WWAN) associated with uplink and downlink communications. Such sidelink / D2D communication may be performed through various wireless communications systems, such as wireless fidelity (Wi-Fi) systems, Bluetooth systems, Long Term Evolution (LTE) systems, New Radio (NR) systems, etc.
[0032] The UEs 102 and the base stations 104 / RUs 106 may each include a plurality of antennas. The plurality of antennas may correspond to antenna elements, antenna panels, and / or antenna arrays that may facilitate beamforming operations. For example, the RU 106b transmits a downlink beamformed signal based on a first set of communication beams 132 to the UE 102b in one or more transmit directions of the RU 106b. The UE 102b may receive the downlink beamformed signal based on a second set of communication beams 134b from the RU 106b in one or more receive directions of the UE 102b. In a further example, the UE 102b may also transmit an uplink beamformed signal (e.g., sounding reference signal (SRS) ) to the RU 106b based on the second set of communication beams 134b in one or more transmit directions of the UE 102b. The RU 106b may receive the uplink beamformed signal from the UE 102b in one or more receive directions of the RU 106b. The UE 102b may perform beam training to determine the best receive and transmit directions for the beamformed signals. The transmit and receive directions for the UEs 102 and the base stations 104 / RUs 106 may or may not be the same.
[0033] In further examples, beamformed signals may be communicated between a first base station / RU 106a and a second base station 104e. For instance, the base station 104e of the cell 190e may transmit a beamformed signal to the RU 106a based on the communication beams 138 in one or more transmit directions of the base station 104e. The RU 106a may receive the beamformed signal from the base station 104e of the cell 190e based on the RU communication beams 136 in one or more receive directions of the RU 106a. In further examples, the base station 104e transmits a downlink beamformed signal to the UE 102e based on the communication beams 138 in one or more transmit directions of the base station 104e. The UE 102e receives the downlink beamformed signal from the base station 104e based on UE communication beams 130 in one or more receive directions of the UE 102e. The UE 102e may also transmit an uplink beamformed signal to the base station 104e based on the UE communication beams 130 in one or more transmit directions of the UE 102e, such that the base station 104e may receive the uplink beamformed signal from the UE 102e in one or more receive directions of the base station 104e.
[0034] The base station 104 may include and / or be referred to as a network entity. That is, “network entity” may refer to the base station 104 or at least one unit of the base station 104, such as the RU 106, the DU 108, and / or the CU 110. The base station 104 may also include and / or be referred to as a next generation evolved Node B (ng-eNB) , a next generation NB (gNB) , an evolved NB (eNB) , an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , a TRP, a network node, network equipment, or other related terminology. The base station 104 or an entity at the base station 104 can be implemented as an IAB node, a relay node, a sidelink node, an aggregated (monolithic) base station, or a disaggregated base station including one or more RUs 106, DUs 108, and / or CUs 110. A set of aggregated or disaggregated base stations may be referred to as a next generation-radio access network (NG-RAN) . In some examples, the UE 102a operates in dual connectivity (DC) with the base station 104e and the base station / RU 106a. In such cases, the base station 104e can be a master node and the base station / RU 160a can be a secondary node.
[0035] Still referring to FIG. 1, in certain aspects, any of the UEs 102 may include a report component 140 configured to receive, from a network entity, a channel state information-reference signal (CSI-RS) on a channel measurement resource (CMR) configured for collection of data associated with at least one of channel state information (CSI) compression or CSI prediction; and transmit, to the network entity, a CSI report including precoder information for the data based on the CSI-RS on the CMR.
[0036] In certain aspects, any of the base stations 104 or a network entity of the base stations 104 may include a configuration component 150 configured to transmit, to a UE, a CSI-RS on a CMR configured for collection of data associated with at least one of CSI compression or CSI prediction; and receive, from the UE, a CSI report including precoder information for the data based on the CSI-RS on the CMR.
[0037] Accordingly, FIG. 1 describes a wireless communication system that may be implemented in connection with aspects of one or more other figures described herein. Further, although the following description may be focused on 5G NR, the concepts described herein may be applicable to other similar areas, such as 5G-Advanced and future versions, LTE, LTE-advanced (LTE-A) , and other wireless technologies, such as 6G.
[0038] FIG. 2 illustrates a diagram 200 of a CSI compression technique based on a machine learning (ML) model for CSI compression. For the CSI compression, the UE 102 measures the CSI based on a CSI-RS, and the UE 102 can compress the CSI with a machine learning (ML) model 216 for the CSI compression. Then, the UE 102 transmits the compressed CSI to the network entity 104. The network entity 104 uses another ML model 220 to reconstruct the CSI 222 based on the received compressed CSI 218. Referring to FIG. 2, Cx, y, z 214 indicates a coefficient for the measured CSI for a subband x, CSI-RS antenna port y, and layer or UE antenna port z. Dx 218 indicates the xth coefficients for the compressed CSI, and C'x, y, z 222 indicates the coefficient for the recovered CSI for subband x, CSI-RS antenna port y, and layer or UE antenna port z.
[0039] FIG. 3 illustrates an example 300 of CSI prediction technique based on the ML CSI prediction model. The network entity 104 can predict the CSI in future slot (s) based on the received CSI reports. The network entity 104 can transmit on the physical downlink shared channel (PDSCH) based on the predicted CSI. Referring to FIG. 3, CSI reports (e.g., 324A-324C) are the inputs to the ML based CSI prediction model 326 to predict CSI. The network entity 104 transmits the PDSCH (e.g., 328A-328B) based on the predicted CSI. Thus, FIG. 4 illustrates a signaling diagram of an example scenario in which UE 102 and network entity 104 exchanges messages and implement procedures for performing report content configuration and report procedure.
[0040] FIG. 4 illustrates a signaling diagram 400 of an example scenario in which UE 102 and network entity 104 exchanges messages and implement procedures for performing report content configuration and report procedure, according to some embodiments. The network entity 104 may correspond to the base station or an entity at the base station, such as the RU 106, the DU 108, the CU 110, etc.
[0041] In some examples, initially, the UE 102 may transmit 402, to the network entity 104, (and the network entity 104 may receive 402) a UE capability report indicating a capability of the UE 102 for CSI reporting of the data associated with at least one of the CSI compression or the CSI prediction. The UE capability report may also indicate one or more than one of the parameters: a maximum amount of reported CSI per CSI report instance, a maximum number of CSI-RS measurement instances for the CSI report, a maximum offset between two consecutive CSI-RS resources, a maximum number of measured antenna ports across for the CSI-RS measurement instances, supported CSI report content, a minimum periodicity for the CSI report, or a supported time-domain behavior (e.g., periodic, semi-persistent, or aperiodic) for the CSI-RS or the CSI report.
[0042] The UE 102 receives 404, from a network entity 104, (and the network entity 104 transmits 404) a configuration for the CSI report associated with the data via control signaling, e.g., radio resource control (RRC) signaling, such as an RRC_Reconfiguration message. The configuration indicates at least one of: the CMR for the CSI-RS or a reporting quality for the CSI report.
[0043] The configuration further indicates CSI report content for the CSI report. The CSI report content includes at least one of: a channel eigenvector, singular values, an average channel report, a beam index, or a beam combining matrix.
[0044] In an embodiment, the network entity 104 configures the UE 102 to report the channel eigenvector (s) based on the CMR (s) . The UE 102 can identify the channel eigenvector for a subband b at CMR instance t based on the singular value decomposition (SVD) of the channel covariance matrix as follows:
[0045] where, Ht, k indicates the measured channel at subcarrier k for the CMR instance t with the dimension of NRx×NTx; NRx is the number of receiving antenna ports in the UE side and NTx is the number of transmission antenna ports in network entity side; Nb is the number of subcarriers in subband b; Gb is the subcarrier set for subband b; Ut, b is the left singular vector; St, b is the singular values; Vt, bis the right singular vector (channel eigenvector) .
[0046] The UE 102 reports the first R columns for the channel eigenvector Vt, b. In some implementations, the value of R may be configured by the network entity 104 via RRC signaling, e.g., an RRC parameter such as reportRank, in the CSI report configuration for data collection, or medium access control-control element (MAC CE) or downlink control information (DCI) , e.g., the MAC CE or DCI triggering the CSI report for data collection.
[0047] In some other implementations, the value of R may be reported by the UE 102 by the UE capability signaling, e.g., supported rank for CSI report for data collection, or the CSI report for data collection, e.g., RI.
[0048] In some implementations, the network entity 104 configures at least one of the parameters for the subband indication for the CSI report for data collection: the number of subbands; the number of resource blocks (RBs) per subband; the reported subband (s) .
[0049] The UE 102 may further determine the RBs for each subband based on the bandwidth, i.e., allocated RBs, for the CMR for CSI report for data collection. In some implementations, the UE 102 reports the absolute amplitude and phase for each coefficient in the channel eigenvector. The UE 102 may perform a normalization for each coefficient based on the strongest coefficient. The number of bits for amplitude and / or phase per coefficient may be predefined, e.g., 4 bits for amplitude report and 4 bits for phase report, or configured by the network entity 104 via RRC signaling, e.g., RRC parameter (s) in the CSI report configuration for data collection, or MAC CE or DCI, e.g., the MAC CE or DCI triggering the CSI report for data collection.
[0050] In some other implementations, the UE 102 reports the absolute amplitude and phase for the strongest coefficient (s) in each layer, subband, and / or CMR instance. The UE 102 reports an indicator of the location of each strongest coefficient within a layer, subband, and / or CMR instance. The UE 102 may perform a normalization for each coefficient based on the strongest coefficient. Then, the UE 102 reports the differential amplitude and absolute phase for other coefficients with the strongest coefficient in the same layer, subband, and / or CMR instance as the reference. The number of bits for amplitude and / or phase per strongest coefficient and other coefficient may be predefined, e.g., 6 bits for amplitude report and 4 bits for phase report per strongest coefficient and 4 bits for amplitude report and 3 bits for phase report per other coefficient, or configured by the network entity 104 commonly or separately via RRC signaling, e.g., RRC parameter (s) in the CSI report configuration for data collection, or MAC CE or DCI, e.g., the MAC CE or DCI triggering the CSI report for data collection.
[0051] In an embodiment, the network entity 104 configures the UE 102 to report the channel eigenvector (s) and the singular values based on the CMR (s) . In addition to report the channel eigenvector (s) based on the CMR (s) , the UE 102 further reports the first R singular values in St, b.
[0052] In some implementations, the UE 102 reports wideband singular values, where the UE 102 determines the singular values based on SVD of the channel covariance matrix for the whole bandwidth of the CMR.
[0053] In some implementations, the UE 102 reports singular values per subband, i.e., the first R singular values in St, b.
[0054] In some implementations, the UE 102 reports the absolute amplitude for each singular value. The UE 102 may perform a normalization for each singular value based on the strongest singular value across the subbands / CMR instance or per subband / CMR instance. The number of bits for amplitude per singular value may be predefined, e.g., 6 bits, or configured by the network entity via RRC signaling, e.g., RRC parameter (s) in the CSI report configuration for data collection, or MAC CE or DCI, e.g., the MAC CE or DCI triggering the CSI report for data collection.
[0055] In an embodiment, the network entity 104 configures the UE 102 to report the averaged channel based on the CMR (s) . The UE 102 may report the averaged channel per subband to the network entity. In one example, the UE 102 determines the averaged channel for a subband b at CMR instance t as follows:
[0056] In some implementations, the UE 102 may report the number of receiving antenna ports by UE capability or the CSI report for data collection. In one example, the number of receiving antenna ports is the same as the maximum number of downlink layers the UE 102 reported via UE capability report. In some other implementations, the number of receiving antenna ports may be configured by the network entity 104 via RRC signaling, e.g., RRC parameter (s) in the CSI report configuration for data collection, or MAC CE or DCI, e.g., the MAC CE or DCI triggering the CSI report for data collection. In one example, the number of receiving antenna ports is the same as the maximum number of downlink layers configured by the network entity 104.
[0057] In some implementations, the UE 102 reports the absolute amplitude and phase for each coefficient in the averaged channel. The UE 102 may perform a normalization for each coefficient based on the strongest coefficient. The number of bits for amplitude and / or phase per coefficient may be predefined, e.g., 4 bits for amplitude report and 4 bits for phase report, or configured by the network entity 104 via RRC signaling, e.g., RRC parameter (s) in the CSI report configuration for data collection, or MAC CE or DCI, e.g., the MAC CE or DCI triggering the CSI report for data collection.
[0058] In some other implementations, the UE 102 reports the absolute amplitude and phase for the strongest coefficient (s) for each receiving antenna port, subband, and / or CMR instance. The UE 102 reports an indicator of the location of each strongest coefficient within a receiving antenna port, subband, and / or CMR instance. The UE 102 may perform a normalization for each coefficient based on the strongest coefficient. Then, the UE 102 reports the differential amplitude and absolute phase for other coefficients with the strongest coefficient in the same receiving antenna port, subband, and / or CMR instance as the reference. The number of bits for amplitude and / or phase per strongest coefficient and other coefficient may be predefined, e.g., 6 bits for amplitude report and 4 bits for phase report per strongest coefficient and 4 bits for amplitude report and 3 bits for phase report per other coefficient, or configured by the network entity commonly or separately via RRC signaling, e.g., RRC parameter (s) in the CSI report configuration for data collection, or MAC CE or DCI, e.g., the MAC CE or DCI triggering the CSI report for data collection.
[0059] In an embodiment, the network entity 104 configures the UE 102 to report the beam index (es) and beam combining matrix based on the CMR (s) . The UE 102 can determine the beams and beam combining matrix as follows:
[0060] where indicates the beams selected by the reported L beam index (es) based a configured codebook for CMR instance t and subband b with the dimension of NRx×2L; indicates the beam combining matrix for CMR instance t and subband b with the dimension of 2L×R. The UE selects the beam index (es) based on the configured codebook and the channel for the CMR instance t and subband b.
[0061] Alternatively, the UE 102 can determine the beams and beam combining matrix as follows:
[0062] where indicates the beams selected by the reported L beam index (es) based a configured codebook for CMR instance t across all subbands. The UE 102 selects the beam index (es) based on the configured codebook and the wideband channel for the CMR instance t.
[0063] Alternatively, the UE 102 can determine the beams and beam combining matrix as follows:
[0064] where W (1) indicates the beams selected by the reported L beam index (es) based a configured codebook for across all subbands and CMR instances. The UE 102 selects the beam index (es) based on the configured codebook and the wideband channel across the CMR instances.
[0065] Alternatively, the UE 102 can determine the beams and beam combining matrix as follows:
[0066] where indicates the beams selected by the reported L beam index (es) based a configured codebook for subband b across CMR instances. The UE 102 selects the beam index (es) based on the configured codebook and the subband channel across the CMR instances.
[0067] In some implementations, the network entity 104 may configure the time and / or frequency domain granularity for the beam index report by RRC signaling, MAC CE or DCI. In one example, the network entity 104 may configure the number of consecutive CMR instances for each beam index (es) set report. In another example, the network entity 104 may configure whether to report the beam index (es) set per CMR instance or across the CMRs. In another example, the network entity 104 may configure whether to report wideband or subband beam index (es) .
[0068] In some implementations, the network entity 104 configures the codebook for the beam index selection. In one example, the network entity 104 may configure the Type2 codebook for beam selection.
[0069] In some implementations, the UE 102 reports the absolute amplitude and phase for each coefficient in the beam combining matrix. The UE 102 may perform a normalization for each coefficient based on the strongest coefficient. The number of bits for amplitude and / or phase per coefficient may be predefined, e.g., 4 bits for amplitude report and 4 bits for phase report, or configured by the network entity via RRC signaling, e.g., RRC parameter (s) in the CSI report configuration for data collection, or MAC CE or DCI, e.g., the MAC CE or DCI triggering the CSI report for data collection.
[0070] In some other implementations, the UE 102 reports the absolute amplitude and phase for the strongest coefficient (s) for the beam combining matrix in each layer, subband, and / or CMR instance. The UE 102 reports an indicator indicating location of each strongest coefficient within a layer, subband, and / or CMR instance. The UE 102 may perform a normalization for each coefficient based on the strongest coefficient. Then, the UE 102 reports the differential amplitude and absolute phase for other coefficients with the strongest coefficient in the same layer, subband, and / or CMR instance as the reference. The number of bits for amplitude and / or phase per strongest coefficient and other coefficient may be predefined, e.g., 6 bits for amplitude report and 4 bits for phase report per strongest coefficient and 4 bits for amplitude report and 3 bits for phase report per other coefficient, or configured by the network entity 104 commonly or separately via RRC signaling, e.g., RRC parameter (s) in the CSI report configuration for data collection, or MAC CE or DCI, e.g., the MAC CE or DCI triggering the CSI report for data collection.
[0071] In an embodiment, the network entity 104 configures the UE 102 to report the beam index (es) , beam combining matrix and the singular values based on the CMR (s) . In addition to reporting the beam index (es) and beam combining matrix based on the CMR(s) , the UE 102 further reports the first R singular values in St, b. As described above, the UE 102 reports the singular values based on the same embodiments as the UE reports the channel eigenvector (s) , the singular values based on the CMR (s) , and first R singular values in St, b.
[0072] The network entity 104 may transmit 406, to the UE 102 (and the UE 102 may receive 406 from the network entity 104) a MAC CE or DCI triggering the CSI report for the CSI-RS resource and / or the configured CSI report configurations.
[0073] For a certain type of CSI report, e.g., periodic CSI report, the network entity 104 further configures the periodicity and the slot offset for the CSI report. For a semi-persistent CSI report or aperiodic CSI report, the network entity 104 may transmit a MAC CE or DCI to trigger the CSI report. For a semi-persistent CSI-RS or aperiodic CSI-RS, the network entity 104 may transmit a MAC CE or a DCI to trigger the CSI-RS.
[0074] The UE 102 determines 408 the measurement and the report scheme for the CSI report for collection of data based on an occupancy rule for a CSI processing unit (CPU) , or a minimum processing delay for the CSI report.
[0075] In an embodiment, for a CSI report for data collection, the UE 102 determines the number of CPUs based on an amount of reported CSI, e.g., the value of X. In one example, the number of CPUs may be XQ, where Q may be predefined, e.g., Q=1 or reported by the UE 102 via UE capability. The UE 102 may determine the CPU (s) are occupied from the first symbol or last symbol of the first CMR instance until the last symbol of the CSI report.
[0076] In another embodiment, for a CSI report for data collection, the UE 102 determines the number of CPUs based on the number of measured CMR instances, e.g., a value T. In one example, the number of CPUs may be TQ, where Q may be predefined, e.g., Q =1 or reported by the UE 102 via UE capability. The UE 102 may determine the CPU (s) are occupied from the first symbol or last symbol of the first CMR instance until the last symbol of the CSI report.
[0077] In another embodiment, for a CSI report for data collection, the number of CPUs may be predefined or reported by the UE capability. The UE 102 may determine the CPU(s) are occupied from the first symbol or last symbol of the first CMR instance until the last symbol of the CSI report.
[0078] In an embedment, the UE 102 may further determine the number of CPUs for a CSI report for data collection based on whether additional CSI report for CSI acquisition is configured or not configured. If the additional CSI report is configured, the UE 102 may determine the number of CPUs as XQ+U or TQ+U, where U may be predefined, e.g., U=1 or reported by the UE 102 via UE capability. The UE 102 may determine the CPU (s) are occupied from the first symbol or last symbol of the first CMR instance until the last symbol of the CSI report.
[0079] In an embodiment, the network entity 104 may refrain from scheduling the CSI report (s) that have a greater number of CPUs than the maximum number of CPUs the UE reports via UE capability. In some implementations, if the number of CPUs for the scheduled CSI report (s) exceeds the maximum number of CPUs the UE supports, the UE 102 may refrain from transmitting the CSI report (s) with lower priority. In some other implementations, if the number of CPUs for the scheduled CSI report (s) exceeds the maximum number of CPUs the UE 102 supports, the UE 102 may transmit outdated CSI for the CSI report (s) with lower priority. For the CSI report for data collection, the UE 102 may report whether the CSI is outdated or current.
[0080] In some implementations, the priority for the CSI report with data collection is higher than the priority for CSI report for CSI acquisition and CSI report for layer-1 reference signal received power (L1-RSRP) report or layer 1 signal-to-interference plus noise ratio (L1-SINR) report. In some other implementations, the priority for the CSI report with data collection is lower than the priority for CSI report for CSI acquisition and higher than the priority for CSI report for L1-RSRP report or L1-SINR report. In some other implementations, the priority for the CSI report with data collection is lower than the priority for CSI report for CSI acquisition and CSI report for L1-RSRP report or L1-SINR report. In some other implementations, the priority for the CSI report for data collection is the same as the priority for CSI report for CSI acquisition. The priority may be further determined based on the CSI report configuration identifier (ID) for both types of CSI.
[0081] In an embodiment, for a CSI report for data collection, the UE determines the minimum processing delay Z and Z' based on the amount of reported CSI, e.g., the value of X. In one example, Z=XZk, and Z'=XZk'. In another example, Z=X+Zk, and Z'=X+Zk' where Zk and Zk' may be predefined, e.g., Zk=Z2 and Zk'= Z2', and Z2 and Z2' are predefined or reported by the UE 102 via UE capability.
[0082] The minimum processing delay Z indicates the processing delay between the last symbol of the physical downlink control channel (PDCCH) scheduling the aperiodic CSI report for data collection and the first symbol of the CSI report for data collection. The minimum processing delay Z' indicates the processing delay between the last symbol of the CMR for CSI report for data collection and the first symbol of the CSI report for data collection.
[0083] In another embodiment, for a CSI report for data collection, the UE determines minimum processing delay Z and Z' based on the number of measured CMR instances, e.g., the value of T. In one example, Z=TZk, and Z'=TZk'. In another example, Z=T+Zk, and Z'=T+Zk', where Zk and Zk' may be predefined, e.g., Zk=Z2 and Zk'= Z2', and Z2 and Z2' are predefined or reported by the UE 102 via UE capability.
[0084] In another embodiment, for a CSI report for data collection, the minimum processing delay may be predefined, e.g., Z=Z2 and Z'= Z2', or reported by the UE capability. In one example, the processing delay is defined as Z=Z2+r and Z'= Z2'+r, where r is reported by the UE capability.
[0085] In an embodiment, the UE 102 may further determine a minimum processing delay for a CSI report for data collection based on whether additional CSI report for CSI acquisition is configured or not configured. If the additional CSI report is configured, the UE 102 may determine an additional minimum processing delay, where the additional minimum processing delay may be predefined or reported by the UE 102 via UE capability.
[0086] In an embodiment, the network entity 104 may refrain from scheduling the CSI report (s) for data collection with smaller scheduling offset than the minimum processing delay. In some implementations, if the scheduling offset is smaller than the minimum processing delay, the UE 102 may refrain from transmitting the CSI report (s) . In some other implementations, if the scheduling offset is smaller than the minimum processing delay, the UE 102 may transmit the outdated CSI for the CSI report (s) . For the CSI report for data collection, the UE 102 may report whether the CSI is outdated or current.
[0087] After the UE determines the measurement and report scheme, the UE 102 receives 410, from the network entity 104, (and the network entity 104 transmits 410 to the UE 102) a CSI-RS on a channel measurement resource (CMR) configured for collection of data associated with at least one of CSI compression or CSI prediction.
[0088] The UE 102 transmits 412, to the network entity 104, (and the network 104 entity receives 412 from the UE 102) a CSI report including precoder information for the data based on the CSI-RS on the CMR. The UE 102 may transmit the CSI report via a physical uplink control channel (PUCCH) , or uplink control information (UCI) multiplexed on a physical uplink shared channel (PUSCH) or the MAC CE.
[0089] Unless otherwise specified, an RRC signaling may indicate an RRC reconfiguration message from the network entity 104 to the UE 102, or a system information block (SIB) , where the SIB can be an existing SIB (e.g., SIB1) or a new SIB (e.g., SIB J, where J is an integer above 21) transmitted by the network entity 104. In addition, the network entity 104 may obtain the UE capability via UE capability report signaling or from another network entity 104 or a core network (e.g., Access and Mobility Management Function (AMF) ) . In yet some other implementations, the network entity 104 may receive the UE capability from another network entity (e.g., gNB or eNB) .
[0090] FIG. 4 describes a signaling diagram 400 of an example scenario in which a UE and a network entity exchange messages and implement procedures for performing report content configuration and report procedure, and FIG. 5 illustrates an example for a channel quality indicator (CQI) report for multiple number of layers.
[0091] Now turning to FIG. 5 which illustrates an example 500 for the CQI report for multiple number of layers. In an embodiment, the network entity 104 configures the UE 102 to report at least one CQI based on the CSI report configuration for data collection. Thus, the network entity 104 may configure the CSI report configuration for both data collection and CSI acquisition.
[0092] In some implementations, the UE 102 reports the CQI based on the reported precoder information 514. In one example, the UE 102 calculates the CQI 530A-530C based on the first R columns of the reported precoders 514.
[0093] In some other implementations, the UE 102 reports multiple CQIs for different number of layers (i.e., different ranks) . In some implementations, the UE 102 reports the CQIs corresponding to the first 1, 2, ..., R columns of the reported precoders respectively. Referring to FIG. 5, for example, the UE 102 reports CQI 530A for 1 layer (corresponding to CQI for rank 1) , CQI 530B for 2 layers (corresponding to CQI for rank 2) , and CQI 530C for 4 layers (corresponding to CQI for rank 4) .
[0094] In some other implementations, the network entity 104 may configure a rank restriction for CQI report, where the network entity 104 configures the number of layers for the each reported CQI. In one example, the network entity 104 may configure a R-bit bitmap for rank restriction for CQI report, where if the value of bit x is 1, the UE 102 reports the CQI for x layers. Otherwise, the UE 102 refrains from reporting the CQI for x layers.
[0095] In some other implementations, the UE 102 reports one or more than one RIs for the one or more than one reported CQIs in the CSI report.
[0096] In some implementations, the UE 102 reports the CQI based on the reported precoder information and measurement of one CMR instance. In one example, the UE 102 calculates the CQI based on the first R columns of the reported precoders and the measurement of the latest CMR instance for precoder measurement.
[0097] In some implementations, the UE 102 reports the CQIs based on the reported precoder information and measurement of one or more than one CMR instances. In some implementations, the UE 102 calculates the CQI based on each CMR instance. In some other implementations, the network entity 104 configures the CMR instances for CQI calculation. In some other implementations, the UE 102 reports the CMR instance (s) for CQI calculation in the CSI report.
[0098] In some implementations, the network entity 104 may configure the UE 102 to report wideband CQI or subband CQIs by RRC signaling, MAC CE, or DCI. The network entity 104 may provide a common or separate subband configuration for the CQI report and precoder information report.
[0099] In some implementations, the UE 102 may report the UE capability indicating whether the UE 102 supports the CQI report for the CSI report for data collection.
[0100] Tables 1 to 8 illustrates examples for the CSI report for both data collection and CSI acquisition.
[0101] In some implementations, the UE 102 may transmit the CSI report for both data collection and CSI acquisition in CSI part 1 in a long PUCCH format, e.g., PUCCH with more than 4 symbols, or PUSCH. In some other implementations, the UE 102 may transmit the CSI report for both data collection and CSI acquisition in CSI part 2 in a long PUCCH format, e.g., PUCCH with more than 4 symbols, or PUSCH. In some other implementations, the UE 102 may transmit some of the information, e.g., RI and / or CQI for the first codeword, for CSI report for both data collection and CSI acquisition in CSI part 1 and remaining information, e.g., precoder information for data collection and / or the CQI for the second codeword, for CSI report for both data collection and CSI acquisition in CSI part 2 in a long PUCCH format, e.g., PUCCH with more than 4 symbols, or PUSCH.
[0102] Table 1: An example for CSI report for both data collection and CSI acquisition
[0103] Table 2: Another example for CSI report for both data collection and CSI acquisition
[0104] Table 3: Another example for CSI report for both data collection and CSI acquisition
[0105] Table 4: Another example for CSI report for both data collection and CSI acquisition
[0106] Table 5: Another example for CSI report for both data collection and CSI acquisition
[0107] Table 6: Another example for CSI report for both data collection and CSI acquisition
[0108] Table 7: Another example for CSI report for both data collection and CSI acquisition
[0109] Table 8: Another example for CSI report for both data collection and CSI acquisition
[0110] FIG. 6A illustrates an example 600 for the CSI report for X=3 CMR instances based on a reference time. In an embodiment, for periodic / semi-persistent CSI-RS based CMR, the UE 102 measures and reports the CSI for data collection for the X instances of the CMRs before a reference time. Referring to FIG. 6, the UE 102 reports the CSI report 624 for data collection for the X= 3 CMR instances (e.g., 630B-630D) before a reference time 632. Although FIG. 6A shows four CMR instances (e.g., 630A-630D) , three of which are reported by the UE 102, it is understood that more than three or four CMR instances may be reported by the UE 102 based on various aspects describe in detail below.
[0111] In some implementations, the reference time 632 may be predefined. For example, the reference time 632 may be predefined before the minimum processing delay for the CSI report for data collection before the first symbol of the CSI report. In some other implementations, the network entity 104 may configure the reference time 632 via RRC signaling, MAC CE, or DCI. In one example, the network entity 104 may configure the reference time 632 as an offset before the first symbol of the CSI report for data collection or the PDCCH or MAC CE triggering the beam report for data collection. In some other implementations, the UE 102 reports the reference time 632 in the CSI report. In one example, the UE 102 includes report measurement instances or measured slot index (es) for the reported CSIs in the CSI report.
[0112] FIG. 6B illustrates an example 630 for the CSI report for X report instances and Y averaging instances based on a reference time. In some other implementations, with regard to the measurement accuracy, the network entity 104 may configure the number of averaging instances (or number of measurement instances per report) Y and the number of report instance X. The UE 102 measures the CSI based on the measurement of every Y averaging instances. Referring to FIG. 6B, for example, the network entity 104 configures three averaging instances (or averaging windows) (e.g., 634A-634C) and seven CMR instances (e.g., 630A-630G) based on the reference time 632. The network entity 104 configures an averaging window 634A for the CMR instance 2 630B and the CMR instance 3 630C. The UE 102 may report the UE capability indicating the maximum value of Y and / or XY.
[0113] In some other implementations, the network entity 104 configures the total number of measurement instances T and the number of report instance X. Then, the UE 102 can derive the number of averaging instances Y = T / X. In some other implementations, the network entity 104 configures the total number of measurement instances T and the number of averaging instance Y. Then, the UE 102 can derive the number of report instances X = T / Y.
[0114] Although FIG. 6B shows seven CMR instances (e.g., 630A-630G) , it is understood that more or less CMR instances may be reported by the UE 102 based on various aspects describe in detail below. Similarly, although FIG. 6B shows three averaging instances (e.g., 634A-634C) , it is understood that more or less averaging instances may be configured by the network entity 104 based on various aspects describe in detail below.
[0115] FIG. 6C illustrates an example 650 for the CSI report based on multiple aperiodic CSI-RS instances. The example 650 illustrates the CSI report for X=3 CMR instances and Y=2 averaging instances based on aperiodic CSI-RS.
[0116] In an embodiment, for aperiodic CSI-RS based CMR, the network entity 104 configures one or more than one CSI-RS resources. The network entity 104 may configure the CSI-RS resources in different slots and / or symbols. The network entity 104 may provide the same configuration for at least one of the following parameters for the aperiodic CSI-RS resources: transmission configuration indicator (TCI) state, allocated RBs, subcarriers, number of ports, transmission power, e.g., power offset between the CSI-RS and SSB and / or PDSCH. The network entity 104 may transmit the aperiodic CSI-RS resources from the same antenna ports.
[0117] In another embodiment, the network entity 104 configures one aperiodic CSI-RS resource with one or more than one repetitions as the CMR. The network entity 104 further configures the slot offset and / or symbol offset between every two consecutive repetitions. The number of repetitions and / or the slot / symbol offset may be configured by RRC signaling or DCI, e.g., the DCI triggering the CSI report.
[0118] In an embodiment, for aperiodic CSI-RS based CMR, the UE 102 measures the aperiodic CSI-RS resources or repetitions (CMR instances) triggered by the network entity 104 and reports the CSI based on the measured CMR instances. In some implementations, the UE 102 may report T CSIs corresponding to the T configured or triggered CMR instances. In some implementations, the UE 102 may report X CSIs corresponding to the T configured or triggered CMR instances, where each reported CSI is based on the averaging of Y consecutive CMR instances (Y) . The value of X and / or Y may be configured by the network entity by RRC signaling or DCI, e.g., the DCI triggering the CSI report.
[0119] Referring to FIG. 6C, for example, the network entity triggers six CMR instances (e.g., 630A-630F) via a PDCCH 636. The UE 102 may report one CSI report 624 corresponding to the six triggered CMR instances (630A-630F) .
[0120] FIGs. 7-8 show methods for implementing one or more aspects of FIGs. 4-6C. In particular, FIG. 7 shows an implementation by the UE 102 of the one or more aspects of FIGs. 4-6C. FIG. 8 shows an implementation by the network entity 104 of the one or more aspects of FIGs. 4-6C.
[0121] FIG. 7 illustrates a flowchart 700 of a method of wireless communication at a UE. With reference to FIGs. 1-6C and 9, the method may be performed by the UE 102, the UE apparatus 902, etc., which may include the memory 926′, 906′, 916, and which may correspond to the entire UE 102 or the entire UE apparatus 902, or a component of the UE 102 or the UE apparatus 902, such as the wireless baseband processor 926 and / or the application processor 906.
[0122] The UE 102 may transmit 702, to the network entity 104, a UE capability report indicating a capability of the UE (102) for CSI reporting of the data associated with the at least one of the CSI compression or the CSI prediction. For example, referring to FIG. 4, the UE 102 transmits 402, to the network entity 104, (the network entity 104 may receive 402 from the UE 102) a UE capability report indicating a capability of the UE 102 for CSI reporting of the data associated with the at least one of the CSI compression or the CSI prediction.
[0123] The UE 102 may receive 704, from the network entity 104, a configuration for the CSI report associated with the data, the configuration indicating at least one of: the CMR for the CSI-RS or a reporting quality for the CSI report. For example, referring to FIG. 4, the UE 102 receives 404, from a network entity 104, a configuration for the CSI report associated with the data via a control signaling, e.g., RRC signaling (RRCReconfiguration) . The configuration indicates at least one of: the CMR for the CSI-RS or a reporting quality for the CSI report.
[0124] The UE 102 may receive 706, from the network entity 104, MAC CE or DCI triggering the CSI report for the CSI-RS resource and / or the configured CSI report configurations. For example, referring to FIG. 4, the UE receives 406 a MAC CE or DCI triggering the CSI report for the CSI-RS resource and / or the configured CSI report configurations.
[0125] The UE 102 receives 710, from the network entity 104, a CSI-RS on a CMR configured for collection of data associated with at least one of CSI compression or CSI prediction. For example, referring to FIG. 4, after the UE receives the CSI-RS, the UE 102 receives 410, from the network entity 104, a CSI-RS on a CMR configured for collection of data associated with at least one of CSI compression or CSI prediction.
[0126] The UE 102 transmits 712, to the network entity 104, a CSI report including precoder information for the data based on the CSI-RS on the CMR. For example, referring to FIG. 4, the UE 102 transmits 412, to the network entity 104, (the network 104 entity receives 412 from the UE 102) a CSI report including precoder information for the data based on the CSI-RS on the CMR.
[0127] FIG. 7 describes a method from a UE-side of a wireless communication link, whereas FIG. 8 describes a method from a network-side of the wireless communication link.
[0128] FIG. 8 is a flowchart 800 of a method of wireless communication at a network entity. With reference to FIGs. 1-6C and 10, the method may be performed by one or more network entities 104, which may correspond to a base station or a unit of the base station, such as the RU 106, the DU 108, the CU 110, an RU processor 1006, a DU processor 1026, a CU processor 1046, etc. The one or more network entities 104 may include memory 1006' / 1026' / 1046', which may correspond to an entirety of the one or more network entities 104, or a component of the one or more network entities 104, such as the RU processor 1006, the DU processor 1026, or the CU processor 1046.
[0129] The network entity 104 may receive 802, from the UE 102, a UE capability report indicating a capability of the UE (102) for CSI reporting of the data associated with the at least one of the CSI compression or the CSI prediction. For example, referring to FIG. 4, the network entity 104 receives 402, from the UE 102, a UE capability report indicating a capability of the UE 102 for CSI reporting of the data associated with the at least one of the CSI compression or the CSI prediction.
[0130] The network entity104 may transmit 804, to the UE 102, a configuration for the CSI report associated with the data, the configuration indicating at least one of: the CMR for the CSI-RS or a reporting quality for the CSI report. For example, referring to FIG. 4, the network entity 104 transmits 404, to the UE 102, a configuration for the CSI report associated with the data via a control signaling, e.g., RRC signaling (RRCReconfiguration) .
[0131] The network entity 104 may transmit 806, to the UE 102, a MAC CE or DCI triggering the CSI report for the CSI-RS resource and / or the configured CSI report configurations. For example, referring to FIG. 4, the network entity 104 transmits 806, to the UE 102, a MAC CE or DCI triggering the CSI report for the CSI-RS resource and / or the configured CSI report configurations.
[0132] The network entity 104 transmits 810, to the UE 102, a CSI-RS on a CMR configured for collection of data associated with at least one of CSI compression or CSI prediction. For example, referring to FIG. 4, the network entity 104 transmits 410 to the UE 102 a CSI-RS on a channel measurement resource (CMR) configured for collection of data associated with at least one of CSI compression or CSI prediction.
[0133] The network entity 104 receives 812, from the UE 102, a CSI report including precoder information for the data based on the CSI-RS on the CMR. For example, referring to FIG. 4, the network 104 entity receives 412 from the UE 102 a CSI report including precoder information for the data based on the CSI-RS on the CMR.
[0134] A UE apparatus 902, as described in FIG. 9, may perform the method of flowchart 700. The one or more network entities 104, as described in FIG. 10, may perform the method of flowchart 800.
[0135] FIG. 9 is a diagram 900 illustrating an example of a hardware implementation for a UE apparatus 902. The UE apparatus 902 may be the UE 102, a component of the UE 102, or may implement UE functionality. The UE apparatus 902 may include an application processor 906, which may have on-chip memory 906'. In examples, the application processor 906 may be coupled to a secure digital (SD) card 908 and / or a display 910. The application processor 906 may also be coupled to a sensor (s) module 912, a power supply 914, an additional module of memory 916, a camera 918, and / or other related components. For example, the sensor (s) module 912 may control a barometric pressure sensor / altimeter, a motion sensor such as an inertial management unit (IMU) , a gyroscope, accelerometer (s) , a light detection and ranging (LIDAR) device, a radio-assisted detection and ranging (RADAR) device, a sound navigation and ranging (SONAR) device, a magnetometer, an audio device, and / or other technologies used for positioning.
[0136] The UE apparatus 902 may further include a wireless baseband processor 926, which may be referred to as a modem. The wireless baseband processor 926 may have on-chip memory 926′. Along with, and similar to, the application processor 906, the wireless baseband processor 926 may also be coupled to the sensor (s) module 912, the power supply 914, the additional module of memory 916, the camera 918, and / or other related components. The wireless baseband processor 926 may be additionally coupled to one or more subscriber identity module (SIM) card (s) 920 and / or one or more transceivers 930 (e.g., wireless RF transceivers) .
[0137] Within the one or more transceivers 930, the UE apparatus 902 may include a Bluetooth module 932, a WLAN module 934, an SPS module 936 (e.g., GNSS module) , and / or a cellular module 938. The Bluetooth module 932, the WLAN module 934, the SPS module 936, and the cellular module 938 may each include an on-chip transceiver (TRX) , or in some cases, just a transmitter (TX) or just a receiver (RX) . The Bluetooth module 932, the WLAN module 934, the SPS module 936, and the cellular module 938 may each include dedicated antennas and / or utilize antennas 940 for communication with one or more other nodes. For example, the UE apparatus 902 can communicate through the transceiver (s) 930 via the antennas 940 with another UE (e.g., sidelink communication) and / or with a network entity 104 (e.g., uplink / downlink communication) , where the network entity 104 may correspond to a base station or a unit of the base station, such as the RU 106, the DU 108, or the CU 110.
[0138] The wireless baseband processor 926 and the application processor 906 may each include a computer-readable medium / memory 926′, 906′, respectively. The additional module of memory 916 may also be considered a computer-readable medium / memory. Each computer-readable medium / memory 926′, 906′, 916 may be non-transitory. The wireless baseband processor 926 and the application processor 906 may each be responsible for general processing, including execution of software stored on the computer-readable medium / memory 926′, 906′, 916. The software, when executed by the wireless baseband processor 926 / application processor 906, causes the wireless baseband processor 926 / application processor 906 to perform the various functions described herein. The computer-readable medium / memory may also be used for storing data that is manipulated by the wireless baseband processor 926 / application processor 906 when executing the software. The wireless baseband processor 926 / application processor 906 may be a component of the UE 102. The UE apparatus 902 may be a processor chip (e.g., modem and / or application) and include just the wireless baseband processor 926 and / or the application processor 906. In other examples, the UE apparatus 902 may be the entire UE 102 and include the additional modules of the apparatus 902.
[0139] As discussed in FIG. 1 and implemented with respect to FIG. 7, the report component 140 configured to receive, from a network entity, a channel state information-reference signal (CSI-RS) on a channel measurement resource (CMR) configured for collection of data associated with at least one of channel state information (CSI) compression or CSI prediction; and transmit, to the network entity, a CSI report including precoder information for the data based on the CSI-RS on the CMR.
[0140] The report component 140 may be within the application processor 906 (e.g., at 140a) , the wireless baseband processor 926 (e.g., at 140b) , or both the application processor 906 and the wireless baseband processor 926. The report component 140a-140b may be one or more hardware components specifically configured to carry out the stated processes / algorithm, implemented by one or more processors configured to perform the stated processes / algorithm, stored within a computer-readable medium for implementation by the one or more processors, or a combination thereof.
[0141] FIG. 10 is a diagram 1000 illustrating an example of a hardware implementation for one or more network entities 104. The one or more network entities 104 may be a base station, a component of a base station, or may implement base station functionality. The one or more network entities 104 may include, or may correspond to, at least one of the RU 106, the DU, 108, or the CU 110. The CU 110 may include a CU processor 1046, which may have on-chip memory 1046′. In some aspects, the CU 110 may further include an additional module of memory 1056 and / or a communications interface 1048, both of which may be coupled to the CU processor 1046. The CU 110 can communicate with the DU 108 through a midhaul link 162, such as an F1 interface between the communications interface 1048 of the CU 110 and a communications interface 1028 of the DU 108.
[0142] The DU 108 may include a DU processor 1026, which may have on-chip memory 1026′. In some aspects, the DU 108 may further include an additional module of memory 1036 and / or the communications interface 1028, both of which may be coupled to the DU processor 1026. The DU 108 can communicate with the RU 106 through a fronthaul link 160 between the communications interface 1028 of the DU 108 and a communications interface 1008 of the RU 106.
[0143] The RU 106 may include an RU processor 1006, which may have on-chip memory 1006′. In some aspects, the RU 106 may further include an additional module of memory 1016, the communications interface 1008, and one or more transceivers 1030, all of which may be coupled to the RU processor 1006. The RU 106 may further include antennas 1040, which may be coupled to the one or more transceivers 1030, such that the RU 106 can communicate through the one or more transceivers 1030 via the antennas 1040 with the UE 102.
[0144] The on-chip memory 1006′, 1026′, 1046′ and the additional modules of memory 1016, 1036, 1056 may each be considered a computer-readable medium / memory. Each computer-readable medium / memory may be non-transitory. Each of the processors 1006, 1026, 1046 is responsible for general processing, including execution of software stored on the computer-readable medium / memory. The software, when executed by the corresponding processor (s) 1006, 1026, 1046 causes the processor (s) 1006, 1026, 1046 to perform the various functions described herein. The computer-readable medium / memory may also be used for storing data that is manipulated by the processor (s) 1006, 1026, 1046 when executing the software. In examples, the configuration component 150 may sit at any of the one or more network entities 104, such as at the CU 110; both the CU 110 and the DU 108; each of the CU 110, the DU 108, and the RU 106; the DU 108; both the DU 108 and the RU 106; or the RU 106.
[0145] As discussed in FIG. 1 and implemented with respect to FIG. 8, the configuration component 150 is configured to transmit, to a UE, a CSI-RS on a CMR configured for collection of data associated with at least one of CSI compression or CSI prediction; and receive, from the UE, a CSI report including precoder information for the data based on the CSI-RS on the CMR.
[0146] The configuration component 150 may be within one or more processors of the one or more network entities 104, such as the RU processor 1006 (e.g., at 150a) , the DU processor 1026 (e.g., at 150b) , and / or the CU processor 1046 (e.g., at 150c) . The configuration component 150a-150c may be one or more hardware components specifically configured to carry out the stated processes / algorithm, implemented by one or more processors 1006, 1026, 1046 configured to perform the stated processes / algorithm, stored within a computer-readable medium for implementation by the one or more processors 1006, 1026, 1046, or a combination thereof.
[0147] The specific order or hierarchy of blocks in the processes and flowcharts disclosed herein is an illustration of example approaches. Hence, the specific order or hierarchy of blocks in the processes and flowcharts may be rearranged. Some blocks may also be combined or deleted. Dashed lines may indicate optional elements of the diagrams. The accompanying method claims present elements of the various blocks in an example order, and are not limited to the specific order or hierarchy presented in the claims, processes, and flowcharts.
[0148] The detailed description set forth herein describes various configurations in connection with the drawings and does not represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough explanation of various concepts. However, these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.
[0149] Aspects of wireless communication systems, such as telecommunication systems, are presented with reference to various apparatuses and methods. These apparatuses and methods are described in the following detailed description and are illustrated in the accompanying drawings by various blocks, components, circuits, processes, call flows, systems, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using electronic hardware, computer software, or combinations thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.
[0150] An element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs) , central processing units (CPUs) , application processors, digital signal processors (DSPs) , reduced instruction set computing (RISC) processors, systems-on-chip (SoC) , baseband processors, field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other similar hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software, which may be referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, or any combination thereof.
[0151] If the functionality described herein is implemented in software, the functions may be stored on, or encoded as, one or more instructions or code on a computer-readable medium, such as a non-transitory computer-readable storage medium. Computer-readable media includes computer storage media and can include a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of these types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer. Storage media may be any available media that can be accessed by a computer.
[0152] Aspects, implementations, and / or use cases described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, the aspects, implementations, and / or use cases may come about via integrated chip implementations and other non-module-component based devices, such as end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail / purchasing devices, medical devices, artificial intelligence (AI) -enabled devices, machine learning (ML) -enabled devices, etc. The aspects, implementations, and / or use cases may range from chip-level or modular components to non-modular or non-chip-level implementations, and further to aggregate, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more techniques described herein.
[0153] Devices incorporating the aspects and features described herein may also include additional components and features for the implementation and practice of the claimed and described aspects and features. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes, such as hardware components, antennas, RF-chains, power amplifiers, modulators, buffers, processor (s) , interleavers, adders / summers, etc. Techniques described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, aggregated or disaggregated components, end-user devices, etc., of varying configurations.
[0154] The description herein is provided to enable a person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not limited to the aspects described herein, but are to be interpreted in view of the full scope of the present disclosure consistent with the language of the claims.
[0155] Reference to an element in the singular does not mean “one and only one” unless specifically stated, but rather “one or more. ” Terms such as “if, ” “when, ” and “while” do not imply an immediate temporal relationship or reaction. That is, these phrases, e.g., “when, ” do not imply an immediate action in response to or during the occurrence of an action, but simply imply that if a condition is met then an action will occur, but without requiring a specific or immediate time constraint for the action to occur. The terms “may” , “might” , and “can” , as used in this disclosure, often carry certain connotations. For example, “may” refers to a permissible feature that may or may not occur, “might” refers to a feature that probably occurs, and “can” refers to a capability (e.g., capable of) . The phrase “For example” often carries a similar connotation to “may” and, therefore, “may” is sometimes excluded from sentences that include “for example” or other similar phrases.
[0156] Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C” or “one or more of A, B, or C” include any combination of A, B, and / or C, such as A and B, A and C, B and C, or A and B and C, and may include multiples of A, multiples of B, and / or multiples of C, or may include A only, B only, or C only. Sets should be interpreted as a set of elements where the elements number one or more.
[0157] Unless otherwise specifically indicated, ordinal terms such as “first” and “second” do not necessarily imply an order in time, sequence, numerical value, etc., but are used to distinguish between different instances of a term or phrase that follows each ordinal term. Reference numbers, as used in the specification and figures, are sometimes cross-referenced among drawings to denote same or similar features. A feature that is exactly the same in multiple drawings may be labeled with the same reference number in the multiple drawings. A feature that is similar among the multiple drawings, but not exactly the same, may be labeled with reference numbers that have different leading numbers, but have one or more of the same trailing numbers (e.g., 206, 306, 406, etc., may refer to similar features in the drawings) . Sometimes an “X” is used to universally denote multiple variations of a feature. For instance, “X06” can universally refer to all reference numbers that end in “06” (e.g., 206, 306, 406, etc. ) .
[0158] Structural and functional equivalents to 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 encompassed by the claims. The words “module, ” “mechanism, ” “element, ” “device, ” and the like may not be a substitute for the word “means. ” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for. ” As used herein, the phrase “based on” shall not be construed as a reference to a closed set of information, one or more conditions, one or more factors, or the like. In other words, the phrase “based on A” , where “A” may be information, a condition, a factor, or the like, shall be construed as “based at least on A” unless specifically recited differently.
[0159] The following examples are illustrative only and may be combined with other examples or teachings described herein, without limitation.
[0160] Example 1 is a method of wireless communication at a UE, including: receiving, from a network entity, a CSI-RS on a CMR configured for collection of data associated with at least one of CSI compression or CSI prediction; and transmitting, to the network entity, a CSI report including precoder information for the data based on the CSI-RS on the CMR.
[0161] Example 2 may be combined with Example 1 and further includes that the transmitting the CSI report is based on at least one of: an occupancy rule for a CPU, or a minimum processing delay for the CSI report.
[0162] Example 3 may be combined with any of Examples 1-2 and further include receiving, from a network entity, a configuration for the CSI report associated with the data, the configuration indicating at least one of: the CMR for the CSI-RS or a reporting quality for the CSI report.
[0163] Example 4 may be combined with Example 3 and further includes that the configuration further indicates CSI report content for the CSI report, the CSI report content comprises at least one of: a channel eigenvector, singular values, an average channel report, a beam index, a beam combining matrix, one or more rank indicators, or one or more channel quality indicators.
[0164] Example 5 may be combined with Example 4 and further includes that the configuration indicates at least one of: a number of columns for the channel eigenvectors, a number of columns for the channel eigenvectors with the singular values, a number of receiving antenna ports, a time and frequency domain granularity for a reporting of the beam index, or a codebook for the beam index.
[0165] Example 6 may be combined with Example 5 and further includes that the CSI report includes at least one of: a first number of columns for the channel eigenvectors, a first number of columns for the channel eigenvectors and the singular values, the average channel report, the beam index and the beam combining matrix, or the beam index, the beam combining matrix, the singular values, and a first number of columns for the singular values.
[0166] Example 7 may be combined with any of Examples 2-6 and further includes that the configuration indicates a reference time for a CSI measurement based on a periodic CSI-RS or a semi-persistent CSI-RS.
[0167] Example 8 may be combined with any of Examples 2-6 and further includes that the configuration indicates one or more CMR instances for a CSI measurement of an aperiodic CSI-RS.
[0168] Example 9 may be combined with any of Examples 1-8 and further includes: transmitting, to the network entity, a UE capability report indicating a capability of the UE for CSI reporting of the data associated with the at least one of the CSI compression or the CSI prediction.
[0169] Example 10 may be combined with Example 9 and further includes that the UE capability report indicates at least one of: a maximum amount of reported CSI per CSI report instance, a maximum number of CSI-RS measurement instances for the CSI report, a maximum offset between two consecutive CSI-RS resources, a maximum number of measured antenna ports across for the CSI-RS measurement instances, supported CSI report content, a minimum periodicity for the CSI report, or a supported time-domain behavior for the CSI-RS or the CSI report.
[0170] Example 11 is a method of wireless communication at a network entity, including: transmitting, to a UE, a CSI-RS on a CMR configured for collection of data associated with at least one of CSI compression or CSI prediction; and receiving, from the UE, a CSI report including precoder information for the data based on the CSI-RS on the CMR.
[0171] Example 12 may be combined with Example 11 and further includes configuring the CSI report based on at least one of: an occupancy rule for a CPU, or a minimum processing delay for the CSI report.
[0172] Example 13 may be combined with any of Examples 11-12 and further includes: transmitting, to the UE, a configuration for the CSI report associated with the data, the configuration indicating at least one of: the CMR for the CSI-RS or a reporting quality for the CSI report.
[0173] Example 14 may be combined with Example 13 and further includes that the configuration further indicates CSI report content for the CSI report, the CSI report content comprises at least one of: a channel eigenvector, singular values, an average channel report, a beam index, a beam combining matrix, one or more rank indicators, one or more channel quality indicators.
[0174] Example 15 may be combined with Example 14 and further includes that the configuration indicates at least one of: a number of columns for the channel eigenvectors, a number of columns for the channel eigenvectors with the singular values, a number of receiving antenna ports, a time and frequency domain granularity for a reporting of the beam index, or a codebook for the beam index, .
[0175] Example 16 may be combined with any of Examples 12-15 and further includes that the configuration indicates a reference time for a CSI measurement based on a periodic CSI-RS or a semi-persistent CSI-RS.
[0176] Example 17 may be combined with any of Examples 12-15 and further includes that the configuration indicates one or more CMR instances for a CSI measurement of an aperiodic CSI-RS.
[0177] Example 18 may be combined with any of Examples 11-17 and further includes receiving, from the UE, a UE capability report indicating a capability of the UE for CSI reporting of the data associated with the at least one of the CSI compression or the CSI prediction.
[0178] Example 19 may be combined with Example 18 and further includes that the UE capability report indicates at least one of: a maximum amount of reported CSI per CSI report instance, a maximum number of CSI-RS measurement instances for the CSI report, a maximum offset between two consecutive CSI-RS resources, a maximum number of measured antenna ports across for the CSI-RS measurement instances, supported CSI report content, a minimum periodicity for the CSI report, or a supported time-domain behavior for the CSI-RS or the CSI report.
[0179] Example 20 is an apparatus for wireless communication for implementing a method as in any of examples 1-19.
[0180] Example 21 is an apparatus for wireless communication including means for implementing a method as in any of examples 1-19.
[0181] Example 22 is a non-transitory computer-readable medium storing computer executable code, the code when executed by a processor causes the processor to implement a method as in any of examples 1-19.
Claims
1.A method of wireless communication at a user equipment (UE) (102) , comprising:receiving (410) , from a network entity (104) , a channel state information-reference signal (CSI-RS) on a channel measurement resource (CMR) configured for collection of data associated with at least one of channel state information (CSI) compression or CSI prediction; andtransmitting (412) , to the network entity (104) , a CSI report including precoder information for the data based on the CSI-RS on the CMR.2.The method of claim 1, wherein the transmitting (412) the CSI report is based on at least one of:an occupancy rule for a CSI processing unit (CPU) , ora minimum processing delay for the CSI report.3.The method of any of claims 1-2, further comprising:receiving (404) , from a network entity (104) , a configuration for the CSI report associated with the data, the configuration indicating at least one of: the CMR for the CSI-RS or a reporting quality for the CSI report.4.The method of claim 3, wherein the configuration further indicates CSI report content for the CSI report, the CSI report content comprises at least one of:a channel eigenvector,singular values,an average channel report,a beam index,a beam combining matrix,one or more rank indicators (RIs) , orone or more channel quality indicators (CQIs) .5.The method of claim 4, wherein the configuration indicates at least one of:a number of columns for the channel eigenvectors, a number of columns for the channel eigenvectors with the singular values,a number of receiving antenna ports,a time and frequency domain granularity for a reporting of the beam index, ora codebook for the beam index.6.The method of claim 5, wherein the CSI report includes at least one of:a first number of columns for the channel eigenvectors,a first number of columns for the channel eigenvectors and the singular values,the average channel report,the beam index and the beam combining matrix, orthe beam index, the beam combining matrix, the singular values, and a first number of columns for the singular values.7.The method of any of claims 2-6, wherein the configuration indicates a reference time for a CSI measurement based on a periodic CSI-RS or a semi-persistent CSI-RS.8.The method of any of claims 2-6, wherein the configuration indicates one or more CMR instances for a CSI measurement of an aperiodic CSI-RS.9.The method of any of claims 1-8, further comprising:transmitting (402) , to the network entity (104) , a UE capability report indicating a capability of the UE (102) for CSI reporting of the data associated with the at least one of the CSI compression or the CSI prediction.10.The method of claim 9, wherein the UE capability report indicates at least one of:a maximum amount of reported CSI per CSI report instance,a maximum number of CSI-RS measurement instances for the CSI report,a maximum offset between two consecutive CSI-RS resources,a maximum number of measured antenna ports across for the CSI-RS measurement instances,supported CSI report content,a minimum periodicity for the CSI report, ora supported time-domain behavior for the CSI-RS or the CSI report.11.A method of wireless communication at a network entity (104) , comprising:transmitting (404) , to a user equipment (UE) (102) , a channel state information-reference signal (CSI-RS) on a channel measurement resource (CMR) configured for collection of data associated with at least one of channel state information (CSI) compression or CSI prediction; andreceiving (412) , from the UE (102) , a CSI report including precoder information for the data based on the CSI-RS on the CMR.12.The method of claim 11, further comprising configuring the CSI report based on at least one of:an occupancy rule for a CSI processing unit (CPU) , ora minimum processing delay for the CSI report.13.The method of any of claims 11-12, further comprising:transmitting (404) , to the UE (102) , a configuration for the CSI report associated with the data, the configuration indicating at least one of: the CMR for the CSI-RS or a reporting quality for the CSI report.14.The method of claim 13, wherein the configuration further indicates CSI report content for the CSI report, the CSI report content comprises at least one of:a channel eigenvector,singular values,an average channel report,a beam index, ora beam combining matrix,one or more rank indicators (RIs) , orone or more channel quality indicators (CQIs) .15.The method of claim 14, wherein the configuration indicates at least one of:a number of columns for the channel eigenvectors,a number of columns for the channel eigenvectors with the singular values,a number of receiving antenna ports,a time and frequency domain granularity for a reporting of the beam index, ora codebook for the beam index.16.The method of any of claims 12-15, wherein the configuration indicates a reference time for a CSI measurement based on a periodic CSI-RS or a semi-persistent CSI-RS.17.The method of any of claims 12-15, wherein the configuration indicates one or more CMR instances for a CSI measurement of an aperiodic CSI-RS.18.The method of any of claims 11-17, further comprising:receiving (402) , from the UE 102, a UE capability report indicating a capability of the UE (102) for CSI reporting of the data associated with the at least one of the CSI compression or the CSI prediction.19.An apparatus for wireless communication comprising a memory, a transceiver, and a processor coupled to the memory and the transceiver, the apparatus being configured to implement a method as in any of claims 1-18.