Measurement and transmission methods and apparatus for multiple transmission reception points

Abstract

A method of channel state information (CSI) reporting includes receiving, at a user equipment (UE), a CSI reporting configuration from a base station, the CSI reporting configuration being associated with CSI reference signal (CSI-RS) resource sets corresponding to a plurality of transmission reception points (TRPs); performing channel measurements based on the CSI-RS resources corresponding to the plurality of TRPs; determining a precoder matrix indicator (PMI) based on measurement results of the channel measurements, the PMI corresponding to a precoder matrix represented as W of a Type II CSI codebook; the precoder matrix having a spatial domain (SD) basis vector matrix represented as W1, SD basis selection of the SD basis vector matrix being TRP specific; and transmitting, to the base station, a CSI report, the CSI report including the PMI.

Description

[0001] Cross-references

[0002] This invention claims priority to Indian Patent Application No. 202221012693, filed March 9, 2022, entitled "Methods for multiple-transmission-reception-point Measurement and Transmission in communication systems," and U.S. Patent Application No. 18 / 169,613, filed February 15, 2023, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This invention relates to wireless communication, and more particularly to multi-antenna transmission operations at networks and mobile devices in wireless communication systems. Background Technology

[0004] A large number of steerable antenna elements can be used for transmission and reception on the network or device side. In higher frequency bands, a large number of antenna elements can be used for beamforming to extend coverage. In lower frequency bands, a large number of antenna elements can be used to spatially separate users to increase spectrum transmission capacity. CSI for operation of massive MIMO schemes can be obtained through feedback from Channel State Information (CSI) reports, where CSI reports are based on the transmission of reference signals in the downlink or uplink between the network and mobile devices. Summary of the Invention

[0005] The present invention provides a first method for CSI reporting. The first method includes: receiving a CSI reporting configuration at a user equipment (UE) from a base station, the CSI reporting configuration being associated with a set of CSI reference signals (CSI-RS) resources corresponding to a plurality of transmission reception points (TRPs); performing channel measurements based on the CSI-RS resources corresponding to the plurality of TRPs; determining a precoder matrix indicator (PMI) based on the measurement results of the channel measurements, the PMI corresponding to a precoder matrix represented as W of type IICSI codebook; the precoder matrix having a spatial domain (SD) basis vector matrix represented as W1, the SD basis selection of the SD basis vector matrix being TRP-specific; and sending a CSI report to the base station, the CSI report including the PMI.

[0006] In one implementation, the SD basis vector matrix has the following form:

[0007]

[0008] Where, N T L is the number of antenna ports of multiple TRPs, L is the number of basis vectors corresponding to one antenna polarization in W1, and N is the number of antenna ports of multiple TRPs. P It is the number of multiple TRPs. It is the SD basis vector matrix of the p-th TRP, p = 1, ..., N P . It is an SD basis matrix and has the following form

[0009]

[0010] in, This is the number of antenna ports of the p-th TRP, where p = 1, ..., N. P And L p Let be the number of SD basis vectors in each polarization of the p-th TRP, such that and

[0011] In one embodiment, the SD basis vector matrix includes TRP-specific SD basis matrices, each corresponding to one of a plurality of TRPs. In another embodiment, the SD basis vector matrix includes TRP-specific SD basis matrices, each corresponding to one of a plurality of TRPs, and the TRP-specific SD basis matrices have a different number of SD basis vectors. For example, one of the TRP-specific SD basis matrices includes a first basis vector of a first polarization of the corresponding TRP and a second basis vector of a second polarization of the corresponding TRP, the first basis vector being identical to the second basis vector.

[0012] In one implementation, the SD basis selection of the SD basis vector matrix is ​​layer-common. In one implementation, the SD basis vector matrix includes SD basis vectors corresponding to different TRPs among a plurality of TRPs, and co-located TRPs among the plurality of TRPs have the same SD basis vectors. In one implementation, the PMI includes an indication of the SD basis vectors contained in the SD basis vector matrix, the SD basis vectors corresponding to corresponding TRPs among the plurality of TRPs, wherein two co-located TRPs among the plurality of TRPs share the same set of SD basis vectors in the SD basis vectors of the PMI. In an example, the method further includes: in response to receiving an indication from a base station regarding which TRPs among the plurality of TRPs are co-located, determining, based on the indication, that two co-located TRPs report the same set of SD basis vectors. In an example, the method further includes determining, based on calculated SD basis vectors corresponding to different TRPs, that two co-located TRPs report the same set of SD basis vectors.

[0013] Aspects of the present invention provide a first apparatus including circuitry. The circuitry is configured to receive a CSI report configuration from a base station, the CSI report configuration being associated with a CSI-RS resource set corresponding to a TRP; perform channel measurements based on the CSI-RS resources corresponding to the plurality of TRPs; determine a PMI based on the measurement results of the channel measurements, the PMI corresponding to a precoder matrix of a type IICSI codebook, the precoder matrix having an SD basis vector matrix, the SD basis selection of the SD basis vector matrix being TRP-specific; and send a CSI report to the base station, the CSI report including the PMI.

[0014] Aspects of the present invention provide a first non-transitory computer-readable medium for storing instructions that, when executed by a processor, cause the processor to perform the first method.

[0015] A second method for CSI reporting is provided in various aspects of the present invention. The second method includes: receiving a CSI reporting configuration at a UE from a base station, the CSI reporting configuration being associated with a set of CSI-RS resources corresponding to a plurality of TRPs; performing channel measurements based on the CSI-RS resources corresponding to the plurality of TRPs; determining a first PMI based on the measurement results of the channel measurements, the first PMI corresponding to a first precoder matrix denoted W of type IICSI codebook, the first precoder matrix having a first SD / frequency domain (FD) coefficient matrix denoted W2, coefficient rows in the first SD / FD coefficient matrix corresponding to SD basis vectors in an SD basis vector matrix denoted W1, coefficient columns in the first SD / FD coefficient matrix corresponding to FD basis vectors in an FD basis vector matrix, the first PMI including a first FD basis indicator indicating that the FD basis selection in the first SD / FD coefficient matrix corresponding to any TRP is independent of the FD basis selection of any other TRP; and sending a CSI report to the base station, the CSI report including the first PMI.

[0016] In one implementation, the first FD base indicator includes an initial window position indicator and an FD base index for each of the plurality of TRPs. In another implementation, the method further includes determining a second PMI based on a second precoder matrix of type IICSI codebook, the second precoder matrix having a second SD / FD coefficient matrix, the second PMI including a second FD base indicator indicating that the FD base selection in the second SD / FD coefficient matrix is ​​common to the plurality of TRPs. In one example, the second FD base indicator includes only one initial window position indicator and only one FD base index for the plurality of TRPs.

[0017] In one implementation, non-zero coefficients (NZCs) are selected from the first SD / FD coefficient matrix across multiple TRPs. In another implementation, the strongest coefficients are selected from the first SD / FD coefficient matrix across multiple TRPs. In yet another implementation, reference amplitude coefficients are selected from the first SD / FD coefficient matrix across multiple TRPs.

[0018] In one implementation, TRP-specific reference amplitude coefficients are selected from the first SD / FD coefficient matrix. In one example, the TRP-specific reference amplitude coefficients are polarization-common. In another example, the TRP-specific reference amplitude coefficients are polarization-specific. In one implementation, the PMI includes a TRP-common NZC bitmap indicating the NZC positions in the first SD / FD coefficient matrix. In another implementation, the PMI includes a TRP-specific NZC bitmap indicating the NZC positions in the first SD / FD coefficient matrix.

[0019] Aspects of the present invention provide a second apparatus including circuitry. The circuitry is configured to receive a CSI report configuration from a base station, the CSI report configuration being associated with a CSI-RS resource set corresponding to a plurality of TRPs; perform channel measurements based on the CSI-RS resources corresponding to the plurality of TRPs; determine a first PMI based on the measurement results of the channel measurements, the first PMI corresponding to a first precoder matrix represented as W of a type IICSI codebook, the first precoder matrix having a first SD / FD coefficient matrix represented as W2, the coefficient rows in the first SD / FD coefficient matrix corresponding to SD basis vectors in an SD basis vector matrix represented as W1, the coefficient columns in the first SD / FD coefficient matrix corresponding to FD basis vectors in an FD basis vector matrix, the first PMI including a first FD basis indicator indicating that the FD basis selection in the first SD / FD coefficient matrix corresponding to any TRP is independent of the FD basis selection of any other TRP; and send a CSI report to the base station, the CSI report including the first PMI.

[0020] Aspects of the present invention provide a second non-transitory computer-readable medium for storing instructions that, when executed by a processor, cause the processor to perform the second method.

[0021] A third method for CSI reporting is provided by various aspects of the present invention. The third method includes: receiving a CSI reporting configuration at a UE from a base station, the CSI reporting configuration being associated with a CSI-RS resource set corresponding to a plurality of TRPs, the CSI-RS resources being organized into one or more resource groups, the CSI reporting configuration including one or more antenna configurations (N1, N2), each antenna configuration corresponding to one or more of the plurality of TRPs, the one or more antenna configurations (N1, N2) respectively corresponding to the one or more resource groups. N1 and N2 are respectively the number of antenna ports in the vertical and horizontal directions of the one or more TRPs; performing channel measurements based on the CSI-RS resources corresponding to the plurality of TRPs; determining a PMI based on the measurement results of the channel measurements and the one or more antenna configurations (N1, N2) respectively corresponding to one or more of the plurality of TRPs; and sending a CSI report to the base station, the CSI report including the PMI.

[0022] In one implementation, the PMI corresponds to the precoder matrix of the type IICSI codebook. In one implementation, a first antenna configuration (N1, N2) of one or more antenna configurations (N1, N2) corresponds to at least two co-located TRPs among a plurality of TRPs, where N1 and N2 are the number of antenna ports in the vertical and horizontal directions for each co-located TRP, respectively. In one implementation, the CSI report configuration also includes a power indicator indicating how to adjust the transmission power of the TRPs among the plurality of TRPs. For example, the UE performs channel-quality indicator (CQI) estimation based on this power indicator.

[0023] In one embodiment, the CSI reporting configuration further includes a power indicator indicating which of the plurality of TRPs share the same total power. In one embodiment, the CSI reporting configuration further includes a power indicator indicating that at least one of the plurality of TRPs transmits at full power. In one embodiment, the CSI reporting configuration further includes a power indicator indicating that each of the plurality of TRPs transmits at full power.

[0024] A third apparatus including circuitry is provided in various aspects of the present invention. The circuitry is configured to receive, at a UE, a CSI report configuration from a base station, the CSI report configuration being associated with a set of CSI-RS resources corresponding to a plurality of TRPs, the CSI-RS resources being organized into one or more resource groups, the CSI report configuration including one or more antenna configurations (N1, N2), each antenna configuration corresponding to one or more of the plurality of TRPs, the one or more antenna configurations (N1, N2) respectively corresponding to the one or more resource groups. N1 and N2 are respectively the number of antenna ports in the vertical and horizontal directions of the one or more TRPs; perform channel measurements based on the CSI-RS resources corresponding to the plurality of TRPs; determine a PMI based on the measurement results of the channel measurements and the one or more antenna configurations (N1, N2) respectively corresponding to one or more of the plurality of TRPs; and send a CSI report to the base station, the CSI report including the PMI.

[0025] Aspects of the present invention provide a third non-transitory computer-readable medium for storing instructions that, when executed by a processor, cause the processor to perform the method. Attached Figure Description

[0026] This invention provides some embodiments as examples, which will be described in detail below with reference to the accompanying drawings, wherein the same numbers represent the same components, wherein:

[0027] Figures 1 to 3 An example of mapping a CSI-RS port or a sounding reference signal (SRS) port to a physical antenna is shown.

[0028] Figure 4 A linear multi-antenna transmission scheme in a transmitter according to an embodiment of the present invention is shown.

[0029] Figure 5 An example of simulating multi-antenna processing is shown.

[0030] Figure 6 An example of hybrid multi-antenna processing according to some embodiments of the present invention is shown.

[0031] Figure 7 The first example of a single transmit-receive point (sTRP) transmission is shown.

[0032] Figure 8 A second example of sTRP transport is shown.

[0033] Figure 9An example 900 of multiple-TRP (mTRP) transmission according to an embodiment of the present invention is shown.

[0034] Figure 10 An example of coherent joint transmission (CJT) for two TRP 1002-1003 is shown.

[0035] Figure 11 A CSI measurement and reporting process 1100 according to an embodiment of the present invention is shown.

[0036] Figure 12A and Figure 12B An example of resource group configuration is shown.

[0037] Figures 13A to 13B An example of CSI-RS resource configuration is shown, which is only for mTRP CJT reports (not for sTRP reports).

[0038] Figures 14A to 14B An example of CSI-RS resource configuration is shown, which is only for mTRP CJT reports (not for sTRP reports).

[0039] Figures 15A to 15B Examples of CSI-RS resource configurations for joint reporting of sTRP and mTRP CJT, sTRP CSI reporting, or mTRP CSI reporting are shown.

[0040] Figure 16 The first example of W1 feedback reduction is shown. As illustrated, four TRPs, from TRP1 to TRP4, were deployed.

[0041] Figure 17 A second example of W1 feedback reduction is shown.

[0042] Figure 18 An example of a report with compressed SD basis vector matrices is shown.

[0043] Figure 19A This shows the switching between sTRP and mTRP.

[0044] Figure 19B It shows in Figure 19A Another example of reduced W1 feedback in a scenario involving mixed sTRP and mTRP CSI reports.

[0045] Figure 20 The Type II codebook precoder structure 2000 for mTRP CJT feedback is shown.

[0046] Figure 21An example of NZC selection according to an embodiment of the present invention is shown.

[0047] Figures 22A to 22B An example of NZC selection for mTRP CSI reports is shown according to an embodiment of the present invention.

[0048] Figures 23A to 23B Another example of NZC selection for mTRP CSI reports is shown according to an embodiment of the present invention.

[0049] Figure 24 An example of an alternative scheme for FD basis vector selection according to an embodiment of the present invention is shown.

[0050] Figure 25 An example of the initial window position and FD base index in the FD coefficient matrix W2 is shown.

[0051] Figure 26 An example is shown where different mTRP sets can be switched to serve the UE due to the UE's mobility.

[0052] Figure 27 Two types (two variants) of codebook structures for CSI feedback are shown.

[0053] Figure 28A An example of CSI reporting configuration is shown.

[0054] Figure 28B An example of a codebook configuration is shown.

[0055] Figures 29A to 29B Examples of four TRP CJT transport scenarios are shown.

[0056] Figures 30A to 30B Examples of four TRP CJT transport scenarios are shown.

[0057] Figure 31 This illustrates an example of how a gNB can derive an SD / FD base from a joint mTRP channel.

[0058] Figure 32 It shows that the UE can be polarized in a common and free manner from P CSI-RS Example of selecting K1 ports from a set of ports.

[0059] Figure 33 The process 3300 for mTRP CSI measurement and reporting according to an embodiment of the present invention is shown.

[0060] Figure 34 Another process 3400 for mTRP CSI measurement and reporting according to an embodiment of the present invention is shown.

[0061] Figure 35 Another process 3500 for mTRP CSI measurement and reporting according to an embodiment of the present invention is shown.

[0062] Figure 36 An exemplary device 3600 according to an embodiment of the present invention is shown. Detailed Implementation

[0063] I. Multi-antenna operation

[0064] 1. Reference Signal and Channel State Information (CSI)

[0065] In some implementations, knowledge of the radio link can be obtained by measuring a reference signal transmitted on the radio link during channel sounding processing. The reference signal in the downlink direction may be referred to as CSI-RS. The reference signal in the uplink direction may be referred to as SRS.

[0066] CSI-RS can be configured on a per-device basis. A configured CSI-RS can correspond to one or more different antenna ports (called CSI-RS ports). Each CSI-RS port can correspond to a channel to be probed. For example, a multi-port CSI-RS can include 32 per-antenna-port CSI-RS transmitted orthogonally on 32 CSI-RS ports. Each per-antenna-port CSI-RS corresponds to a CSI-RS port.

[0067] CSI-RS can be configured for a specific bandwidth (e.g., a portion of the bandwidth). Within the configured bandwidth, CSI-RS can be configured for every N resource blocks. N can be 1, 2, 3, etc. Within a resource block, a CSI-RS can occupy one or more element resources within a time slot. For multi-port CSI-RS, the group of element resources is shared by multiple CSI-RS per antenna port, for example, based on a combination of code-domain sharing (CDM), frequency-domain sharing (FDM), or time-domain sharing (TDM).

[0068] The device can be configured with one or more CSI-RS resource sets. For example, the device can receive a CSI resource configuration specifying one or more CSI-RS resource sets. Each resource set includes one or more configured CSI-RS. Each resource set also includes pointers to a set of New Radio (NR) synchronization signal (SS) blocks. CSI-RS resource sets can be configured for periodic, semi-persistent, or aperiodic transmissions. For example, semi-persistent CSI-RS transmissions can be activated or deactivated based on a MAC control element (CE). Aperiodic CSI-RS transmissions can be triggered using downlink control information (DCI).

[0069] Similarly, an SRS can support one or more antenna ports (referred to as SRS ports). Different SRS ports can share the same set of resource elements and the same base SRS sequence. Different rotations can be applied to separate different SRS ports. Applying phase rotation (or phase shift) in the frequency domain is equivalent to applying cyclic shift in the time domain. Similar to CSI-RS, the device can be configured with one or more SRS resource sets. Each resource set can include one or more configured SRSs. SRS resource sets can be configured for periodic transmission, semi-persistent transmission (controlled by MAC CE), or aperiodic transmission (triggered by DCI).

[0070] Figures 1 to 3 An example of mapping a CSI-RS port or SRS port to a physical antenna is shown. Figure 1 In the example, M port CSI-RS or SRS (CSI-RS / SRS) correspond to M antenna ports (CSI-RS ports or SRS ports). The M antenna ports are connected to N physical antennas via a spatial filter (labeled F). The M port CSI-RS / SRS are processed by the spatial filter before being mapped to the N physical antennas. Due to spatial filtering, one or more transmission beams can be formed for the transmission of the M port CSI-RS / SRS. Typically, N can be greater than M.

[0071] exist Figure 2 In the example, two separate spatial filters, F1 and F2, are applied to two CSI-RS / SRS#1 and #2, but they are transmitted through the same set of physical antennas at the same time or at different times. Due to the spatial filtering, the two CSI-RS / SRS#1 and #2 are beamformed in different directions.

[0072] exist Figure 3In the example, multiple antenna panels are used for transmission. The two CSI-RS / SRS#1 and #2 are processed using two separate spatial filters F1 and F2, and transmitted simultaneously or at different times on two antenna panels P1 and P2, respectively. Due to spatial filtering and the corresponding antenna panels, the two CSI-RS / SRS#1 and #2 are beamformed in different directions.

[0073] like Figures 1 to 3 As shown in the example, the channel being probed based on CSI-RS / SRS is not a physical radio channel, but rather a channel corresponding to a CSI-RS port or an SRS port.

[0074] In some implementations, the network (e.g., a base station) can configure a CSI reporting configuration for the device. The device can perform channel measurements based on the CSI reporting configuration and report the measurement results to the network. For example, the CSI reporting configuration can specify a set of quantities to be reported. These quantities may include CQI, rank indicator (RI), PMI, etc. These quantities are collectively referred to as CSI. The quantities also include reference-signal-received power (RSRP), which reflects the received signal strength.

[0075] CSI reporting configuration can further specify downlink resources that can be measured to derive the specified quantities. For example, CSI reporting configuration can describe or indicate one or more CSI-RS resource sets, each including one or more CSI-RSs. For instance, a single multiport CSI-RS can be configured to report combinations of CQI, RI, and PMI for link adaptation and multi-antenna precoding. Multiple CSI-RSs can be configured for beam management, and each CSI-RS can be beamformed and transmitted in different directions. In some scenarios, the device can perform measurements without reporting based on the configured resources. For example, the device can perform measurements for receiver-side beamforming and multi-antenna precoding without reporting.

[0076] The reporting configuration can further describe when and how reporting is performed. For example, reports can be periodic, semi-persistent, or aperiodic. Reports can be activated (deactivated) based on MAC CE or triggered via DCI. Measurement results for periodic and semi-persistent reporting can be carried in the physical uplink control channel (PUCCH). Measurement results for aperiodic reporting can be carried in the physical uplink shared channel (PUSCH).

[0077] 2. Multi-antenna transmission

[0078] A Digital and Analog Multi-Antenna Processing

[0079] Figure 4 A linear multi-antenna transmission scheme in a transmitter according to an embodiment of the present invention is illustrated. As shown, by using a transmitter with a size of N... T ×N L Multiply by the transfer matrix W, and then multiply N. L Layer data (e.g., modulation symbols) mapped to N T There are N transmitting antennas. Vector X represents N. L Layer data. Vector Y represents the data corresponding to N. T N antennas T One signal.

[0080] In various examples, the multi-antenna processing represented by matrix W can be applied to either the analog or digital portion of the transmit chain. Alternatively, a hybrid approach can be employed, where multi-antenna processing can be applied to both the analog and digital portions of the transmit chain. Therefore, in various implementations, multi-antenna processing can be analog multi-antenna processing, digital multi-antenna processing, or hybrid multi-antenna processing.

[0081] In analog processing, a spatial filter F can be applied to provide phase shifts for each antenna to form a transmission beam. Figure 5 An example of simulated multi-antenna processing is shown. In some examples, simulation processing is performed carrier-by-carrier for downlink transmissions. Therefore, frequency-multiplexed beamforming is not performed for transmissions located in different directions relative to the base station. To cover different devices located in different directions, beam scanning is performed through simulation processing.

[0082] In digital processing, each element of the transmission matrix W can include a phase shift and a scaling factor, which provides greater flexibility in controlling the beamforming direction. For example, simultaneous multi-beamforming can be achieved to cover multiple devices located in different directions relative to the base station. The transmission matrix W used in digital multi-antenna processing is called the precoder matrix. The corresponding multi-antenna processing is called multi-antenna precoding.

[0083] Precoders and spatial filters can be sequentially connected in hybrid multi-antenna processing to form a directional transmission beam. Figure 6An example of hybrid multi-antenna processing according to some embodiments of the present invention is shown. As illustrated, modulation symbol layer 601 is mapped to CSI-RS antenna port 603 via precoder 602. The output from precoder 602 is mapped to physical antenna 605 via spatial filter (F) 604. In some examples, spatial filter 604 is used to form a wider beam, while precoder 602 is used to form one or more narrower beams along the direction of the wider beam. By selecting specific precoder 602 and spatial filter 604, the transmitter can determine one or more beams to cover one or more receivers distributed in different locations.

[0084] Similar to transmitter-side processing, receivers can apply analog, digital, or hybrid multi-antenna processing to beamforming reception of signals arriving from different directions.

[0085] B. Downlink Multi-Antenna Precoding

[0086] In some implementations, to support network selection for a precoder used for downlink transmissions (such as physical downlink shared channel (PDSCH) transmissions), the device may perform measurements based on CSI-RS and report the measurement results (e.g., CSI reports) to the network based on configurations received from the network (e.g., CSI report configurations). The network can then determine the precoder based on the measurement results.

[0087] In some examples, CSI reports may include RI, PMI, COI, etc. RI can indicate the appropriate transport rank (number of transport layers N) used for downlink transmission. L The PMI can indicate the appropriate precoder matrix M corresponding to the selected rank. Given the selected precoder matrix, the CQI can indicate the appropriate channel coding rate and modulation scheme.

[0088] In some implementations, the value of PMI can correspond to a specific precoder matrix selected from the precoder codebook. The precoder codebook provides a set of candidate precoder matrices. Besides the number of transport layers N... L In addition, the device also considers a specific number (N) of antenna ports of the configured CSI-RS associated with the CSI reporting configuration. RS To select the PMI. In one example, for N T and N L Each valid combination provides at least one codebook.

[0089] In some implementations, two types of CSI are defined for different scenarios: Type I CSI and Type IICSI. The different types of CSI are associated with different sets of precoder codebooks with different structures and sizes.

[0090] The codebook for Type I CSI can be relatively simple and designed to focus transmitted energy at the target receiver. Type I CSI can include two subtypes: Type I single-panel CSI and Type I multi-panel CSI. These two subtypes correspond to different antenna configurations on the network or transmitter side. The codebook for Type I ICSI can provide channel information with higher spatial granularity than Type I CSI. Type I ICSI can be targeted at multi-user multiple-input multiple-output (MU-MIMO) scenarios.

[0091] II. Type IICSI codebook structure

[0092] In some implementations, Type IICSI feedback can be based on a linear combination (LC) codebook. For example, the channel's eigenvectors can be (approximately) represented as a linear combination of L Discrete Fourier Transform (DFT) vectors. The UE can report CSI including the DFT vectors and the coefficients used to combine the DFT vectors. If the channel has multiple principal eigenvectors (higher-rank channels), the UE can report multiple eigenvectors. The DFT beam of the DFT vectors can be reported in a wideband (WB) manner (a common report for all subbands (SB)). The amplitude and phase of the coefficients can be reported separately using corresponding codebooks. For example, the coefficient phase can be frequency-selective, and therefore reported for each SB. The coefficient amplitude can be reported in a WB manner.

[0093] In some implementations, the weighted vector (or precoder matrix) of rank-1 type IICSI can have the following form:

[0094]

[0095] Among them, for polarization r and rank l, w r,lIt is a weighted linear combination of L orthogonal beams that are polarized one by one. The weighting vector W can be determined as follows. The DFT beam matrix W1 can have a size of 2N1N2×2L, where L orthogonal vectors / beams can be selected one by one from a set of oversampled O1O2N1N2 DFT beams. N1 and N2 are the numbers of antenna ports in the same polarization direction in the horizontal and vertical domains. O1 and O2 are the oversampling factors in the corresponding dimensions. The linear combination of the L orthogonal vectors achieves compression in the spatial domain (SD). The L orthogonal vectors can be called SD components or SD bases. The linear combination subband matrix W2 can be determined such that for each subband, the weighted linear combination of the columns of W1 produces the l strongest eigenvectors of the channel covariance matrix. It can be seen that when the number of layers and subbands increases, the number of combination coefficients increases linearly, resulting in a large CSI reporting overhead.

[0096] In some embodiments, the type II CSI precoder of this kind is further compressed by using the frequency domain (FD) correlation within W2. DFT compression can be applied to W2. For example, W2 can have a size of 2L×N3, where 2L is the number of SD beams and N3 is the number of subbands. The frequency compression matrix W can be determined by selecting a set of orthogonal vectors from the columns of an oversampled DFT codebook. f . The matrix W f can have a size of N3×M (M < N3). M is the number of FD basis vectors selected after compression. FD compression can be applied to each layer to obtain a linear combination coefficient matrix.

[0097]

[0098] The compression matrix W f can be considered as the equivalent of the SD basis matrix W1 for frequency compression. Therefore, the type II CSI precoder matrix can have the following format:

[0099] The elements within can be called FD coefficients. After frequency compression, the FD coefficient matrix can be sparse. Moreover, most of the energy is concentrated in several coefficients. Therefore, several of the most important FD coefficients for reporting in can be determined. The rest can be assumed to be zero.

[0100] III. Deployment of Single TRP and Multiple TRPs

[0101] In this invention, the terms "transmit / receive point (TRP)," "antenna panel (or panel)," "antenna group (or port group)," "cell," and "sector" are used interchangeably to refer to antennas located in the same location. The techniques, methods, processes, procedures, examples, or implementations disclosed using TRPs or panels as examples can also be applied to antenna groups, cells, or sectors. In a deployment, a sector may correspond to one or more cells, a cell may correspond to one or more TRPs, and a TRP may correspond to one or more antenna panels. However, each of a sector, cell, TRP, or panel can be considered as a group of antennas used to apply the techniques disclosed herein.

[0102] 1. Single TRP deployment

[0103] Figure 7 A first example of a single TRP (sTRP) transmission is shown. The TRP 700 is configured with a single antenna panel 701. Antenna panel 701 includes a 32-port square (or rectangular) antenna array. This antenna array has a horizontal dimension of N1 = 4 and a vertical dimension of N2 = 4. N1 and N2 are the number of cross-polarized antenna elements. Each cross-polarized antenna element includes two cross-polarized antennas. Each cross-polarized antenna element can correspond to a pair of well-isolated spatial paths used for diversity or spatial multiplexing. Antennas located in the same position on antenna panel 701 allow the same DFT basis vectors to be used on the polarization in the precoder matrix. These DFT basis vectors can be linearly combined to approximate an optimal precoder. Figure 7 Examples of suitable codebooks for a single TRP transfer may include the Third Generation Partnership Project (3GPP) Release 15 Type I codebook, Release 15 Type II codebook, and Release 16e Type II codebook for a single board.

[0104] Figure 8 A second example of sTRP transmission is shown. The TRP 800 is configured with four antenna panels 801-804. Each antenna panel 801 includes a 32-port square (or rectangular) antenna array. The dimensions of the antenna array are (N1, N2) = (4, 4). The spacing between the last antenna element of the first panel and the first antenna element of the next panel is different from the spacing between antenna elements within each antenna panel 801-804. Therefore, a suitable precoder may include a W1 matrix and a W2 matrix. The W1 matrix defines a beam for each polarization and panel. The W2 matrix provides in-phase communication between common polarizations of each subband and between panels. Figure 8 Examples of suitable codebooks for multi-panel single TRP transmissions may include 3GPP Release 15 Type I codebooks for multi-panel transmissions.

[0105] 2. Multi-TRP Deployment

[0106] Multiple large-interval (distributed) transmit-receive points (TRPs) can operate in CJT mode or non-coherent joint transmission (NCJT). In NCJT, different layers can be transmitted from multiple TRPs without coordination. Interlayer interference reduces throughput and coverage. In CJT, multiple TRPs can be controlled to operate in a coordinated manner. Therefore, signals from different TRPs can constructively interfere with each other to improve throughput and coverage and reduce interlayer interference. To support CJT with multiple TRPs, the in-phase and amplitude (or power) differences between TRPs can be measured and reported from the mobile device to the network. Based on this reported information, the network can control the TRPs to perform coherent joint transmission. Therefore, mTRP CJT CSI measurement and reporting schemes are employed in the various embodiments disclosed herein. These schemes may include novel mechanisms for CSI-RS configuration, CSI reporting configuration, and CJT codebook structures.

[0107] Figure 9 An example 900 of mTRP transmission according to an embodiment of the present invention is shown. UE 901 receives CSI-RS signals from four TRPs 911-914. Each TRP may be configured with one or more antenna panels. These TRPs 911-914 may be controlled by the same base station (e.g., gNB) and may operate cooperatively for CJT. Due to the geographical distribution of the TRPs 911-914, synchronization signals transmitted from the TRPs 911-914 to UE 901 may take different paths. To enable the TRPs 911-914 to operate in CJT mode, a CSI measurement and reporting process can be performed between the TRPs 911-914 and UE 901. Based on the reported CSI, CJT for the TRPs 911-914 can be implemented.

[0108] Figure 10 Two examples of CJTs for TRP 1002-1003 are shown. See below for reference. Figure 10 Introducing the system model. Two TRPs 1002-1003 are configured to direct traffic to a system with N... R UE 1001 on each of its reception (rx) ports jointly transmits signals. (v layers). TRP 1 1002 has One transmission (tx) port, TRP 2 1003 has There are TX ports. The total number of valid TX ports is The downlink (DL) channel from TRP 11002 to UE 1001 is The precoder from TRP 11002 to UE 1001 is The DL channel from TRP 2 1003 to UE 1001 is The precoder from TRP 2 1003 to UE 1001 is Therefore, the signal received at UE 1001 can be

[0109]

[0110] in, and These are the effective channel matrix and the effective precoder matrix.

[0111] 3. mTRP CJT's CSI Reporting Process

[0112] Figure 11 A CSI measurement and reporting process 1100 according to an embodiment of the present invention is illustrated. In process 1100, CSI is reported from UE 1102 to base stations connected to a set of geographically distributed TRPs 1101. Process 1100 may include six steps from step S1110 to step S1160.

[0113] In step S1110, the network (or base station) can use radio resource control (RRC) signaling to instruct UE 1102 on CSI-RS resource configuration and CSI report configuration. For example, through resource configuration, the base station can configure multiple CSI-RS resources from a CSI-RS resource set for UE 1102. These multiple CSI-RS resources may correspond to one or more channel measurement resources (CMRs) specified in the CSI report configuration. For example, the CSI report configuration may be associated with one or more resource configurations. The CSI report configuration may indicate a codebook type, such as Type I codebook type or Type II codebook type.

[0114] In step S1120, the base station can then trigger UE 1102 to perform a CSI measurement and reporting procedure (e.g., by sending an RRC message, a MAC CE command, or a DCI). TRP 1101 can then send a CSI-RS to UE 1102. In S1130, UE 1102 can receive the CSI-RS and perform channel measurements according to the CSI-RS configuration and CSI reporting configuration. In S1140, based on the measurement results, UE 1102 can derive the CSI, including, for example, PMI, RI, CQI, etc. UE 1102 can then report the CSI to the base station.

[0115] In step S1150, the base station performs PDSCH transmission from TRP 1101 based on the reported PMI, RI, and CQI. In S1160, UE 1102 can receive the PDSCH and decode the data carried in the PDSCH. Process 1100 can end at step S1150.

[0116] IV. CSI-RS Resource Allocation

[0117] In some implementations, the network can configure the UE using a CSI-RS resource set. The CSI-RS resource set may include multiple CSI-RS resources. The CSI-RS resource set can be used for CSI measurement and reporting for mTRP CJTs. The CSI-RS resource set may include multiple resource groups. Each resource group includes at least one CSI-RS resource. CSI-RS resources within the same resource group may mean that the CSI-RS resources can be transmitted from the same co-located TRP, panel, or multiple TRPs. The UE may assume that CSI-RS resources belonging to the same resource group can be transmitted under the same Quasi-Co Location (QCL) assumption. In some implementations, the network can configure and trigger the UE using a CSI reporting configuration. The CSI reporting configuration can associate a CSI-RS resource set with at least one channel measurement selection information. The channel measurement selection information can indicate which CSI-RS resources in the CSI-RS resource set should be measured together. The UE can measure multiple resources or multiple resource groups based on at least one channel measurement selection information to estimate CSI information for CSI reporting.

[0118] In some implementations, to combine mTRP CJT CSI and sTRP CSI in the CSI report, the UE may be configured with multiple channel measurement selection pieces of information to indicate which CSI resources should be estimated. Each channel measurement selection piece of information may be associated with or represented by at least one CSI-RS Resource Indicator (CRI). In some examples, a CRI may indicate at least one CSI-RS resource belonging to a resource group. In some examples, a CRI may indicate at least two CSI-RS resources belonging to at least two resource groups used for mTRP CJT transmissions. In some examples, a channel measurement selection piece of information may indicate at least one CRI. The CRIs used for indexing sTRP CSI and mTRP CSI may be separated.

[0119] Figure 12A and Figure 12B An example of resource group configuration is shown. Figure 12A In the CSI resource settings, resource set #0 includes four RS resources, RS#1 to RS#4. These four RS resources are divided into three resource groups, 1 to 3. The first resource group includes RS#1 and RS#2. The second and third resource groups include RS#3 and RS#4, respectively.

[0120] Figure 12B Four TRPs (TRP 1 to TRP 4) are shown. TRP1 and TRP2 are co-located. Therefore, for CSI reporting purposes, signals from TRP1 and TRP2 can be considered quasi-co-located (QCLed). TRP3 and TRP4 are located at different distances from TRP1 and TRP2. As shown, Figure 12A The four RS resources configured in the middle are respectively allocated to Figure 12B The resource group consists of four TRPs, 1 through 4. Specifically, RS#1 and RS#2 within the same resource group 1 are assigned to co-located TRPs 1 through 2. When reporting CSI (including in-phase / amplitude / power difference) based on the resource group, TRP1 and TRP2 can be considered as a single unit. This reduces the signaling cost of CSI reporting.

[0121] Example #0 - CSI-RS Resource Settings

[0122] Figures 13A to 13B This example shows a CSI-RS resource configuration used only for mTRP CJT reporting (no reporting for sTRP). For example, as... Figure 13A As shown, the network (or base station) allocates K=4 CSI-RS resources {RS#1, RS#2, RS#3, RS#4} from the CSI-RS resource set to the UE only for reporting mTRP CJT CSI. Figure 13BAs shown, a group of 4 TRPs {TRP1, TRP2, TRP3, TRP4} are geographically separated. Four CSI-RS resources {RS#1, RS#2, RS#3, RS#4} are sent from each of the 4 TRPs {TRP1, TRP2, TRP3, TRP4}. In some examples, such as... Figure 13A As shown, the four CSI-RS resources can be grouped into four resource groups, from resource group #1 to resource group #4. Each resource group contains one CSI-RS resource. Each resource group corresponds to a geographically separated TRP. In some examples, when there is a one-to-one mapping between CSI-RS resources and resource groups, the resource groups can be omitted from the configuration.

[0123] Example #1 - CSI-RS Resource Settings

[0124] Figures 14A to 14B This example shows a CSI-RS resource configuration used only for mTRP CJT reporting (no reporting for sTRP). For example, as... Figure 14A As shown, the network (or base station) allocates K=4 CSI-RS resources {RS#1, RS#2, RS#3, RS#4} from the CSI-RS resource set to the UE only for reporting mTRP CJT CSI. Figure 14B As shown, a group of 4 TRPs {TRP1, TRP2, TRP3, TRP4} is deployed. TRP1 and TRP2 are co-located. TRP3 and TRP4 are geographically separated. Four CSI-RS resources {RS#1, RS#2, RS#3, RS#4} are sent from the four TRPs {TRP1, TRP2, TRP3, TRP4} respectively. The four CSI-RS resources are grouped into three resource groups from resource group #1 to resource group #3, as follows: Figure 14A As shown. Resource group #1 includes CSI-RS resources RS#1 and RS#2. Resource groups #2 and #3 include CSI-RS resources RS#3 and RS#4, respectively. Grouping CSI-RS resources RS#1 and RS#2 into the same resource group #1 implicitly indicates to the UE that {RS#1, RS#2} are co-located and have the same QCL (quasi-co-location) assumption.

[0125] Example #2 - CSI-RS Resource Settings

[0126] Figures 15A to 15B Examples of CSI-RS resource configurations for sTRP and mTRP CJT joint reporting, sTRP CSI reporting, or mTRP CSI reporting are shown. For example, such as... Figure 15AAs shown, the network (or base station) configures a CSI-RS resource set for the UE. The CSI-RS resource set may include K = 4 CSI-RS resources {RS#1, RS#2, RS#3, RS#4}. For example... Figure 15B As shown, four CSI-RS resources can be allocated or sent from four TRPs {TRP1, TRP2, TRP3, TRP4} respectively. As illustrated, the four TRPs {TRP1, TRP2, TRP3, TRP4} are geographically separated.

[0127] Furthermore, a CSI-RS resource set may include indications of one or more CJT sets. In some examples, each CJT set may include one or more CSI-RS resources configured in the CSI-RS resource set. In some examples, each CJT set may include more than one CSI-RS resource configured in the CSI-RS resource set. Figure 15A In the CSI-RS resource set, K is shown as being included. CJT = Two CJT sets, CJT set #1 and CJT set #2. CJT set #1 includes CSI-RS resources from RS#1 to RS#4. CJT set #2 includes CSI-RS resources from RS#1 to RS#3. The CJT sets can be used for mTRP CJT CSI reporting. Different CJT sets can indicate different CJT transmission assumptions.

[0128] In addition, Figure 15A In the CSI-RS resource sets shown, each CSI-RS resource and CSI-RS resource set can be associated with a CRI. In some examples, CRIs for sTRP and mTRP measurements may or may not be provided separately. Figure 15A In the example, four CRIs {CRI#1, CRI#2, CRI#3, CRI#4} corresponding to four CSIs - RS {RS#1, RS#2, RS#3, RS#4} are provided for sTRP CSI resources. Two CRIs {CRI#1, CRI#2} corresponding to CJT set #1 and CJT set #2 are provided for mTRP CSI reporting. The UE can report CSIs (PMI, RI, CQI, etc.) accompanied by CRIs (e.g., in the form of CRI indexes).

[0129] V. Type IICSI codebook design for mTRP transmission

[0130] 1. Overall precoder structure of PMI in the CSI report

[0131] In some implementations, the total mTRP CJT precoder reported by the first UE in the PMI can have a size P. CSI-RS ×v and take the following form

[0132]

[0133] In the above formula, n represents the sub-band of the channel, and n = 0, 1, ..., N³⁻¹. CSI-RS This represents the total number of CSI-RS ports at the UE. v is the transmission rank. W T [n] is the PMI subband n corresponding to layer r=1,…,v. CSI-RS ×1 pre-encoder, making

[0134]

[0135] W (p) [n] is the p-th TRP. Precoder, p = 1, ... N P . N is the number of CSI-RS ports for the p-th TRP. p This is the total number of TRPs configured for CJT.

[0136] For ease of representation, the superscripts of each matrix are omitted in the following description. The overall mTRP CJT preencoder can be represented as follows:

[0137]

[0138] W1 indicates shared spatial domain information of the layers (e.g., SD basis vectors). For example, different layers can share the same SD basis vector matrix W1. W2 represents layer-specific linear combination coefficients (e.g., FD coefficients). f This represents layer-specific frequency domain information (e.g., FD basis vectors).

[0139] 2. W1 Matrix Design

[0140] In some implementations, W1 represents the spatial domain (SD) DFT basis vectors, which are shared by the broadband common matrix and layer common report. The SD basis matrix W1 used for mTRP CJT can take the following form:

[0141]

[0142] Where, N P It is the number of coherently transmitted TRPs. It can be The SD basis matrix represents the SD basis vector of the p-th TRP. For example, It has the following forms

[0143] This represents the number of tx ports in the TRP, where p = 1, ..., N.P And L p It is the number of SD basis vectors in each polarization of the TRP, p = 1, ..., N P , making and

[0144] It can be seen that the SD basis matrix W1 used for mTRP CJT can have a block diagonal structure. The block diagonal structure of W1 implies a TRP-specific SD basis selection. For example, different TRPs can correspond to different... When each TRP is configured with a CSI-RS resource in the mTRP transport, each CSI-RS resource corresponds to a specific In other words, SD base selection is performed on a per-CSI-RS resource basis. Furthermore, This can include a common polarization SD basis. For example, basis vectors. It is shared between the two polarizations. Therefore, for a given CSI-RS resource, the SD basis selection can be polarization-common. Just as W1 indicates information about the layer common spatial domain, for a given CSI-RS resource, the SD basis selection can also be layer-common.

[0145] The design principles of W1 are as follows. First, W1 has a block diagonal structure. Tx ports across different TRPs act as isolated spatial paths that can be used for diversity / multiplexing. Second, geographically separated TRPs mean that the SD basis vectors for TRPs are different, i.e., for p≠q, Third, for a specific UE, the line-of-sight (LOS) or non-line-of-sight (NLOS) conditions can differ for different TRPs. In this case, it can be expected that the number of SD basis vectors will be different across TRPs, i.e., for p≠q, L... p ≠L q For example, {L p p = 1, ..., N P} can be a higher layer configured by the base station. Or, it can be an L layer for all TRPs. p The total number can be configured by the base station. The UE can report {L p p = 1, ..., N P}

[0146] A.W1 feedback decreased

[0147] If the p-th TRP and the q-th TRP are co-located, the co-located TRPs can use the same SD basis vector, i.e., W1 (p) =W1 (q)Therefore, this knowledge can be used to reduce UE computation / feedback overhead. In various implementations, the following two methods can be used to reduce W1 feedback:

[0148] Alternative Option 1: The base station (e.g., gNB) uses higher-layer signaling, such as RRC or MAC-CE, to inform the UE about the co-located TRP.

[0149] Alternative Option 2: Based on the calculated W1 (p) The UE can determine that only W1 reports with different SD information. (p) .

[0150] Example #3-W1 feedback reduction (Alternative option 1.1)

[0151] In some examples, if some TRPs are co-located, the network (NW) can inform the UE of the co-location relationship between the TRPs. In various implementations, there are multiple ways to inform the UE of location information. For example, the network can configure CSI-RS resources for TRPs located in the same location within the same resource group. CSI reports associated with CSI-RS resources in the same resource group can share the same W1 information. For example, TRPs or CSI-RS resources corresponding to co-location within the same resource group can share a single W1 information. Used for CSI reporting. In this configuration, antenna configurations (N1, N2) and (O1, O2) can be configured for each CSI-RS resource (Alternative Option 1.1).

[0152] Figure 16 The first example of W1 feedback reduction is shown. As illustrated, four TRPs, TRP1 through TRP4, are deployed. Each TRP has a configuration of (N1, N2) = (4, 1) and eight CSI-RS ports. A total of four TRPs have P... CSI-RS = 32 CSI-RS ports. The four CSI-RS resources, RS#1 to RS#4, are each configured by 4 TRPs.

[0153] Figure 16 The document lists four scenarios (1601-1604) for TRP co-location configurations. In scenario 1601, the four TRPs are non-co-located. The network can signal the resource group configuration to the first UE as follows: {Resource Group #1 (RS#1), Resource Group #2 (RS#2), Resource Group #3 (RS#3), Resource Group #4 (RS#4)}. The document also includes four SD base matrices for each TRP. They can be different. Four SD base matrices can be reported in the CSI reports corresponding to the four CSI-RS resources {RS#1, RS#2, RS#3, RS#4} respectively.

[0154] In scenario 1602, TRPs {TRP1, TRP2} are co-located, and TRPs {(TRP1 / TRP2), TRP3, TRP4} are non-co-located. The network can signal the resource group configuration to the first UE as follows: {Resource Group #1 (RS#1, RS#2), Resource Group #2 (RS#3), Resource Group #3 (RS#4)}. The four SD base matrices can be... The SD basis matrices of TRP1 and TRP2 can be similar or identical. Therefore, three SD basis matrices can be reported in the CSI report corresponding to the four CSI-RS resources {RS#1, RS#2, RS#3, RS#4}.

[0155] In scenario 1603, TRPs {TRP2, TRP3} are co-located, while TRPs {TRP1, (TRP2 / TRP3), TRP4} are located at different positions. The network can signal the resource group configuration to the first UE as follows: {Resource Group #1 (RS#1), Resource Group #2 (RS#2, RS#3), Resource Group #3 (RS#4)}. The four SD base matrices can be... The SD basis matrices of TRP2 and TRP3 can be similar or identical. Therefore, three SD basis matrices can be reported in the CSI report corresponding to the four CSI-RS resources {RS#1, RS#2, RS#3, RS#4}.

[0156] In scenario 1604, TRP{TRP1, TRP2} are co-addressable. TRP{TRP3, TRP4} are also co-addressable. TRP{(TRP1 / TRP2), (TRP3 / TRP4)} are non-co-addressable. The four SD basis matrices can be... The SD basis matrices of TRP1 and TRP2 can be similar or identical. The SD basis matrices of TRP3 and TRP4 can also be similar or identical. Therefore, two SD basis matrices can be reported in the CSI report corresponding to the four CSI-RS resources {RS#1, RS#2, RS#3, RS#4}.

[0157] Example #4-W1 feedback reduction (Alternative option 1.2)

[0158] Figure 17 A second example of W1 feedback reduction is shown. (Compared to...) Figure 17The example is similar, deploying four TRPs from TRP1 to TRP4. The four TRPs have a total of P... CSI-RS = 32 CSI-RS ports. Configure four CSI-RS resources from RS#1 to RS#4 from four TRPs respectively. Listings regarding... Figure 17 The document lists four TRP co-location configuration scenarios 1701-1704. Scenarios 1701-1704 are similar to scenarios 1601-1604. Therefore, a similar CSI-RS resource grouping scheme can be used to notify the UE of the TRP co-location configuration (or deployment). The document also includes an SD base matrix corresponding to the CSI-RS resources configured for multiple co-location TRPs. The same SD base matrix can be shared in CSI reports to reduce CSI feedback overhead.

[0159] and Figure 16 Unlike the examples, the combined antenna configuration (N1, N2) is configured for the CSI-RS resources corresponding to the co-located TRPs (Alternative Scheme 1.2). In some examples, the CSI-RS resources corresponding to the co-located TRPs are grouped into the same resource group. For example, in scenario 1702, TRP1 and TRP2 are co-located. Therefore, the combined antenna configuration (8, 1) is configured for the CSI-RS resources RS#1 and RS#2 corresponding to the co-located TRP1 and TRP2. Similarly, in scenario 1704, the combined antenna configuration (8, 1) is configured for the CSI-RS resources RS#1 and RS#2 corresponding to the co-located TRP1 and TRP2, while another combined antenna configuration (8, 1) is configured for the CSI-RS resources RS#3 and RS#4 corresponding to the co-located TRP3 and TRP4.

[0160] Example #5-W1 feedback reduction (Alternative option 2.1)

[0161] In some examples, W1 is calculated based on CSI-RS measurements. (p) The UE can report only W1 with different SD basis vector information. (p) Set. For example, for W1 corresponding to two co-located TRPs. (1) and W1 (2) Report an SD basis vector matrix W1 (1) or W1 (2) Instead of reporting both.

[0162] Figure 18 An example of a report compressing the SD basis vector matrix W1 is shown. The PMI report format for the W1 matrix can be TRP-specific, for example... For example, Rotation factor (i) including SD basis 1,1 ) and SD base indicator (i 1,2):

[0163] For the p-th TRP, in, and

[0164] For the p-th TRP,

[0165] Considering the 4-TRP CJT CSI report, if the SD matrix calculated for TRP1 and TRP2 is the same, i.e. like Figure 18 As shown, the UE can further compress W1. In one example, the UE can report... and Each has only 3 elements instead of 4, such as Figure 18 As shown. In one example, the UE can further report additional quadruple indices, such as i 1,3 ={1,1,2,3}, to indicate the corresponding element indices of the four TRPs. Indices with the same value can indicate corresponding multiple W1s sharing the same SD basis vector matrix. (p) .

[0166] Example #6 - W1 Feedback Reduction (Alternative Solution 2.2): W1 PMI Sharing for Dynamic sTRP and mTRP Switching

[0167] Figure 19A The diagram illustrates the sTRP and mTRP handover scenario. As shown, four TRPs, from TRP1 to TRP4, are deployed around UE 1901. Initially, UE 1901 communicates with a single TRP (TRP4). UE 1901 moves away from TRP4 towards TRP1, TRP2, and TRP3. Based on CSI reports from UE 1901, the base station (not shown) can control UE 1901 and the four TRPs to switch from previous sTRP transmissions to mTRP transmissions. Figure 19A In this scheme, the CSI of the channel between UE 1901 and the four TRPs can be reported to the base station to support dynamic sTRP and mTRP handover.

[0168] To support dynamic handover between sTRP and mTRP transmissions, UE 1901 can report one CSI from both CJT and sTRP. For example, UE 1901 can report one CSI reflecting the channel conditions between UE 1901 and four TRPs. Alternatively, UE 1901 can report one CSI for CJT and X CSIs for a single TRP transmission. For example, X ∈ {0,1,2,3,4} can be configured. In this alternative scenario, separate CRI indices for CJT and single TRP measurements can be configured from the base station to UE 1901. Based on the CSI-RS measurements, individual CSIs corresponding to the respective CRIs can be derived and reported.

[0169] In the alternative approach described above, the W1 matrix can be shared between sTRP and mTRP CSI reports. For example, there is only one W1 matrix corresponding to each TRP. Figure 19B It shows in Figure 19A Another example of reduced W1 feedback in a scenario involving hybrid sTRP and mTRP CSI reporting. As shown, the report corresponds to one sTRP CSI for each TRP, including CRI, RI, PMI (W1, W2, W...). f ) and CQI. Corresponding to 4 TRPs, one mTRP CSI is reported. The mTRP CSI can include CRI, RI, PMI ( and ) and CQI. However, the SD basis matrix W1 is omitted from the mTRP CSI. The base station receives the data contained in the four sTRP CSIs. Then, the W1SD basis matrix can be obtained accordingly.

[0170] 3. W2 Matrix Design

[0171] Figure 20 A Type II codebook preencoder structure 2000 for mTRP CJT feedback is shown. This preencoder structure 2000 can correspond to the preencoder described above.

[0172]

[0173] Where W1 represents the matrix of broadband SD basis vectors, W2 represents the matrix of spatial frequency compression coefficients that linearly combine the SD basis vectors, and W... f This represents the DFT basis vectors used for FD compression. As shown, W1 has dimensions of... W2 has the following dimensions: Where N3 is the number of subbands in the mTRP transmission channel. W f It has dimensions of N3×N3. From W fChoose M FD basis vectors. Accordingly, in Figure 20 In the example, W2 includes M columns of frequency coefficients.

[0174] In the M column of coefficients, the highest effective coefficient 2001 can be selected and quantized. After quantization, a set of NZCs can be reported in the corresponding SCI. For example, the selected linear combination coefficients of W2 can be reported to gNB in ​​the form of the single strongest coefficient in a specific polarization, the reference amplitude of other polarizations, the polarization-specific difference amplitude, and the phase coefficient.

[0175] In some examples, the W2 coefficient report can be presented as a set of coefficient indicators within the CSI report. For instance, coefficient indicators can be categorized as follows:

[0176] -SCI (Strongest coefficient indicator): i 1,8

[0177] -ACI (Amplitude coefficient indicator)

[0178] o Reference range: i 2,3

[0179] o Difference amplitude: i 2,4 (As opposed to SCI or ACI)

[0180] -PCI (Phase coefficient indicator): i 2,5

[0181] -NZC bitmap: i 1,7 (Indicates the position of the coefficients in W2)

[0182] In some examples, the W2 design can follow these principles:

[0183] - NZC can be selected across TRPs. For example, W2 coefficients corresponding to different TRPs can be considered together to select or determine the coefficients to be reported.

[0184] oAccording to To determine the maximum number of NZCs layer by layer, where β is the NZC selection ratio.

[0185] - The strongest coefficient across all TRPs (SCI) - No amplitude and phase are reported for the SCI.

[0186] - The reference amplitude indicator can be

[0187] oTRP common to all TRPs, i.e., a reference range across all TRPs.

[0188] oTRP is specific, meaning each TRP has a reference amplitude.

[0189] o-polarization is common, that is, a reference amplitude of both polarizations.

[0190] o-polarization is specific; that is, each polarization has a reference amplitude.

[0191] The reference amplitude can be quantized, for example, to 4 bits.

[0192] - All other NZC values ​​are quantized relative to the corresponding reference amplitude, for example, using 3 bits (i.e., differential amplitude).

[0193] - All NZC phases can be quantized as, for example, 16PSK instead of SCI.

[0194] -NZC bitmaps can be common to TRPs or specific to TRPs.

[0195] oTRP common: Total bitmap size is

[0196] oTRP specific: Total bitmap size is

[0197] in

[0198] ■ It is the selected / service TRP set

[0199] ■N′ p It is the number of TRPs selected, that is,

[0200] ■L p It is the number of beams of the p-th TRP.

[0201] ■M p It is the number of selected FD bases for the p-th TRP.

[0202] ■M is the number of common FD bases in TRP.

[0203] Figure 21 An example of NZC selection according to an embodiment of the present invention is shown. Figure 21 In the example, and These are the reference amplitudes for the p-th TRP, which are polarized to 0 and 1, respectively.

[0204] Example #7 - NZC Selection

[0205] Figures 22A to 22BAn example of NZC selection for mTRP CSI reporting according to an embodiment of the present invention is shown. Four TRPs are present in the CSI report. Each TRP has two antenna polarizations. Corresponding to each polarization, two SD basis vectors (L...) are reported. p =2). For the 4 TRPs, M=3 FD basis vectors were selected. Figure 22A Different types of indicators for reporting the W2 coefficient and the corresponding selection methods (TRP common or TRP specific) are shown. Figure 22B The linear combination coefficient matrix W2 is shown. The layout of matrix elements in the region. As shown, determine the common SCI for the TRP corresponding to coefficient 2201. Determine the common reference amplitude for the TRP corresponding to coefficient 2202.

[0206] To determine the differential amplitudes of other NZCs, TRP-specific NZCs (such as coefficients 2203-2204) can be selected. Each differential amplitude of these TRP-specific selected NZCs can be determined relative to a corresponding reference amplitude, depending on which polarization the selected NZC belongs to. For example, matrix elements (or coefficients) 2203 and 2204 belong to the first and second antenna polarizations, respectively. Therefore, the reference amplitudes of elements 2202 and 2201 are used to determine the differential amplitudes of elements 2203 and 2204, respectively. The differential amplitudes of the TRP-specific selected NZCs can be quantified before CSI reporting.

[0207] Example #8 - NZC selection

[0208] Figures 23A to 23B Another example of NZC selection for mTRP CSI reporting according to an embodiment of the present invention is shown. Similarly, four TRPs exist in the CSI report. Each TRP has two polarizations. Corresponding to each polarization, two SD basis vectors (L...) are reported. p =2). Select M=3 FD basis vectors for the four TRPs. Figure 23A Different types of indicators for reporting the W2 coefficient and the corresponding selection methods (TRP common or TRP specific) are shown. Figure 23B The linear combination coefficient matrix W2 is shown. The layout of matrix elements in the region. Similarly, determine the SCI common to the TRP corresponding to coefficient 2305.

[0209] and Figures 22A to 22BUnlike other examples, multiple reference amplitudes are selected in a TRP-specific and polarization-specific manner. For instance, two selected reference amplitudes correspond to coefficients (or matrix elements) 2301 and 2302 with different polarizations and belonging to the same TRP 1. Two selected reference amplitudes correspond to coefficients (or matrix elements) 2303 and 2304 with different polarizations and belonging to the same TRP 2. Therefore, to determine the differential amplitudes of other NZCs, the TRP-specific selected NZCs can be compared with the corresponding TRP-specific and polarization-specific reference amplitudes.

[0210] 4.W f Matrix design

[0211] As described above, the overall mTRP CJT precoder can be represented as follows:

[0212]

[0213] Matrix W f This represents the frequency domain (FD) basis vectors used for frequency domain compression. In various implementations, the FD basis selection design can follow the principles outlined below (Alternative Scheme 1 and Alternative Scheme 2). FD compression can have two options.

[0214] Alternative Option 1: TRP-independent (or TRP-specific) FD basis selection. M can be selected for the p-th TRP. p FD basis vectors p = 1, ..., N P The overall frequency domain basis vector set can be Make and The main principle is to consider the subband phase transitions on the TRPs caused by the time offset between the corresponding TRPs. In some examples, a TRP-specific FD basis vector selection method can be applied to mTRP transmissions, where the deployed TRPs include co-located TRPs.

[0215] Alternative Option 2: TRP Common (or Joint) FD Base Vector Selection. M FD base vectors can be selected across TRPs (for all TRPs). In some examples, the cross-TRP (or TRP common) FD base vector selection method can be applied to mTRP transports, where the deployed TRPs include geographically distributed TRPs.

[0216] Figure 24 Examples of alternative schemes for FD basis vector selection according to embodiments of the present invention are shown. Two alternative schemes are illustrated: alternative scheme 1, TRP-independent FD basis selection, and alternative scheme 2, TRP-common FD basis selection. The coefficient matrices in both alternative scheme 1 and alternative scheme 2 are shown. Including the coefficient matrix of each TRP For the SD basis matrix of alternative scheme 1 Select SD basis vectors for each TRP. For example, for TRP... (1) Choose M1 SD basis vectors. This is the TRP. (2) Choose M² SD basis vectors. This is the TRP. (Np) Select M Np SD basis vectors. For alternative scheme 2, the SD basis matrix... Select SD basis vectors across TRP.

[0217] Corresponding to alternative schemes 1 and 2 for the two FD base selections, the overall mTRP CJT precoder can take the following two forms:

[0218] Alternative Option 1:

[0219] Alternative Option 2:

[0220] As shown, for N p Independent FD basis selection for each TRP (alternative scheme 1), and the FD basis vector matrix for each TRP. The choice of FD basis is different for different TRPs. For a common FD basis choice among TRPs, different TRPs share the same FD basis vector matrix.

[0221] Example #9-W f FD base selection

[0222] In some examples, CSI reports are used for W f FD basis indicator of a matrix (i 1,5 and i 1,6 Includes the initial window position M initial (For example, for N3>19) and FD base index n3, where

[0223] i 1,5 :M initial ∈{-2M+1,-2M+2,…,0}

[0224] i 1,6 :n3=[n 3,0 ,…,n 3,M-1 And n 3,f ∈{0,1,…,N3-1}

[0225] Corresponding to the alternative schemes for SD basis selection mentioned above, the PMI report format for FD basis vectors can have two designs:

[0226] - Alternative Option 1: Report FD base indicator for each TRP (TRP specific).

[0227] Considering four TRP scenarios, the report format could be i 1,5 :

[0228] and i 1,6 :

[0229] - Alternative Option 2: Report FD base indicators across all TRPs (common to all TRPs)

[0230] The report format can be i 1,5 :{M initial} and i 1,6 :{n3}

[0231] Figure 25 An example of the initial window position and FD basis index in the FD coefficient matrix W2 is shown. As illustrated, Alternative Scheme 1 corresponds to the PMI report format for Alternative Scheme 1 FD basis vectors. Different TRPs have different indicators. and Alternative Scheme 2 corresponds to the PMI report format for Alternative Scheme 2 of the FD basis vectors. Different TRPs share the same indicator M. initial and n 3,l .

[0232] VI. Dynamic TRP Selection

[0233] For example, due to UE movement and obstruction, a UE may require multiple sets of CSI-RS resources from multiple TRPs for mTRP measurements and CJT / NCJT transmission measurements. In some cases, a UE may be served by at least two dominant TRPs (with greater received power from at least two dominant TRPs). Non-dominant TRPs may be disabled or used by other UEs. A flexible design for network and UE selection of appropriate TRPs for mTRP measurements and transmissions is described here.

[0234] Figure 26 An example is shown where different mTRP sets can be switched to serve a UE due to UE movement. As shown, UE1 is initially served by 4 TRPs from TRP1 to TRP4, and subsequently by 3 TRPs from TRP1 to TRP3. UE2 is initially served by 3 TRPs from TRP2 to TRP4, and subsequently by 1 TRP4.

[0235] In one example, a UE can perform measurements such as RSRP and RSRQ on a set of measurement objects {TRP1, TRP2, TRP3, TRP4, TRP5, TRP6, TRP7, TRP8}. The network can determine one or more mTRP measurement sets for that UE based on measurement results reported from the UE. The network can have a CSI reporting configuration with multiple CSI-RS resources and one or more CRIs, which can be configured by the UE to perform CSI measurements and reporting. For example, multiple CSI-RS resources can be sent from multiple TRPs of an mTRP measurement set. One or more CRIs can be associated with one or more mTRP measurement sets. For example, the measurement set associated with a CRI used for CSI measurement and estimation can be one or more of {TRP1, TRP2, TRP3}, {TRP1, TRP2}, {TRP2, TRP3}, {TRP1, TRP3}, {TRP1}, {TRP2}, or {TRP3}.

[0236] Based on the CSI report configuration, the UE can estimate the CSI report and feed it back to the network. The UE can indicate in the CSI report which CRIs are better or which TRPs may not be needed (which TRPs may be more important). The network can select TRPs for the UE to send PDSCH, PDCCH, etc., based on the CSI report. For example, the set selected for mTRP transmission based on the CSI report could be {TRP1, TRP2, TRP3}. Alternatively, the UE can perform the selection and report the selection result to the base station.

[0237] Based on the Type II codebook structure described herein, in some implementations, a TRP selection matrix W0 is introduced for CSI feedback from the UE to the network. Figure 27 Two types (two variants) of codebook structures for CSI feedback are shown. Both types of codebook structures are based on a Type II codebook structure and a TRP selection matrix W0. The two types of codebook structures can take the following forms:

[0238] Variant 1:

[0239] Variant 2:

[0240] Figure 27 The example shown corresponds to a situation where there are 4 candidate TRPs on the network side and each TRP has N. Tp In a scenario with multiple antenna ports, the UE can measure CSI-RS from four TRPs during the CSI reporting process. Based on the measurement results, the UE can provide a CSI report to the network. The CSI report can indicate the selected TRP and its associated precoder. For example, the CSI report may include information about... Figure 27The matrices W0, W1, W2 and / or W shown f Information.

[0241] W0 is the TRP / port / beam selection matrix. W0 can be used to dynamically report the CSI for a specific TRP / port. Figure 27 As shown, the TRP selection matrix can include multiple submatrices. Each submatrix has N... Tp Multiply by N Tp (or 2L) p ×2L p The size of the submatrix is ​​[size missing]. Each submatrix corresponds to one of the four candidate TRPs. For an unselected TRP (e.g., the second of the four TRPs), the corresponding submatrix can be a zero matrix (each element is zero). For a selected TRP (e.g., the first, third, or fourth TRP), the corresponding submatrix can be an identity matrix.

[0242] Variant 1 reduces feedback overhead. With this variant, the network may not be aware of the SD information of unselected TRPs. Variant 2 reports the SD information of all TRPs within the coordination set in W1. The network can use an unselected TRP to serve another UE, or it can use the SD information of an unselected TRP to mitigate inter-TRP interference. Furthermore, with Variant 2, W1 can be reported in a wideband manner, and W0 can be reported in a subband manner based on subband precoder coefficients. In some examples, the network can use RRC, MAC CE, or DCI signaling to configure whether to use the selection matrix W0. In some examples, TRP / port selection criteria can be based on TRP power efficiency, channel correlation or capacity, interference mitigation, etc.

[0243] Example #10 - Dynamic TRP Selection

[0244] In the example, when the network uses RRS signaling to configure the UE to report the TRP matrix W0, the UE can report a TRP selection indicator i0 representing the TRP selection matrix W0. For example, the TRP selection indicator i0 can have integer values ​​arranged as follows:

[0245]

[0246] Where, N p N′ is the number of candidate TRPs or TRPs configured in the network. p It is the number of service TRPs selected by the UE, and Given N p and N′ p The total number of different possibilities for W0 in the case of N p N′ is selected from the candidate TRPs. p(A combination of TRPs). In one example, N p and N′ p The value of N can be signaled to the UE from the network. In some examples, N can be determined based on considerations such as network capacity, the number of UEs to be served, UE capabilities, and UE requests, according to the negotiation between the network and the UE. p and N′ p The value of .

[0247] In some examples, W0 can be mapped to CRI feedback. When a single TRP is used for transmission, the UE typically selects a CRI to provide feedback to the optimal BS beam or chooses a TRP from candidate TRPs for RI / PMI / CQI feedback. In the case of joint transmission (JT) via mTRPs, the UE can select and report multiple CRIs mapped to multiple TRPs for NCJT / CJTRI / PMI / CQI feedback. A mapping relationship exists between the TRP selection matrix W0 and the selection of CRIs (e.g., represented by a bitmap).

[0248] For the report of W1, in one example, the structure W = W0W1W2W was used. f In this case, the UE can avoid feeding back W1 information for the unselected TRP. For example... Figure 27 As shown in variant 1, the submatrix corresponding to the second TRP (TRP2) is not reported in the CSI report because the second TRP was not selected. This saves signaling costs. When using the structure W = W1W0W2W f Even in the case of this, the UE can still provide W1 information for the unselected TRP.

[0249] For W2 and W f In this reporting mechanism, the UE can avoid reporting information about unselected TRPs to save feedback overhead. For example, one or more indicators are predefined or configured to report W2 and W... f The information carried in the report. For TRPs that are not selected, the corresponding indicator for the unselected TRP can be removed from the report.

[0250] VII. CSI Report Configuration

[0251] In some implementations, CSI reporting configurations can be configured via higher-level (above the physical layer) signaling (e.g., MAC CE and RRC). A CSI reporting configuration may include one or more codebook configurations. A codebook configuration may include one or more antenna configurations (N1, N2) for precoder estimation and selection. For example, an antenna configuration (N1, N2) may correspond to a CSI-RS resource or a resource group. Figure 28AAn example of a CSI report configuration is shown. The CSI report configuration includes a codebook configuration. Figure 28B An example of a codebook configuration is shown. The codebook configuration includes codebook subset restriction information. The subset restriction information includes a set of antenna configurations (N1, N2). Each antenna configuration (N1, N2) corresponds to a CSI-RS resource or a group of CSI-RS resources.

[0252] In some examples, the CSI-RS resource set configured for the UE comprises multiple resource groups. The UE can be configured with one or more codebook configurations for precoder estimation and selection across multiple resource groups. A codebook configuration can include one or more values ​​of (N1, N2). Each value of (N1, N2) can correspond to a resource group. Figure 17 As shown in the example, in case 1702, {TRP1, TRP2} are co-located. CSI-RS {RS#1, RS#2} are included in resource group 1. Therefore, one antenna configuration (8, 1) is provided for TRP1 and TRP2 together. Similarly, in case 1703, one antenna configuration (8, 1) is provided for resource group 2. In case 1704, two antenna configurations (8, 1) and (8, 1) are provided for resource groups 1 and 2 respectively.

[0253] In some implementations, the CSI report configuration may include at least one power indicator to indicate how the transmit power of at least one resource group belonging to the CRI or which TRPs share the same total power. For example, if the resource set includes only one resource or one resource group for a single TRP transmission, the precoder power is typically normalized to 1, and a power indicator is not required. In other examples, at least one power indicator may be provided for mTRP CJT transmissions because different TRPs may use different transmit powers, and some TRPs may share the same power source or the same total power. The UE may use at least one power indicator to estimate the PMI and CQI for CSI reporting.

[0254] Example #11 - Power Indicator

[0255] In some examples, based on at least one power indicator, the UE can understand which of the following power conditioning methods or modes is being used for TRP transmission.

[0256] Method 1: Each TRP in the selected TRP set transmits at full power, i.e., the precoder used by the p-th TRP is...

[0257]

[0258] in

[0259] And v is the transmission rank and It is a collection of coherent service TRPs. It is a TRP power regulation pre-encoder. W (p) It is the CJT precoder reported by the UE.

[0260] Method 2: At least one TRP from the selected TRP set, for example, the first TRP... The first TRP is transmitted at full power. The precoder used by a TRP can be

[0261]

[0262] Where c = max{c1,c2,c3,c4} and

[0263] The network can configure which method the UE uses via RRC or MAC CE signaling.

[0264] Example #12 - Power Indicator

[0265] In some examples, the network (e.g., gNB) can signal a power indicator to the UE. The power indicator can indicate that at least one TRP in the selected set of TRPs, such as the p-th TRP, should transmit at full power. For example, the p-th TRP with full power is determined by p = arg max{c1,c2,c3,c4}, where It is the precoder normalization factor for the p-th TRP, and v is the transport rank and It is a collection of coherent service TRPs.

[0266] The precoder used by the p-th TRP performs the following power regulation via the factor c = max{c1,c2,c3,c4}.

[0267]

[0268] It is a TRP power regulation pre-encoder. W (p) This is the CJT precoder reported by the UE. The precoder norm of the p-th TRP. Meaning the first Each TRP transmits full power.

[0269] The UE can use the power indicator to estimate the CQI reported by the CSI.

[0270] Figures 29A to 29BAn example of four TRP CJT transmission scenarios is shown. The precoder normalization factors {c1,c2,c3,c4} are determined to be {0.3, 0.4, 0.2, 0.1}. Therefore, TRP2 is determined to transmit at full power, and the power adjustment factor is determined to be 0.4. All four TRPs can be power-amplified using the same adjustment factor. There is no impact on interference between TRPs. In one example, the UE and the network can each determine the precoder normalization factor and adjustment factor. In another example, the UE can report the precoder normalization factor and / or adjustment factor to the network.

[0271] Example #13 - Power Indicator

[0272] In some examples, a power indicator from the network can instruct the UE to transmit at full power for each TRP in the selected TRP set.

[0273] The pre-encoder used by the p-th TRP is power-regulated as follows:

[0274]

[0275] Where the pre-encoder normalization factor c p Defined as in the example above. The precoder norm for each TRP. This means that each TRP is transmitted at full power. The UE can use the power indicator to estimate the CQI used for CSI reporting.

[0276] Figures 30A to 30B An example of a four-TRP CJT transmission scenario is shown. The precoder normalization factors {c1, c2, c3, c4} are determined to be {0.3, 0.4, 0.2, 0.1}. All TRPs perform full-power transmission. All four TRPs can be power-scaled using different adjustment factors. Interference between TRPs may increase. In the example, the UE and the network can each determine the precoder normalization factor and adjustment factor. In the example, the UE can report the precoder normalization factor and / or adjustment factor to the network.

[0277] VIII. Reduction of CSI feedback for joint reporting of mTRP and sTRP.

[0278] In some implementations, in order to mix mTRP NCJT / CJT CSI and sTRP CSI in the CSI report, the UE can be configured with multiple CRIs to indicate which CSI information to estimate. Figure 15AAn example of this configuration is provided. A CRI can indicate at least one CSI-RS resource belonging to at least one resource group. The CRI indexes for sTRP CSI and mTRP CSI can be separate. For CSI reports that include both sTRP CSI and mTRP CSI, the mTRP CSI can reuse the sTRP CSI to reduce the content size of the mTRP CSI.

[0279] In some examples, the UE can be configured in the CSI report configuration to use the same codebook type for both sTRP CSI and mTRP CSI feedback. A typical codebook design can have a precoder structure W = W1W2 (e.g., 3GPP NR DL Type I codebook and Version 15 Type II codebook) or (For example, NR DL version 16 type II codebook). Based on the codebook and precoder disclosed herein, designs are derived, and CSI reports can reuse sTRP CSI W1, W2W3, or... Furthermore, it reduces the content size of mTRP CSI. For example, the UE can configure CSI feedback reduction information through CSI report configuration.

[0280] Example #14 - Reduced CSI Feedback

[0281] In some examples, the design for mTRP CSI is derived based on the codebook and precoder, for example, based on the NR version 17NCJT CSI architecture or other CSI architectures. The UE can reuse W1, W1W2 or W1W2 of the mTRP CSI. This reduces the content size of the mTRP CSI. For example, the UE is configured to measure and report the sTRP CSI and mTRP CSI of TRP1, TRP2, and TRP3 in the CSI report. The UE can measure and derive the sTRP precoders for TRP1, TRP2, and TRP3 separately, and reuse the sTRP precoders in the mTRP precoder deriving and feedback. For example, the sTRP precoders for TRP1, TRP2, and TRP3 can be...

[0282] TRP1

[0283] TRP2

[0284] TRP3 The W1 matrix of the mTRP precoder can be

[0285]

[0286] If the UE is configured by RRC or MAC CE, the CSI report may not include W1 or W1W2 of the mTRP precoder.

[0287] Example #15 - Reduced CSI Feedback

[0288] In some examples, the network can configure the UE to reuse W1W2 or sTRP CSI. The CSI report will then provide additional precoder information for mTRP CSI. This additional precoder information may include indices of cyclic phase delay (CDD) parameters or matrices to apply phase shifts on each layer or combine multiple layers into fewer layers, as shown below.

[0289] For example, configure UE measurements and report TRP1, TRP2, and TRP3 sTRP CSI and mTRP CSI in the CSI report. The sTRP precoders of TRP1, TRP2, and TRP3 can be...

[0290] TRP1

[0291] TRP2

[0292] TRP3

[0293] The mTRP{TRP1, TRP2, TRP3} precoder can be Where i is the subcarrier index, and matrices D and U are the precoded CDD parts. Matrices D and U can be of size (W (k) The number of layers, W (k) The identity matrix or other CDD matrix (number of layers), as shown in section 6.3.4.2.2 of 3GPP 36.211V10.7.0, for example, is used for CDD design.

[0294]

[0295] Where v is W (k) The number of layers, and N t This represents the total number of TX antennas. The table below provides examples of D and U.

[0296]

[0297] Example #16 - Reduced CSI Feedback

[0298] For example, configure UE measurements and report TRP1, TRP2, and TRP3 sTRP CSI and mTRP CSI in the CSI report. The sTRP precoder of TRP1, TRP2, and TRP3 can be

[0299] TRP1

[0300] TRP2

[0301] TRP3

[0302] The mTRP{TRP1, TRP2, TRP3} precoder can be

[0303]

[0304] Where i is the subcarrier or subband index, and Φ(i) can be a matrix that applies phase shifts on each layer or combines multiple layers into fewer layers. If Φ(i) is a matrix that applies phase shifts, then it can be... Φ(i) is a v×v diagonal matrix including the phase. v is the number of layers in W(i). Φ(i) can be designed to apply phase shifts, amplitude variations, and layer combinations. Some examples of Φ(i) are provided below.

[0305]

[0306] IX. Codebook Design Based on IIPS Codebook of Version 17fe

[0307] 1. W1 Design:

[0308] In some examples, there are two possible designs for the W1 matrix.

[0309] Select each TRP port individually

[0310] Cross-TRP port selection

[0311] For individual TRP port selection, in some examples, the gNB can send... N precoded CSI-RS, where N p It is the number of collaborative TRPs, and 2L p This represents the number of SD / SD-FD pairs (precoded CSI-RS ports) in the p-th cooperative TRP. A simple example of this precoded CSI-RS is when the gNB determines the SD / FD base for each TRP. The UE can also use W0 from N p Select N′ from the collaborative TRPs P The UE can obtain the 2L from the service TRP for the p'th service. p′Select 2K from the ports. p′ One port. This choice can be polarized jointly and freely, that is, from From the possible combinations, starting with 2L p′ Select 2K from the ports. p′ One port.

[0312] For cross-TRP port selection, it can be expected that the gNB can perform coordinated beamforming CSI-RS transmissions from all cooperating TRPs, obtained from the UL channel. For example, the gNB can receive transmissions from, for instance, from, the UL channel. Figure 31 The joint mTRP channel shown derives the SD-FD basis (gNB implementation problem). Based on the UL channel, the gNB can even transmit precoded CSI-RS from different TRPs at different powers.

[0313] The total number of precoded (beamforming) CSI-RS ports can be P CSI-RS .like Figure 32 As shown, the UE can be from In each combination, from P, in a polarized common and free manner. CSI-RS Select port K1 from the available ports.

[0314] 2. W2 Design:

[0315] Depending on the W1 approach used, there are two possible designs. For individual W1TRPs, the same design principles as the W2 design disclosed above can be expected to be used. For cross-TRP W1, the UE essentially treats multiple TRPs as a single giant TRP and performs port selection on a single precoded mTRP channel as described above; therefore, the W2 design can follow the traditional version 17W2 design.

[0316] 3.W f design:

[0317] In 3GPP Release 17, the UE is configured with N=2 or N=4 consecutive DFT vectors starting from 0, from which the UE selects the vectors used for W. f M = 2 vectors. Since most frequency selectivity in the channel can be handled by precoded CSI-RS, W f The main purpose is to compensate for residual frequency selectivity and imperfect delay reciprocity. Furthermore, W f The design can consider TRP-specific FD basis selection. For example, TRP p selects M from N=2 or N=4 consecutive DFT vectors. p There are FD bases. However, for all TRPs, the number of FD bases selected is Make That is, the union of each TRP FD basis vector is the N FD basis of the overall configuration.

[0318] Other examples of X.mTRP measurements and transmissions

[0319] In the first example, the method by which the UE performs wireless communication includes the following steps:

[0320] - Receive signaling from a network entity to instruct a CSI reporting configuration, the channel state information reporting configuration including at least one codebook configuration, and at least one of a power indicator and CSI feedback reduction information, and associated with at least one CSI-RS resource configuration for channel measurement, wherein the at least one CSI-RS resource configuration associates at least two resource groups and at least one channel measurement selection information;

[0321] - Estimate channel information based on the CSI report configuration;

[0322] - Based on the estimated channel information, and at least one of at least one power indicator and CSI feedback reduction information, derive at least one PMI and CQI; and

[0323] - Send a CSI report to the network entity.

[0324] In the second example based on the first example, the at least one channel measurement selection information indicates which CSI-RS resources should be estimated to arrive at the at least one PMI;

[0325] In the third example based on the first example, each resource group includes at least one CSI-RS resource, and the UE considers that at least one CSI-RS resource in the resource group is sent from a co-located geographic location.

[0326] In the fourth example based on the second example, if one of the channel measurement selection information indicates at least two CSI-RS resources belonging to at least two different resource groups, the UE considers that the CSI-RS resources indicated by the at least one of the channel measurement selection information are simultaneously transmitted for JT transmission.

[0327] In the fifth example based on the first example, at least one codebook configuration indicates at least one set of codebook parameters associated with at least one CSI-RS resource configuration or at least one channel measurement selection information.

[0328] In the sixth example based on the fifth example, the at least one codebook parameter set includes at least one of the following:

[0329] - The number L of beam vectors associated with the p-th CSI-RS resource or resource group indicated by the corresponding channel measurement selection information. p ;

[0330] - The NZC selection ratio β associated with the p-th CSI-RS resource or resource group indicated by the corresponding channel measurement selection information. p .

[0331] In the seventh example, based on the first example, each PMI is derived from W1, W2, and W... f It is derived from at least two of the codebook matrices.

[0332] In the eighth example based on the seventh example, the W1 codebook matrix has a block diagonal structure with at least two sub-matrices in its diagonal, and the p-th sub-matrix of the at least two sub-matrices contains a spatial beam vector associated with the p-th CSI-RS resource or resource group indicated by the corresponding channel measurement selection information.

[0333] In the ninth example, based on the seventh example, the W2 codebook matrix contains the beam vector from W1 and W f The complex linear combination coefficients of the delay vector based on DFT in the model.

[0334] In the tenth example, which is based on the seventh example, W f The codebook matrix contains a delay vector based on the DFT.

[0335] In the eleventh example, which is based on the seventh example, each PMI is also derived from the resource selection matrix W0, and W0 indicates which CSI-RS resource or resource group is more important, as indicated by the corresponding channel measurement selection information.

[0336] In the twelfth example, which is based on the eleventh example, the network entity uses higher-layer signaling to instruct the UE whether to use the resource selection matrix W0.

[0337] In the thirteenth example, based on the seventh example, W1, W2, and W... f The precoding coefficients also take into account at least one power indicator for power regulation, wherein the at least one power indicator is indicated by the network entity via higher-layer signaling.

[0338] In the fourteenth example based on the first example, the at least one CQI is calculated and reported based on the at least one power indicator.

[0339] In the fifteenth example, based on the first example, each codebook configuration is associated with one of the at least one channel measurement selection information.

[0340] In the sixteenth example based on the seventh example, the W1 codebook matrix has a block diagonal structure with at least two submatrices in its diagonal, and the p-th submatrix of the at least two submatrices is a selection matrix that includes a single non-zero element in each column and is associated with the p-th CSI-RS resource or resource group indicated by the corresponding channel measurement selection information.

[0341] Other examples of XI.mTRP measurement and transmission

[0342] Figure 33 A process 3300 for mTRP CSI measurement and reporting according to an embodiment of the present invention is shown. Process 3300 may begin at step S3301 and proceed to step S3310.

[0343] In step S3310, the UE receives the CSI report configuration from the base station. The CSI report configuration is associated with a CSI-RS resource set. Each CSI-RS resource may correspond to one or more TRPs.

[0344] In step S3320, channel measurements can be performed based on CSI-RS resources sent from multiple TRPs.

[0345] In step S3330, the PMI can be determined based on the measurement results of the channel measurement. The PMI can correspond to a precoder matrix represented as W in the type IICSI codebook. For example, the PMI can include multiple indicators indicating elements belonging to the precoder matrix. The precoder matrix can have an SD basis vector matrix represented as W1. The SD basis selection of the SD basis vector matrix can be TRP-specific. For example, an SD basis can be selected for each TRP. Each TRP can have a corresponding set of SD basis vectors.

[0346] In step S3340, a CSI report may be sent to the base station. The CSI report includes the PMI. Process 3300 proceeds to step S3399 and terminates at step S3399.

[0347] Figure 34 Another process 3400 for mTRP CSI measurement and reporting according to an embodiment of the present invention is shown. Process 3400 begins at step S3401 and proceeds to step S3410.

[0348] In step S3410, the UE receives the CSI report configuration from the base station. The CSI report configuration is associated with a CSI-RS resource set. Each CSI-RS resource may correspond to one or more TRPs.

[0349] In step S3420, channel measurements are performed based on CSI-RS resources sent from multiple TRPs.

[0350] In step S3430, the PMI is determined based on the measurement results of the channel measurement. The PMI can correspond to a precoder matrix represented as W in the type IICSI codebook. The precoder matrix can have an SD / FD coefficient matrix (or linear combination coefficient matrix) represented as W2. The coefficient rows in the SD / FD coefficient matrix correspond to the SD basis vectors in the SD basis vector matrix represented as W1. The coefficient columns in the SD / FD coefficient matrix correspond to the SD basis vectors in the SD basis vector matrix represented as W2. f The FD basis vectors in the FD basis vector matrix correspond to each other. The PMI includes an FD basis indicator. The FD basis indicator indicates that the FD basis selection for any TRP in the SD / FD coefficient matrix is ​​independent of the FD basis selection for any other TRP.

[0351] In step S3440, a CSI report is sent to the base station. The CSI report includes the PMI. Process 3400 proceeds to step S3499 and terminates at step S3499.

[0352] Figure 35 Another process 3500 for mTRP CSI measurement and reporting according to an embodiment of the present invention is shown. Process 3500 begins at step S3501 and proceeds to step S3510.

[0353] In step S3510, the UE receives a CSI report configuration from the base station. The CSI report configuration may be associated with a CSI-RS resource set. Each CSI-RS resource may correspond to one or more TRPs. CSI-RS resources may be organized into one or more resource groups. The CSI report configuration includes one or more antenna configurations (N1, N2). Each antenna configuration corresponds to one or more TRPs. One or more antenna configurations correspond to one or more resource groups respectively. N1 and N2 are the number of antenna ports of the corresponding one or more TRPs having the same polarization direction in the vertical and horizontal directions, respectively.

[0354] In step S3520, channel measurements are performed based on the CSI-RS resources corresponding to the multiple TRPs.

[0355] In step S3530, the PMI can be determined based on the measurement results of the channel measurement and one or more antenna configurations (N1, N2).

[0356] In step S3540, a CSI report is sent to the base station. The CSI report includes the PMI. Process 3500 proceeds to step S3599 and terminates at step S3599.

[0357] XII. Exemplary Device

[0358] Figure 36 An exemplary apparatus 3600 according to an embodiment of the present invention is shown. Apparatus 3600 can be configured to perform various functions according to one or more embodiments or examples described herein. Therefore, apparatus 3600 can provide means for implementing the mechanisms, techniques, processes, functions, components, and systems described herein. For example, in the various embodiments and examples described herein, apparatus 3600 can be used to implement the functions of a UE or BS (control TRP). Apparatus 3600 may include a general-purpose processor or specially designed circuitry to implement the various functions, components, or processes described in the various embodiments. Apparatus 3600 may include processing circuitry 3610, memory 3620, and radio frequency (RF) module 3630.

[0359] In various examples, processing circuitry 3610 may include circuitry configured to perform the functions and processes described herein, with or without software. In various examples, processing circuitry 3610 may be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), a field-programmable gate array (FPGA), a digitally enhanced circuit, or similar elements or combinations thereof.

[0360] In some other examples, processing circuitry 3610 may be configured to execute program instructions to perform the various functions and processes described herein (Central Processing Unit, CPU). Therefore, memory 3620 may be configured to store program instructions. When program instructions are executed, processing circuitry 3610 may perform these functions and processes. Memory 3620 may also store other programs or data, such as operating systems, application programs, etc. Memory 3620 may include non-transitory storage media, such as read-only memory (ROM), random-access memory (RAM), flash memory, solid-state memory, hard disk drives, optical disk drives, etc.

[0361] In one implementation, RF module 3630 receives processed data signals from processing circuitry 3610 and converts the data signals into beamforming wireless signals transmitted via antenna array 3640, and vice versa. In some examples, RF module 3630 may include a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), an up-converter, a down-converter, filters, and amplifiers for receive and transmit operations. In some examples, RF module 3630 may include multi-antenna circuitry for beamforming operations. For example, multi-antenna circuitry may include uplink spatial filter circuitry for adjusting the amplitude of analog signals and downlink spatial filter circuitry. Antenna array 3640 may include one or more antenna arrays organized into multiple antenna panels or antenna groups.

[0362] Device 3600 may optionally include other components, such as input and output devices, additional or signal processing circuitry, etc. Therefore, device 3600 is capable of performing other additional functions, such as executing application programs and processing alternative communication protocols.

[0363] The processes and functions described herein can be implemented as computer programs, wherein when executed by one or more processors, the computer programs cause one or more processors to perform the corresponding processes and functions. The computer programs can be stored or distributed on suitable media, such as optical storage media or solid-state media provided together with or as part of other hardware. The computer programs can also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems. For example, the computer programs can be acquired and loaded into devices, including acquiring the computer programs via physical media or distributed systems (e.g., servers connected to the Internet).

[0364] Computer programs can be accessed from computer-readable media, which provide program instructions for use by or in connection with a computer or any instruction execution system. The computer-readable media can include any means of storing, communicating, propagating, or transmitting computer programs for use by or in connection with an instruction execution system, apparatus, or device. The computer-readable media can be a magnetic, optical, electronic, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. The computer-readable media can include computer-readable non-provisioning storage media, such as semiconductor or solid-state memory, magnetic tape, removable computer disks, RAM, ROM, magnetic disks, and optical disks. The computer-readable non-provisioning storage media can include all types of computer-readable media, including magnetic storage media, optical storage media, flash memory media, and solid-state storage media.

[0365] Although aspects of the invention have been described in conjunction with specific exemplary embodiments, various alternatives, modifications, and changes can be made to these examples. Therefore, the embodiments described herein are illustrative only and not restrictive. Changes may be made without departing from the scope set forth in the claims.

Claims

1. A measurement and transmission method with multiple transmitting and receiving points, comprising: The user equipment receives a channel state information report configuration from the base station. The channel state information report configuration includes a power indicator indicating how to adjust the transmission power of a plurality of transmit and receive points. The channel state information report configuration is associated with a channel state information reference signal resource set, which corresponds to a plurality of transmit and receive points. The channel state information reference signal resources are organized into one or more resource groups. The channel state information report configuration includes one or more antenna configurations N1, N2, each antenna configuration corresponding to one or more of the plurality of transmit and receive points. The one or more antenna configurations N1, N2 correspond to the one or more resource groups, and N1 and N2 are the number of antenna ports in the vertical and horizontal directions of the one or more transmit and receive points, respectively. Channel measurements are performed based on the channel state information reference signal resources corresponding to the plurality of transmitting and receiving points; Based on the measurement results of the channel measurement and the antenna configurations N1, N2 corresponding to one or more of the plurality of transmit and receive points, a precoder matrix indicator is determined; as well as A channel state information report is sent to the base station, the channel state information report including the precoder matrix indicator.

2. The measurement and transmission method with multiple transmitting and receiving points according to claim 1, characterized in that, The precoder matrix indicator corresponds to the precoder matrix of the Type II channel state information codebook.

3. The measurement and transmission method with multiple transmitting and receiving points according to claim 1, characterized in that, The first antenna in one or more antenna configurations N1 and N2 is configured as N. 1,1 N 2,1 N corresponds to at least two co-located transmit / receive points among the plurality of transmit / receive points. 1,1 and N 2,1 These represent the number of antenna ports in the vertical and horizontal directions for each co-located transmit / receive point.

4. The measurement and transmission method with multiple transmitting and receiving points according to claim 1, characterized in that, The user equipment performs channel quality indicator estimation based on the power indicator.

5. The measurement and transmission method with multiple transmitting and receiving points according to claim 1, characterized in that, The channel state information reporting configuration also includes a power indicator that indicates which of the plurality of transmit / receive points share the same total power.

6. The measurement and transmission method with multiple transmitting and receiving points according to claim 1, characterized in that, The channel state information reporting configuration also includes a power indicator that instructs at least one of the plurality of transmit / receive points to transmit at full power.

7. The measurement and transmission method with multiple transmitting and receiving points according to claim 1, characterized in that, The channel state information reporting configuration also includes a power indicator that instructs each of the plurality of transmit / receive points to transmit at full power.

8. An apparatus for multi-transmitter / receiver measurement and transmission, the apparatus comprising circuitry, the circuitry being: The channel state information report configuration received from the base station includes a power indicator indicating how to adjust the transmission power of a plurality of transmit / receive points. The channel state information report configuration is associated with a channel state information reference signal resource set, which corresponds to a plurality of transmit / receive points. The channel state information reference signal resources are organized into one or more resource groups. The channel state information report configuration includes one or more antenna configurations N1 and N2, each antenna configuration corresponding to one or more of the plurality of transmit / receive points. The one or more antenna configurations N1 and N2 correspond to the one or more resource groups, and N1 and N2 are respectively the number of antenna ports of each of the one or more transmit / receive points in the vertical and horizontal directions. Channel measurements are performed based on the channel state information reference signal resources corresponding to the plurality of transmitting and receiving points; Based on the measurement results of the channel measurement and the antenna configurations N1, N2 corresponding to one or more of the plurality of transmit and receive points, a precoder matrix indicator is determined; as well as A channel state information report is sent to the base station, the channel state information report including the precoder matrix indicator.

9. The apparatus according to claim 8, characterized in that, The precoder matrix indicator corresponds to the precoder matrix of the Type II channel state information codebook.

10. The apparatus according to claim 8, characterized in that, The first antenna in one or more antenna configurations N1 and N2 is configured as N. 1,1 N 2,1 N corresponds to at least two co-located transmit / receive points among the plurality of transmit / receive points. 1,1 and N 2,1 These represent the number of antenna ports in the vertical and horizontal directions for each co-located transmit / receive point.

11. The apparatus according to claim 8, characterized in that, The device performs channel quality indicator estimation based on the power indicator.

12. The apparatus according to claim 8, characterized in that, The channel state information reporting configuration also includes a power indicator that indicates which of the plurality of transmit / receive points share the same total power.

13. The apparatus according to claim 8, characterized in that, The channel state information reporting configuration also includes a power indicator that instructs at least one of the plurality of transmit / receive points to transmit at full power.

14. The apparatus according to claim 8, characterized in that, The channel state information reporting configuration also includes a power indicator that instructs each of the plurality of transmit / receive points to transmit at full power.

15. A non-transitory computer-readable storage medium for storing program instructions, characterized in that, The program instructions execute the steps of the measurement and transmission method for multiple transmitting and receiving points as described in any one of claims 1-7.

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