TW202337161A - Methods for multiple-transmission-reception-point measurement and transmission、apparatus and storage medium thereof - Google Patents

Abstract

A method of channel state information (CSI) report can include receiving a CSI report configuration at a user equipment (UE) from a base station, the CSI report configuration being associated with a set of CSI reference signal (CSI-RS) resources corresponding to multiple transmission reception points (TRPs), performing a channel measurement based on the CSI-RSs resources corresponding to the multiple TRPs, determining a precoder matrix indicator (PMI) based on measurement results of the channel measurement, the PMI corresponding to a precoder matrix, denoted W , of a Type II CSI codebook, the precoder matrix having a spatial domain (SD) basis vector matrix, denoted W ₁ , SD basis selection of the SD basis vector matrix being TRP-specific, and transmitting a CSI report to the base station, the CSI report including the PMI.

Description

Measurement and transmission method, device and storage medium for multiple sending and receiving points

Embodiments of the present invention relate generally to wireless mobile communications, and, more particularly, to multi-antenna transmission operations at the network and mobile devices in wireless communications systems.

A large number of steerable antenna elements can be used for transmission and reception on the network side or on the device side. In higher frequency bands, a larger number of antenna elements can be used for beamforming to extend coverage. In lower frequency bands, a large number of antenna units can be used to spatially separate users to increase spectrum transmission capacity. CSI for operation of large-scale multi-antenna schemes can be obtained through feedback of channel state information (CSI) reports, which are based on reference signals in the downlink or uplink between the network and the mobile device. transmission on the road.

Aspects of the present invention provide a first method of CSI reporting. The first method includes: receiving a CSI report configuration from a base station at a user equipment (UE), where the CSI report configuration corresponds to a plurality of transmission reception points (TRPs) corresponding to CSI reference signals ( CSI reference signal (CSI-RS) resource set; perform channel measurement based on the CSI-RS resources corresponding to the plurality of TRPs; determine a precoder matrix indicator (precoder matrix) based on the measurement result of the channel measurement indicator (PMI), which corresponds to the precoder matrix denoted W of the Type II CSI codebook; the precoder matrix has a spatial domain (SD) basis vector matrix denoted W ₁ , the SD The SD basis selection of the basis vector matrix is TRP specific; and a CSI report is sent to the base station, the CSI report including the PMI.

In one embodiment, the SD basis vector matrix has the following form: Where, N _T is the number of antenna ports of a plurality of TRPs, L is the number of basis vectors corresponding to one antenna polarization in W ₁ , N _P is the number of a plurality of TRPs, is the SD basis vector matrix of the p-th TRP, . is the SD basis matrix and has the form in, is the number of antenna ports of the p-th TRP, , and L _p is the number of SD basis vectors in each polarization of the p-th TRP, such that and .

In one embodiment, the SD basis vector matrices include TRP-specific SD basis matrices, each SD basis matrix corresponding to one of a plurality of TRPs. In one embodiment, the SD basis vector matrices include TRP-specific SD basis matrices, each SD basis matrix corresponding to one of a plurality of TRPs, the TRP-specific SD basis matrices having different numbers of SD basis vectors. For example, one of the TRP-specific SD basis matrices includes a first basis vector corresponding to a first polarization of the TRP and a second basis vector corresponding to a second polarization of the TRP, the first basis vector being the same as the second basis vector.

In one embodiment, the SD basis selection of the SD basis vector matrix is layer-common. In one embodiment, the SD basis vector matrix includes SD basis vectors corresponding to different TRPs in the plurality of TRPs, and co-located TRPs in the plurality of TRPs have the same SD basis vectors. In one embodiment, 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 in a plurality of TRPs, wherein two of the plurality of TRPs that are co-located in the PMI share The same set of SD basis vectors in the SD basis vectors. In an example, the method further includes, in response to receiving an indication from the base station as to which TRPs of the plurality of TRPs are co-located, determining based on the indication that two TRPs that are co-located report the same set of SD basis vectors. In an example, the method further includes determining to report the same set of SD basis vectors for the two TRPs that co-localize based on the calculated SD basis vectors corresponding to different TRPs.

Aspects of the invention provide a first device including a circuit. The circuit 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 the TRP; performing channel measurement based on the CSI-RS resources corresponding to the plurality of TRPs; based on the The measurement results of the channel measurements determine the PMI corresponding to the precoder matrix of the Type II CSI codebook having an SD basis vector matrix whose SD basis selection is TRP specific ; and sending a CSI report to the base station, where the CSI report includes the PMI.

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

Aspects of the present invention provide a second method of CSI reporting. The second method includes: receiving a CSI report configuration from a base station at the UE, the CSI report configuration being associated with a CSI-RS resource set corresponding to a plurality of TRPs; based on the CSI-RS corresponding to the plurality of TRPs The resource performs channel measurement; determines a first PMI based on the measurement result of the channel measurement, the first PMI corresponds to a first precoder matrix represented by W of the Type II CSI codebook, the first precoder matrix There is a first SD/frequency domain (FD) coefficient matrix denoted as W2 , a coefficient column (row) in the first SD/FD coefficient matrix corresponding to the SD in the SD basis vector matrix denoted as _W1 basis vectors, a coefficient row (column) in the first SD/FD coefficient matrix corresponds to an FD basis vector in the FD basis vector matrix, the first PMI includes a first FD basis indicator, the first FD basis an indicator indicating that the FD base selection corresponding to any TRP in the first SD/FD coefficient matrix is independent of the FD base selection of any other TRP; and sending a CSI report to the base station, the CSI report including the first PMI .

In one embodiment, the first FD base indicator includes an initial window position indicator and an FD base index for each of the plurality of TRPs. In one embodiment, the method further includes determining a second PMI based on a second precoder matrix of a Type II CSI codebook, the second precoder matrix having a second SD/FD coefficient matrix, the second PMI including a second FD basis indicator indicating that the FD basis selection in the second SD/FD coefficient matrix is TRP common for 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 a plurality of TRPs.

In one embodiment, non-zero-coefficients (NZC) are selected from the first SD/FD coefficient matrix across a plurality of TRPs. In one embodiment, the strongest coefficients are selected from the first SD/FD coefficient matrix across a plurality of TRPs. In one embodiment, the reference amplitude coefficients are selected from the first SD/FD coefficient matrix across a plurality of TRPs.

In one embodiment, the 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 one example, the TRP-specific reference amplitude coefficients are polarization-specific. In one embodiment, the PMI includes a TRP common NZC lattice indicating the NZC position in the first SD/FD coefficient matrix. In one embodiment, the PMI includes a TRP-specific NZC bitmap indicating the NZC position in the first SD/FD coefficient matrix.

Aspects of the invention provide a second device including a circuit. The circuit is configured to receive a CSI reporting configuration from a base station, the CSI reporting configuration being associated with a set of CSI-RS resources corresponding to a plurality of TRPs; and performing channel measurements based on the CSI-RS resources corresponding to the plurality of TRPs. ; Based on the measurement results of the channel measurement, determine a first PMI corresponding to a first precoder matrix represented by W of the Type II CSI codebook, the first precoder matrix has a value represented by The first SD/FD coefficient matrix of W2 , the coefficient columns in the first SD/FD coefficient matrix correspond to the SD basis vectors in the SD basis vector matrix represented as W1 , and the coefficient columns in the first SD/FD coefficient matrix correspond to The coefficient row corresponds to the FD basis vector in the FD basis vector matrix, and the first PMI includes a first FD basis indicator indicating the first SD/FD coefficient matrix corresponding to any TRP. FD base selection is independent of FD base selection of any other TRP; and sending a CSI report to the base station, the CSI report including the first PMI.

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

Aspects of the present invention provide a third method of CSI reporting. The third method includes receiving, at the UE, a CSI reporting configuration from a base station, the CSI reporting 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 Multiple resource groups, the CSI report configuration includes one or more antenna configurations (N ₁ , N ₂ ), each antenna configuration corresponds to one or more of the plurality of TRPs, the one or more Multiple antenna configurations (N ₁ , N ₂ ) respectively correspond to the one or more resource groups. N ₁ and N ₂ are respectively the number of antenna ports in the vertical and horizontal directions of the one or more TRPs; channel measurement is performed based on the CSI-RS resources corresponding to the plurality of TRPs; based on the channel measuring the measurement results and the one or more antenna configurations (N ₁ , N ₂ ) each corresponding to one or more of the plurality of TRPs, determining a PMI; and transmitting the CSI to the base station report, the CSI report includes the PMI.

In one embodiment, the PMI corresponds to the precoder matrix of a Type II CSI codebook. In one embodiment, a first of one or more antenna configurations (N ₁ , N ₂ ) corresponds to _at least two co-located TRPs of _the plurality of TRPs, N ₁ and N ₂ are the number of antenna ports in the vertical and horizontal directions respectively for each co-located TRP. In one embodiment, the CSI reporting configuration further includes a power indicator indicating how to adjust the transmission power of a TRP among the plurality of TRPs. For example, the UE performs channel-quality indicator (CQI) estimation based on the power indicator.

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 TRP of the plurality of TRPs is transmitted at full power. In one embodiment, the CSI reporting configuration further includes a power indicator indicating that each of the plurality of TRPs is transmitted at full power.

Aspects of the invention provide a third device including a circuit. The circuitry is configured to receive, at the UE, a CSI reporting configuration from a base station, the CSI reporting 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 group, the CSI report configuration includes one or more antenna configurations (N ₁ , N ₂ ), each antenna configuration corresponds to one or more of the plurality of TRPs, the one or more The antenna configurations (N ₁ , N ₂ ) respectively correspond to the one or more resource groups. N ₁ and N ₂ are respectively the number of antenna ports in the vertical and horizontal directions of the one or more TRPs; channel measurement is performed based on the CSI-RS resources corresponding to the plurality of TRPs; based on the channel measuring the measurement results and the one or more antenna configurations (N ₁ , N ₂ ) each corresponding to one or more of the plurality of TRPs, determining a PMI; and transmitting the CSI to the base station report, the CSI report includes the PMI.

Aspects of the invention provide a third non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform the method.

I. Multiple antenna operation

1. Reference signal and channel status information ( CSI )

In some embodiments, knowledge of the radio link can be obtained by measuring reference signals transmitted over the radio link during the channel detection process. The reference signal in the downlink direction may be called CSI-RS. The reference signal in the uplink direction may be called SRS.

CSI-RS can be configured on a device-by-device basis. The configured CSI-RS may correspond to one or more different antenna ports (referred to as CSI-RS ports). Each CSI-RS port can correspond to a channel to be probed. For example, multi-port CSI-RS may include 32 per-antenna port CSI-RS transmitted orthogonally over 32 CSI-RS ports. Each antenna port (per-antenna-port) CSI-RS corresponds to the CSI-RS port.

CSI-RS can be configured for a specific bandwidth (eg, 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 may occupy a set of one or more element resources within a time slot. For multi-port CSI-RS, the group of unit resources is shared by a plurality of CSI-RSs for each antenna port, such as based on code-domain sharing (CDM), frequency-domain sharing (FDM) or time-domain sharing. A combination of time-domain sharing (TDM).

A device may be configured with one or multiple CSI-RS resource sets. For example, a device may receive a CSI resource configuration specifying one or more CSI-RS resource sets. Each resource set includes one or more configured CSI-RSs. 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 transmission. For example, semi-persistent CSI-RS transmission can be enabled or disabled based on a MAC control element (CE). Aperiodic CSI-RS transmission can be triggered by means of downlink control information (DCI).

Similarly, SRS can support one or more antenna ports (called SRS ports). Different SRS ports of SRS can share the same set of resource elements and the same basic 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 a cyclic shift in the time domain. Similar to CSI-RS, a device can be configured with one or multiple SRS resource sets. Each resource set may include one or multiple configured SRSs. The SRS resource set can be configured for periodic transmission, semi-persistent transmission (controlled by MAC CE) or aperiodic transmission (triggered by DCI).

Figures 1 to 3 show examples of mapping CSI-RS ports or SRS ports to physical antennas. In the example of Figure 1, M ports of CSI-RS or SRS (CSI-RS/SRS) correspond to M antenna ports (CSI-RS port or SRS port). M antenna ports are connected to N physical antennas through spatial filters (marked F). M port CSI-RS/SRS are processed by spatial filters before being mapped to N physical antennas. Due to spatial filtering, one or more transmission beams can be formed for transmission of M-port CSI-RS/SRS. Generally, N can be larger than M.

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

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

As shown in the examples in Figures 1 to 3, the channel detected based on CSI-RS/SRS is not a physical radio channel, but a channel corresponding to the CSI-RS port or SRS port.

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

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

Report configurations can further describe when and how reports are performed. For example, reports can be periodic, semi-persistent, or aperiodic. The reporting can be activated (deactivated) based on MAC CE or triggered by means of DCI. Measurement results for periodic and semi-persistent reporting can be carried in the physical uplink control channel (PUCCH). Measurement results for aperiodic reporting may be carried in the physical uplink shared channel (PUSCH).

2. Multi-antenna transmission

A Digital and analog multi-antenna processing

Figure 4 shows a linear multi-antenna transmission scheme in a transmitter according to an embodiment of the invention. As shown, NL layer data ( _eg , modulation symbols) are _mapped to NT transmit antennas by multiplying by a transmission matrix W of size _NT × _NL . The vector X represents the N _L layer data. Vector Y represents _{NT signals corresponding to NT antennas} .

In various examples, the multi-antenna processing represented by matrix W may be applied to the analog portion of the transmit chain or the digital portion of the transmit chain. Alternatively, a hybrid approach can be adopted, where multi-antenna processing can be applied to both the analog and digital parts of the transmit chain. Thus, in various implementations, multi-antenna processing may be analog multi-antenna processing, digital multi-antenna processing, or hybrid multi-antenna processing.

In the case of analog processing, a spatial filter F can be applied to provide an antenna-by-antenna phase shift to form the transmission beam. Figure 5 shows an example of analog multi-antenna processing. In some examples, analog processing is performed on a carrier-by-carrier basis for downlink transmissions. Therefore, frequency reuse beamformed transmissions are not performed for devices located in different directions relative to the base station. In order to cover different devices located in different directions, beam scanning is performed through analog processing.

In the case of digital processing, each element of the transmission matrix W can include phase shifts and scale factors, which provides higher flexibility for controlling the beamforming direction. For example, simultaneous multi-beam-beamforming can be obtained 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.

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

Similar to transmitter-side processing, the receiver can apply analog, digital, or hybrid multi-antenna processing for beamformed reception of signals arriving from different directions.

B. Downlink multi-antenna precoding

In some embodiments, to support network selection of precoders for downlink transmissions, such as physical downlink shared channel (PDSCH) transmissions, a device may perform measurements based on CSI-RS and Reporting measurement results (eg, CSI report) to the network based on configuration received from the network (eg, CSI report configuration). The network can then determine the precoder based on the measurements.

In some examples, the CSI report may include RI, PMI, COI, etc. The RI may indicate a suitable transmission rank (number of transmission layers _NL ) for downlink transmission. The PMI may indicate a suitable 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.

In some embodiments, the value of PMI may correspond to a specific precoder matrix selected from the precoder codebook. The precoder codebook provides a set of candidate precoder matrices. In addition to the number of transport layers _NL , the apparatus selects the PMI based on a specific number of configured CSI-RS antenna ports ( _NRS ) associated with the CSI reporting configuration. In one example, at least one codebook is provided for every valid combination of _NT and _NL .

In some implementations, two types of CSI are defined corresponding to different scenarios: Type I CSI and Type II CSI. Different types of CSI are associated with different sets of precoder codebooks with different structures and sizes.

Codebooks for Type I CSI can be relatively simple and aim to focus the 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. Codebooks used for Type II CSI can provide channel information with higher spatial granularity than Type I CSI. Type II CSI can target multi-user multiple-input multiple-output (MIMO) (MU-MIMO) scenarios.

II. Type IICSI codebook structure

In some implementations, Type II CSI feedback may be based on a linear combination (LC) codebook. For example, the eigenvector of a channel can be (approximately) represented as a linear combination of L Discrete Fourier Transform (DFT) vectors. The UE may report CSI including DFT vectors and coefficients used to combine the DFT vectors. If a channel has a plurality of main eigenvectors (higher rank channels), the UE may report a plurality of eigenvectors. DFT beams of DFT vectors can be reported in a wideband (WB) manner (one common report for all subbands (SB)). The amplitude and phase of the coefficients can be reported separately using the corresponding codebook. For example, the coefficient phase can be frequency selective and therefore reported for each SB. Coefficient magnitudes can be reported in WB fashion.

In some embodiments, the weighting vector (or precoder matrix) of rank 1 Type II CSI may have the following form: where, for polarization r and rank l , w _r,l is a weighted linear combination of L orthogonal beams polarized one by one. The weighting vector W can be determined as follows. The DFT beam matrix _W1 can have the size _{of 2N1N2} × 2L , where L orthogonal vectors/beams can be selected from a set of _{oversampled O1O2N1N2 DFT beams} on a polarization-by-polarization basis. N ₁ and N ₂ are the number of antenna ports with the same polarization direction in the horizontal and vertical domains. O ₁ and O ₂ are the oversampling factors in the corresponding dimensions. The linear combination of L orthogonal vectors achieves compression in the spatial domain (SD). The L orthogonal vectors can be called SD components or SD basis. The linear combination subband matrix _W2 can be determined such that for each subband, a 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 combining coefficients increases linearly, resulting in large CSI reporting overhead.

In some embodiments, frequency domain (FD) correlation within _W2 is exploited to further compress the Type II CSI precoder. DFT compression can be applied on W ₂ . For example, _W may 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 _f can be determined by selecting a set of orthogonal vectors from the columns of the oversampled DFT codebook. The matrix W _f may have a size of N ₃ × M ( M < N ₃ ). 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 : The compression matrix W _f can be thought of as the equivalent of the SD basis matrix W ₁ for frequency compression. Therefore, the Type II CSI precoder matrix can have the following format: 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 a few coefficients. Therefore, it can be determined are used to report several of the most important FD coefficients. The rest can be assumed to be zero.

III. single TRP and plural TRP Deployment

In the present invention, the terms "transmitting and receiving point (TRP)", "antenna panel (or panel)", "antenna group (or port group)", "cell" and "magnetic zone" may be used interchangeably to refer to areas located antenna at the same location. Techniques, methods, processes, procedures, examples or embodiments disclosed using TRPs or panels as examples may also be applied to antenna groups, cells or magnetic zones. In a deployment, a magnetic zone 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 the zones, cells, TRPs, or panels may be considered a set of antennas for applying the techniques disclosed herein.

1. single TRP deploy

Figure 7 shows a first example of a single TRP (sTRP) transmission. TRP 700 is configured with a single antenna panel 701. Antenna panel 701 includes a 32-port square (or rectangular) antenna array. The antenna array has a horizontal dimension of N ₁ =4 and a vertical dimension of N ₂ =4. N ₁ and N ₂ are the number of cross-polarized antenna elements. Each cross-polarized antenna unit includes two cross-polarized antennas. Each cross-polarized antenna element may correspond to a pair of well-isolated spatial paths for diversity or spatial multiplexing. Co-located antennas of the antenna panel 701 allow the use of the same DFT basis vectors on the polarizations in the precoder matrix. These DFT basis vectors can be linearly combined for a near-optimal precoder. Examples of suitable codebooks for a single TRP transmission of the Figure 7 example may include a Third Generation Partnership Project (3GPP) Release 15 Type I codebook for a single board, Version 15 Type II codebook and Version 16e Type II codebook.

Figure 8 shows a second example of sTRP transmission. TRP 800 is configured with 4 antenna panels 801-804. Each antenna panel 801 includes a 32-port square (or rectangular) antenna array. The size of the antenna array is (N ₁ , N ₂ ) = (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 of the antenna elements within each antenna panel 801-804. Therefore, a suitable precoder may include a _W1 matrix and a _W2 matrix. The W ₁ matrix defines a beam on a polarization and panel-by-panel basis. The W ₂ matrix provides in-phase between co-polarizations sub-band by sub-band and in-phase between panels. Examples of suitable codebooks for multi-panel single TRP transmission in the Figure 8 example may include the 3GPP Release 15 Type I codebook for multi-panel.

2. many TRP deploy

A plurality of widely spaced (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 between the multiple TRPs. 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 can reduce inter-layer interference. To support CJTs with multiple TRPs, the in-phase and amplitude (or power) differences between TRPs can be measured and reported to the network from the mobile device. Based on this reported information, the network can control the TRP to perform coherent joint transmissions. Therefore, the mTRP CJT CSI measurement and reporting scheme is employed in various embodiments disclosed herein. These solutions may include new mechanisms for CSI-RS configuration, CSI report configuration and CJT codebook structure.

Figure 9 shows an example 900 of mTRP transmission in accordance with an embodiment of the invention. UE 901 receives CSI-RS signals from 4 TRPs 911-914. Each TRP can be configured with one or more antenna panels. These TRPs 911-914 can be controlled by the same base station (eg, gNB) and can operate cooperatively for CJT. Due to the geographical location of the TRPs 911-914, the synchronization signals sent from the TRPs 911-914 to the UE 901 may take different paths. To enable the TRP 911-914 to operate in CJT mode, CSI measurement and reporting procedures may be performed between the TRP 911-914 and the UE 901. Based on the reported CSI, CJT for TRP 911-914 can be achieved.

Figure 10 shows an example of CJT for two TRPs 1002-1003. The system model is introduced below with reference to Figure 10. Two TRPs 1002-1003 configured to jointly send signals to UE 1001 with _NR reception (rx) ports ( layer). TRP 1 1002 has Transmission (tx) port, TRP 2 1003 has A tx port. The total valid number of tx ports is . The downlink (DL) channel from TRP 1 1002 to UE 1001 is . The precoder from TRP 1 1002 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 in, and are the effective channel matrix and the effective precoder matrix.

3.mTRP CJT of CSI reporting process

Figure 11 illustrates a CSI measurement and reporting process 1100 in accordance with an embodiment of the present invention. In process 1100, CSI is reported from a UE 1102 to base stations connected to a set of geographically distributed TRPs 1101. The process 1100 may include 6 steps from step S1110 to step S1160.

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

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

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

IV. CSI-RS Resource allocation

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

In some embodiments, in order to mix mTRP CJT CSI and sTRP CSI in the CSI report, the UE may be configured with a plurality of channel measurement selection information to indicate which CSI resources should be estimated. Each channel measurement selection information may be associated with or represented by at least one CSI-RS Resource Indicator (CRI). In some examples, one CRI may indicate at least one CSI-RS resource belonging to a resource group. In some examples, one CRI may indicate at least two CSI-RS resources belonging to at least two resource groups used for mTRP CJT transmission. In some examples, one channel measurement selection information may indicate at least one CRI. The CRI used for indexing sTRP CSI and mTRP CSI can be separated.

Figures 12A and 12B show examples of resource group configurations. In the CSI resource setting of Figure 12A, resource set #0 includes 4 RS resources RS#1 to RS#4. The 4 RS resources are divided into 3 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.

Figure 12B shows 4 TRPs (TRP 1 to TRP 4). TRP1 and TRP2 colocalize with each other. Therefore, for CSI reporting purposes, the signals from TRP1 and TRP2 can be considered quasi-localized (QCLed). TRP3 and TRP4 are located at different distances from TRP1 and TRP2. As shown, the four RS resources configured in Figure 12A are respectively allocated to the four TRPs 1 to 4 in Figure 12B. Specifically, RS#1 and RS#2 in the same resource group 1 are allocated to co-located TRPs 1 to 2. When reporting CSI (including in-phase/magnitude/power differences) based on resource groups, TRP1 and TRP2 can be treated as one unit. In this way, the signaling cost of CSI reporting can be reduced.

Example #0-CSI-RS Resource settings

Figures 13A and 13B show examples of CSI-RS resource configuration for mTRP CJT reporting only (no reporting for sTRP). For example, as shown in Figure 13A, the network (or base station) only concentrates K = 4 CSI-RS resources {RS#1, RS#2, RS#3 in order to report mTRP CJT CSI. , RS#4} is configured to the UE. As shown in Figure 13B, 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 four TRPs {TRP1, TRP2, TRP3, TRP4} respectively. In some examples, as shown in Figure 13A, 4 CSI-RS resources may be grouped into 4 resource groups from resource group #1 to resource group #4. The resource group includes a CSI-RS resource. Each resource group corresponds to a geographically separated TRP. In some examples, when CSI-RS resources and resource groups are 1-to-1 mapping, the resource group may be omitted from the configuration.

Example #1-CSI-RS Resource settings

Figures 14A and 14B show examples of CSI-RS resource configuration for mTRP CJT reporting only (no reporting for sTRP). For example, as shown in Figure 14A, the network (or base station) concentrates K = 4 CSI-RS resources {RS#1, RS#2, RS#3 in order to report mTRP CJT CSI. , RS#4} is configured to the UE. As shown in Figure 14B, a set of 4 TRPs {TRP1, TRP2, TRP3, TRP4} are deployed. TRP1 and TRP2 colocalize. TRP3 and TRP4 are geographically separated. Four CSI-RS resources {RS#1, RS#2, RS#3, RS#4} are sent from 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 shown in Figure 14A. 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 can implicitly indicate to the UE that {RS#1, RS#2} are co-located and have the same QCL (quasi-co-location) assumption .

Example #2-CSI-RS Resource settings

Figures 15A and 15B show examples of CSI-RS resource configuration for sTRP and mTRP CJT joint reporting, sTRP CSI reporting or mTRP CSI reporting. For example, as shown in Figure 15A, 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}. As shown in Figure 15B, 4 CSI-RS resources can be allocated or transmitted from 4 TRPs {TRP1, TRP2, TRP3, TRP4} respectively. As shown, the four TRPs {TRP1, TRP2, TRP3, TRP4} are geographically separated.

Furthermore, the CSI-RS resource set may include an indication of one or more CJT sets. In some examples, each CJT set may include one or more CSI-RS resources configured in a 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. In Figure 15A, the CSI-RS resource set is shown to include K _CJT =2 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 set may be used for mTRP CJT CSI reporting. Different CJT sets can indicate different CJT transmission assumptions.

Furthermore, in the CSI-RS resource set shown in Figure 15A, each CSI-RS resource and CSI-RS resource set may be associated with a CRI. In some examples, CRIs for sTRP and mTRP measurements may or may not be provided separately. In the example of Figure 15A, 4 CRIs {CRI#1, CRI#2, CRI#3 respectively corresponding to 4 CSI-RSs {RS#1, RS#2, RS#3, RS#4}, CRI#4} is provided for sTRP CSI resources. Two CRIs {CRI#1, CRI#2} corresponding to CJT set #1 and CJT set #2 are provided respectively for mTRP CSI reporting. The UE may report CSI (PMI, RI, CQI, etc.) accompanied by CRI (eg, in the form of CRI index).

V. used for mTRP Type of transfer IICSI Code book design

1.CSI Reporting PMI The overall precoder structure of

In some embodiments, the overall mTRP CJT precoder reported in the PMI by the first UE may have a size and takes the following form, In the above equation, n represents the subband of the channel, and . is the total number of CSI-RS ports at the UE. is the transmission rank. W ^T [ n ] is the layer corresponding to PMI subband n of precoder such that W ^(p) [ n ] is the p -th TRP precoder, . is the number of CSI-RS ports of the p- th TRP. N _p is the total number of TRPs configured for the CJT.

For ease of presentation, the superscript of each matrix is omitted in the following description. The overall mTRP CJT precoder can be expressed as follows: W = = . W ₁ indicates the common spatial domain information of the layer (for example, SD basis vector). For example, different layers can share the same SD basis vector matrix W ₁ . W ₂ exhibits layer-specific linear combination coefficients (e.g., FD coefficients). W _f displays layer-specific frequency domain information (e.g., FD basis vectors).

2. W ₁ matrix design

In some embodiments, W ₁ represents the spatial domain (SD) DFT basis vectors that are commonly reported by the wideband and sum layers. The SD basis matrix W ₁ for mTRP CJT can take the form: Where, N _P is the number of coherently transmitted TRPs. can be SD basis matrix and represents the SD basis vector of the p -th TRP. For example, has the following form is the number of tx ports in TRP, , and L _p is the number of SD basis vectors in each polarization of TRP, , making and .

It can be seen that the SD basis matrix W ₁ for mTRP CJT can have a block diagonal structure. W ₁ for block diagonal structure implies TRP specific SD basis selection. For example, different TRPs can correspond to different . When each TRP is configured with CSI-RS resources in mTRP transmission, each CSI-RS resource corresponds to a specific . In other words, SD base selection is per CSI-RS resource. and, A common polarization SD base may be included. For example, basis vectors is shared between the two polarizations. Therefore, for a given CSI-RS resource, SD base selection can be polarization common. If W ₁ indicates layer-common spatial domain information, for a given CSI-RS resource, SD base selection may also be layer-common.

The design principle of W ₁ is as follows. First, W ₁ 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 means that the SD basis vectors for TRPs are different, i.e. for , . Third, line-of-sight (LOS) or non-line-of-sight (NLOS) conditions for different TRPs may be different relative to a specific UE. In this case, one can expect that across TRP, the number of SD basis vectors is different, i.e. for , . For example, { L _p , } Can be a higher layer configured by the base station. Alternatively, the total number of L _p for all TRPs can be configured by the base station. The UE may report { L _p , }.

A. W ₁ reduced feedback

If the p-th TRP co-localizes with the q-th TRP, the co-localized TRPs can use the same SD basis vector, i.e., . Therefore, utilizing this knowledge can reduce UE computation/feedback overhead. In various implementations, the following two methods can be adopted to reduce W ₁ feedback: Alternative 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. information. Alternative 2: Based on calculated , the UE can determine to report only those with different SD information .

Example #3- W ₁ Reduced feedback (alternative 1.1 )

In some examples, if some TRPs are co-located, the network (NW) can notify the UE of the co-located relationship between TRPs. In various implementations, there are multiple ways to notify the UE of co-location information. For example, the network can configure CSI-RS resources of TRPs located at the same location in the same resource group. CSI reports associated with CSI-RS resources in the same resource group can share the same W ₁ information. For example, TRP or CSI-RS resources corresponding to co-location in the same resource group can share a Used for CSI reporting. Under such a configuration, antenna configurations ( N ₁ , N ₂ ) and ( O ₁ , O ₂ ) can be configured for each CSI-RS resource (alternative 1.1).

Figure 16 shows a first example of W ₁ feedback reduction. As shown, 4 TRPs from TRP1 to TRP4 are deployed. Each TRP has a configuration of ( N ₁ , N ₂ ) = (4, 1) and 8 CSI-RS ports. A total of 4 TRPs have CSI-RS port. The four CSI-RS resources from RS#1 to RS#4 are configured by 4 TRPs respectively.

Figure 16 lists four scenarios 1601-1604 of TRP co-localization configurations. In scenario 1601, the 4 TRPs are non-co-located. The network may 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)｝. 4 SD basis matrices for each TRP { } can be different. Four SD basis matrices { can be reported in CSI reports corresponding to four CSI-RS resources {RS#1, RS#2, RS#3, RS#4} respectively. }.

In scenario 1602, TRP {TRP1, TRP2} is co-localized and TRP {(TRP1/TRP2), TRP3, TRP4} is non-co-localized. The network may 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 4 SD basis matrices can be { }. The SD basis matrices of TRP1 and TRP2 can be similar or identical. Therefore, 3 SD basis matrices { }.

In scenario 1603, TRP {TRP2, TRP3} are co-localized, and TRP {TRP1, (TRP2/TRP3), TRP4} are located at different locations. The network may 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 4 SD basis matrices can be { }. The SD basis matrices of TRP2 and TRP3 can be similar or identical. Therefore, 3 SD basis matrices { }.

In scenario 1604, TRPs {TRP1, TRP2} are co-localized. TRP {TRP3, TRP4} are also co-localized. TRP {(TRP1/TRP2), (TRP3/TRP4)} are non-colocalized. The 4 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 be similar or identical. Therefore, 2 SD basis matrices { }.

Example #4 - W ₁ Reduced feedback (alternative 1.2 )

Figure 17 shows a second example of W ₁ feedback reduction. Similar to the example in Figure 17, 4 TRPs from TRP1 to TRP4 are deployed. 4 TRPs have a total of CSI-RS port. Four CSI-RS resources from RS#1 to RS#4 are configured from four TRPs respectively. Four scenarios 1701-1704 are listed regarding the TRP co-localization configuration listed in Figure 17. Scenarios 1701-1704 are similar to scenarios 1601-1604. Therefore, the CSI-RS resource grouping scheme can be similarly adopted to inform the UE of the TRP co-location configuration (or deployment). SD basis matrix corresponding to CSI-RS resources allocated to a plurality of co-located TRPs The same SD base matrix can be shared in CSI reports to reduce CSI feedback overhead.

Unlike the example of Figure 16, the combined antenna configuration ( _N1 , _N2 ) is configured for CSI-RS resources corresponding to co-located TRPs (alternative 1.2). In some examples, CSI-RS resources corresponding to co-located TRPs are grouped into the same resource group. For example, in scenario 1702, TRP1 and TRP2 co-localize. Therefore, a 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, combined antenna configuration (8, 1) is configured for CSI-RS resources RS#1 and RS#2 corresponding to co-located TRP1 and TRP2, while another combined antenna configuration (8, 1) Configured for CSI-RS resources RS#3 and RS#4 corresponding to co-located TRP3 and TRP4.

Example #5- W ₁ Reduced feedback (alternative 2.1 )

In some examples, based on calculation based on CSI-RS measurement results , the UE can only report those with different SD basis vector information set. For example, for two colocalized TRPs corresponding to and , reports a matrix of SD basis vectors or , instead of reporting both.

Figure 18 shows an example of reporting compressed SD basis vector matrix W ₁ . The PMI reporting format for the W ₁ matrix can be TRP specific, e.g. { , , , }. For example, Contains the rotation factor ( i _1,1 ) and SD basis indicator ( i _1,2 ) of the SD basis: --> For the p-th TRP, ,in, and , -->For the p-th TRP, .

Considering the 4-TRP CJT CSI report, if the SD matrices calculated for TRP1 and TRP2 are the same, i.e. , as shown in Figure 18, the UE can further compress W ₁ . In one example, the UE may report { ; ; }and { ; ; }, each having only 3 elements instead of 4, as shown in Figure 18. In one example, the UE may further report an additional quadruple index, e.g. , to indicate the corresponding element index of the four TRPs. Indexes with the same value can indicate corresponding complex numbers that share the same SD basis vector matrix. .

Example #6– W ₁ Reduced feedback (alternative 2.2 ): used for dynamic sTRP and mTRP switched W ₁ PMI share

Figure 19A shows the case of sTRP and mTRP switching. 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 the CSI report from UE 1901, the base station (not shown) can control UE 1901 and 4 TRP to switch from previous sTRP transmission to mTRP transmission. In the scheme of Figure 19A, CSI on the channel between UE 1901 and 4 TRPs can be reported to the base station to support dynamic sTRP and mTRP handover.

To support dynamic switching between sTRP and mTRP transmission, the UE 1901 can report CJT and one CSI in sTRP. For example, UE 1901 may report one CSI that reflects the channel conditions between UE 1901 and 4 TRPs. Alternatively, UE 1901 may report one CSI for CJT and X CSI for a single TRP transmission. For example, you can configure . In this alternative scenario, separate CRI indexes for CJT and single TRP measurements may be configured separately from the base station to the UE 1901. Based on the CSI-RS measurements, individual CSI corresponding to the corresponding CRI can be derived and reported.

In the above alternative, the W ₁ matrix can be shared between sTRP and mTRP CSI reporting. For example, only one W ₁ matrix corresponding to each TRP is reported. Figure 19B shows another example of Wi _feedback reduction in the scenario of mixed sTRP and mTRP CSI reporting of Figure 19A. As shown, one sTRP CSI corresponding to each TRP is reported, including CRI, RI, PMI ( , , ) and CQI. Corresponding to 4 TRPs, one mTRP CSI is reported. mTRP CSI can include CRI, RI, PMI ( { }and ) and CQI. However, the SD basis matrix W ₁ is omitted from the mTRP CSI. When the base station receives the 4 sTRP CSI , , , After that, the W ₁ SD basis matrix can be derived accordingly.

3. W ₂ matrix design

Figure 20 shows a Type II codebook precoder structure 2000 for mTRP CJT feedback. The precoder structure 2000 may correspond to the precoder described above, W = = Among them, _W1 represents the matrix of wideband SD basis vectors, _W2 represents the matrix of spatial frequency compression coefficients that linearly combines SD basis vectors, and _Wf represents the DFT basis vectors used for FD compression. As shown, W ₁ has dimensions . W ₂ has dimensions of , where N ₃ is the number of subbands of the mTRP transmission channel. W _f has dimensions . Select M FD basis vectors from W _f . Accordingly, in the example of Figure 20, M columns of frequency coefficients are included in _W2 .

Among the M column coefficients, the most significant coefficient 2001 can be selected and quantified. After quantification, a set of NZCs can be reported in the corresponding SCI. For example, the selected linear combination coefficients of W ₂ may be reported to gNB in the form of the single strongest coefficient in a specific polarization, reference amplitudes for other polarizations, polarization-specific differential amplitudes, and phase coefficients.

In some examples, the W ₂ coefficients may be reported as a set of coefficient indicators in the CSI report. For example, coefficient indicators can be classified as: - SCI (Strongest coefficient indicator): i _1,8 - ACI (Amplitude coefficient indicator) o Reference amplitude: i _2,3 o Differential amplitude : i _2,4 (relative to SCI or ACI) - PCI (Phase coefficient indicator, Phase coefficient indicator): i _{2,5 -} NZC dot plot: i _1,7 (indicates the position of the coefficient in W ₂ )

In some examples, W2 designs can follow the following principles: - NZC can _be selected across TRPs. For example, the W ₂ coefficients corresponding to different TRPs can be considered together for selecting or determining which coefficients to report. o Basis to determine the maximum number of layer-by-layer NZCs, where It is the NZC selection ratio. - One strongest coefficient across all TRPs (SCI) - No amplitude and phase are reported for SCI. - The reference amplitude indicator may be o TRP common, i.e. one reference amplitude across all TRPs o TRP specific, i.e. one reference amplitude per TRP o Polarization common, i.e. one reference amplitude for both polarizations o polarization specific, i.e. each polarization has a reference amplitude o The reference amplitude can be quantized to e.g. 4 bits - all other NZCs are quantized relative to the corresponding reference amplitude, e.g. using 3 bits (i.e. differential amplitude). - All NZC phases instead of SCI can be quantized to e.g. 16 PSK. -NZC bitmap can be TRP common, or TRP specific o TRP common: total bitmap size is o TRP specific: Total bitmap size is , in§ is the selected/service TRP set§ is the number of selected TRPs, i.e., § L _p is the number of beams of the p-th TRP § M _p is the number of selected FD bases of the p-th TRP § M is the number of FD bases common to the TRPs.

Figure 21 shows an example of NZC selection according to an embodiment of the invention. In the example in Figure 21, and are the reference amplitudes of the p-th TRP of polarization 0 and 1 respectively.

Example #7-NZC select

Figures 22A-22B illustrate examples of NZC selection for mTRP CSI reporting in accordance with embodiments of the present invention. There are 4 TRPs present in the CSI report. Each TRP has two antenna polarizations. Corresponding to each polarization, 2 SD basis vectors ( L _p =2) are reported. M=3 FD basis vectors were selected for 4 TRPs. Figure 22A shows the different types of indicators and corresponding selection methods (TRP common or TRP specific) for reporting W ₂ coefficients. Figure 22B shows M× in the linear combination coefficient matrix W ₂ The layout of the matrix elements in the region. As shown, the SCI common to the TRP corresponding to coefficient 2201 is determined. Determine the common reference amplitude for the TRP corresponding to coefficient 2202.

To determine the differential magnitude of other NZCs, a TRP-specific NZC (such as coefficients 2203-2204) can be selected. Each differential amplitude of these TRP-specific selected NZCs can be determined relative to the 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 antenna polarization and the second antenna polarization 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 magnitude of TRP-specific selected NZCs can be quantified prior to CSI reporting.

Example #8-NZC select

Figures 23A-23B illustrate another example of NZC selection for mTRP CSI reporting in accordance with embodiments of the present invention. Similarly, 4 TRPs are present in the CSI report. Each TRP has two polarizations. Corresponding to each polarization, 2 SD basis vectors ( L _p =2) are reported. M=3 FD basis vectors are selected for the 4 TRPs. Figure 23A shows the different types of indicators and corresponding selection methods (TRP common or TRP specific) for reporting W ₂ coefficients. Figure 23B shows the linear combination coefficient matrix W ₂ in M× The layout of the matrix elements in the region. Similarly, the SCI common to the TRP corresponding to coefficient 2305 is determined.

Unlike the examples of Figures 22A-22B, the plurality of reference amplitudes are selected in a TRP-specific and polarization-specific manner. For example, the two selected reference amplitudes correspond to coefficients (or matrix elements) 2301 and 2302 that have different polarizations and belong to the same TRP 1. The two selected reference amplitudes correspond to coefficients (or matrix elements) 2303 and 2304 that have different polarizations and belong to the same TRP 2. Therefore, in order to determine the differential amplitudes of other NZCs, the TRP-specific selected NZC can be compared with the corresponding TRP-specific and polarization-specific reference amplitudes.

4. W _f matrix design

As mentioned above, the overall mTRP CJT precoder can be expressed as follows: W = = . The matrix W _f represents the frequency domain (FD) basis vector used for frequency domain compression. In various embodiments, FD-based selection designs may follow the following principles (Alternative 1 and Alternative 2). There are two options for FD compression.

Alternative 1 : TRP independent (or TRP specific) FD base selection. M _p FD basis vectors can be selected for the p-th TRP . The overall frequency domain basis vector set can be , making and . The main principle is to consider subband phase jumps on TRPs due to time offsets between corresponding TRPs. In some examples, TRP-specific FD basis vector selection methods may be applied to mTRP transmissions where the deployed TRPs include co-located TRPs.

Alternative 2 : TRP common (or joint) FD base selection. M FD basis vectors can be selected across TRPs (for all TRPs). In some examples, the cross-TRP (or TRP common) FD basis vector selection method may be applied to mTRP transmissions, where the deployed TRPs include geographically distributed TRPs.

Figure 24 shows an example of an FD basis vector selection alternative in accordance with an embodiment of the invention. Two alternatives are shown: Alternative 1, TRP independent FD base selection, and Alternative 2, TRP common FD base selection. As shown, the coefficient matrices in both Alternative 1 and Alternative 2 ( ) includes the TRP-by-TRP coefficient matrix { , ,…, }. For the SD basis matrix of alternative 1 ( ), select SD basis vectors TRP by TRP. For example, select M ₁ SD basis vectors for TRP ⁽¹⁾ . Select M ₂ SD basis vectors for TRP ⁽²⁾ . Select M _Np SD basis vectors for TRP ^(Np) . For the SD basis matrix of alternative 2 ( ), select SD basis vectors across TRP.

Corresponding to the two FD base selection alternatives 1 and 2, the overall mTRP CJT precoder can take the following two forms: Alternative 1: Alternative 2: As shown, for independent FD basis selection across N _p TRPs (alternative 1), the TRP-by-TRP FD basis vector matrix { }It is different for different TRPs. For TRP common FD basis selection, different TRPs share the same FD basis vector matrix .

Example #9– W _f of FD base selection

In some examples, the FD basis indicators ( i _1,5 and i _1,6 ) for the W _f matrix in the CSI report include the initial window position M _initial (e.g., for N ₃ > 19) and the FD basis index n ₃ ,in and

Corresponding to the SD base selection alternative above, the PMI reporting format for FD basis vectors can have two designs: - Alternative 1: Report the FD basis indicator (TRP specific) for each TRP. Considering 4 TRP cases, the report format can be i _1,5 : { , , , } and i _1,6 : { , , , }. - Alternative 2: Report FD base indicator across all TRPs (common to TRPs) The reporting format can be i _1,5 : { } and i _1,6 : { }

Figure 25 shows an example of the initial window position and FD base index in _the FD coefficient matrix W2 . As shown, the Alternative 1 case corresponds to the PMI reporting format of FD basis vector Alternative 1. Different TRPs have different indicators and . The Alternative 2 case corresponds to the PMI reporting format of Alternative 2 for FD basis vectors. Different TRPs have the same indicator and .

VI. Dynamic TRP select

For example, due to UE actions and blocking, the UE may need to measure multiple sets of CSI-RS resources from multiple TRPs for mTRP measurements and CJT/NCJT transmissions. In some cases, a UE may be served by at least two dominant TRPs (larger received power comes from at least two dominant TRPs). Non-dominant TRP can be turned off or used for other UEs. A flexible design for the network and UE to select the appropriate TRP for mTRP measurement and transmission is described here.

Figure 26 shows an example where a different set of mTRPs may be switched to serve a UE due to its actions. 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.

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

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 a TRP 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 may be {TRP1, TRP2, TRP3}. Alternatively, the UE may perform the selection and report the selection result to the base station.

Based on the Type II codebook structure described herein, in some embodiments, a TRP selection matrix W ₀ is introduced for CSI feedback from the UE to the network. Figure 27 shows two types (two variants) of codebook structures for CSI feedback. These two types of codebook structures are based on the Type II codebook structure and the TRP selection matrix W ₀ . Two types of codebook structures can take the following forms: Variation 1: ; Variation 2: .

The example shown in Figure 27 corresponds to the scenario where there are 4 candidate TRPs on the network side and each TRP has N _Tp antenna ports. During the CSI reporting process, the UE can measure CSI-RS from 4 TRPs. Based on the measurement results, the UE can provide CSI reports to the network. The CSI report may indicate the selected TRP and associated precoder. For example, the CSI report may include information about matrices W ₀ , W ₁ , W ₂ and/or W _f shown in Figure 27.

W ₀ is the TRP/port/beam selection matrix. W ₀ can be used to dynamically report CSI for a specific TRP/port. As shown in Figure 27, the TRP selection matrix may include a complex number of submatrices. Each sub-matrix has size N _Tp by N _Tp (or 2L _p ×2L _p ). Each sub-matrix corresponds to one of the 4 candidate TRPs. For a TRP that is not selected (e.g., the second of 4 TRPs), the corresponding submatrix can be a zero matrix (each element is zero). For a selected TRP (eg, a first TRP, a third TRP, or a fourth TRP), the corresponding sub-matrix may be an identity matrix.

For variant 1, the feedback overhead can be reduced. With this variant, the network may not know the SD information of unselected TRPs. For variant 2, the SD information of all TRPs in the coordination set can be reported in W ₁ . The network may use the unselected TRP to serve another UE, or the network may use the SD information of the unselected TRP to mitigate inter-TRP interference. Furthermore, for variant 2, W ₁ may be reported in a broadband manner and W ₀ may be reported in a subband manner based on the subband precoder coefficients. In some examples, the network may use RRC, MAC CE or DCI signaling to configure whether to use the selection matrix W ₀ . In some examples, TRP/port selection criteria may be based on TRP power efficiency, channel correlation or capacity, interference mitigation, etc.

Example #10- Dynamic TRP select

In an example, when the network uses RRS signaling to configure the UE to report the TRP matrix W ₀ , the UE may report a TRP selection indicator i ₀ representing the TRP selection matrix W ₀ . For example, the TRP selection indicator i ₀ may have integer values arranged as {0, 1, 2, ..., }, where N _p is the number of candidate TRPs or TRPs configured on the network, is the number of serving TRPs selected by the UE, and is given N _p and The total number of possibilities for different W ₀ (selected from N _p candidate TRPs combination of TRPs). In one example, N _p and The value of can be signaled to the UE from the network. In some examples, _Np and value.

In some examples, W ₀ can be mapped to CRI feedback. In the case where a single TRP is used for transmission, the UE usually selects a CRI to feed back the best BS beam or selects a TRP for RI/PMI/CQI feedback from candidate TRPs. In the case of mTRP joint transmission (JT), the UE can select and report multiple CRIs mapped to multiple TRPs for NCJT/CJTRI/PMI/CQI feedback. There is a mapping relationship between the TRP selection matrix W ₀ and the selection of CRI (e.g., represented by a dot plot).

For the report of W ₁ , in one example the structure is used In this case, the UE can avoid feeding back the W ₁ information of the unselected TRP. As shown in the variant 1 structure in Figure 27, the sub-matrix corresponding to the second TRP (TRP2) is not reported in the CSI report because the second TRP is not selected. In this way, signaling costs can be saved. using the structure In this case, the UE can still feed back the W ₁ information of the unselected TRP.

For the reporting of W ₂ and W _f , the UE can avoid reporting information of unselected TRPs to save feedback overhead. For example, one or more indicators are predefined or configured for reporting information carried in _W2 and _Wf . For unselected TRPs, the corresponding indicator corresponding to the unselected TRP may be removed from the report.

VII.CSI Report configuration

In some embodiments, CSI reporting configuration may be configured through higher layer (above the physical layer) signaling (eg, MAC CE and RRC). The CSI reporting configuration may include one or more codebook configurations. A codebook configuration may include one or more antenna configurations ( N ₁ , N ₂ ) for precoder estimation and selection. For example, one antenna configuration ( N ₁ , N ₂ ) may correspond to one CSI-RS resource or resource group. Figure 28A shows an example of CSI reporting configuration. CSI report configuration includes codebook configuration. Figure 28B shows an example of codebook configuration. The codebook configuration includes codebook subset restriction information. The subset restriction information includes a set of antenna configurations ( N ₁ , N ₂ ). Each antenna configuration ( N ₁ , N ₂ ) corresponds to a CSI-RS resource or CSI-RS resource group.

In some examples, the CSI-RS resource set configured to the UE includes a plurality of resource groups. A UE may be configured with one or more codebook configurations for precoder estimation and selection over a plurality of resource groups. A codebook configuration may include one or more values of ( N ₁ , N ₂ ). Each value of ( N ₁ , N ₂ ) can correspond to a resource group. As shown in the example of Figure 17, for the case of 1702, {TRP1, TRP2} co-localized. CSI-RS {RS#1, RS#2} is included in resource group 1. Therefore, TRP1 and TRP2 are provided together with an antenna configuration (8,1). Similarly, in case 1703, resource group 2 is provided with an antenna configuration (8,1). In the case of 1704, two antenna configurations (8,1) and (8,1) are provided for resource groups 1 and 2 respectively.

In some embodiments, the CSI report configuration may include at least one power indicator to indicate how to adjust at least 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 only includes one resource or one resource group for a single TRP transmission, the precoder power is usually normalized to 1 and no power indicator is required. In other examples, at least one power indicator may be provided for mTRP CJT transmissions, since different TRPs may use different transmission 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 PMI and CQI for CSI reporting.

Example #11- power indicator

In some examples, based on at least one power indicator, the UE may understand which of the following power adjustment methods or modes is used for TRP transmission.

Method 1: Each TRP in a selected TRP set is transmitted at full power, i.e., the precoder used by the p-th TRP is , in and is the transmission rank and Is a set of related service TRPs. It is a TRP power adjustment precoder. is the CJT precoder reported by the UE.

Method 2: At least one TRP in the selected TRP set, e.g. TRP, sent at full power. By the first The precoder used by a TRP can be , among which and .

The network can configure which method the UE uses through RRC or MAC CE signaling.

Example #12- power indicator

In some examples, the network (eg, gNB) may signal the power indicator to the UE. The power indicator may indicate that at least one TRP in the selected TRP set, such as the p-th TRP, is transmitted at full power. For example, the p-th TRP with full power is given by to determine, among which is the precoder normalization factor of the p-th TRP, and is the transmission rank and Is a set of related service TRPs.

Precoder passthrough factor used by the p-th TRP Make the following power adjustments, It is a TRP power adjustment precoder. is the CJT precoder reported by the UE. Precoder norm of p-th TRP means the first Each TRP transmits full power.

The UE may use the power indicator to estimate the CQI of the CSI report.

Figures 29A to 29B show examples of 4 TRP CJT transmission scenarios. Precoder normalization factor It is determined as {0.3, 0.4, 0.2, 0.1}. Therefore, it is determined that TRP2 is transmitted at full power. And determine the power adjustment factor to be 0.4. All 4 TRPs can be amplified with the same adjustment factor. Has no effect on interference between TRPs. In one example, the UE and the network may each determine the precoder normalization factor and adjustment factor. In one example, the UE may report the precoder normalization factor and/or adjustment factor to the network.

Example #13- power indicator

In some examples, a power indicator from the network may indicate to the UE that each TRP in the selected TRP set is sent at full power.

The precoder used by the p-th TRP is power adjusted as: , where the precoder normalization factor c _p is defined as the same as in the above example. Precoder norm for each TRP Meaning each TRP is sent at full power. The UE may use the power indicator to estimate CQI for CSI reporting.

Figures 30A to 30B show examples of 4 TRP CJT transmission scenarios. Precoder normalization factor It is determined as {0.3, 0.4, 0.2, 0.1}. All TRPs perform full power transmission. All 4 TRPs can be powered up via different adjustment factors. Interference between TRPs may increase. In an example, the UE and the network may each determine the precoder normalization factor and adjustment factor. In one example, the UE may report the precoder normalization factor and/or adjustment factor to the network.

VIII. used for mTRP and sTRP jointly reported CSI reduced feedback

In some embodiments, to mix mTRP NCJT/CJT CSI and sTRP CSI in the CSI report, the UE may be configured with a plurality of CRIs to indicate which CSI information to estimate. Figure 15A provides an example of this configuration. One CRI may indicate at least one CSI-RS resource belonging to at least one resource group. The CRI indexes of sTRP CSI and mTRP CSI can be separated. For CSI reports that include sTRP CSI and mTRP CSI, mTRP CSI can reuse sTRP CSI to reduce the content size of mTRP CSI.

In some examples, the UE may be configured in the CSI reporting configuration for the same codebook type for sTRP CSI and mTRP CSI feedback. Common codebook designs can have precoder structures (e.g. 3GPP NR DL Type I codebook and Release 15 Type II codebook) or (e.g. NR DL version 16 Type II codebook). Based on the codebook and precoder disclosed in this article, the CSI report can reuse the sTRP CSI , or , and reduce the content size of mTRP CSI. For example, the UE can configure CSI feedback reduction information through CSI reporting configuration.

Example #14-CSI reduced feedback

In some examples, the design for mTRP CSI is derived based on the codebook and precoder, for example, based on the NR Release 17 NCJT CSI architecture or other CSI architecture, the UE can reuse the sTRP CSI , or , and reduce the content size of mTRP CSI. For example, the UE is configured to measure and feedback TRP1, TRP2 and TRP3 sTRP CSI and mTRP CSI in the CSI report. The UE can measure and derive the sTRP precoder for TRP1, TRP2 and TRP3 respectively, and reuse the sTRP precoder on mTRP precoder derivation and feedback. For example, the sTRP precoder for TRP1, TRP2, and TRP3 can be TRP1 TRP2 TRP3 The W ₁ matrix of the mTRP precoder can be

If the UE is configured by RRC or MAC CE, the CSI report may not include W ₁ or W ₁ W ₂ of the mTRP precoder.

Example #15-CSI reduced feedback

In some examples, the network may configure the UE to reuse sTRP CSI or , and feed back additional precoder information for mTRP CSI in the CSI report. Additional precoder information may include cyclic phase delay (CDD) parameters or indices into matrices to apply phase shifts on each layer or to combine multiple layers into fewer layers, as shown below.

For example, configure the UE to measure and feed back TRP1, TRP2 and TRP3 sTRP CSI and mTRP CSI in the CSI report. The sTRP precoder for TRP1, TRP2, and TRP3 can be TRP1 TRP2 TRP3

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 ( The number of layers, number of layers) or other CDD matrix, such as 3GPP 36.211 V10.7.0 section 6.3.4.2.2 CDD design as shown below: , where v is The number of layers, and N _t is the total number of TX antennas. The table below provides examples of D and U. v 2 3

Example #16-CSI reduced feedback

For example, configure the UE to measure and feed back TRP1, TRP2 and TRP3 sTRP CSI and mTRP CSI in the CSI report. The sTRP precoder for TRP1, TRP2 and TRP3 can be TRP1 TRP2 TRP3

The mTRP {TRP1, TRP2, TRP3} precoder can be , where i is the subcarrier or subband index, and This can be done by applying a phase shift on each layer or by combining multiple layers into a matrix of fewer layers. if is the matrix to which the phase shift is applied, then it can be . It includes phase diagonal matrix. yes of layers. Can be designed to apply phase shifts, amplitude changes and layer combinations. Provided below Some examples of. Example of Combine 2 layers into 1 layer Combine 2 layers into 1 layer , , Combine 4 layers into 1 layer Combine 4 layers into 1 layer , , , , , , , , , , , ,

IX. Based on version 17fe Type IIPS code book design

1. W ₁ design:

In some examples, there can be two possible designs for the W ₁ matrix. TRP port by TRP port selection Cross TRP port selection

For per-TRP port selection, in some examples the gNB can send precoded CSI-RS, where N _p is the number of cooperating TRPs, and 2 L _p represents the number of SD/SD-FD pairs (precoded CSI-RS ports) in the p-th cooperating TRP. A simple example of such precoded CSI-RS is when the gNB determines the SD/FD basis on a TRP-by-TRP basis. The UE may also select from N _p cooperative TRPs according to W ₀ service TRP. The UE may start from the Choose from ports A port. The choice can be polarized jointly and freely, i.e., from possible combinations from Choose from ports A port.

For cross-TRP port selection, it can be expected that from the UL channel, the gNB can perform coordinated beamformed CSI-RS transmissions from all cooperating TRPs. For example, gNB can derive the SD-FD basis from the joint mTRP channel as shown in Figure 31 (gNB implementation issue). Based on the UL channel, the gNB can even send precoded CSI-RS from different TRPs with different powers.

The total number of precoded (beamformed) CSI-RS ports can be . As shown in Figure 32, the UE can in a collective and free way of polarization from Select K ₁ ports among the ports.

2. W ₂ design:

Depending on the W ₁ method used, there are two possible designs. For individual W ₁ TRPs, it can be expected that the same design principles of the W ₂ design disclosed above can be used. For cross-TRP W ₁ , the UE essentially treats the plurality of TRPs as a single giant TRP and performs port selection on a single precoded mTRP channel as described above, so the W ₂ design can follow the traditional Release 17 W ₂ design.

3. W _f design:

In the 3GPP Release 17 design, the UE is configured with N = 2 or N = 4 consecutive DFT vectors starting from 0, from which the UE selects M = 2 vectors for W _f . Since most of the frequency selectivity in the channel can be handled by precoded CSI-RS, the main purpose of this _W is to compensate for the residual frequency selectivity and imperfect delay reciprocity. Further, the W _f design can consider TRP-specific FD base selection. For example, TRP p selects M _p FD bases from N = 2 or N = 4 consecutive DFT vectors. However, for all TRPs, the number of FD bases chosen is , making . That is, the union of TRP-by-TRP FD basis vectors is the overall configuration of N FD basis.

X.mTRP Other examples of measurement and transmission

In the first example, the method for UE to perform wireless communication includes the following steps: - Receive signaling from a network entity to indicate a CSI reporting configuration, the channel status information reporting configuration including at least one codebook configuration, and at least one of at least one power indicator and CSI feedback reduction information, and associate it for channel measurement At least one CSI-RS resource configuration, wherein the at least one CSI-RS resource configuration associates at least two resource groups and at least one channel measurement selection information; - Estimating channel information based on the CSI report configuration; - deriving at least one PMI and CQI based on the estimated channel information and at least one of at least one power indicator and CSI feedback reduction information; and -Sending a CSI report to the network entity.

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

In a 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 transmitted from a co-located geographical location.

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

In a fifth example based on the first example, the at least one codebook configuration indicates at least one codebook parameter set associated with at least one CSI-RS resource configuration or at least one channel measurement selection information.

In a sixth example based on the fifth example, the at least one codebook parameter set includes at least one of the following information: - the p-th CSI-RS resource or resource group indicated by the corresponding channel measurement selection information The number of associated beam vectors L _p ; - the NZC selection ratio β _p associated with the pth CSI-RS resource or resource group indicated by the corresponding channel measurement selection information.

In a seventh example based on the first example, each PMI is derived from at least two of the W ₁ , W ₂ and W _f codebook matrices.

In an eighth example based on the seventh example, the W ₁ codebook matrix has a block diagonal structure with at least two submatrices in its diagonal, and the p-th submatrix of at least the two submatrices contains The spatial beam vector associated with the p-th CSI-RS resource or resource group indicated by the corresponding channel measurement selection information.

In a ninth example based on the seventh example, the W ₂ codebook matrix contains complex linear combination coefficients of the beam vector in W ₁ and the DFT-based delay vector in W _f .

In the tenth example based on the seventh example, the W _f codebook matrix contains DFT-based delay vectors.

In an eleventh example based on the seventh example, each PMI is also derived from the resource selection matrix W ₀ , and W ₀ indicates which CSI-RS resource or resource group indicated by the corresponding channel measurement selection information is more important.

In a twelfth example based on the eleventh example, the network entity uses higher layer signaling to indicate to the UE whether to use the resource selection matrix W ₀ .

In a thirteenth example based on the seventh example, the precoding coefficients of W ₁ , W ₂ and W _f also take into account at least one power indicator for power adjustment, wherein the at least one power indicator is determined by the network Entities are indicated via higher layer signaling.

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

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

In a sixteenth example based on the seventh example, the W ₁ 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 in Each column includes a selection matrix with a single non-zero element and is associated with the p-th CSI-RS resource or resource group indicated by the corresponding channel measurement selection information.

XI.mTRP Other examples of measurement and transmission

Figure 33 illustrates a process 3300 of mTRP CSI measurement and reporting in accordance with an embodiment of the present invention. Process 3300 may begin at step S3301 and proceed to step S3310.

In step S3310, CSI reporting configuration is received from the base station at the UE. The CSI reporting configuration is associated with the CSI-RS resource set. Each CSI-RS resource may correspond to one or more TRPs among a plurality of TRPs.

In step S3320, channel measurement may be performed based on CSI-RS resources transmitted from a plurality of TRPs.

In step S3330, the PMI may be determined based on the measurement results of the channel measurement. The PMI may correspond to the precoder matrix denoted W of the Type II CSI codebook. For example, the PMI may include a plurality of indicators indicating elements belonging to the precoder matrix. The precoder matrix may have a SD basis vector matrix denoted W ₁ . The selection of SD basis for 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.

In step S3340, the 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.

Figure 34 illustrates another process 3400 for mTRP CSI measurement and reporting in accordance with an embodiment of the present invention. Process 3400 begins at step S3401 and proceeds to step S3410.

In step S3410, CSI reporting configuration is received from the base station at the UE. The CSI reporting configuration is associated with the CSI-RS resource set. Each CSI-RS resource may correspond to one or more TRPs among a plurality of TRPs.

In step S3420, channel measurement is performed based on CSI-RS resources transmitted from a plurality of TRPs.

In step S3430, the PMI is determined based on the measurement result of the channel measurement. The PMI may correspond to the precoder matrix denoted W of the Type II CSI codebook. The precoder matrix may have an SD/FD coefficient matrix represented as W ₂ (or called a linear combination coefficient matrix). The coefficient columns in the SD/FD coefficient matrix correspond to the SD basis vectors in the SD basis vector matrix denoted W ₁ . Coefficient rows in the SD/FD coefficient matrix correspond to FD basis vectors in the FD basis vector matrix denoted W _f . The PMI includes an FD base 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.

In step S3440, the 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.

Figure 35 illustrates another process 3500 for mTRP CSI measurement and reporting in accordance with an embodiment of the present invention. Process 3500 begins at step S3501 and proceeds to step S3510.

In step S3510, CSI reporting configuration is received from the base station at the UE. A CSI reporting configuration can be associated with a CSI-RS resource set. Each CSI-RS resource may correspond to one or more of the TRPs. CSI-RS resources may be organized into one or more resource groups. The CSI reporting configuration includes one or more antenna configurations (N ₁ , N ₂ ). Each antenna configuration corresponds to one or more of a plurality of TRPs. One or more antenna configurations respectively correspond to one or more resource groups. N ₁ and N ₂ are the number of antenna ports of the corresponding one or more TRPs with the same polarization direction in the vertical and horizontal directions, respectively.

In step S3520, channel measurement is performed based on CSI-RS resources corresponding to a plurality of TRPs.

In step S3530, the PMI may be determined based on the measurement results of the channel measurement and one or more antenna configurations (N ₁ , N ₂ ).

In step S3540, the 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.

XII. Exemplary device

Figure 36 illustrates an exemplary apparatus 3600 in accordance with an embodiment of the invention. Device 3600 may be configured to perform various functions in accordance with one or more implementations or examples described herein. Accordingly, apparatus 3600 may provide means for implementing the mechanisms, techniques, processes, functions, elements, and systems described herein. For example, in various embodiments and examples described herein, apparatus 3600 may be used to implement the functionality of a UE or BS (controlling TRP). Apparatus 3600 may include a general-purpose processor or specially designed circuitry to implement various functions, elements, or processes described in various embodiments. The device 3600 may include a processing circuit 3610, a memory 3620, and a radio frequency (RF) module 3630.

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, the processing circuit 3610 may be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Programmable Logic Device (PLD), or a Field Programmable Gate Array. FPGA), digitally enhanced circuit (digitally enhanced circuit) or similar components or a combination thereof.

In some other examples, processing circuitry 3610 may be configured as a Central Processing Unit (CPU) that executes program instructions to perform various functions and processes described herein. Accordingly, memory 3620 may be configured to store program instructions. When executing program instructions, processing circuitry 3610 may perform these functions and processes. The memory 3620 can 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, CD drives, etc.

In one embodiment, the RF module 3630 receives the processed data signal from the processing circuit 3610 and converts the data signal into a beamformed wireless signal transmitted through the antenna array 3640, and vice versa. In some examples, the RF module 3630 may include a digital to analog converter (DAC), an analog to digital converter (ADC), an upconverter, and a downconverter for receiving and transmitting operating filters and amplifiers. In some examples, RF module 3630 may include multiple antenna circuits for beamforming operations. For example, the multi-antenna circuit may include an uplink spatial filter circuit that adjusts the amplitude of the analog signal and a downlink spatial filter circuit. Antenna array 3640 may include one or more antenna arrays organized into a plurality of antenna panels or antenna groups.

Device 3600 may optionally include other components such as input and output devices, additional or signal processing circuitry, and the like. Therefore, device 3600 is capable of performing other additional functions, such as executing applications and handling alternative protocols.

The processes and functions described herein may be implemented as computer programs, where the computer program, when executed by one or more processors, causes the one or more processors to perform the corresponding processes and functions. The computer program may be stored or distributed on suitable media, such as optical storage media or solid-state media provided with or as part of other hardware. Computer programs may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems. For example, a computer program may be obtained and loaded into a device, including through physical media or a distributed system such as a server connected to the Internet.

A computer program can be accessed from a computer-readable medium that provides program instructions for use by or in connection with a computer or any instruction execution system. The computer-readable medium may include any device that stores, communicates, propagates, or transports computer programs for use on or in connection with an instruction execution system, device, or device. The computer-readable medium may be a magnetic, optical, electronic, electromagnetic, infrared, or semiconductor system (or apparatus or device) or propagation medium. The computer-readable medium may include computer-readable non-transitory storage media, such as semiconductor or solid-state memory, tapes, removable computer disks, RAM, ROM, magnetic disks, optical disks, etc. The computer-readable non-transitory storage media may include all types of computer-readable media, including magnetic storage media, optical storage media, flash memory media, and solid-state storage media.

Although aspects of the invention have been described in connection with specific exemplary embodiments, various substitutions, modifications and changes are possible to these examples. Accordingly, the described embodiments of the present invention are illustrative only and not restrictive. Changes may be made without departing from the scope of the patent application.

601: Modulation symbol layer 602: Precoder 603:Antenna port 604: Spatial filter 605:Physical antenna 700,800,910,911,913,914,1002,1003,1101:TRP 701,801,802,803,804: Antenna panel 900:Example 901,1001,1102,1901:UE 1100,3300,3400,3500: process S1110,S1120,S1130,S1140,S1150,S1160,S3301,S3310,S3320,S3330,S3340,S3399,S3401,S3410,S3420,S3430,S3440,S3499,S3501,S3510,S3 520,S3530,S3540,S3599: Steps 1601,1602,1603,1604,1701,1702,1703,1704: scene 2000: Precoder structure 2001,2201,2202,2203,2204,2301,2302,2303,2304,2305: coefficient 3600:Device 3610: Processing circuit 3620:Memory 3630:RF module 3640:Antenna Array

The present invention proposes some implementations as examples, which will be described in detail below with reference to the accompanying drawings, where the same numbers represent the same components, wherein: Figures 1 to 3 illustrate the use of CSI-RS ports or sounding reference signals. signal, SRS) port mapping to a physical antenna. Figure 4 shows a linear multi-antenna transmission scheme in a transmitter according to an embodiment of the invention. Figure 5 shows an example of analog multi-antenna processing. Figure 6 shows an example of hybrid multi-antenna processing in accordance with some embodiments of the invention. Figure 7 shows a first example of single TRP (sTRP) transmission. Figure 8 shows a second example of sTRP transmission. Figure 9 shows an example 900 of multiple-TRP (mTRP) transmission according to an embodiment of the present invention. Figure 10 shows an example of coherent joint transmission (CJT) of two TRPs 1002-1003. Figure 11 illustrates a CSI measurement and reporting process 1100 in accordance with an embodiment of the present invention. Figures 12A and 12B show examples of resource group configurations. Figures 13A to 13B show examples of CSI-RS resource configuration for mTRP CJT reporting only (no reporting for sTRP). Figures 14A to 14B show examples of CSI-RS resource configuration for mTRP CJT reporting only (no reporting for sTRP). Figures 15A to 15B illustrate examples of CSI-RS resource configuration for joint reporting of sTRP and mTRP CJT, sTRP CSI reporting, or mTRP CSI reporting. Figure 16 shows a first example of W1 feedback reduction. As shown, 4 TRPs from TRP1 to TRP4 are deployed. Figure 17 shows a second example of W1 feedback reduction. Figure 18 shows an example of reporting a compressed SD basis vector matrix. Figure 19A shows the case of sTRP and mTRP switching. Figure 19B shows another example of _Wi feedback reduction in the scenario of mixed sTRP and mTRP CSI reporting of Figure 19A. Figure 20 shows a Type II codebook precoder structure 2000 for mTRP CJT feedback. Figure 21 shows an example of NZC selection according to an embodiment of the invention. Figures 22A-22B illustrate examples of NZC selection for mTRP CSI reporting in accordance with embodiments of the present invention. Figures 23A-23B illustrate another example of NZC selection for mTRP CSI reporting according to embodiments of the present invention. Figure 24 shows an example of an FD basis vector selection alternative in accordance with an embodiment of the invention. Fig. 25 shows an example of the initial window position and FD base index in the FD coefficient matrix W2 . Figure 26 shows an example where different mTRP sets may be switched to serve a UE due to its mobility. Figure 27 shows two types (two variants) of codebook structures for CSI feedback. Figure 28A shows an example of CSI reporting configuration. Figure 28B shows an example of codebook configuration. Figures 29A to 29B show examples of 4 TRP CJT transmission scenarios. Figures 30A to 30B show examples of 4 TRP CJT transmission scenarios. Figure 31 shows an example where the gNB can derive the SD/FD basis from the joint mTRP channel. Figure 32 shows an example in which the UE can select K1 ports from the PCSI-RS ports in a polarization common and free manner. Figure 33 illustrates a process 3300 of mTRP CSI measurement and reporting in accordance with an embodiment of the present invention. Figure 34 illustrates another process 3400 for mTRP CSI measurement and reporting in accordance with an embodiment of the present invention. Figure 35 illustrates another process 3500 for mTRP CSI measurement and reporting in accordance with an embodiment of the present invention. Figure 36 illustrates an exemplary apparatus 3600 in accordance with an embodiment of the invention.

S3301, S3310, S3320, S3330, S3340, S3399: steps

Claims (13)

A measurement and transmission method for multiple transmitting and receiving points, including: receiving a channel status information report configuration from a base station at a user equipment, the channel status information report configuration being associated with a channel status information reference signal resource set, The channel status information reference signal resource set corresponds to a plurality of transmitting and receiving points; a channel measurement is performed based on the channel status information reference signal resource corresponding to the plurality of transmitting and receiving points; and a channel measurement is determined based on the measurement result of the channel measurement. A precoder matrix indicator corresponding to a precoder matrix denoted W of a Type II channel state information codebook, the precoder matrix having a space denoted W ₁ a domain basis vector matrix, the spatial domain basis selection of the spatial domain basis vector matrix is specific to the transmitting and receiving points; and sending a channel status information report to the base station, the channel status information report including the precoder matrix indicator. The measurement and transmission method of multiple transmitting and receiving points as described in claim 1, wherein the spatial domain basis vector matrix has the following form: Where, _NT is the number of antenna ports of the plurality of receiving points, L is the number of basis vectors corresponding to one antenna polarization in W ₁ , _NP is the number of the plurality of transmitting and receiving points, is a spatial domain basis vector matrix of the p-th sending and receiving point, . The measurement and transmission method of multiple transmitting and receiving points as described in request item 2, wherein, yes The spatial domain basis matrix of and has the following form , in, is the number of antenna ports of the p-th transmitting and receiving point, , and L _p is the number of spatial domain basis vectors in each polarization of the p-th transmitting and receiving point, such that and . The measurement and transmission method of multiple transmitting and receiving points as described in claim 1, wherein the spatial domain basis vector matrix includes a spatial domain basis matrix specific to the transmitting and receiving points, and each spatial domain basis matrix is related to the plurality of transmitting and receiving points. Corresponds to one point. The measurement and transmission method of multiple transmitting and receiving points as described in claim 1, wherein the spatial domain basis vector matrix includes a spatial domain basis matrix specific to the transmitting and receiving points, and each spatial domain basis matrix is related to the plurality of transmitting and receiving points. Corresponding to one point, the specific spatial domain basis matrix of the sending and receiving points has different numbers of spatial domain basis vectors. The measurement and transmission method of multiple transmitting and receiving points as described in claim 5, wherein one of the spatial domain basis matrices specific to the transmitting and receiving points includes a first basis vector sum of a first polarization of the corresponding transmitting and receiving points. A second basis vector of a second polarization corresponding to the sending and receiving point, where the first basis vector is the same as the second basis vector. The measurement and transmission method of multiple transmitting and receiving points as described in claim 1, wherein the spatial domain basis selection of the spatial domain basis vector matrix is common to layers. The measurement and transmission method of multiple transmitting and receiving points as described in claim 1, wherein the spatial domain basis vector matrix includes spatial domain basis vectors corresponding to different transmitting and receiving points among the plurality of transmitting and receiving points, and the The co-located sending and receiving points among the plurality of sending and receiving points have the same spatial domain basis vector. The measurement and transmission method of multiple transmitting and receiving points as described in claim 1, wherein the precoder matrix indicator includes an indication of the spatial domain basis vector contained in the spatial domain basis vector matrix, and the spatial domain basis vector The vector corresponds to a corresponding transmitting and receiving point among the plurality of transmitting and receiving points, wherein two co-located transmitting and receiving points among the plurality of transmitting and receiving points share the spatial domain base in the precoder matrix indicator. The same set of spatial domain basis vectors in the vector. The measurement and transmission method of multiple transmitting and receiving points as described in request item 9 also includes: In response to receiving an indication from the base station as to which of the plurality of transmitting and receiving points are co-located, it is determined based on the indication to report the same set of spatial domain basis vectors for the two co-located transmitting and receiving points. The measurement and transmission method of multiple transmitting and receiving points as described in request item 9 also includes: Based on the calculated spatial domain basis vectors corresponding to different sending and receiving points, it is determined that the same set of spatial domain basis vectors is reported for the two co-located sending and receiving points. A device for measurement and transmission of multiple transmitting and receiving points, the device includes a circuit, the circuit: receives a channel status information report configuration from a base station, the channel status information report configuration is referenced to a channel status information A signal resource set is associated, and the channel status information reference signal resource set corresponds to a plurality of transmitting and receiving points; based on the channel status information reference signal resource corresponding to the plurality of transmitting and receiving points, a channel measurement is performed; based on the channel The measured measurement results determine a precoder matrix indicator corresponding to a precoder matrix represented by W of a Type II channel state information codebook, the precoder matrix having a representation of is a spatial domain basis vector matrix of W ₁ , the spatial domain basis selection of the spatial domain basis vector matrix is specific to the transmitting and receiving points; and a channel status information report is sent to the base station, and the channel status information report includes The precoder matrix indicator. A non-transitory computer-readable medium, the non-transitory computer-readable medium stores instructions, and the instructions execute a measurement and transmission method of multiple transmitting and receiving points, including the following steps: receiving a channel status information report configuration from a base station , the channel status information report configuration is associated with a channel status information reference signal resource set, and the channel status information reference signal resource set corresponds to a plurality of sending and receiving points; based on the channel status corresponding to the plurality of sending and receiving points The information refers to the signal resource, and a channel measurement is performed; a precoder matrix indicator is determined based on the measurement result of the channel measurement, and the precoder matrix indicator and a Type II channel status information codebook are expressed as W Corresponding to the precoder matrix, the precoder matrix has a spatial domain basis vector matrix represented as W ₁ , and the spatial domain basis selection of the spatial domain basis vector matrix is specific to the transmitting and receiving points; and to the base station Send a channel status information report, the channel status information report including the precoder matrix indicator.

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