UE selects and reports number of spatial beams for coherent joint transmission

Abstract

The present disclosure relates to a method of type II channel state information (CSI) reporting when it is used for coherent joint transmission (CJT) from multiple transmit / receive points (TRPs) to user equipment devices (UEs). The network node may configure CSI reference signal (CSI-RS) resources for the UE, each CSI-RS resource being associated with a respective TRP. The UE may measure the channel and send back a CSI report including the CSI measurements to the network node. The CSI report may also include a number of selected spatial beams or CSI-RS ports for each of the CSI-RS resources. The CSI report may also include a number of frequency domain (FD) basis vectors selected based on the number of spatial beams or CSI-RS ports selected for each of the CSI-RS resources.

Description

[0001] Related Applications

[0002] This application claims the benefit of provisional patent application serial number 63 / 395,629, filed on August 5, 2022, the disclosure of which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present disclosure relates to a method for selecting and reporting the number of spatial beams for coherent joint transmission in a wireless communication system. Background Art

[0004] A. Codebook-based precoding

[0005] Multiple antenna technology can significantly improve the data rate and reliability of wireless communication systems. Performance is particularly improved if both the transmitter and the receiver are equipped with multiple antennas, thereby creating a multiple-input multiple-output (MIMO) communication channel. Such systems and / or related technologies are generally referred to as MIMO.

[0006] A core component of fifth-generation (5G) wireless networks, or New Radio (NR), is support for MIMO antenna deployments and MIMO-related technologies such as spatial multiplexing, which can be used to increase data rates under favorable channel conditions. Figure 1 An example of spatial multiplexing is shown. The information carrying symbol vector s 102 is combined with N T xr precoding matrix or precoder W 104 (which is used in N T The precoding matrix is ​​typically selected from a codebook of possible precoding matrices and is typically indicated by means of a precoding matrix indicator (PMI) that specifies a unique precoding matrix in the codebook for a given number of symbol streams. The r symbols 106 in s 102 each correspond to a MIMO layer, and r 106 is called the transmission rank, which is equal to the number of columns of the precoder W 104. In this way, spatial multiplexing is achieved since multiple symbols can be sent simultaneously on the same time / frequency resource element (RE). The number of symbols r is typically adapted to suit the current channel characteristics.

[0007] NR uses Orthogonal Division Multiplexing (OFDM) in the downlink. The reception N at a user equipment device (UE) on a certain RE R x 1 vector y n can be expressed as:

[0008] y n =H n W n +e n

[0009] Among them, e n is the receiver noise / interference vector. Precoder W 104 can be constant in frequency (ie, wideband), or frequency selective (ie, per subband).

[0010] Precoder W 104 is selected to match N R xN T MIMO channel matrix H n This results in the so-called channel-dependent precoding. This is also often referred to as closed-loop precoding.

[0011] In closed-loop precoding, the UE feeds back a suggestion about a suitable precoder to the NR Node B (gNB) in the form of a PMI based on downlink channel measurements. For this purpose, the UE is configured with a channel state information (CSI) reporting configuration, which includes the CSI reference signal (CSI-RS) used for channel measurement and the codebook (CB) of candidate precoders. In addition to the precoder, the feedback may also include a rank indicator (RI) and one or two channel quality indicators (CQI). RI, PMI and CQI are part of the CSI feedback. In NR, CSI feedback can be wideband (where one CSI is reported for the entire channel bandwidth) or frequency selective (where one CSI is reported for each subband, which is defined as a number of consecutive physical resource blocks (PRBs) ranging between 4-32 PRBs (depending on the bandwidth part (BWP) size)).

[0012] Given the CSI feedback from the UE, the gNB determines the transmission parameters it wishes to use to send to the UE, including the precoding matrix, transmission rank, and modulation and coding scheme (MCS).

[0013] B. 2D Antenna Array

[0014] Two-dimensional (2D) antenna arrays are widely used, and such antenna arrays may be composed of a number N of antenna ports in a first dimension (eg, horizontal dimension). 1 , the number of antenna ports N in a second dimension (eg, a vertical dimension) perpendicular to the first dimension 2 , and the number of polarizations N p Therefore, the total number of antenna ports is N = N 1 N 2 N p The concept of an antenna port is non-limiting in the sense that it can refer to any virtualization (e.g., linear mapping) of a physical antenna element. For example, a pair of physical antenna elements may be fed the same signal and thus share the same virtualized antenna port.

[0015] exist Figure 2 The diagram shows a dual-polarized antenna element (ie, N p =2) of 4x4 (ie, N 1 ×N 2 ) array. (N p =2), with N 1 = 4 horizontal antenna elements 202 and N 2 =4 vertical antenna elements 204.

[0016] Precoding can be interpreted as multiplying the signal to be transmitted by a set of beamforming weights on the antenna ports before transmission. A typical approach is to tailor the precoder to the antenna shape factor, i.e., consider N when designing the precoder codebook. 1 、N 2 and N p .

[0017] C. Channel State Information Reference Signal (CSI-RS)

[0018] For CSI measurement and feedback, CSI-RS is defined. CSI-RS is transmitted on the antenna port at the gNB and is used by the UE to measure the downlink channel between the antenna port and each of the UE's receive antenna ports. The transmit antenna port is also called a CSI-RS port. The number of CSI-RS ports supported in NR is {1,2,4,8,12,16,24,32}. By measuring the received CSI-RS, the UE can estimate the channel (including the radio propagation channel) and the antenna gain on which the CSI-RS is traveling. The CSI-RS used for the above purpose is also called non-zero power (NZP) CSI-RS.

[0019] The CSI-RS may be configured to be transmitted in certain REs in a slot and in certain slots. Figure 3 An example of CSI-RS REs 304 for 12 antenna ports 302 is shown, where 1 RE per RB per port is shown.

[0020] In addition, interference measurement resources (IMR) are also defined in NR for UE to measure interference. IMR resources contain 4 REs, 4 frequency-adjacent REs in the same OFDM symbol, or 2 times 2 time and frequency-adjacent REs in a time slot. By measuring both the NZP CSI-RS-based channel and the IMR-based interference, the UE can estimate the effective channel and the noise plus interference to determine the CSI. In addition, the UE in NR can be configured to measure interference based on one or more NZP CSI-RS resources.

[0021] D. CSI framework in NR

[0022] In NR, a UE can be configured with multiple CSI report settings and multiple CSI-RS resource settings. Each resource setting can contain multiple resource sets, and each resource set can contain up to 8 CSI-RS resources. For each CSI report setting, the UE feeds back one CSI report.

[0023] Each CSI report setting contains at least the following information:

[0024] ●CSI-RS resource settings for channel measurement;

[0025] ●IMR resource set for interference measurement;

[0026] ● Optionally, a CSI-RS resource set for interference measurement;

[0027] ● Temporal behavior, i.e., periodic, semi-persistent, or aperiodic reporting;

[0028] Frequency granularity, i.e., broadband or sub-band;

[0029] ● CSI parameters to be reported, such as RI, PMI, CQI, and CSI-RS resource indicator (CRI), in case there are multiple CSI-RS resources in a resource set;

[0030] Codebook type (i.e., Type I or Type II), and codebook subset restrictions;

[0031] ● measurement limitations; and

[0032] ● Subband size. Indicates one of two possible subband sizes, with a value range depending on the bandwidth of the BWP. One CQI / PMI is fed back per subband (if configured for subband reporting).

[0033] E. DFT-based precoder

[0034] One common type of precoding is to use a DFT precoder, where the precoder vector for precoding a single layer transmission on a single polarization uniform linear array (ULA) with N antennas is defined as:

[0035]

[0036] where k=0, 1, ...ON-1 is the precoder index and O is an integer oversampling factor. k Also known as a one-dimensional (1-D) DFT beam, with beam index k. If the ULA is along the horizontal dimension, each DFT beam points in the azimuth direction. If the ULA is along the vertical dimension, each DFT beam points in the elevation direction. Each precoder corresponds to a DFT beam.

[0037] The Kronecker product of two precoder vectors can be used to create a two-dimensional uniform planar array (UPA) (with N in one dimension). 1 antenna ports and N in another dimension 2 The corresponding precoder vector of each antenna port is as follows:

[0038]

[0039] in, and is a 1-D DFT beam in each of the two dimensions, open and O 1 and O 2 They are respectively 1 and N 2 Oversampling factor in the two dimensions associated. k,l Also known as a two-dimensional (2-D) DFT beam, it is characterized by two beam indices (k, l), one in each dimension. Each precoder corresponds to a 2D DFT beam.

[0040] Furthermore, the DFT precoder for dual-polarization UPA can be extended as follows:

[0041]

[0042] Among them, e jφ is the in-phase factor, which can be selected from the M-PSK alphabet, such as QPK, where

[0043] The precoder matrix W for multi-layer transmission can be created by appending the DFT precoder vector columns 2D,DP ,like:

[0044] W 2D,DP =[w 2D,DP (k 1 , l 1 ,φ 1 ) 2D,DP (k 2 , l 2 ,φ 2 ) … w 2D,DP (k r , l r ,φ r )]

[0045] Where r is the number of transmission layers. This DFT-based precoder is used, for example, for Type I CSI feedback in NR, where each layer is associated with a 2D DFT beam.

[0046] F. MU-MIMO

[0047] For multi-user MIMO (MU-MIMO), two or more users in the same cell are co-scheduled on the same time-frequency resources. That is, multiple data streams are sent to different UEs on the same time-frequency resources, and each UE can be assigned one or more layers. By sending several streams simultaneously, the capacity of the system can be increased.

[0048] To avoid cross-UE or layer interference, a zero-forcing (ZF) type of precoder can be used, where the feedback precoders associated with all co-scheduled UEs in the same time-frequency resources are used together to generate a new set of orthogonal precoders. This requires that each feedback precoder is a good representation of the underlying channel.

[0049] However, a single DFT beam is generally not a good representation of the channels associated with a layer under multipath propagation, since each layer may be transmitted on multiple paths (each path corresponding to a DFT beam).

[0050] To improve the above single DFT beam based precoder, CSI feedback based on type II codebook was introduced in NR Rel-15 and further enhanced in NR Rel-16 and Rel-17. The basic concept is that due to multipath propagation, each layer may contain more than one DFT beam. Therefore, an improved precoder can be created by combining multiple DFT beams for each layer, and the UE feeds back both the multiple DFT beams and the combining coefficients.

[0051] G. NR Rel-15 Type II Codebook

[0052] In NR Rel-15, the precoder is enhanced based on the type II codebook, where the precoder is a combination of multiple DFT beams. For each precoder, the UE feeds back the corresponding selected multiple DFT beams and the combining coefficients. The precoder can be reported for each layer and each subband. A common set of DFT beams is selected for all subbands and all layers. The number of DFT beams to be selected is radio resource control (RRC) configured.

[0053] For a given 2D cross-polarized antenna array (with N in one dimension on each polarization 1 antenna ports and N in another dimension 2 antenna ports), the precoding vector based on the NR Rel-15 Type II codebook for each layer l∈{1,2} and subband can be expressed as:

[0054] w l =W 1 w 2.l

[0055] in:

[0056]

[0057] The size is P CSI-RS / 2×1 selected 2-D DFT beam set, P CSI-RS =2N 1 N 2 , and is the beam index in each dimension for the i-th selected DFT beam. L∈{2,3,4} is the number of DFT beams to be selected and is configured by RRC; and

[0058] w 2,l =[w 2,l,0 , w 2,l,1 , ..., w 2,l,2L-1 ] T ,in, are the combining coefficients associated with the ith beam, and and They are w 2,l,i The broadband amplitude, sub-band amplitude, and phase factor of .

[0059] w l In section 5.2.2.2.3 of 3GPP specification TS 38.214 V15.16.0 it is expressed as:

[0060]

[0061] in, q 1 ∈{0, 1, ..., O 1 -1},q 2 ∈{0, 1, ..., O 2 -1}, i=0, 1, ..., L-1. p=1,2.

[0062] H. NR Rel-16 enhanced type II codebook

[0063] The Rel-15 type II codebook is enhanced in NR Rel-16, where instead of reporting separate precoders for different subbands, the precoders for all subbands are reported together by using the so-called frequency domain basis. It exploits the frequency domain channel correlation by representing the precoder changes in the frequency domain with a set of frequency domain DFT basis vectors (which will be referred to as frequency domain basis vectors for short). Due to the channel correlation in frequency, only a few DFT basis vectors can be used to represent the precoder changes on all subbands. By doing so, the feedback overhead can be reduced, or the performance can be improved at the same feedback overhead.

[0064] For a given CSI-RS resource (with N in one dimension 1 CSI-RS antenna ports and N in another dimension 2 CSI-RS antenna ports and with two polarizations), the precoding vector based on Rel-16 type II codebook for each layer l (l=1, ..., v) and on all subbands can be expressed as:

[0065]

[0066] in:

[0067] ● is for layer l in the PMI subband (with subband index t∈{0, 1, ..., N 3 -1}) CSI-RS ×1 precoding vector, where P CSI-RS =2N 1 N 2 is the number of CSI-RS ports in the configured NZP CSI-RS resources;

[0068] ●N 3 =N SB ×R is the number of subbands used for PMI, where N SB is the number of CQI subbands, and R∈{1,2} is the scaling factor, N SB Both R and R are RRC configured;

[0069] W 1 Same as in Rel-15 Type II codebook;

[0070] ● For layer l, the size is N 3 ×M v The frequency domain (FD) compression matrix includes M v selected FD basis vectors, and and t=0,1,...,N3 -1, f=0,1,...,M v -1. is the number of selected FD basis vectors, which depends on the rank v and the RRC configured parameter pv. The supported p v The values ​​of can be found in Table 1;

[0071] ○For NN 3 ≤19, one-step free choice was used;

[0072] ■For each layer, the selected FD basis vectors are In TS 38.214 V15.16.0, the combination indicator is indicated by index i 1，6，l Given, which is reported by the UE to the gNB;

[0073] ○For N 3 >19, using two-step selection with a common intermediate subset of layers (IntS);

[0074] ■ In the first step, a window-based layer public IntS selection is used, which is obtained by M initial IntS is parameterized by the FD basis vectors {mod(M initial +n,N 3 ), n = 0, 1, ..., 2M v -1}. In TS 38.214 V15.16.0, the selected IntS is determined by the UE via the parameter i 15 Reported to the gNB, which is reported per layer as part of the reported PMI;

[0075] ■In the second step, the selected FD basis vectors are used for each layer In TS 38.214 V15.16.0, the combination indicator is indicated by index i 1,6,l given, which is reported by the UE to the gNB; and

[0076] ● The size is 2L×M v For layer l, only A subset of coefficients are non-zero and reported by the UE. The rest Unreported coefficients are considered zero.

[0077] ○ is the maximum number of non-zero coefficients per layer, where β is a parameter configured by RRC. The supported β values ​​are shown in Table 1.

[0078] ○ For v∈{2,3,4}, the total number of non-zero coefficients summed over all layers K should be satisfied NZ ≤2K 0 .

[0079] ○ For each layer, the selected coefficient subset is 2LM v In the bitmap 1's instructions, i 1,7,l .

[0080] ○ The strongest coefficient of layer l (its magnitude and phase are not reported) is given by i 1,8,l ,∈{0, 1, ..., 2L-1} indicates.

[0081] ○ The amplitude coefficient in is given by i 2,3,l and i 2，4，l Instructions, and The phase coefficient in is given by i 2,5,l instruct.

[0082] The above is described in TS 38.214 V15.16.0 Section 5.2.2.2.5, where: is represented as follows:

[0083]

[0084] in, is the number reported by the UE, and

[0085] ● 1 ,q 2} is passed through the parameter i 1，1 Reported, while {n 1 , n 2} is passed through the parameter i 1，2 Reported.

[0086] ● is the Mv FD basis vectors The index of .

[0087] ● is the coefficient The broadband amplitude in both polarizations, and is the coefficient The subband amplitude is yes part of.

[0088] ● yes The phase coefficient of l,i,f ∈{0,...,15} is cl，f =[c l,0,f …c l,2L-1，f ] part of.

[0089] Table 1: Type II codebook for Rel-16 enhancement for L, β and p v Codebook parameter configuration

[0090]

[0091] I. NR Rel-16 enhanced type II port selection codebook

[0092] An enhanced Type II (eType II) port selection (PS) codebook is also introduced in Rel-16, which is intended for beamforming CSI-RS, that is, each CSI-RS port corresponds to a 2D spatial beam. Based on the measurement, the UE selects the best CSI-RS port and recommends the rank, precoding matrix, and CQI conditioned on the rank and precoding matrix to the gNB.

[0093] The precoding matrix includes a linear combination of the selected CSI-RS ports. For a given transmission layer l (where l∈{1,...,v}, and v is the rank indicated by the rank indicator (RI)), the precoder matrix has the same form as the Rel16 enhanced type II codebook, namely:

[0094]

[0095] and W f，l Same as in Rel-16 enhanced type II codebook. The main difference is that W 1 , which is of size P CSI-RS ×2L port selection matrix, consisting of Given, where Is the size of The port selection vector is contained in the position The element with value one at the position indicates an element of the selected CSI-RS port, while all other elements have value zero, e.g. 0 =[1, 0, ..., 0] T and L is the number of CSI-RS ports selected from each polarization, and the same ports are selected for both polarizations. The supported values ​​of L can be found in Table 2. The value of d is configured with the higher layer parameter portSelectionSamplingSize, where d∈{1,2,3,4} and

[0096] The selected CSI-RS port is determined by Indication, which is reported by the UE to the gNB. 1,2 Not relevant and therefore not reported.

[0097] Table 2: Port selection type II codebook for Rel-16 enhancement for L, β and p v Codebook parameter configuration

[0098]

[0099] For Rel-16 enhanced type IICSI feedback, the CSI report consists of two parts. Part 1 has a fixed payload size and is used to identify the number of information bits in Part 2. Part 1 contains RI, CQI, and an indication of the total number of non-zero amplitude coefficients across layers, i.e., Part 2 contains the PMI. Parts 1 and 2 are coded separately.

[0100] J. NR Rel-17 further enhanced Type II port selection codebook

[0101] The Rel-16 port selection codebook is further enhanced in Rel-17, where it is assumed that each CSI-RS port is associated with a channel delay, and different channel delays are associated with different CSI-RS ports. It is also assumed that the delay associated with the CSI-RS port has been pre-compensated before being transmitted, and therefore, only one or two frequency domain basis vectors can be selected by the UE, i.e., M v ∈{1, 2}. One or two FD basis vectors are the same for all layers, so M is used instead of M v .

[0102] The L CSI-RS ports or beams to be selected at each polarization are indirectly configured as L = αP CSI-RS / 2, where the parameter α is configured by RRC, as shown in Table 3. Based on L ports selection vector From P CSI-RS A total of 2L CSI-RS ports are selected from the ports, which are identified by the following formula:

[0103] m=[m (0) ...m (L-1) ]

[0104]

[0105] It is indexed by i 1,2 Instructions, where:

[0106]

[0107] M selected FD basis vectors f∈{0,...,M-1} is given by n3 Identification, and where:

[0108]

[0109] where the indices f∈{0, ..., M-1} are assigned such that Increases with f. n 3 By index i 1,6 instruct.

[0110] Table 3: Codebook parameter configuration for α, M and β for the type II port selection codebook further enhanced for Rel-17

[0111]

[0112]

[0113] K. 2.1.11 Coherent Joint PDSCH Transmission from Multiple TRPs

[0114] In NR Rel-18, it has been agreed to support coherent joint downlink transmission (CJT) from multiple transmit and receive points (TRPs) by extending the Rel-16 and Rel-17 enhanced type II codebook over multiple TRPs. In case of CJT, each layer of the PDSCH is transmitted from multiple TRPs. Figure 4 An example is shown in FIG, where a PDSCH 406 with two layers is transmitted from two TRPs 402 and 404 by applying two different precoding matrices 408 and 410 to the PDSCH 406 at TRP1 and TRP2. The two precoders 408 and 410 are designed so that for each layer, the signals received from the two TRPs 402 and 404 are phase aligned at the UE 412 and, therefore, are coherently combined at the UE 412.

[0115] There are some challenges. One of the configuration parameters in all Rel-15 to Rel-17 Type II codebooks and their extensions to CJT is the number of spatial beams L selected by the UE for PMI feedback. Note that in the case of a port selection codebook, L is related to the number of CSI-RS ports selected by the UE (i.e., the selected number of CSI-RS ports is given by 2L). For each MIMO layer and for each PMI subband, the linear combination coefficients of the L beams are reported.

[0116] In Rel-16 enhanced Type II CB and Type II port selection CB, L∈{2, 4, 6}, with the following restrictions:

[0117] ●When P CSI-RS =4, L=2;

[0118] ●When 4 <P CSI-RS <32, L∈{2,4}; and

[0119] ●When P CSI-RS When =32, L∈{2, 4, 6}.

[0120] When the traditional Rel-16 and Rel-17 Type II CB is extended to DL CJT on multiple TRPs in Rel-18, it is envisioned that multiple CSI-RS resources or multiple antenna port groups in a single CSI-RS resource will be configured, where the CSI-RS port in each resource or antenna port group is transmitted from one of the multiple TRPs, and L spatial beams on the multiple CSI-RS resources can be configured.

[0121] In one method, L may depend on the aggregate number of CSI-RS ports across all CSI-RS resources.

[0122] However, according to this method, if there are three TRPs and three CSI-RS resources are each configured with two CSI-RS ports, the aggregate number of CSI-RS ports is P CSI-RS =6, however, this is not the number of CSI-RS ports supported in a conventional Type II CB.

[0123] Alternatively, L can be configured per CSI-RS resource or per antenna port group. Then, the total number of selected beams will be the aggregation of the beams configured for all resources or antenna port groups. However, this means that the UE must report L spatial beams for each TRP, even though the TRP may not be good for participating in CJT (e.g., because the signal from the TRP is very weak), and therefore, introduces unnecessary overhead.

[0124] Therefore, it is obvious that how to configure, report the number of spatial beams or the number of CSI-RS ports to be selected is a difficult problem in extending the traditional Type II CB to multiple TRPs for coherent joint DL transmission. Summary of the invention

[0125] The present disclosure relates to a method for reducing type II channel state information (CSI) reporting overhead when type II channel state information (CSI) reporting is used for coherent joint transmission (CJT) from multiple transmit / receive points (TRPs) to a user equipment (UE), where some TRPs are not suitable for CJT to the UE. A network node may configure CSI reference signal (CSI-RS) resources for the UE, each associated with a corresponding TRP. The UE may measure the channel and send a CSI report including the CSI measurement back to the network node. The CSI report may also include the number of selected spatial beams for each CSI-RS resource in the CSI resources. The CSI report may also include the number of frequency domain (FD) basis vectors selected based on the number of CSI-RS resources from which at least one beam or port is selected.

[0126] In one embodiment, a method performed by a UE for reducing CSI reporting overhead for a CJT from multiple TRPs is provided. The method may include receiving a configuration having a CSI reporting configuration based on a type II codebook (CB) from a network node, the CSI reporting configuration including N RS CSI reference signal CSI-RS resources (each associated with one of the plurality of TRPs) and a maximum total number of L spatial beams included in the CSI for CJT. The method may also include receiving a CSI including N RS The method may also include transmitting a CSI-RS resource and reporting a request for CSI based on a type II CB according to a CSI reporting configuration. RS CSI-R resources, measure channels, and calculate CSI based on the aggregation of the measured channels by selecting L' spatial beams (where L' is an integer and is less than or equal to L), and for N RS Each of the N CSI-RS resources RS The method may include sending a CSI report including a beam index for each of the L′ spatial beams, and wherein the first part of the CSI report also includes a beam index for each of the N′ spatial beams. RS Each of the N CSI-RS resources RS The number of selected spatial beams for CSI-RS resources.

[0127] In another embodiment, a UE may be provided, comprising a memory storing computer executable instructions and a processor executing the computer executable instructions to perform operations. The operations may include receiving a configuration having a CSI reporting configuration based on a Type II CB from a network node, the CSI reporting configuration including N RSCSI reference signal CSI-RS resources (each associated with one of the plurality of TRPs) and a maximum total number of L spatial beams included in the CSI for CJT. The operation may also include receiving a CSI including N RS The operation may also include transmitting a CSI-RS resource based on N and requesting to report CSI based on the type II CB according to the CSI reporting configuration. RS CSI-R resources, measure channels, and calculate CSI based on the aggregation of the measured channels by selecting L' spatial beams (where L' is an integer and is less than or equal to L), and for N RS Each of the N CSI-RS resources RS The operation may include sending a CSI report, the CSI report including a beam index for each of the L' spatial beams, and wherein the first part of the CSI report also includes a beam index for each of the N' spatial beams. RS Each of the N CSI-RS resources RS The number of selected spatial beams for CSI-RS resources.

[0128] In one embodiment, a method for reducing CSI reporting overhead of a CJT from multiple TRPs performed by a UE may be provided. The method may include receiving a configuration having a CSI reporting configuration based on a Type II CB from a network node, the CSI reporting configuration including N RS CSI-RS resources (each associated with one of the plurality of TRPs) and a maximum total number of L spatial beams included in the CSI for CJT. The method may include receiving a CSI including N RS The method may include transmitting N CSI-RS resources and requesting to report CSI based on type II CB according to the CSI reporting configuration. RS CSI-RS resources, measuring channels, and calculating CSI based on an aggregation of the measured channels by selecting L' spatial beams, where L' is an integer and is less than or equal to L. The method may include determining the number of selected FD basis vectors based on the number of CSI-RS resources from which at least one beam or port is selected. The method may also include sending a CSI report, the CSI report including a beam index for each of the L' spatial beams, wherein a second part of the CSI report includes the number of FD basis vectors.

[0129] In another embodiment, a UE may be provided, comprising a memory storing computer executable instructions and a processor executing the computer executable instructions to perform operations. The operations may include receiving a configuration having a CSI reporting configuration based on a Type II CB from a network node, the CSI reporting configuration including NRS CSI-RS resources (each associated with one of the plurality of TRPs) and a maximum total number of L spatial beams included in the CSI for CJT. The operation may include receiving a CSI including N RS The operation may include transmitting N CSI-RS resources and requesting to report CSI based on type II CB according to the CSI reporting configuration. RS CSI-RS resources, measuring channels, and calculating CSI based on an aggregation of the measured channels by selecting L' spatial beams, where L' is an integer and is less than or equal to L. The operation may include determining the number of selected FD basis vectors based on the number of CSI-RS resources from which at least one beam or port is selected. The operation may also include sending a CSI report, the CSI report including a beam index for each of the L' spatial beams, wherein a second part of the CSI report includes the number of FD basis vectors.

[0130] In one embodiment, a method for reducing CSI reporting overhead of CJT from multiple TRPs to a UE is provided. The method includes configuring a CSI reporting configuration based on a Type II CB for the UE, the CSI reporting configuration including N RS The method includes transmitting N CSI reference signal CSI-RS resources (each associated with one of the plurality of TRPs) and a parameter L specifying the maximum number of spatial beams included in the CSI for CJT. RS The method includes receiving a CSI report from the UE, the CSI report including CSI associated with L' spatial beams, where L' is an integer and is less than or equal to L, wherein the first part of the CSI report also includes CSI for N RS Each of the N CSI-RS resources RS The number of selected spatial beams for the CSI-RS resources. The method includes constructing a precoding matrix for each of a plurality of TRPs based on the CSI report, and applying the precoding matrix to a physical downlink shared channel (PDSCH) at each of the plurality of TRPs.

[0131] In one embodiment, a network node is provided, which includes a memory storing computer executable instructions and a processor executing the computer executable instructions to perform operations. The operations include configuring a CSI report configuration based on a Type II CB for a UE, the CSI report configuration including N RSCSI reference signal CSI-RS resources (each associated with one of the multiple TRPs) and a parameter L specifying the maximum number of spatial beams included in the CSI for CJT. The operation includes sending N RS CSI-RS resources and requesting the UE to report CSI based on the type II CB according to the CSI reporting configuration. The operation includes receiving a CSI report from the UE, the CSI report including CSI associated with L' spatial beams, where L' is an integer and is less than or equal to L, wherein the first part of the CSI report also includes CSI for N RS Each of the N CSI-RS resources RS The number of selected spatial beams for the CSI-RS resources. The operation includes constructing a precoding matrix for each of a plurality of TRPs based on the CSI report, and applying the precoding matrix to the PDSCH at each of the plurality of TRPs.

[0132] In another embodiment, a method for reducing CSI reporting overhead of CJT from multiple TRPs to a UE is provided, performed by one or more network nodes. The method includes configuring a CSI reporting configuration based on a Type II CB for the UE, the CSI reporting configuration including N RS The method includes transmitting N CSI reference signal CSI-RS resources (each associated with one of the plurality of TRPs) and a parameter L specifying the maximum number of spatial beams included in the CSI for CJT. RS CSI-RS resources, and requesting the UE to report CSI based on type IICB according to the CSI report configuration. The method includes receiving a CSI report from the UE, the CSI report containing CSI associated with L' spatial beams, where L' is an integer and is less than or equal to L, wherein a second part of the CSI report includes a number of FD basis vectors selected based on the number of CSI-RS resources from which at least one beam or port is selected. The method includes constructing a precoding matrix for each of a plurality of TRPs based on the CSI report, and applying the precoding matrix to the PDSCH at each of the plurality of TRPs.

[0133] In one embodiment, a network node is provided, which includes a memory storing computer executable instructions and a processor executing the computer executable instructions to perform operations. The operations include configuring a CSI report configuration based on a Type II CB for a UE, the CSI report configuration including N RS CSI reference signal CSI-RS resources (each associated with one of the multiple TRPs) and a parameter L specifying the maximum number of spatial beams included in the CSI for CJT. The operation includes sending N RSCSI-RS resources, and requesting the UE to report CSI based on type IICB according to the CSI reporting configuration. The operation includes receiving a CSI report from the UE, the CSI report containing CSI associated with L' spatial beams, where L' is an integer and is less than or equal to L, wherein a second part of the CSI report includes a number of FD basis vectors selected based on the number of CSI-RS resources from which at least one beam or port is selected. The operation includes constructing a precoding matrix for each of a plurality of TRPs based on the CSI report, and applying the precoding matrix to the PDSCH at each of the plurality of TRPs.

[0134] Certain embodiments may provide one or more of the following technical advantages: The proposed solution reduces Type IICSI reporting overhead when it is used for coherent joint transmission from multiple TRPs to a UE where some TRPs are not suitable for CJT to the UE. BRIEF DESCRIPTION OF THE DRAWINGS

[0135] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure.

[0136] Figure 1 An example of spatial multiplexing according to an embodiment of the present disclosure is shown;

[0137] Figure 2 shows an example of a 4x4 array with dual polarized antenna elements according to an embodiment of the present disclosure;

[0138] Figure 3 An example of a channel state information (CSI) resource element for 12 antenna ports according to an embodiment of the present disclosure is shown;

[0139] Figure 4 An example of coherent joint transmission (CJT) according to an embodiment of the present disclosure is shown;

[0140] Figure 5 An example of coherent joint transmission from multiple transmit / receive points (TRPs) to a user equipment device (UE) according to an embodiment of the present disclosure is shown;

[0141] Figure 6 is a flow chart of a method performed by a network node for reducing CSI reporting overhead for CJT of a UE from multiple TRPs according to an embodiment of the present disclosure;

[0142] Figure 7 is a flowchart of a method performed by a UE for reducing CSI reporting overhead of a CJT from multiple TRPs according to an embodiment of the present disclosure;

[0143] Figure 8 An example of a communication system according to an embodiment of the present disclosure is shown;

[0144] Fig. 9 A UE according to an embodiment of the present disclosure is shown;

[0145] Fig.10 A network node according to an embodiment of the present disclosure is shown;

[0146] Fig.11 is a block diagram of a host according to an embodiment of the present disclosure;

[0147] Fig.12 is a block diagram illustrating a virtualization environment in which functions implemented by some embodiments may be virtualized according to an embodiment of the present disclosure; and

[0148] Fig.13 A communication schematic diagram showing a host communicating with a UE via a network node on a partial wireless connection according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0149] The embodiments set forth below represent information that enables those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. After reading the following description according to the accompanying drawings, those skilled in the art will understand the concepts of the present disclosure and will recognize the application of these concepts not particularly mentioned herein. It should be understood that these concepts and applications fall within the scope of the present disclosure.

[0150] Certain aspects of the present disclosure and embodiments thereof may provide solutions to the above challenges. A method for configuring L spatial beams for downlink (DL) coherent joint transmission (CJT) transmission for a Rel-16 type II codebook (CB) or 2L ports for channel state information (CSI) feedback based on Rel-17 type II port selection CB. The method comprises:

[0151] ●For up to N RS CSI reference signal CSI-RS resources are configured with L (L=2, 3, 4, 6, 8) spatial beams or ports.

[0152] The user equipment (UE) measures the channel based on the CSI-RS resources and selects spatial beams or ports for CJT CSI calculation, where L'≤L, and L s is the selected beam or port associated with the sth CSI-RS resource.

[0153] ● The UE reports L' or {L in part 1 of the corresponding CSI report s , s=1,...,N RS} and rank and channel quality indicator (CQI). s =0, it indicates that the associated sth CSI-RS resource or transmission / reception point (TRP) is not selected for CJT.

[0154] ●UE selectively reports per TRP beam, i.e., L for the sth CSI-RS resource s selected beams, and if L s =0, the associated sth CSI-RS resource or TRP is not selected for CJT.

[0155] ●UE selectively reports per TRP beam, i.e., 2L for the sth CSI-RS resource s selected CSI-RS ports, and if L s =0, the associated sth CSI-RS resource or TRP is not selected for CJT.

[0156] ● The UE may select and report a smaller number of spatial beams than the configured number of beams, i.e., L' <= L. L' or {L s , s=1,...,N RS} is reported in part 1 of the CSI report together with rank and CQI.

[0157] Certain embodiments may provide one or more of the following technical advantages: The proposed solution reduces Type IICSI reporting overhead when it is used for coherent joint transmission from multiple TRPs to a UE where some TRPs are not suitable for CJT to the UE.

[0158] exist Figure 5 An example is shown in FIG. 1 , in which two CSI-RS resources 508 and 510 (ie, N RS =2), CSI-RS#1 and CSI-RS#2, each including the number of CSI-RS ports, and these two CSI-RS resources are transmitted from two TRPs 502 and 504 to UE 506.

[0159] Can be Figure 6 and Figure 7 Methods 600 and 700 in hereinafter summarize the general process of the proposed Type II CSI reporting enhancement for coherent joint transmission of multiple TRPs.

[0160] Method 600 may begin at step 602, where the method includes configuring UE 506 with a Type II CB-based CSI report, which includes N RS CSI-RS resources and L spatial beams for CJT.

[0161] Note that in some alternative embodiments, a single CSI-RS resource may be configured with a first subset of CSI-RS ports associated with a first TRP (also referred to as a first CSI-RS port group or a first antenna port group) and a second subset of ports associated with a second TRP (also referred to as a second CSI-RS port group or a second antenna port group). Although the embodiments described hereinafter in the present disclosure cover the case of multiple CSI-RS resources, these embodiments are equally applicable to the case of a single CSI-RS resource with multiple CSI-RS port groups. In order to apply the embodiments to the single CSI-RS resource case, the sth CSI-RS resource in the description of the embodiments is replaced by the sth CSI-RS port group.

[0162] The UE 506 may be configured with L = 2, 3, 4, 6, 8 spatial beams for Type II CSI reporting with up to 4 CSI-RS resources. Some constraints may be applied to L so that L is equal to or less than half of the aggregate number of CSI-RS ports on the configured CSI-RS resources. For example,

[0163] ● For two CSI-RS resources, each resource has four CSI-RS ports, L≤4,

[0164] ● For three CSI-RS resources, each resource has four CSI-RS ports, L≤6,

[0165] In another scenario, L can be configured as L=N Rs L 0 , where L 0 L is the number of beams per CSI-RS resource or TRP. 0 Possible candidate values ​​for may be 1, 2, and 4.

[0166] For the Rel-17 Type II port selection codebook, L represents the CSI-RS port for each polarization, where L is not directly configurable. Instead, it is scaled via the parameter Configured so that L = αP CSI-RS / 2. To extend the CSI feedback based on Rel-17 Type II port selection codebook for DL ​​CJT, in one embodiment, a single α parameter is configured, which is applied to all configured N RS CSI-RS resources to determine the total number of selected ports. s =αP CSI-RS，s / 2, of which 2L s The port is from the sth (s=1, ..., N RS )CSI-RS resources, and

[0167] In another embodiment, α s (s=1,...,N RS ) is configured per CSI-PR resource. s The port is from the sth (s=1, ..., N RS )CSI-RS resources are selected, where L s =α s P CSI-RS，s / 2.

[0168] In step 604, the network node or TRP 502 or 504 sends N RS CSI-RS resources, and request UE 506 to report CJT CSI based on Type II CB according to the CSI reporting configuration in step 602.

[0169] Then, UE 506 will estimate the sth CSI-RS resource from the individual per-TRP channels. Get aggregated DL channels The sth CSI-RS resource is in the order of resources configured in the CSI report configuration in step 602. For example, if two CSI-RS resources are configured as {CSI-RS resource #x, CSI-RS resource #y} for CJT CSI reporting, the first CSI-RS resource (i.e., s=1) is CSI-RS resource #x, and the second CSI-RS resource (i.e., s=2) is CSI-RS resource #y.

[0170] If different physical downlink shared channels (PDSCH) for CSI-RS power offsets are configured for different CSI-RS resources, the channels measured on each CSI-RS resource need to be scaled according to the configured power offset before forming the aggregated channel. For example, if a -3dB power offset is configured for a CSI-RS resource, the measured channels based on the CSI-RS resource need to be scaled

[0171] UE 506 based on aggregated DL channels To calculate the Type II precoding matrix indicator (PMI). Assume that the UE 506 is configured with a set of parameters for CJT CSI reporting in step 602 as follows:

[0172] L: the total number of spatial beams on all CSI-RS resources or TRPs

[0173] ● R∈{1,2}: scaling factor for PMI subband size

[0174] ●p v: Parameter used to configure the number of frequency domain (FD) basis vectors for a given rank v, i.e., Among them, N 3 =N CQI R and N CQI is the number of CQI subbands

[0175] β: Maximum number of non-zero coefficients (NZC) used to configure each layer (i.e., ) parameters. The total number of NZCs on all layers, K NZ ≤2K 0

[0176] For MIMO layer l, the precoder matrix W on all TRPs l By size P CSI-RS ×N 3 The matrix gives:

[0177]

[0178] in:

[0179] ● is for layer l in a subband (with subband index t∈{0, 1, ..., N 3 -1}) CSI-RS ×1 precoding vector, where All N RS The total number of CSI-RS ports in the NZP CSI-RS resources, P CSI-RS，s =2N 1,s N 2,s is the number of CSI-RS ports in the sth NZP CSI-RS resource, where N 1,s and N 2,s are the number of antenna ports in the first and second dimensions, respectively. Note that the number of CSI-RS ports in different NZP CSI-RS resources can be the same or different.

[0180] ● The size is P CSI-RS ×2L' block diagonal space matrix, where L' is the matrix with all N RS The total number of selected spatial waves associated with NZP CSI-RS resources

[0181] ● is the size P associated with the sth NZP CSI-RS resource CSI-RS，s ×2L s The precoding matrix, s = 1, ..., N RS and

[0182] ○ The size is P CSI-RS，s / 2×1 set of selected 2-D DFT beams

[0183] ○

[0184] ○ If N 2,s >1; and If N2,s=1

[0185] ○ q 1，s ∈{0, 1, ..., O 1,s -1), q 2，s ∈{0, 1, ..., O 2,s -1), i=0, 1, ... L s -1, and O 1,s and O 2,s Along N 1,s and N 2,s Oversampling factor for the dimension .

[0186] ○ If port selection type II CSI is configured, each CSI-RS port in all CSI-RS resources corresponds to a 2-D spatial beam, and in, YesP CSI-RS，s / 2×1 vector, which is indexed by contains the value 1 in some elements and zeros elsewhere, where the first element is the element with index 0,

[0187]

[0188] ● is of size N 3 ×M v The frequency domain (FD) compression matrix of M v selected FD basis vectors, where And and k, t = 0, 1, ..., N 3 -1. W f，l Common to all CSI-RS resources or TRPs

[0189] ● The size is 2L'×M v The coefficient matrix of

[0190] ●N 3is the number of PMI sub-bands common to all CSI-RS resources or the TRP

[0191] In an alternative expression, each precoding vector can be represented as follows:

[0192]

[0193] where γ l is a scaling factor such that:

[0194]

[0195] v is the number of layers, is the precoder associated with the sth CSI-RS resource or the TRP and consists of two parts, for the first polarization and for the second polarization, is the FD basis vector index of the fth selected FD basis vector, is the coefficient c associated with the polarization index p and the CSI-RS resource index s l,i,f , and is the broadband amplitude associated with the layer l, the polarization index p, and the CSI-RS resource index s, and is the sub-band amplitude associated with the layer l, the ith selected spatial beam, the fth selected FD basis vector, the polarization index p, and the CSI-RS resource index s.

[0196] In one embodiment, the total number L′ of beams selected by the UE 506 can be less than the number of configured beams, i.e., This is useful because the actual useful beams seen by the UE 506 can be fewer than the configured beams, and when L′ < L, the feedback overhead can be reduced.

[0197] In some scenarios, not all configured TRPs are suitable for CJT for the UE 506, and the UE 506 can determine that a subset of TRPs or CSI-RS resources may be suitable for participating in CJT. When the UE 506 does not select a TRP for CJT, there are no selected beams associated with the TRP or CSI-RS resources. Therefore, in one embodiment, the number of selected beams for each configured CSI-RS resource is also reported as part of the CSI, i.e., reporting where L s = 0, s ∈ (1,..., N RS ) means that the sth CSI-RS resource or the TRP is not selected for CJT.

[0198] In step 606, the method includes receiving a CSI report from the UE 506 that includes CSI associated with L' spatial beams, where the L' spatial beams are less than the L spatial beams. When L'<L is supported, the CSI payload size may vary based on L'. To help the network determine the payload size for correct decoding, in one embodiment, L' is reported in part 1 of the CSI report. Part 1 has a fixed payload size, and after decoding part 1 of the CSI report, the gNB should know L' and can therefore determine the payload size of part 2 of the CSI. Alternatively, the number of selected beams associated with each CSI-RS resource is reported in part 1, that is, Part 1 of the CSI contains the information necessary to determine the payload size of part 2 of the CSI.

[0199] The CSI reported will include:

[0200] ●Part 1:

[0201] ○ Layer or rank indicator (RI): v

[0202] ○ Total number of selected beams: L′; In some embodiments, the number of selected beams for each CSI-RS resource may be indicated in CSI part 1, i.e.,

[0203] ○The total number of non-zero coefficients on all layers

[0204] ○CQI

[0205] ●Part 2:

[0206] ○ The number of selected beams associated with each CSI-RS resource: (if they were not reported in Part 1).

[0207] ○ Beam index of the selected beam for each selected CSI-RS resource Right now,

[0208] ■

[0209] ○ The indices of the selected FD basis vectors for each layer

[0210] ○The length of each layer is 2L′M v bits of non-zero coefficient bitmap,

[0211] ○ Quantized wideband amplitude per layer, per polarization, and per CSI-RS resource associated with non-zero coefficients

[0212] ○ For each layer, for the coefficient The index {i * ,s * , p *} has the maximum magnitude over all selected CSI-RS resources, all selected FD basis vectors, and both polarizations

[0213] ■i * ∈{0, 1, ..., L s -1};s * ∈{1,…,N RS}; p * ∈{0, 1}

[0214] ■

[0215] ■c l,i,f,p,s Depend on Normalization, that is,

[0216] ■ yes The quantized version of the phase factor

[0217] ■ yes A quantized version of the magnitude

[0218] ■f * Not reported, but W f，l The columns of are cyclically shifted so that f * Corresponding to column 1, the reported After the corresponding cyclic shift

[0219] When reporting L in Part 1 s =0, it should be understood that the sth CSI-RS resource is not selected for the above-mentioned CJTCSI calculation, and therefore the associated parameters are not reported in Part 2.

[0220] In step 608 of the method, the gNB constructs a precoding matrix according to Equations 1 to 7 for each of the multiple TRPs based on the CJTCSI report, and in step 610 of the method, applies the precoding matrix to the PDSCH before sending at the multiple TRPs 502 and 504.

[0221] In another embodiment, the number of selected FD basis vectors is based on the number of CSI-RS resources from which at least one beam or port is selected. For example, in the CJT case, the number of selected FD basis vectors may be defined as Among them, the parameter p′v depends on the number of TRPs from which beams or ports are selected (recall that the number of selected TRPs is given by the number of CSI-RS resources from which at least one beam or port is selected). For a larger number of selected TRPs, p′ may be specified v This is beneficial because a larger number of TRPs selected for CJT will likely result in a larger delay spread, in which case selecting a larger p′v will result in a larger number of selected FD basis vectors. Similarly, for a smaller number of selected TRPs, a smaller value of p′v can be specified, which can be used to select a smaller number of FD basis vectors.

[0222] Although two TRPs 502 and 504 are used in the above examples for discussion, the concepts can be easily extended to more than two TRPs.

[0223] exist Figure 7 In the method 700 (which is a method performed by UE 506) starts at step 702, wherein the method includes receiving a configuration of a CSI report based on a type II codebook CB from a network node, the CSI report configuration including N RS The total number of CSI reference signal CSI-RS resources and L spatial beams used for CJT.

[0224] At step 704, the method includes receiving a RS The transmission of CSI-RS resources and the request to report CJT CSI based on Type II CB according to the CSI reporting configuration in step 702.

[0225] At step 706, the method includes: RS CSI-R resources are used to measure channels, and CSI is calculated based on an aggregation of the measured channels by selecting L′ spatial beams, where L′ is an integer and is less than or equal to L spatial beams.

[0226] As part of step 706, the UE 506 then estimates the Get aggregated DL channels If different PDSCHs for CSI-RS power offsets are configured for different CSI-RS resources, the channels measured on each CSI-RS resource need to be scaled according to the configured power offset before forming the aggregated channel. For example, if a -3dB power offset is configured for a CSI-RS resource, the measured channels based on the CSI-RS resource need to be scaled

[0227] UE 506 based on aggregated DL channels To calculate Type II PMI. It can be assumed that UE 506 is configured with a set of parameters for CJT CSI reporting as follows:

[0228] L: the total number of spatial beams on all CSI-RS resources or TRPs

[0229] ● R∈{1,2}: scaling factor for PMI subband size

[0230] ●p v : Parameter used to configure the number of FD basis vectors for a given rank v, i.e., Among them, N 3 =N CQI R and N CQI is the number of CQI subbands

[0231] β: Maximum number of non-zero coefficients (NZC) used to configure each layer (i.e., ) parameters. The total number of NZCs on all layers, K NZ ≤2K 0

[0232] For MIMO layer l, the precoder matrix W on all TRPs l By size P CSI-RS ×N 3 The matrix gives:

[0233]

[0234] in:

[0235] ● is for layer l in a subband (with subband index t∈{0, 1, ..., N 3 -1}) CSI-RS ×1 precoding vector, where All N RS The total number of CSI-RS ports in the NZP CSI-RS resources, P CSI-RS，s =2N 1，s N 2,s is the number of CSI-RS ports in the sth NZP CSI-RS resource, where N 1，s and N 2,s are the number of antenna ports in the first and second dimensions, respectively. Note that the number of CSI-RS ports in different NZP CSI-RS resources can be the same or different.

[0236] ● The size is P CSI-RS×2L' block diagonal space matrix, where L' is the matrix with all N RS Total number of selected spatial beams associated with the NZP CSI-RS resource

[0237] ● is the size P associated with the sth NZP CSI-RS resource CSI-RS，s ×2L s The precoding matrix, s = 1, ..., N RS and

[0238] ○ The size is P CSI-RS，s / 2×1 set of selected 2-D DFT beams

[0239] ○

[0240] ○ If N 2，s >1; and If N 2，s =1

[0241] ○ q 1，s ∈{0, 1, ..., O 1,s -1), q 2，s ∈{0, 1, ..., O 2,s -1), i=0, 1, ... L s -1, and O 1，s and O 2，s Along N 1,s and N 2,s The oversampling factor of the dimension

[0242] ○ If port selection type II CSI is configured, each CSI-RS port in all CSI-RS resources corresponds to a 2-D spatial beam, and in, YesP CSI-RS，s / 2×1 vector, which is indexed by contains the value 1 in some elements and zeros elsewhere, where the first element is the element with index 0,

[0243] ● is of size N 3 ×M v The frequency domain (FD) compression matrix of M v selected FD basis vectors, where and one k, t = 0, 1, ..., N 3 -1. W f，l Common to all CSI-RS resources or TRPs

[0244] ● The size is 2L'×M v The coefficient matrix of

[0245] ●N 3 is the number of PMI subbands common to all CSI-RS resources or TRPs

[0246] In the alternative expression, each precoding vector can be expressed as follows:

[0247]

[0248] where γl is a scaling factor such that:

[0249]

[0250] v is the number of layers, is the precoder associated with the sth CSI-RS resource or TRP and consists of two parts, for the first polarization and For the second polarization, is the FD basis vector index of the fth selected FD basis vector, is the coefficient c associated with the polarization index p and the CSI-RS resource index s l，i，f ,as well as is the wideband amplitude associated with layer l, polarization index p, and CSI-RS resource index s, and is the subband amplitude associated with layer l, the i-th selected spatial beam, the f-th selected FD basis vector, the polarization index p, and the CSI-RS resource index s.

[0251] In one embodiment, the total number of beams L′ selected by the UE 506 may be less than the number of configured beams, i.e., This is useful because the actual useful beams seen by the UE 506 may be less than the configured beams, and when L′<L, feedback overhead may be reduced.

[0252] In some scenarios, not all configured TRPs are suitable for CJT for UE 506, and UE 506 may determine that a subset of TRPs or CSI-RS resources are suitable for participating in CJT. When UE 506 does not select a TRP for CJT, there is no selected beam associated with the TRP or CSI-RS resource. Therefore, in one embodiment, the number of selected beams for each configured CSI-RS resource is also reported as part of the CSI, i.e., the number of selected beams is reported. Among them, L s =0,s∈(1,...,N RS ) means that the sth CSI-RS resource or TRP is not selected for CJT.

[0253] In step 708, the method includes sending a CSI report including a beam index for each of the L' spatial beams.

[0254] Figure 8 An example of a communication system 800 is shown in accordance with some embodiments.

[0255] In this example, communication system 800 includes telecommunication network 802, which includes access network 804 (such as radio access network (RAN)) and core network 806 (which includes one or more core network nodes 808). Access network 804 includes one or more access network nodes, such as network nodes 810A and 810B (one or more of which may be generally referred to as network node 810), or any other similar third generation partnership project (3GPP) access node or non-3GPP access point (AP). Network node 810 facilitates direct or indirect connection of user equipment (UE), such as by connecting UE 812A, 812B, 812C, and 812D (one or more of which may be generally referred to as UE 812) to core network 806 over one or more wireless connections.

[0256] Example wireless communications over wireless connections include sending and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. In addition, in various embodiments, the communication system 800 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals, whether via a wired or wireless connection. The communication system 800 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0257] UE 812 may be any of a variety of communication devices, including wireless devices that are arranged, configured, and / or operable to communicate wirelessly with network node 810 and other communication devices. Similarly, network node 810 is arranged, capable, configured, and / or operable to communicate directly or indirectly with UE 812 and / or with other network nodes or devices in telecommunication network 802 to enable and / or provide network access (such as wireless network access) and / or perform other functions (such as management in telecommunication network 802).

[0258] In the depicted example, the core network 806 connects the network node 810 to one or more hosts (such as the host 816). These connections may be direct, or indirect via one or more intermediate networks or devices. In other examples, the network node may be directly coupled to the host. The core network 806 includes one or more core network nodes (e.g., core network node 808), which are composed of hardware and software components. The features of these components may be substantially similar to those described with respect to the UE, network node, and / or host, so that their description is generally applicable to the corresponding components of the core network node 808. The example core network node includes one or more functions of the following: a mobile switching center (MSC), a mobility management entity (MME), a home subscriber server (HSS), an access and mobility management function (AMF), a session management function (SMF), an authentication server function (AUSF), a subscription identifier de-hiding function (SIDF), a unified data management (UDM), a security edge protection agent (SEPP), a network open function (NEF), and / or a user plane function (UPF).

[0259] The host 816 may be owned or controlled by a service provider other than the operator or provider of the access network 804 and / or the telecommunications network 802, and may be operated by or on behalf of the service provider. The host 816 may host various applications to provide one or more services. Examples of such applications include live and pre-recorded audio / video content, data collection services (such as retrieving and compiling data on various environmental conditions detected by multiple UEs), analytical functions, social media, functions for controlling or otherwise interacting with remote devices, functions for alarm and monitoring centers, or any other such functions performed by a server.

[0260] Overall, Figure 8 The communication system 800 implements the connection between the UE, the network node, and the host. In this sense, the communication system 800 can be configured to operate according to predefined rules or procedures, such as specific standards, including but not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable second, third, fourth or fifth generation (2G, 3G, 4G or 5G) standards, or any applicable future generation standards (e.g., sixth generation (6G)); Wireless Local Area Network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard (WiFi); and / or any other suitable wireless communication standards, such as Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any Low Power Wide Area Network (LPWAN) standards, such as LoRa and Sigfox.

[0261] In some examples, telecommunication network 802 is a cellular network implementing 3GPP standardized features. Thus, telecommunication network 802 can support network slicing to provide different logical networks to different devices connected to telecommunication network 802. For example, telecommunication network 802 can provide ultra-reliable low-latency communication (URLLC) services to some UEs, while providing enhanced mobile broadband (eMBB) services to other UEs, and / or provide massive machine type communication (mMTC) / massive Internet of Things (IoT) services to more other UEs.

[0262] In some examples, UE 812 is configured to send and / or receive information without direct human-machine interaction. For example, the UE can be designed to send information to the access network 804 according to a predetermined schedule when triggered by an internal or external event or in response to a request from the access network 804. In addition, the UE can be configured to operate in a single or multiple radio access technology (RAT) or multi-standard mode. For example, the UE can operate with any one or a combination of WiFi, new radio (NR), and LTE, i.e., configured for multi-radio dual connectivity (MR-DC), such as Evolved UMTS Terrestrial RAN (E-UTRAN) NR-Dual Connectivity (EN-DC).

[0263] In this example, the hub 814 communicates with the access network 804 to facilitate indirect communication between one or more UEs (e.g., UE 812C and / or 812D) and a network node (e.g., network node 810B). In some examples, the hub 814 can be a controller, a router, a content source and analysis, or any other communication device described herein with respect to the UE. For example, the hub 814 can be a broadband router that enables the UE to access the core network 806. As another example, the hub 814 can be a controller that sends commands or instructions to one or more actuators in the UE. The command or instruction can be received from the UE, the network node 810, or received by an executable code, a script, a process, or other instructions in the hub 814. As another example, the hub 814 can be a data collector that acts as a temporary storage device for UE data, and in some embodiments, analysis or other processing of the data can be performed. As another example, the hub 814 can be a content source. For example, for a UE that is a virtual reality (VR) headset, display, speaker, or other media delivery device, the hub 814 can retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, and then the hub 814 provides it to the UE directly, after performing local processing, and / or after adding additional local content. In another example, the hub 814 acts as a proxy server or coordinator for the UE, especially when one or more UEs are low-energy IoT devices.

[0264] Hub 814 can have constant / persistent or intermittent connection with network node 810B. Hub 814 can also allow different communication schemes and / or scheduling between hub 814 and UE (e.g., UE 812C and / or 812D) and hub 814 and core network 806. In other examples, hub 814 is connected to core network 806 and / or one or more UE via wired connection. In addition, hub 814 can be configured to be connected to machine to machine (M2M) service provider and / or connected to another UE via direct connection through access network 804. In some scenarios, UE can establish wireless connection with network node 810, while still connected via hub 814 via wired or wireless connection. In some embodiments, hub 814 can be a dedicated hub--that is, the main function of the hub is to route communication from UE to network node 810B / from network node 810B to UE. In other embodiments, hub 814 may be a non-dedicated hub—that is, a device operable to route communications between UEs and network node 810B, but which is additionally operable as a communications origin and / or destination for certain data channels.

[0265] Fig. 9 UE 900 according to some embodiments is shown. As used herein, UE refers to a device capable of, configured, arranged, and / or operable to wirelessly communicate with a network node and / or other UEs. Examples of UEs include, but are not limited to, smartphones, mobile phones, cellular phones, voice over Internet protocol (VoIP) phones, wireless local loop phones, desktop computers, personal digital assistants (PDAs), wireless cameras, game consoles or devices, music storage devices, playback devices, wearable terminal devices, wireless endpoints, mobile stations, tablet computers, laptops, laptop embedded devices (LEEs), laptop mounted devices (LMEs), smart devices, wireless client equipment (CPEs), vehicle-mounted or vehicle-mounted embedded / integrated wireless devices, etc. Other examples include any UE identified by 3GPP, including narrowband Internet of Things (NB-IoT) UEs, machine type communications (MTC) UEs, and / or enhanced MTC (eMTC) UEs.

[0266] The UE may support device-to-device (D2D) communications, for example, by implementing 3GPP standards for sidelink communications, dedicated short-range communications (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, the UE may not necessarily have a user in the sense of a human user owning and / or operating the associated device. Instead, the UE may represent a device that is intended to be sold to or operated by a human user, but may not be associated with a specific human user, or may not initially be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, the UE may represent a device that is not intended to be sold to or operated by an end user, but may be associated with or operated for the benefit of a user (e.g., a smart meter).

[0267] UE 900 includes a processing circuit 902 that is operatively coupled to an input / output interface 906, a power supply 908, a memory 910, a communication interface 912, and / or any other components or any combination thereof via a bus 904. Some UEs may use Fig. 9 All or a subset of the components shown in . The degree of integration between components may vary from UE to UE. In addition, some UEs may include multiple instances of components, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0268] The processing circuit 902 is configured to process instructions and data, and may be configured to implement any sequential state machine operable to execute instructions stored in the memory 910 as a machine-readable computer program. The processing circuit 902 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), etc.); programmable logic together with suitable firmware; one or more stored computer programs, general-purpose processors (such as microprocessors or digital signal processors (DSPs)) together with suitable software; or any combination of the above. For example, the processing circuit 902 may include multiple central processing units (CPUs).

[0269] In this example, the input / output interface 906 can be configured to provide one or more interfaces to an input device, an output device, or one or more input and / or output devices. Examples of output devices include speakers, sound cards, video cards, displays, monitors, printers, actuators, transmitters, smart cards, another output device, or any combination thereof. An input device can allow a user to capture information into the UE 900. Examples of input devices include touch-sensitive or presence-sensitive displays, cameras (e.g., digital cameras, digital video cameras, webcams, etc.), microphones, sensors, mice, trackballs, directional keys, trackpads, rollers, smart cards, etc. The presence-sensitive display can include a capacitive or resistive touch sensor to sense input from a user. The sensor can be an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device can use an interface port of the same type as an input device. For example, a universal serial bus (USB) port can be used to provide input devices and output devices.

[0270] In some embodiments, the power supply 908 is configured as a battery or a battery pack. Other types of power supplies may be used, such as an external power supply (e.g., a power outlet), a photovoltaic device, or a battery. The power supply 908 may also include a power supply circuit for delivering power from the power supply 908 itself and / or an external power supply to various parts of the UE 900 via an input circuit or interface (such as a power cable). The delivered power may be used, for example, to charge the power supply 908. The power supply circuit may perform any formatting, conversion, or other modification on the power from the power supply 908 to make the power suitable for the various components of the UE 900 being powered.

[0271] The memory 910 may be or be configured to include a memory such as a random access memory (RAM), a read-only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrical EPROM (EEPROM), a magnetic disk, an optical disk, a hard disk, a removable cassette, a flash drive, etc. In one example, the memory 910 includes one or more application programs 914, such as an operating system, a web browser application, a widget, a gadget engine, or other applications, and corresponding data 916. The memory 910 may store any one of a variety of operating systems or a combination of operating systems for use by the UE 900.

[0272] The memory 910 may be configured to include a plurality of physical drive units, such as a redundant array of independent disks (RAID), a flash memory, a USB flash drive, an external hard drive, a thumb drive, a pen drive, a key drive, a high-density digital versatile disc (HD-DVD) optical drive, an internal hard drive, a Blu-ray optical drive, a holographic digital data storage (HDDS) optical drive, an external micro dual in-line memory module (DIMM), a synchronous dynamic RAM (SDRAM), an external micro DIMM SDRAM, a smart card memory (such as a tamper-proof module in the form of a universal integrated circuit card (UICC), including one or more subscriber identity modules (SIMs), such as a universal SIM (USIM) and / or an Internet Protocol Multimedia Service Identity Module (ISIM)), other memories, or any combination thereof. The UICC may be, for example, an embedded UICC (eUICC), an integrated UICC (iUICC), or a removable UICC commonly referred to as a “SIM card”. The memory 910 may allow the UE 900 to access instructions, applications, etc. stored on a temporary or non-temporary memory medium to offload data or upload data. An article of manufacture, such as an article of manufacture using a communication system, may be tangibly embodied as or in memory 910, which may be or include a device-readable storage medium.

[0273] The processing circuit 902 may be configured to communicate with an access network or other network using a communication interface 912. The communication interface 912 may include one or more communication subsystems and may include or be communicatively coupled to an antenna 922. The communication interface 912 may include one or more transceivers for communication, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 918 and / or a receiver 920 suitable for providing network communications (e.g., optical, electrical, frequency allocation, etc.). In addition, the transmitter 918 and the receiver 920 may be coupled to one or more antennas (e.g., antenna 922) and may share circuit components, software, or firmware, or may alternatively be implemented separately.

[0274] In the illustrated embodiment, the communication functions of the communication interface 912 may include cellular communication, WiFi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communication (such as Bluetooth, NFC), location-based communication (such as using a global positioning system (GPS) to determine location), other similar communication functions, or any combination thereof. Communication can be implemented according to one or more communication protocols and / or standards, such as IEEE 802.11, code division multiplexing access (CDMA), wideband CDMA (WCDMA), GSM, LTE, NR, UMTS, WiMax, Ethernet, transmission control protocol / Internet protocol (TCP / IP), synchronous optical network (SONET), asynchronous transfer mode (ATM), fast user datagram protocol Internet connection (QUIC), hypertext transfer protocol (HTTP), etc.

[0275] Regardless of the type of sensor, the UE may provide an output of the data captured by its sensor through its communication interface 912 or via a wireless connection to a network node. The data captured by the UE's sensor may be transmitted to the network node via another UE over a wireless connection. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to balance the reporting load from several sensors), in response to a trigger event (e.g., sending an alarm when moisture is detected), in response to a request (e.g., a user-initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0276] As another example, the UE includes an actuator, motor, or switch associated with a communication interface that is configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input, the state of the actuator, motor, or switch can change. For example, the UE can include a motor that adjusts a control surface or rotor of a drone in flight based on the received input, or adjusts a robotic arm performing a medical procedure based on the received input.

[0277] When the UE is in the form of an IoT device, it can be a device for one or more application areas, including but not limited to urban wearable technology, extended industrial applications, and healthcare. Non-limiting examples of such IoT devices include the following devices or devices embedded in the following devices: connected refrigerators or freezers, televisions, connected lighting devices, electricity meters, robotic vacuum cleaners, voice-controlled smart speakers, home security cameras, motion detectors, thermostats, smoke detectors, door / window sensors, flood / humidity sensors, electric door locks, connected doorbells, air conditioning systems (such as heat pumps), self-driving cars, surveillance systems, weather monitoring devices, vehicle parking monitoring devices, electric vehicle charging stations, smart watches, fitness trackers, head-mounted displays for augmented reality (AR) or VR, wearable devices for tactile enhancement or sensory enhancement, sprinklers, animal or item tracking devices, sensors for monitoring plants or animals, industrial robots, unmanned aerial vehicles (UAVs), and any type of medical equipment (such as heart rate monitors or remote-controlled surgical robots). In addition to including Fig. 9 In addition to the other components described in relation to UE 900 shown in FIG. 1 , a UE in the form of an IoT device may further include circuits and / or software depending on the intended application of the IoT device.

[0278] As another specific example, in an IoT scenario, a UE may represent a machine or other device that performs monitoring and / or measurement and sends the results of such monitoring and / or measurement to another UE and / or a network node. In this case, the UE may be an M2M device, which may be referred to as an MTC device in the 3GPP context. As a specific example, a UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, bus, truck, ship, airplane, or other device capable of monitoring and / or reporting its operating status or other functions associated with its operation.

[0279] In practice, any number of UEs may be used together for a single use case. For example, a first UE may be a drone or integrated into a drone and provide the drone's speed information (obtained via a speed sensor) to a second UE, which is a remote control that operates the drone. When the user makes changes from the remote control, the first UE may adjust the throttle on the drone (e.g., by controlling an actuator) to increase or decrease the speed of the drone. The first and / or second UE may also include more than one of the above functions. For example, the UE may include sensors and actuators and handle data communications for the speed sensor and actuator.

[0280] Fig.10A network node 1000 according to some embodiments is shown. As used herein, a network node refers to a device capable of, configured, arranged, and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or devices in a telecommunications network. Examples of network nodes include, but are not limited to, APs (e.g., radio APs), base stations (BSs) (e.g., radio BSs, Node Bs, evolved Node Bs (eNBs), and NR Node Bs (gNBs)).

[0281] BSs may be classified based on the amount of coverage they provide (or, in other words, their transmit power level), and therefore, depending on the amount of coverage provided, they may be referred to as femto BSs, pico BSs, micro BSs, or macro BSs. A BS may be a relay node or a relay donor node that controls a relay. A network node may also include one or more (or all) parts of a distributed radio BS, such as a centralized digital unit and / or a remote radio unit (RRU), sometimes referred to as a remote radio head (RRH). Such an RRU may or may not be integrated with an antenna as an antenna-integrated radio. Parts of a distributed radio BS may also be referred to as nodes in a distributed antenna system (DAS).

[0282] Other examples of network nodes include multiple transmit / receive point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment (such as MSRBS), network controllers (such as radio network controllers (RNC) or BS controllers (BSC)), base transceiver stations (BTS), transmit / receive points, transmission nodes, multi-cell / multicast coordination entities (MCEs), operations and maintenance (O&M) nodes, operations support system (OSS) nodes, self-organizing network (SON) nodes, positioning nodes (e.g., evolved serving mobile positioning center (E-SMLC)), and / or minimization of drive tests (MDT).

[0283] The network node 1000 includes a processing circuit 1002, a memory 1004, a communication interface 1006, and a power supply 1008. The network node 1000 may be composed of multiple physically separate components (e.g., a node B component and an RNC component, or a BTS component and a BSC component, etc.), each of which may have its own components. In certain scenarios where the network node 1000 includes multiple separate components (e.g., BTS and BSC components), one or more separate components may be shared between several network nodes. For example, a single RNC may control multiple node Bs. In such a scenario, each unique node B and RNC pair may be considered as a single separate network node in some cases. In some embodiments, the network node 1000 may be configured to support multiple RATs. In such an embodiment, some components may be repeated (e.g., separate memories 1004 for different RATs), and some components may be reused (e.g., antennas 1010 may be shared by different RATs). The network node 1000 may also include multiple different sets of illustrated components for different wireless technologies integrated into the network node 1000, such as GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, Long Range Wide Area Network (LoRaWAN), Radio Frequency Identification (RFID), or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chips or chipsets and other components within the network node 1000.

[0284] The processing circuit 1002 may include a microprocessor, a controller, a microcontroller, a CPU, a DSP, an ASIC, an FPGA, or any other suitable computing device, a combination of one or more of the resources, or a combination of hardware, software, and / or encoded logic that is operable to provide the functionality of the network node 1000 alone or in combination with other network node 1000 components (such as memory 1004).

[0285] In some embodiments, the processing circuit 1002 includes a system on a chip (SOC). In some embodiments, the processing circuit 1002 includes one or more radio frequency (RF) transceiver circuits 1012 and baseband processing circuits 1014. In some embodiments, the RF transceiver circuits 1012 and baseband processing circuits 1014 may be located on separate chips (or chipsets), circuit boards, or units (such as a radio unit and a digital unit). In alternative embodiments, part or all of the RF transceiver circuits 1012 and baseband processing circuits 1014 may be located on the same chip or chipset, circuit board, or unit.

[0286] The memory 1004 may include any form of volatile or non-volatile computer-readable memory, including but not limited to persistent memory, solid-state memory, remotely mounted memory, magnetic media, optical media, RAM, ROM, mass storage media (e.g., hard disk), removable storage media (e.g., flash drive, compact disk (CD), or digital video disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory device for storing information, data and / or instructions that can be used by the processing circuit 1002. The memory 1004 may store any suitable instructions, data or information, including computer programs, software, applications (including one or more logic, rules, codes, tables, and / or other instructions that can be executed by the processing circuit 1002 and used by the network node 1000). The memory 1004 may be used to store any calculations performed by the processing circuit 1002 and / or any data received via the communication interface 1006. In some embodiments, the processing circuit 1002 and the memory 1004 are integrated.

[0287] The communication interface 1006 is used in the wired or wireless communication of signaling and / or data between network nodes, access networks, and / or UEs. As shown, the communication interface 1006 includes a port / terminal 1016 for, for example, sending data to the network and receiving data from the network via a wired connection. The communication interface 1006 also includes a radio front-end circuit 1018, which may be coupled to the antenna 1010, or may be a part of the antenna 1010 in some embodiments. The radio front-end circuit 1018 includes a filter 1020 and an amplifier 1022. The radio front-end circuit 1018 may be connected to the antenna 1010 and the processing circuit 1002. The radio front-end circuit 1018 may be configured to adjust the signal transmitted between the antenna 1010 and the processing circuit 1002. The radio front-end circuit 1018 may receive digital data to be sent to other network nodes or UEs via a wireless connection. The radio front-end circuit 1018 may use a combination of a filter 1020 and / or an amplifier 1022 to convert digital data into a radio signal with suitable channel and bandwidth parameters. In turn, the radio signals may be transmitted via the antenna 1010. Similarly, when receiving data, the radio signals may be collected by the antenna 1010 and then converted into digital data by the radio front end circuit 1018. The digital data may be passed to the processing circuit 1002. In other embodiments, the communication interface 1006 may include different components and / or different combinations of components.

[0288] In some alternative embodiments, the network node 1000 does not include a separate radio front end circuit 1018; instead, the processing circuit 1002 includes the radio front end circuit and is connected to the antenna 1010. Similarly, in some embodiments, all or part of the RF transceiver circuit 1012 is part of the communication interface 1006. In other embodiments, the communication interface 1006 includes one or more ports or terminals 1016, the radio front end circuit 1018, and the RF transceiver circuit 1012 as part of a radio unit (not shown), and the communication interface 1006 communicates with the baseband processing circuit 1014 that is part of a digital unit (not shown).

[0289] Antenna 1010 may include one or more antennas or antenna arrays configured to send and / or receive wireless signals. Antenna 1010 may be coupled to radio front end circuitry 1018 and may be any type of antenna capable of wirelessly sending and receiving data and / or signals. In some embodiments, antenna 1010 is separate from network node 1000 and connectable to network node 1000 via an interface or port.

[0290] The antenna 1010, the communication interface 1006, and / or the processing circuit 1002 may be configured to perform any receiving operation and / or certain obtaining operations performed by the network node 1000 as described herein. Any information, data, and / or signal may be received from a UE, another network node, and / or any other network device. Similarly, the antenna 1010, the communication interface 1006, and / or the processing circuit 1002 may be configured to perform any sending operation performed by the network node 1000 as described herein. Any information, data, and / or signal may be sent to a UE, another network node, and / or any other network device.

[0291] The power supply 1008 provides power to the various components of the network node 1000 in a form suitable for the respective components (e.g., at the voltage and current levels required by each respective component). The power supply 1008 may also include or be coupled to a power management circuit to provide power to the components of the network node 1000 for performing the functions described herein. For example, the network node 1000 may be connectable to an external power source (e.g., a power grid or a power outlet) via an input circuit or an interface such as a cable, whereby the external power source supplies power to the power circuit of the power supply 1008. As another example, the power supply 1008 may include a power source in the form of a battery or battery pack connected to or integrated into the power circuit. If the external power source fails, the battery may provide backup power.

[0292] Embodiments of the network node 1000 may include, in addition to Fig.10Additional components beyond those shown in the figure may be used to provide certain aspects of the functionality of the network node, including any functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 1000 may include a user interface device to allow information to be input into the network node 1000 and to allow information to be output from the network node 1000. This may allow a user to perform diagnostics, maintenance, repair, and other management functions on the network node 1000.

[0293] Fig.11 is a block diagram of a host 1100 according to various aspects described herein, which may be Figure 8 100 is an embodiment of a host 816. As used herein, the host 1100 can be or include a combination of various hardware and / or software, including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, a container, or a processing resource in a server farm. The host 1100 can provide one or more services to one or more UEs.

[0294] Host 1100 includes processing circuitry 1102, which is operably coupled to input / output interface 1106, network interface 1108, power supply 1110, and memory 1112 via bus 1104. Other components may be included in other embodiments. The features of these components may be similar to those described with respect to previous figures (such as Fig. 9 and Fig.10 ) are substantially similar in features to the devices described in , so that their descriptions are generally applicable to corresponding components of the host 1100.

[0295] The memory 1112 may include one or more computer programs, including one or more host applications 1114 and data 1116, which may include user data, such as data generated by the UE for the host 1100 or data generated by the host 1100 for the UE. The embodiment of the host 1100 may use only a subset or all of the components shown. The host application 1114 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), Moving Picture Experts Group (MPEG), VP9) and audio codecs (e.g., Free Lossless Audio Codec (FLAC), Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for a variety of different categories, types, or UE implementations (e.g., mobile phones, desktop computers, wearable display systems, and head-up display systems). The host application 1114 may also provide user authentication and license checks, and may periodically report health status, routing, and content availability to a central node (such as a device in a core network or on its edge). Thus, the host 1100 can select and / or indicate to the UE a different host for an over-the-top (OTT) service. The host application 1114 can support various protocols, such as HTTP Live Streaming (HLS) protocol, Real-time Messaging Protocol (RTMP), Real-time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (DASH or MPEG-DASH), etc.

[0296] Fig.12 It is a block diagram illustrating a virtualized environment 1200 in which the functions implemented by certain embodiments can be virtualized. In this context, virtualization means creating a virtual version of a device or equipment, which may include a virtualized hardware platform, storage device, and network resources. As used herein, virtualization can be applied to any device or component thereof described herein, and relates to an implementation in which at least a portion of the functions are implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components performed by one or more virtual machines (VMs), which are implemented in one or more virtual environments 1200 hosted by one or more hardware nodes (such as hardware computing devices operated as network nodes, UEs, core network nodes, or hosts). In addition, in embodiments in which a virtual node does not require a radio connection (e.g., a core network node or a host), the node can be fully virtualized.

[0297] Application 1202 (which may also be referred to alternatively as a software instance, a virtual appliance, a network function, a virtual node, a virtual network function, etc.) runs in the virtualization environment 1100 to implement some features, functions, and / or benefits of some embodiments disclosed herein.

[0298] Hardware 1204 includes processing circuitry, memory storing software and / or instructions executable by the hardware processing circuitry, and / or other hardware devices described herein, such as network interfaces, input / output interfaces, etc. The processing circuitry may execute software to instantiate one or more virtualization layers 1206 (also referred to as virtual machine hypervisors or VM monitors (VMMs)), provide VMs 1208A and 1208B (one or more of which are generally referred to as VMs 1208), and / or perform any functions, features, and / or benefits associated with some embodiments described herein. Virtualization layer 1206 may present a virtual operating platform to VMs 1208 that appears to be network hardware.

[0299] VM 1208 includes virtual processing, virtual memory, virtual additional or interface, and virtual storage, and can be run by corresponding virtualization layer 1206. Different embodiments of instances of virtual device 1202 can be implemented on one or more VMs 1208 and can be implemented in different ways. Virtualization of hardware is referred to as network function virtualization (NFV) in some cases. NFV can be used to integrate many network device types onto industry-standard high-capacity server hardware, physical switches, and physical storage, which can be located in data centers and client devices.

[0300] In the context of NFV, VM 1208 can be a software implementation of a physical machine that runs programs as if they were executed on a physical, non-virtualized machine. Each VM 1208 and a portion of the hardware 1204 on which the VM executes (whether dedicated to the VM or shared with other VMs 1208) constitute a separate virtual network element. Still in the context of NFV, a virtual network function is responsible for handling specific network functions running in one or more VMs 1208 on the hardware 1204 and corresponds to an application 1202.

[0301] The hardware 1204 may be implemented in a standalone network node with general or specific components. The hardware 1204 may implement some functions via virtualization. Alternatively, the hardware 1204 may be part of a larger hardware cluster (e.g., such as in a data center or CPE), where many hardware nodes work together and are managed via management and orchestration 1210, which is responsible for, among other things, overseeing the lifecycle management of the application 1202. In some embodiments, the hardware 1204 is coupled to one or more radio units, each of which includes one or more transmitters and one or more receivers that may be coupled to one or more antennas. The radio unit may communicate directly with other hardware nodes via one or more suitable network interfaces, and may be used in conjunction with virtual components to provide radio capabilities to virtual nodes (such as RAN or BS). In some embodiments, some signaling may be provided using a control system 1212, which may alternatively be used for communication between hardware nodes and radio units.

[0302] Fig.13 A communication diagram showing a host 1302 communicating with a UE 1306 via a network node 1304 over a partial wireless connection according to some embodiments. Fig.13 To describe a UE (such as Figure 8 UE 812A and / or Fig. 9 UE 900), network nodes (such as Figure 8 The network node 810A and / or Fig.10 ), and hosts (such as Figure 8 Host 816 and / or Fig.11 An example implementation of host 1100).

[0303] As with the host 1100, embodiments of the host 1302 include hardware, such as a communication interface, a processing circuit, and a memory. The host 1302 also includes software that is stored in or accessible by the host 1302 and executable by the processing circuit. The software includes a host application that can be operable to provide services to a remote user, such as a UE 1306 connected via an OTT connection 1350 extended between the UE 1306 and the host 1302. When providing services to the remote user, the host application can provide user data sent using the OTT connection 1350.

[0304] The network node 1304 includes hardware that enables it to communicate with the host 1302 and the UE 1306 via a connection 1360. The connection 1360 may be direct or through a core network (such as Figure 8The core network 806 of the present invention and / or one or more other intermediate networks (such as one or more public, private, or managed networks) are connected. For example, the intermediate network can be a backbone network or the Internet.

[0305] UE 1306 includes hardware and software that is stored in or accessible by UE 1306 and is executable by the processing circuit of the UE. The software includes a client application, such as a web browser or an operator-specific "app", which can be operable to provide services to human or non-human users via UE 1306 with the support of host 1302. In host 1302, the executing host application can communicate with the executing client application via an OTT connection 1350 that terminates at UE 1306 and host 1302. When providing services to the user, the client application of the UE can receive request data from the host application of the host, and can provide user data in response to the request data. The OTT connection 1350 can transmit both request data and user data. The client application of the UE can interact with the user to generate user data, which is provided to the host application via the OTT connection 1350.

[0306] The OTT connection 1350 may extend via a connection 1360 between the host 1302 and the network node 1304 and via a wireless connection 1370 between the network node 1304 and the UE 1306 to provide connectivity between the host 1302 and the UE 1306. The connection 1360 and the wireless connection 1370 (through which the OTT connection 1350 may be provided) are drawn abstractly to illustrate communications between the host 1302 and the UE 1306 via the network node 1304 without explicit reference to any intermediate devices and the precise message routing via these devices.

[0307] As an example of sending data via the OTT connection 1350, in step 1308, the host 1302 provides user data, which can be performed by executing a host application. In some embodiments, the user data is associated with a specific human user interacting with the UE 1306. In other embodiments, the user data is associated with the UE 1306 that shares data with the host 1302 without explicit human-machine interaction. In step 1310, the host 1302 initiates a transmission carrying the user data to the UE 1306. The host 1302 may initiate the transmission in response to a request sent by the UE 1306. The request may be caused by a human-machine interaction with the UE 1306 or by an operation of a client application executed on the UE 1306. According to the teachings of the embodiments described in the present disclosure, the transmission may be relayed via the network node 1304. Thus, in step 1312, according to the teachings of the embodiments described in the present disclosure, the network node 1304 sends the user data carried in the transmission initiated by the host 1302 to the UE 1306. In step 1314, the UE 1306 receives the user data carried in the transmission, which can be performed by a client application executed on the UE 1306, and the client application is associated with the host application executed by the host 1302.

[0308] In some examples, the UE 1306 executes a client application that provides user data to the host 1302. The user data may be provided in reaction or response to data received from the host 1302. Thus, in step 1316, the UE 1306 may provide user data, which can be performed by executing the client application. When providing the user data, the client application may further consider user input received from the user via the input / output interface of the UE 1306. Regardless of the specific manner of providing the user data, the UE 1306 initiates a transmission of the user data to the host 1302 via the network node 1304 in step 1318. In step 1320, according to the teachings of the embodiments described throughout the present disclosure, the network node 1304 receives the user data from the UE 1306 and initiates a transmission of the received user data to the host 1302. In step 1322, the host 1302 receives the user data carried in the transmission initiated by the UE 1306.

[0309] Using the OTT connection 1350 in which the wireless connection 1370 forms the last segment, one or more of the various embodiments improve the performance of the OTT service provided to the UE 1306. More precisely, the teachings of these embodiments can reduce the feedback overhead, especially when L’ < L, thus improving the performance.

[0310] In an example scenario, factory status information may be collected and analyzed by host 1302. As another example, host 1302 may process audio and video data that may have been retrieved from the UE for use in creating a map. As another example, host 1302 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights). As another example, host 1302 may store surveillance videos uploaded by the UE. As another example, host 1302 may store or control access to media content (such as video, audio, VR, or AR) that may be broadcast, multicast, or unicast to the UE. As other examples, host 1302 may be used for energy pricing, remote control of non-time critical power loads to balance power generation demand, location services, presentation services (such as compiling charts from data collected from remote devices, etc.), or any other function of collecting, retrieving, storing, analyzing, and / or sending data.

[0311] In some examples, a measurement process may be provided for the purpose of monitoring the data rate, latency, and other factors improved by one or more embodiments. There may be an optional network function for reconfiguring the OTT connection 1350 between the host 1302 and the UE 1306 to cope with changes in the measurement results. The measurement process and / or network function for reconfiguring the OTT connection may be implemented in the software and hardware of the host 1302 and / or the UE 1306. In some embodiments, sensors (not shown) may be deployed in or associated with other devices through which the OTT connection 1350 passes; the sensors may participate in the measurement process by providing the values ​​of the monitoring quantities exemplified above or by providing the values ​​of other physical quantities (the software may calculate or estimate the monitoring quantities by the values ​​of these physical quantities). The reconfiguration of the OTT connection 1350 may include message formats, retransmission settings, preferred routes, etc.; the reconfiguration does not necessarily directly change the operation of the network node 1304. Such processes and functions are known and practiced in the art. In some embodiments, the measurement may involve proprietary UE signaling that facilitates the measurement of the throughput, propagation time, latency, etc. of the host 1302. These measurements can be achieved because the software uses the OTT connection 1350 to enable messages (especially "empty" or "dummy" messages) to be sent while monitoring propagation times, errors, etc.

[0312] Although the computing devices (e.g., UE, network node, host) described herein may include illustrated combinations of hardware components, other embodiments may include computing devices with different combinations of components. It is to be understood that these computing devices may include any suitable combination of hardware and / or software required to perform the tasks, features, functions, and methods disclosed herein. Determination, calculation, acquisition, or similar operations may be performed by a processing circuit, which may, for example, process the information by converting the obtained information into other information, comparing the obtained information or the converted information with the information stored in the network node, and / or performing one or more operations based on the obtained information or the converted information to process the information, and making a determination based on the result of the processing. In addition, although the components are described as being located in a larger box or a single box nested in multiple boxes, in fact, the computing device may include multiple different physical components that make up a single illustrated component, and the functions may be divided between separate components. For example, a communication interface may be configured to include any component described herein, and / or the functions of the component may be divided between a processing circuit and a communication interface. In another example, the non-computationally intensive functions of any such component may be implemented in software or firmware, and the computationally intensive functions may be implemented in hardware.

[0313] In some embodiments, some or all of the functionality described herein may be provided by a processing circuit executing instructions stored in a memory, which in some embodiments may be a computer program product in the form of a non-transparent computer-readable storage medium. In alternative embodiments, the processing circuit may provide some or all of the functionality, such as in a hardwired manner, without executing instructions stored on a separate or discrete device-readable storage medium. In any particular embodiment, the processing circuit may be configured to perform the described functionality, regardless of whether instructions stored on a non-transitory computer-readable storage medium are executed. The benefits provided by such functionality are not limited to only the processing circuit or other components of the computing device, but are enjoyed by the entire computing device and / or generally by end users and wireless networks.

[0314] Embodiment 1: A method for reducing channel state information (CSI) reporting overhead for coherent joint transmission (CJT) from multiple transmission and reception points (TRPs) to a user equipment device (UE) performed by one or more network nodes (502, 504), the method comprising: configuring a CSI reporting configuration (602) based on a type II codebook (CB) for a UE (506), the CSI reporting configuration comprising N RS CSI reference signal (CSI-RS) resources (each associated with one of the plurality of TRPs) and a parameter L specifying a maximum number of spatial beams to include in the CSI for CJT; sending (604) NRS CSI-RS resources and requesting a UE (506) to report CSI based on a type IICB according to a CSI report configuration; receiving (606) a CSI report from the UE (506), the CSI report including CSI associated with L' spatial beams, where L' is an integer and is less than or equal to L; constructing (608) a precoding matrix for each of a plurality of TRPs based on the CSI report; and applying (610) the precoding matrix to a physical downlink shared channel (PDSCH) at each of the plurality of TRPs.

[0315] Embodiment 2: A method according to embodiment 1, wherein L' spatial beams are selected beams associated with one or more CSI-RS resources, and wherein, if no beam associated with one of the CSI-RS resources is selected, no corresponding TRP is used for CJT to the UE (506), and no precoding matrix associated with the TRP is reported in the CSI.

[0316] Embodiment 3: The method according to embodiment 1, wherein the CSI report configuration further includes the number of FD basis vectors to be selected.

[0317] Embodiment 4: The method according to embodiment 3, wherein the number of FD basis vectors is based on the number of CSI resources.

[0318] Embodiment 5: A method according to any one of embodiments 1-4, wherein the CSI report includes a first part, which includes one or more of the following: a number of layers or a rank indicator RI, the number of L′ spatial beams, the number of selected spatial beams associated with each CSI-RS resource, the number of non-zero coefficients on all layers; and a channel quality indicator CQI.

[0319] Embodiment 6: A method according to any one of embodiments 1-5, wherein the CSI report includes a second part, which includes one or more of the following: the number of selected beams associated with each CSI-RS resource (if it is not reported in part 1); beam indices of L′ selected beams; indices of multiple selected frequency-domain FD basis vectors for each layer; a non-zero coefficient bitmap for each layer, wherein each bit in the bitmap is associated with a coefficient (the coefficient is associated with the selected beam and the selected FD basis vector at polarization), and wherein the non-zero coefficient is indicated by setting the corresponding bit to one; quantized wideband amplitude for each layer, each polarization, and each CSI-RS resource; for each non-zero coefficient, the quantized subband amplitude relative to the corresponding wideband amplitude; quantized phase information for each non-zero coefficient; and for each layer, each polarization, and each CSI-RS resource, the spatial beam index associated with the non-zero coefficient with the largest amplitude.

[0320] Embodiment 7: The method according to embodiment 6, wherein the size of the second part of the CSI report is based on the number of selected beams.

[0321] Embodiment 8: A method according to any one of embodiments 1-7, wherein the UE (506) is configured with a set of parameters for CSI reporting, the set of parameters including one or more of the following: a total number of L spatial beams; a scaling factor for a precoder matrix indicator PMI subband size; a parameter for configuring the number of frequency domain FD basis vectors for a given rank; and a parameter for configuring the maximum number of non-zero coefficients for each layer.

[0322] Embodiment 9: A network node (502, 504), comprising a memory storing computer executable instructions; and a processor executing the computer executable instructions to perform operations, the operations comprising: configuring a CSI report configuration (602) based on a type II codebook (CB) for a UE (506), the CSI report configuration comprising N RS CSI reference signal (CSI-RS) resources (each associated with one of the plurality of TRPs) and a parameter L specifying a maximum number of spatial beams to include in the CSI for CJT; sending (604) N RSCSI-RS resources and requesting a UE (506) to report CSI based on a type IICB according to a CSI report configuration; receiving (606) a CSI report from the UE (506), the CSI report including CSI associated with L' spatial beams, where L' is an integer and is less than or equal to L; constructing (608) a precoding matrix for each of a plurality of TRPs based on the CSI report; and applying (610) the precoding matrix to a physical downlink shared channel (PDSCH) at each of the plurality of TRPs.

[0323] Embodiment 10: A network node according to embodiment 9, wherein L' spatial beams are selected beams associated with one or more CSI-RS resources, and wherein, if no beam associated with one of the CSI-RS resources is selected, no corresponding TRP is used for CJT to the UE (506), and no precoding matrix associated with the TRP is reported in the CSI.

[0324] Embodiment 11: The network node according to embodiment 9, wherein the CSI report configuration further includes the number of FD basis vectors to be selected.

[0325] Embodiment 12: The network node according to embodiment 11, wherein the number of FD basis vectors is based on the number of CSI resources.

[0326] Embodiment 13: A network node according to any one of embodiments 9-12, wherein the CSI report includes a first part, which includes one or more of the following: a number of layers or a rank indicator RI, the number of L′ spatial beams, the number of selected spatial beams associated with each CSI-RS resource, the number of non-zero coefficients on all layers; and a channel quality indicator CQI.

[0327] Embodiment 14: A network node according to embodiment 13, wherein the CSI report includes a second part, which includes one or more of the following: the number of selected beams associated with each CSI-RS resource (if it is not reported in part 1); beam indices of L′ selected beams; indices of multiple selected frequency-domain FD basis vectors for each layer; a non-zero coefficient bitmap for each layer, wherein each bit in the bitmap is associated with a coefficient (the coefficient is associated with the selected beam and the selected FD basis vector at polarization), and wherein the non-zero coefficient is indicated by setting the corresponding bit to one; quantized wideband amplitude for each layer, each polarization, and each CSI-RS resource; for each non-zero coefficient, the quantized subband amplitude relative to the corresponding wideband amplitude; quantized phase information for each non-zero coefficient; and for each layer, each polarization, and each CSI-RS resource, the spatial beam index associated with the non-zero coefficient with the largest amplitude.

[0328] Embodiment 15: The network node according to embodiment 14, wherein the size of the second part of the CSI report is based on the number of selected beams.

[0329] Embodiment 16: A network node according to any one of embodiments 9-15, wherein the UE (506) is configured with a set of parameters for CSI reporting, the set of parameters comprising one or more of: a total number of L spatial beams; a scaling factor for a precoder matrix indicator PMI subband size; a parameter for configuring the number of frequency domain FD basis vectors for a given rank; and a parameter for configuring the maximum number of non-zero coefficients for each layer.

[0330] Embodiment 17: A method for reducing channel state information (CSI) reporting overhead for coherent joint transmission (CJT) from multiple transmit receive points (TRPs) performed by a user equipment 506 (UE), the method comprising: receiving (702) a configuration having a CSI reporting configuration based on a type II codebook CB from a network node (502, 504), the CSI reporting configuration comprising N RS CSI reference signal CSI-RS resources (each associated with one of the plurality of TRPs) and a maximum total number of L spatial beams included in the CSI for CJT; receiving (704) including N RS The transmission of CSI-RS resources and the request to report the CSI based on type IICB according to the CSI reporting configuration; based on N RSCSI-R resources, measuring (706) channels, and calculating CSI based on an aggregation of the measured channels by selecting L′ spatial beams, where L′ is an integer and is less than or equal to L; and sending (708) a CSI report including a beam index for each of the L′ spatial beams.

[0331] Embodiment 18: A method according to embodiment 17, wherein L' spatial beams are selected beams associated with one or more CSI-RS resources, and wherein, if a beam associated with one of the CSI-RS resources is not selected, the corresponding TRP is not used for CJT to the UE (506), and the precoding matrix associated with the TRP is not reported in the CSI.

[0332] Embodiment 19: The method according to Embodiment 17, wherein the CSI report configuration further includes the number of FD basis vectors to be selected.

[0333] Embodiment 20: The method according to embodiment 19, wherein the number of FD basis vectors is based on the number of CSI resources.

[0334] Embodiment 21: A method according to any one of embodiments 17-20, wherein the CSI report includes a first part, which includes one or more of the following: a number of layers or a rank indicator RI, the number of L′ spatial beams, the number of selected spatial beams associated with each CSI-RS resource, the number of non-zero coefficients on all layers; and a channel quality indicator CQI.

[0335] Embodiment 22: A method according to embodiment 21, wherein the CSI report includes a second part, which includes one or more of the following: the number of selected beams associated with each CSI-RS resource (if it is not reported in part 1); beam indices of L′ selected beams; indices of multiple selected frequency-domain FD basis vectors for each layer; a non-zero coefficient bitmap for each layer, wherein each bit in the bitmap is associated with a coefficient (the coefficient is associated with the selected beam and the selected FD basis vector at polarization), and wherein the non-zero coefficient is indicated by setting the corresponding bit to one; quantized wideband amplitude for each layer, each polarization, and each CSI-RS resource; for each non-zero coefficient, the quantized subband amplitude relative to the corresponding wideband amplitude; quantized phase information for each non-zero coefficient; and for each layer, each polarization, and each CSI-RS resource, the spatial beam index associated with the non-zero coefficient with the largest amplitude.

[0336] Embodiment 23: A method according to embodiment 22, wherein the size of the second part of the CSI report is based on the number of selected beams.

[0337] Embodiment 24: A method according to any one of embodiments 17-23, wherein the UE (506) is configured with a set of parameters for CSI reporting, the set of parameters including one or more of: a total number of L spatial beams; a scaling factor for a precoder matrix indicator PMI subband size; a parameter for configuring the number of frequency domain FD basis vectors for a given rank; and a parameter for configuring the maximum number of non-zero coefficients for each layer.

[0338] Embodiment 25: A user equipment, comprising a memory storing computer executable instructions; and a processor executing the computer executable instructions to perform operations, the operations comprising: receiving (702) a configuration having a CSI report configuration based on a type II codebook CB from a network node (502, 504), the CSI report configuration comprising N RS CSI reference signal CSI-RS resources (each associated with one of the plurality of TRPs) and a maximum total number of L spatial beams included in the CSI for CJT; receiving (704) including N RS The transmission of CSI-RS resources and the request to report the CSI based on type IICB according to the CSI reporting configuration; based on N RS CSI-R resources, measuring (706) channels, and calculating CSI based on an aggregation of the measured channels by selecting L′ spatial beams, where L′ is an integer and is less than or equal to L; and sending (708) a CSI report including a beam index for each of the L′ spatial beams.

[0339] Embodiment 26: A method according to embodiment 25, wherein L' spatial beams are selected beams associated with one or more CSI-RS resources, and wherein, if a beam associated with one of the CSI-RS resources is not selected, the corresponding TRP is not used for CJT to the UE (506), and the precoding matrix associated with the TRP is not reported in the CSI.

[0340] Embodiment 27: The method according to Embodiment 25, wherein the CSI report configuration further includes the number of frequency domain FD basis vectors to be selected.

[0341] Embodiment 28: The method according to embodiment 27, wherein the number of FD basis vectors is based on the number of CSI resources.

[0342] Embodiment 29: A method according to any one of embodiments 25-28, wherein the CSI report includes a first part, which includes one or more of the following: a number of layers or a rank indicator RI, the number of L′ spatial beams, the number of selected spatial beams associated with each CSI-RS resource, the number of non-zero coefficients on all layers; and a channel quality indicator CQI.

[0343] Embodiment 30: A method according to embodiment 29, wherein the CSI report includes a second part, which includes one or more of the following: the number of selected beams associated with each CSI-RS resource (if it is not reported in part 1); beam indices of L′ selected beams; indices of multiple selected frequency-domain FD basis vectors for each layer; a non-zero coefficient bitmap for each layer, wherein each bit in the bitmap is associated with a coefficient (the coefficient is associated with the selected beam and the selected FD basis vector at polarization), and wherein the non-zero coefficient is indicated by setting the corresponding bit to one; quantized wideband amplitude for each layer, each polarization, and each CSI-RS resource; for each non-zero coefficient, the quantized subband amplitude relative to the corresponding wideband amplitude; quantized phase information for each non-zero coefficient; and for each layer, each polarization, and each CSI-RS resource, the spatial beam index associated with the non-zero coefficient with the largest amplitude.

[0344] Embodiment 31: A method according to embodiment 30, wherein the size of the second part of the CSI report is based on the number of selected beams.

[0345] Embodiment 32: A method according to any one of embodiments 25-31, wherein the UE (506) is configured with a set of parameters for CSI reporting, the set of parameters including one or more of: a total number of L spatial beams; a scaling factor for a precoder matrix indicator PMI subband size; a parameter for configuring the number of frequency domain FD basis vectors for a given rank; and a parameter for configuring the maximum number of non-zero coefficients for each layer.

[0346] At least some of the following abbreviations may be used in the present disclosure. If there is an inconsistency between abbreviations, the above usage shall take precedence. If listed multiple times below, the first listing shall take precedence over any subsequent listings.

[0347] ●3GPP Third Generation Partnership Project

[0348] 5G fifth generation

[0349] ●5GC Fifth Generation Core

[0350] ●5GS Fifth Generation System

[0351] AF application function

[0352] ●AMF access and mobility functions

[0353] ●AN access network

[0354] ●AP Access Point

[0355] ●ASIC Application-Specific Integrated Circuit

[0356] ●AUSF authentication server function

[0357] ●CPU Central Processing Unit

[0358] ●DN Data Network

[0359] ●DSP Digital Signal Processor

[0360] ●eNB Enhanced or evolved Node B

[0361] EPS Evolved Packet System

[0362] ●E-UTRA Evolved Universal Terrestrial Radio Access

[0363] ●FPGA Field Programmable Gate Array

[0364] ●GNB New Radio Base Station

[0365] GNB-DU New Radio Station Distributed Unit

[0366] ●HSS Home Subscriber Server

[0367] IoT

[0368] IP Internet Protocol

[0369] LTE Long Term Evolution

[0370] ●MME Mobility Management Entity

[0371] ●MTC Machine Type Communication

[0372] ●NEF network open function

[0373] NF Network Function

[0374] NR New Radio

[0375] ●NRF Network Function Repository Function

[0376] NSSF network slice selection function

[0377] ●OTT (Over-the-Top)

[0378] ●PC Personal Computer

[0379] PCF policy control function

[0380] ●P-GW Packet Data Network Gateway

[0381] QoS Quality of Service

[0382] RAM Random Access Memory

[0383] RAN Radio Access Network

[0384] ●ROM Read Only Memory

[0385] ●RRH Remote Radio Head

[0386] ●RTT Round Trip Time

[0387] ●SCEF service capability exposure function

[0388] ●SMF session management function

[0389] ●UDM unified data management

[0390] UE User Equipment

[0391] UPF User Plane Function

[0392] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered to be within the scope of the concepts disclosed herein.

Claims

1. A method for channel state information (CSI) reporting for coherent joint transmission (CJT) performed by a user equipment (UE) device (506), the method comprising: A configuration having a CSI report configuration and a codebook configuration is received (702) from a network node (502, 504), wherein the CSI report configuration includes N for channel measurement. RS >Indication of 1 CSI reference signal CSI-RS resource; Receive (704) including N RS transmission of CSI-RS resources and a request to report CSI according to the CSI reporting configuration; Based on the N RS CSI-RS resources, measuring (706) a channel, and calculating CSI based on the measured channel, wherein the calculation includes for the N RS For each CSI-RS resource in the CSI-RS resources, determining a number of spatial beams or CSI-RS ports; and Send (708) a CSI report, the CSI report comprising a first part and a second part, wherein the first part comprises RS An indication of the number of spatial beams or CSI-RS ports for each CSI-RS resource in the CSI-RS resources.

2. The method according to claim 1, wherein: The N RS Each CSI-RS resource in the CSI-RS resources is associated with one of the multiple transmit-receive points TRP.

3. The method according to any one of claims 1 to 2, wherein: The codebook configuration further includes an indication of a type II codebook of precoding matrices, wherein each column of the precoding matrix in the codebook is a linear combination of multiple spatial beams or CSI-RS ports.

4. The method according to claim 2, wherein: If a spatial beam or CSI-RS port is not selected for one of the CSI-RS resources, the corresponding CSI-RS resource or TRP is not selected for CJT for the UE (506), and the precoding matrix associated with the TRP is not reported in the CSI.

5. The method according to any one of claims 1 to 4, wherein: The CSI report configuration further includes the number of frequency domain FD basis vectors to be selected.

6. The method according to claim 5, wherein: The number of FD basis vectors depends on N RS The value of .

7. The method according to any one of claims 1 to 6, wherein: The first part of the CSI report further includes one or more of the following: The number of layers or rank indicator RI; The number of non-zero coefficients across all layers; and Channel Quality Indicator CQI.

8. The method according to claim 7, wherein: The second part of the CSI report further includes one or more of the following: The spatial beam or CSI-RS port index of the number of spatial beams or CSI-RS ports indicated for each CSI-RS resource in the first part; The indices of multiple selected frequency-domain FD basis vectors for each layer; a non-zero coefficient bitmap for each layer, wherein each bit in the bitmap is associated with a coefficient associated with the indicated spatial beam or CSI-RS port and the selected FD basis vector at polarization, and wherein a non-zero coefficient is indicated by setting the corresponding bit to one; Quantized wideband amplitude per layer, per polarization, and per CSI-RS resource; for each of the non-zero coefficients, a quantized subband amplitude relative to a corresponding wideband amplitude associated with the same CSI-RS resource; quantized phase information for each of the non-zero coefficients; and • For each layer, each polarization, and each CSI-RS resource, the spatial beam index associated with the non-zero coefficient with the largest magnitude.

9. The method according to claim 8, wherein: The size of the second part of the CSI report is based on the number of spatial beams or ports indicated for each CSI-RS resource in the first part of the CSI report.

10. The method according to any one of claims 1 to 9, wherein: The UE (506) is further configured with a set of parameters for the CSI reporting, the set of parameters comprising one or more of the following: Scaling factor for the precoder matrix indicator PMI subband size; Parameters for configuring the number of frequency-domain FD basis vectors for a given rank; and • Parameters used to configure the maximum number of non-zero coefficients for each layer.

11. A user equipment (UE) device (506), comprising: a memory storing computer executable instructions; as well as a processor executing the computer executable instructions to perform operations comprising: A configuration having a CSI report configuration and a codebook configuration is received (702) from a network node (502, 504), wherein the CSI report configuration includes N for channel measurement. RS >Indication of 1 CSI reference signal CSI-RS resource; Receive (704) including N RS transmission of CSI-RS resources and a request to report CSI according to the CSI reporting configuration; Based on the N RS CSI-RS resources, measuring (706) a channel, and calculating CSI based on the measured channel, wherein the calculation includes for the N RS For each CSI-RS resource in the CSI-RS resources, determining a number of spatial beams or CSI-RS ports; and Send (708) a CSI report, the CSI report comprising a first part and a second part, wherein the first part comprises RS An indication of the number of spatial beams or CSI-RS ports for each CSI-RS resource in the CSI-RS resources.

12. The UE (506) according to claim 11, wherein: The N RS Each CSI-RS resource in the CSI-RS resources is associated with one of the multiple transmit-receive points TRP.

13. The UE (506) according to any one of claims 11 to 12, wherein: The codebook configuration further includes an indication of a type II codebook of precoding matrices, wherein each column of the precoding matrix in the codebook is a linear combination of multiple spatial beams or CSI-RS ports.

14. The UE (506) according to claim 12, wherein: If a spatial beam or CSI-RS port is not selected for one of the CSI-RS resources, the corresponding CSI-RS resource or TRP is not selected for CJT for the UE (506), and the precoding matrix associated with the TRP is not reported in the CSI.

15. The UE (506) according to any one of claims 11 to 14, wherein: The CSI report configuration further includes the number of frequency domain FD basis vectors to be selected.

16. The UE (506) according to claim 15, wherein: The number of FD basis vectors depends on N RS The value of .

17. The UE (506) according to any one of claims 11 to 16, wherein: The first part of the CSI report further includes one or more of the following: The number of layers or rank indicator RI; The number of non-zero coefficients across all layers; and Channel Quality Indicator CQI.

18. The UE (506) according to claim 17, wherein: The second part of the CSI report further includes one or more of the following: The spatial beam or CSI-RS port index of the number of spatial beams or CSI-RS ports indicated for each CSI-RS resource in the first part; The indices of multiple selected frequency-domain FD basis vectors for each layer; a non-zero coefficient bitmap for each layer, wherein each bit in the bitmap is associated with a coefficient associated with the indicated spatial beam or CSI-RS port and the selected FD basis vector at polarization, and wherein a non-zero coefficient is indicated by setting the corresponding bit to one; Quantized wideband amplitude per layer, per polarization, and per CSI-RS resource; for each of the non-zero coefficients, a quantized subband amplitude relative to a corresponding wideband amplitude associated with the same CSI-RS resource; quantized phase information for each of the non-zero coefficients; and • For each layer, each polarization, and each CSI-RS resource, the spatial beam index associated with the non-zero coefficient with the largest magnitude.

19. The UE (506) according to claim 18, wherein: The size of the second part of the CSI report is based on the number of spatial beams or ports indicated for each CSI-RS resource in the first part of the CSI report.

20. The UE (506) according to any one of claims 11 to 19, wherein: The UE (506) is further configured with a set of parameters for the CSI reporting, the set of parameters comprising one or more of the following: Scaling factor for the precoder matrix indicator PMI subband size; Parameters for configuring the number of frequency-domain FD basis vectors for a given rank; and • Parameters used to configure the maximum number of non-zero coefficients for each layer.

21. A method for channel state information (CSI) reporting for coherent joint transmission (CJT) performed by a user equipment (UE) device (506), the method comprising: A configuration (702) having a CSI report configuration and a codebook configuration is received from a network node (502, 504), wherein the CSI report configuration includes N for channel measurement. RS >Indication of 1 CSI reference signal CSI-RS resource; Receive (704) including N RS transmission of CSI-RS resources and a request to report CSI according to the CSI reporting configuration; Based on the N RS CSI-RS resources, measuring (706) a channel, and calculating CSI based on the measured channel, wherein the calculation includes determining a CSI based on the N RS the number of frequency-domain FD basis vectors selected based on the number of spatial beams or CSI-RS ports for each CSI-RS resource in the CSI-RS resources; and The CSI report is sent (708), the CSI report comprising a first part and a second part, wherein the first part comprises RS The method further comprises an indication of a number of spatial beams or CSI-RS ports for each of the CSI-RS resources, and the second part comprises indices of the determined number of FD basis vectors.

22. The method according to claim 21, wherein: The N RS Each CSI-RS resource in the CSI-RS resources is associated with one of the multiple transmit-receive points TRP.

23. The method according to claim 21, wherein: The codebook configuration further includes an indication of a type II codebook of precoding matrices, wherein each column of the precoding matrix in the codebook is a linear combination of multiple spatial beams or CSI-RS ports.

24. A user equipment device (506), comprising: a memory storing computer executable instructions; as well as a processor executing the computer executable instructions to perform operations comprising: A configuration having a CSI report configuration and a codebook configuration is received (702) from a network node (502, 504), wherein the CSI report configuration includes N for channel measurement. RS >Indication of 1 CSI reference signal CSI-RS resource; Receive (704) including N RS transmission of CSI-RS resources and a request to report CSI according to the CSI reporting configuration; Based on the N RS CSI-RS resources, measuring (706) a channel, and calculating CSI based on the measured channel, wherein the calculation includes determining a CSI based on the N RS the number of frequency-domain FD basis vectors selected based on the number of spatial beams or CSI-RS ports for each CSI-RS resource in the CSI-RS resources; and The CSI report is sent (708), the CSI report comprising a first part and a second part, wherein the first part comprises RS The method further comprises an indication of a number of spatial beams or CSI-RS ports for each of the CSI-RS resources, and the second part comprises indices of the determined number of FD basis vectors.

25. The UE (506) according to claim 24, wherein: The N RS Each CSI-RS resource in the CSI-RS resources is associated with one of the multiple transmit-receive points TRP.

26. The UE (506) of claim 24, wherein: The codebook configuration further includes an indication of a type II codebook of precoding matrices, wherein each column of the precoding matrix in the codebook is a linear combination of multiple spatial beams or CSI-RS ports.

27. A method performed by one or more network nodes (502, 504) for facilitating channel state information (CSI) reporting for coherent joint transmission (CJT), the method comprising: The UE (506) is configured (602) with a CSI report configuration and a codebook configuration, wherein the CSI report configuration includes N for channel measurement. RS >Indication of 1 CSI reference signal CSI-RS resource; Send (604) the N RS CSI-RS resources and a request to report CSI according to the CSI reporting configuration; as well as A CSI report is received (606) from the UE (506), the CSI report comprising a first part and a second part, wherein the first part comprises a CSI report for the N RS An indication of the number of spatial beams or CSI-RS ports for each CSI-RS resource in the CSI-RS resources.

28. The method according to claim 27, wherein: The N RS Each CSI-RS resource in the CSI-RS resources is associated with one of the multiple transmit-receive points TRP.

29. The method according to claim 27 or 28, wherein: The codebook configuration further includes an indication of a type II codebook of precoding matrices, wherein each column of the precoding matrix in the codebook is a linear combination of multiple spatial beams or CSI-RS ports.

30. The method of claim 28, wherein: If no spatial beam or CSI-RS port is selected for one of the CSI-RS resources, no corresponding CSI-RS resource or TRP is selected for CJT for the UE (506), and no precoding matrix associated with the TRP is reported in the CSI.

31. The method according to any one of claims 27 to 30, wherein: The CSI report configuration further includes the number of frequency domain FD basis vectors to be selected.

32. The method according to claim 31, wherein: The number of FD basis vectors depends on N RS The value of .

33. The method according to any one of claims 27 to 32, wherein: The first part of the CSI report further includes one or more of the following: The number of layers or rank indicator RI; The number of non-zero coefficients across all layers; and Channel Quality Indicator CQI.

34. The method of claim 33, wherein: The second part of the CSI report further includes one or more of the following: The spatial beam or CSI-RS port index of the number of spatial beams or CSI-RS ports indicated for each CSI-RS resource in the first part; The indices of multiple selected frequency-domain FD basis vectors for each layer; a non-zero coefficient bitmap for each layer, wherein each bit in the bitmap is associated with a coefficient associated with the indicated spatial beam or CSI-RS port and the selected FD basis vector at polarization, and wherein a non-zero coefficient is indicated by setting the corresponding bit to one; Quantized wideband amplitude per layer, per polarization, and per CSI-RS resource; for each of the non-zero coefficients, a quantized subband amplitude relative to a corresponding wideband amplitude associated with the same CSI-RS resource; quantized phase information for each of the non-zero coefficients; and • For each layer, each polarization, and each CSI-RS resource, the spatial beam index associated with the non-zero coefficient with the largest magnitude.

35. The method of claim 34, wherein: The size of the second part of the CSI report is based on the number of spatial beams or ports indicated for each CSI-RS resource in the first part of the CSI report.

36. A method according to any one of claims 27 to 35, wherein: The UE (506) is further configured with a set of parameters for the CSI reporting, the set of parameters comprising one or more of the following: Scaling factor for the precoder matrix indicator PMI subband size; Parameters for configuring the number of frequency-domain FD basis vectors for a given rank; and • Parameters used to configure the maximum number of non-zero coefficients for each layer.

37. A network node (502, 504), comprising: a memory storing computer executable instructions; as well as a processor executing the computer executable instructions to perform operations comprising: The UE (506) is configured (602) with a CSI report configuration and a codebook configuration, wherein the CSI report configuration includes N for channel measurement. RS >Indication of 1 CSI reference signal CSI-RS resource; Send (604) the N RS CSI-RS resources and a request to report CSI according to the CSI reporting configuration; and A CSI report is received (606) from the UE (506), the CSI report comprising a first part and a second part, wherein the first part comprises a CSI report for the N RS An indication of the number of spatial beams or CSI-RS ports for each CSI-RS resource in the CSI-RS resources.

38. The network node (502, 504) of claim 37, wherein: The N RS Each CSI-RS resource in the CSI-RS resources is associated with one of the multiple transmit-receive points TRP.

39. The network node (502, 504) of claim 37 or 38, wherein: The codebook configuration further includes an indication of a type II codebook of precoding matrices, wherein each column of the precoding matrix in the codebook is a linear combination of multiple spatial beams or CSI-RS ports.

40. The network node (502, 504) of claim 38, wherein: If no spatial beam or CSI-RS port is selected for one of the CSI-RS resources, no corresponding CSI-RS resource or TRP is selected for CJT for the UE (506), and no precoding matrix associated with the TRP is reported in the CSI.

41. The network node (502, 504) according to any one of claims 37 to 40, wherein: The CSI report configuration further includes the number of frequency domain FD basis vectors to be selected.

42. The network node (502, 504) of claim 41, wherein: The number of FD basis vectors depends on N RS The value of .

43. The network node (502, 504) according to any one of claims 37 to 42, wherein: The first part of the CSI report further includes one or more of the following: The number of layers or rank indicator RI; The number of non-zero coefficients across all layers; and Channel Quality Indicator CQI.

44. The network node (502, 504) of claim 43, wherein: The second part of the CSI report further includes one or more of the following: The spatial beam or CSI-RS port index of the number of spatial beams or CSI-RS ports indicated for each CSI-RS resource in the first part; The indices of multiple selected frequency-domain FD basis vectors for each layer; a non-zero coefficient bitmap for each layer, wherein each bit in the bitmap is associated with a coefficient associated with the indicated spatial beam or CSI-RS port and the selected FD basis vector at polarization, and wherein a non-zero coefficient is indicated by setting the corresponding bit to one; Quantized wideband amplitude per layer, per polarization, and per CSI-RS resource; for each of the non-zero coefficients, a quantized subband amplitude relative to a corresponding wideband amplitude associated with the same CSI-RS resource; quantized phase information for each of the non-zero coefficients; and • For each layer, each polarization, and each CSI-RS resource, the spatial beam index associated with the non-zero coefficient with the largest magnitude.

45. The network node (502, 504) of claim 44, wherein: The size of the second part of the CSI report is based on the number of spatial beams or ports indicated for each CSI-RS resource in the first part of the CSI report.

46. ​​The network node (502, 504) according to any one of claims 37 to 45, wherein: The UE (506) is further configured with a set of parameters for the CSI reporting, the set of parameters comprising one or more of the following: Scaling factor for the precoder matrix indicator PMI subband size; Parameters for configuring the number of frequency-domain FD basis vectors for a given rank; and • Parameters used to configure the maximum number of non-zero coefficients for each layer.

47. A method performed by one or more network nodes (502, 504) for facilitating channel state information (CSI) reporting for coherent joint transmission (CJT), the method comprising: The UE (506) is configured (602) with a CSI report configuration and a codebook configuration, wherein the CSI report configuration includes N for channel measurement. RS >Indication of 1 CSI reference signal CSI-RS resource; Send (604) the N RS CSI-RS resources and a request to report CSI according to the CSI reporting configuration; as well as A CSI report is received (606) from the UE (506), the CSI report comprising a first part and a second part, wherein the first part comprises a CSI report for the N RS The method further comprises an indication of a number of spatial beams or CSI-RS ports for each of the CSI-RS resources, and the second part comprises indices of the determined number of FD basis vectors.

48. The method of claim 47, wherein: The N RS Each CSI-RS resource in the CSI-RS resources is associated with one of the multiple transmit-receive points TRP.

49. The method of claim 47, wherein: The codebook configuration further includes an indication of a type II codebook of precoding matrices, wherein each column of the precoding matrix in the codebook is a linear combination of multiple spatial beams or CSI-RS ports.

50. A network node (502, 504), comprising: a memory storing computer executable instructions; as well as a processor executing the computer executable instructions to perform operations comprising: The UE (506) is configured (602) with a CSI report configuration and a codebook configuration, wherein the CSI report configuration includes N for channel measurement. RS >Indication of 1 CSI reference signal CSI-RS resource; Send (604) the N RS CSI-RS resources and a request to report CSI according to the CSI reporting configuration; and A CSI report is received (606) from the UE (506), the CSI report comprising a first part and a second part, wherein the first part comprises a CSI report for the N RS The method further comprises an indication of a number of spatial beams or CSI-RS ports for each of the CSI-RS resources, and the second part comprises indices of the determined number of FD basis vectors.

51. The network node (502, 504) of claim 50, wherein: The N RS Each CSI-RS resource in the CSI-RS resources is associated with one of the multiple transmit-receive points TRP.

52. The network node (502, 504) of claim 50, wherein: The codebook configuration further includes an indication of a type II codebook of precoding matrices, wherein each column of the precoding matrix in the codebook is a linear combination of multiple spatial beams or CSI-RS ports.

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