# US 10,122,427 B2 · Method for determining precoding matrix indicator, user equipment, and base station evolved NodeB > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,122,427 B2 - Document ID: US10122427B2 - Status: Granted - Kind: B2 - Application number: 15/834,984 - Filed: 2017-12-07 - Published: 2018-04-05 - Granted: 2018-11-06 - Earliest claimed: 2012-06-14 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Jianguo Wang; Yongxing Zhou - Web page: https://patentgrep.com/patent/US10122427B2 ## CPC - H04B 7/0456: Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting - H04B 7/0469: {taking special antenna structures, e.g. cross polarized antennas into account} - H04B 7/0481: {using subset selection of codebooks} - H04B 7/0617: {for beam forming} - H04B 7/0639: {Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection} - H04B 7/065: {Variable contents, e.g. long-term or short-short} - H04L 25/03949: {equalizer selection or adaptation based on feedback (multiple signaling inclusive of a precoding command for adapting the transmitter H04L1/0031; feedback for transmit diversity systems H04B7/0619; selection of codebook or precoding matrix for MIMO diversity systems H04B7/0456)} - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract The present invention relates to a method for determining a precoding matrix indicator, a user equipment (UE), a base station (e.g., eNB), and a system. The method includes: receiving a reference signal sent by a base station; selecting, based on the reference signal, a precoding matrix from a codebook, where a precoding matrix W included in the codebook is a product of two matrices W1 and W2, where W1 is a block diagonal matrix, where each block matrix is a Kronecker product of a matrix Ai and a matrix Bi; and sending a precoding matrix indicator PMI to the base station, where the PMI corresponds to the selected precoding matrix, so that the base station obtains the precoding matrix according to the PMI. ## Claims ### Claim 1 A method for determining a precoding matrix indicator, the method comprising: receiving, by a user equipment, a reference signal from a base station; determining, by the user equipment, based on the reference signal, a precoding matrix from a codebook, wherein a precoding matrix W comprised in the codebook is a product of two matrices W1 and W2, wherein W1 is a block diagonal matrix, W1=diag{X1, . . . , XNB}, NB>1, wherein each block matrix Xi is a Kronecker product of a matrix Ai and a matrix Bi, Xi=AiBi, 1≤i≤NB, and block matrices in the W1 satisfy that X2j-1=X2j, 1≤j≤NB/2; and sending, by the user equipment, a precoding matrix indicator (PMI) to the base station, wherein the PMI corresponds to the determined precoding matrix. ### Claim 2 (depends on 1) The method according to claim 1, wherein each column of the matrix Ai or the matrix Bi in the block matrix Xi=AiBi is a discrete Fourier transform (DFT) vector or is a column vector of a Hadamard matrix. ### Claim 3 (depends on 1) The method according to claim 1, wherein sending the PMI to the base station comprises: sending the PMI to the base station through a physical uplink control channel or a physical uplink shared channel. ### Claim 4 (depends on 1) The method according to claim 1, wherein multiple block matrices Xi separately correspond to antenna groups of different polarizations or at different locations. ### Claim 5 (depends on 1) The method according to claim 1, wherein each precoding matrix W comprised in the codebook is a product of two matrices W1 and W2 . ### Claim 6 (depends on 1) The method according to claim 1, wherein the matrix W2 is for selection or weighted combination of at least one column vector in the matrix W1 to form the matrix W. ### Claim 7 A method for determining a precoding matrix indicator, the method comprising: sending, by a base station, a reference signal to a user equipment; and receiving, by the base station, a precoding matrix indicator (PMI) from the user equipment, wherein the PMI corresponds to a precoding matrix that is determined by the user equipment, based on the reference signal, from a codebook, wherein a precoding matrix W comprised in the codebook is a product of two matrices W1 and W2, wherein W1 is a block diagonal matrix, W1=diag{X1, . . . , XNB}, NB>1, wherein each block matrix Xi is a Kronecker product of a matrix Ai and a matrix Bi, Xi=AiBi, and block matrices in the W1 satisfy that X2j-1=X2j, 1≤j≤NB/2. ### Claim 8 (depends on 7) The method according to claim 7, wherein each column of the matrix Ai or the matrix Bi in the block matrix Xi=AiBi is a discrete Fourier transform (DFT) vector or is a column vector of a Hadamard matrix. ### Claim 9 (depends on 7) The method according to claim 7, wherein receiving the PMI from the user equipment comprises: receiving the PMI from the user equipment through a physical uplink control channel or a physical uplink shared channel. ### Claim 10 (depends on 7) The method according to claim 7, wherein multiple block matrices Xi separately correspond to antenna groups of different polarizations or at different locations. ### Claim 11 (depends on 7) The method according to claim 7, wherein each precoding matrix W comprised in the codebook is a product of two matrices W1 and W2 . ### Claim 12 (depends on 7) The method according to claim 7, wherein the matrix W2 is for selection or weighted combination of at least one column vector in the matrix W1 to form the matrix W. ### Claim 13 A device, comprising: a receiver, configured to receive a reference signal from a base station; a processor, configured to determine, based on the reference signal, a precoding matrix from a codebook, wherein a precoding matrix W comprised in the codebook is a product of two matrices W1 and W2, wherein W1 is a block diagonal matrix, W1=diag{X1, . . . , XNB}, wherein each block matrix Xi is a Kronecker product of a matrix Ai and a matrix Bi, Xi=AiBi, 1≤i≤NB, and block matrices in the W1 satisfy that X2j-1=X2j, 1≤j≤NB2; and a transmitter, configured to send a precoding matrix indicator (PMI) to the base station, wherein the PMI corresponds to the determined precoding matrix. ### Claim 14 (depends on 13) The device according to claim 13, wherein each column of the matrix Ai or the matrix Bi in the block matrix Xi=AiBi is a discrete Fourier transform (DFT) vector or is a column vector of a Hadamard matrix. ### Claim 15 (depends on 13) The device according to claim 13, wherein the transmitter is configured to send the PMI to the base station through a physical uplink control channel or a physical uplink shared channel. ### Claim 16 (depends on 13) The device according to claim 13, wherein multiple block matrices Xi separately correspond to antenna groups of different polarizations or at different locations. ### Claim 17 (depends on 13) The device according to claim 13, wherein each precoding matrix W comprised in the codebook is a product of two matrices W1 and W2 . ### Claim 18 (depends on 13) The device according to claim 13, wherein the matrix W2 is for selection or weighted combination of at least one column vector in the matrix W1 to form the matrix W. ### Claim 19 A device, comprising: a transmitter, configured to send a reference signal to a user equipment; and a receiver, configured to receive a precoding matrix indicator (PMI) from the user equipment, wherein the PMI corresponds to a precoding matrix that is determined by the user equipment, based on the reference signal, from a codebook, wherein a precoding matrix W comprised in the codebook is a product of two matrices W1 and W2, wherein W1 is a block diagonal matrix, W1=diag{X1, . . . , XNB}, NB>1, wherein each block matrix Xi is a Kronecker product of a matrix Ai and a matrix Bi, Xi=AiBi, and block matrices in the W1 satisfy that X2j-1=X2j, 1≤j≤NB/2. ### Claim 20 (depends on 19) The device according to claim 19, wherein each column of the matrix Ai or the matrix Bi in the block matrix Xi=AiBi is a discrete Fourier transform (DFT) or is a column vector of a Hadamard matrix. ### Claim 21 (depends on 19) The device according to claim 19, wherein the receiver is configured to receive the PMI from the user equipment through a physical uplink control channel or a physical uplink shared channel. ### Claim 22 (depends on 19) The device according to claim 19, wherein multiple block matrices Xi separately correspond to antenna groups of different polarizations or at different locations. ### Claim 23 (depends on 19) The device according to claim 19, wherein each precoding matrix W comprised in the codebook is a product of two matrices W1 and W2 . ### Claim 24 (depends on 1, 19) The device according to claim 19, The method according to claim 1, wherein the matrix W2 is for selection or weighted combination of at least one column vector in the matrix W1 to form the matrix W. ### Claim 25 A non-transitory computer-readable storage medium comprising instructions which, when executed by a computer, cause the computer to: receive a reference signal from a base station; determine, based on the reference signal, a precoding matrix from a codebook, wherein a precoding matrix W comprised in the codebook is a product of two matrices W1 and W2, wherein W1 is a block diagonal matrix, W1=diag{X1, . . . , XNB}, NB>1, wherein each block matrix Xi is a Kronecker product of a matrix Ai and a matrix Bi, Xi=AiBi, 1≤i≤NB, and block matrices in the W1 satisfy that X2j-1=X2j, 1≤j≤NB/2; and send, a precoding matrix indicator (PMI) to the base station, wherein the PMI corresponds to the determined precoding matrix. ### Claim 26 (depends on 25) The non-transitory computer-readable storage medium according to claim 25, wherein each column of the matrix Ai or the matrix Bi in the block matrix Xi=AiBi is a discrete Fourier transform (DFT) vector or is a column vector of a Hadamard matrix. ### Claim 27 (depends on 25) The non-transitory computer-readable storage medium according to claim 25, wherein to send the PMI to the base station, the instructions, when executed by a computer, cause the computer to: send the PMI to the base station through a physical uplink control channel or a physical uplink shared channel. ### Claim 28 (depends on 25) The non-transitory computer-readable storage medium according to claim 25, wherein multiple block matrices Xi separately correspond to antenna groups of different polarizations or at different locations. ### Claim 29 (depends on 25) The non-transitory computer-readable storage medium according to claim 25, wherein each precoding matrix W comprised in the codebook is a product of two matrices W1 and W2. ### Claim 30 (depends on 25) The non-transitory computer-readable storage medium according to claim 25, wherein the matrix W2 is for selection or weighted combination of at least one column vector in the matrix W1 to form the matrix W.