Channel state information feedback method and communications apparatus
A channel state information feedback method includes: a terminal receives first indication information from a network device, and the terminal sends channel state information to the network device. The first indication information is used to indicate a type of a right multiplication matrix in a first codebook, and the first codebook satisfies a formula (I). W is the first codebook, W 1 is a port selection matrix, (II) is a linear superposition coefficient matrix, W f is the right multiplication matrix, and (III) is a conjugate transpose of W f , and is used by the terminal to determine the channel state information based on the first codebook. According to the method, when there are a plurality of codebooks, the codebook used by the terminal to obtain the CSI can be clearly indicated.
1. A communications method, comprising:
receiving, by a terminal, first indication information from a network device, wherein the first indication information indicates a type of a right multiplication matrix in a first codebook, wherein the first codebook satisfies a formula W=W 1 {tilde over (W)} 2 W f H , where W is the first codebook, W 1 is a port selection matrix, {tilde over (W)} 2 is a linear superposition coefficient matrix, W f H is a conjugate transpose of W f , and W f is the right multiplication matrix; and
determining, by the terminal, channel state information based on the first indication information.
2. The method according to claim 1 , wherein the first indication information indicates that the type of the right multiplication matrix W f is a port selection matrix.
3. The method according to claim 1 , wherein the first indication information indicates that the type of the right multiplication matrix W f is one specific column vector.
4. The method according to claim 3 , wherein the one specific column vector is a column vector in which all elements are 1.
5. The method according to claim 1 , wherein the first indication information indicates that the type of the right multiplication matrix W f is a discrete Fourier transform (DFT) matrix, and the DFT matrix comprises a column vector in which all elements are 1.
6. The method according to claim 5 , wherein the first indication information further indicates the column vector in which all elements are 1.
7. The method according to claim 5 , wherein the method further comprises:
receiving, by the terminal, second indication information from the network device, wherein the second indication information indicates the column vector in which all elements are 1.
8. The method according to claim 1 , wherein W 1 is for selecting one or more channel state information reference signal (CSI-RS) port groups, and W f is for selecting one or more CSI-RS ports of the one or more CSI-RS port groups.
9. A communications apparatus, comprising:
at least one processor; and
one or more memories coupled to the at least one processor and storing programming instructions;
wherein the at least one processor is configured to execute the programming instructions to facilitate the following being performed by the communication apparatus:
receiving first indication information from a network device, wherein the first indication information indicates a type of a right multiplication matrix in a first codebook, wherein the first codebook satisfies a formula W=W 1 {tilde over (W)} 2 W f H , where W is the first codebook, W 1 is a port selection matrix, {tilde over (W)} 2 is a linear superposition coefficient matrix, W f H is a conjugate transpose of W f , and W f is the right multiplication matrix; and
determining channel state information based on the first indication information.
10. The communications apparatus according to claim 9 , wherein the first indication information indicates that the type of the right multiplication matrix W f is a port selection matrix.
11. The communications apparatus according to claim 9 , wherein the first indication information indicates that the type of the right multiplication matrix W f is one specific column vector.
12. The communications apparatus according to claim 11 , wherein the one specific column vector is a column vector in which all elements are 1.
13. The communications apparatus according to claim 9 , wherein the first indication information indicates that the type of the right multiplication matrix W f is a discrete Fourier transform (DFT) matrix, and the DFT matrix comprises a column vector in which all elements are 1.
14. The communications apparatus according to claim 13 , wherein the first indication information further indicates the column vector in which all elements are 1.
15. The communications apparatus according to claim 13 , wherein the at least one processor is further configured to execute the programming instructions to facilitate the following being performed by the communication apparatus:
receiving second indication information from the network device, wherein the second indication information indicates the column vector in which all elements are 1.
16. The communications apparatus according to claim 9 , wherein W 1 is for selecting one or more channel state information reference signal (CSI-RS) port groups, and W f is for selecting one or more CSI-RS ports of the one or more CSI-RS port groups.
17. The communications apparatus according to claim 9 , wherein the communications apparatus is a terminal device or a chip.
18. A non-transitory computer-readable storage medium having processor-executable instructions stored thereon, wherein the processor-executable instructions, when executed, facilitate performance of the following:
receiving first indication information from a network device, wherein the first indication information indicates a type of a right multiplication matrix in a first codebook, wherein the first codebook satisfies a formula W=W 1 {tilde over (W)} 2 W f H , where W is the first codebook, W 1 is a port selection matrix, {tilde over (W)} 2 is a linear superposition coefficient matrix, W f H is a conjugate transpose of W f , and W f is the right multiplication matrix; and
determining channel state information based on the first indication information.
19. The non-transitory computer-readable storage medium according to claim 18 , wherein the first indication information indicates that the type of the right multiplication matrix W f is one specific column vector.
20. The non-transitory computer-readable storage medium according to claim 19 , wherein the one specific column vector is a column vector in which all elements are 1.
21. The non-transitory computer-readable storage medium according to claim 18 , wherein the first indication information indicates that the type of the right multiplication matrix W f is a discrete Fourier transform (DFT) matrix, and the DFT matrix comprises a column vector in which all elements are 1.
22. The non-transitory computer-readable storage medium according to claim 21 , wherein the first indication information further indicates the column vector in which all elements are 1.