Codebook configuration method and user equipment

1. A codebook configuration method, comprising:

receiving, by a user equipment (UE), a reference signal that is of an antenna whose quantity of antenna ports is X and that is sent by a base station and configuration information of a codebook subset restriction for the quantity X of antenna ports, wherein the configuration information of the codebook subset restriction for the quantity X of antenna ports comprises first configuration information and second configuration information, and X is a positive integer greater than or equal to 2;

determining, by the UE according to the configuration information of the codebook subset restriction for the quantity X of antenna ports, a precoding matrix on which channel measurement and feedback need to be performed, wherein the codebook subset restriction for the quantity X of antenna ports is used to instruct the UE to select some precoding matrices from all precoding matrices in a codebook whose quantity of antenna ports is X for measurement and feedback; and

obtaining, by the UE via measurement according to the reference signal of the antenna whose quantity of antenna ports is X, the precoding matrix on which channel measurement and feedback need to be performed.

2. The method according to claim 1 , wherein the first configuration information is configuration information of a codebook subset restriction for a quantity X1 of antenna ports, and the second configuration information is configuration information of a codebook subset restriction for a quantity X2 of antenna ports, wherein X=X1×X2.

3. The method according to claim 1 , wherein the first configuration information is configuration information of a codebook subset restriction for a quantity X1 of antenna ports, and the second configuration information is configuration information of a codebook subset restriction for a quantity X2 of antenna ports, wherein X=X1×X2×2.

4. The method according to claim 2 , wherein determining the precoding matrix on which channel measurement and feedback need to be performed comprises:

performing, by the UE, a Kronecker product on a precoding matrix whose quantity of antenna ports is X1 and a precoding matrix whose quantity of antenna ports is X2 to obtain the precoding matrix on which channel measurement and feedback need to be performed.

5. The method according to claim 4 , wherein performing the Kronecker product on the precoding matrix whose quantity of antenna ports is X1 and the precoding matrix whose quantity of antenna ports is X2 to obtain the precoding matrix on which channel measurement and feedback need to be performed comprises:

performing, by the UE, the Kronecker product on the precoding matrix whose quantity of antenna ports is X1 and the precoding matrix whose quantity of antenna ports is X2 to obtain W 1 of a precoding matrix whose quantity of antenna ports is X; and

obtaining, by the UE according to a formula W=W 1 *W 2 , the precoding matrix on which channel measurement and feedback need to be performed, wherein W 2 is a matrix whose dimension comprises X rows and is used to perform column selection and/or phase adjustment on W 1 .

6. The method according to claim 5 , wherein

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{tilde over (X)} V l =[X V l′ X V l′+1 . . . X V l′+N V b −1 ], l=0, . . . , L,l′=f(l), {tilde over (X)} H k =[X H k′ X H k′+1 . . . X H k′+N H b −1 ], k=0, . . . , K,k′=f(k), and ⊗ represents a Kronecker product;

wherein {tilde over (X)} H k corresponds to a precoding matrix in a horizontal direction in W 1 , {tilde over (X)} H k corresponds to a beam group, {tilde over (X)} H k is a set that comprises at least two column vectors, each column vector of {tilde over (X)} H k is a discrete Fourier transform (DFT) vector, and a dimension of each column vector of {tilde over (X)} H k is a quantity of co-polarized antennas in the horizontal direction; K is a quantity of beam groups in the horizontal direction; N H b is a quantity of vectors in a beam group in the horizontal direction; {tilde over (X)} V l corresponds to a precoding matrix in a vertical direction in W1, {tilde over (X)} V l corresponds to a beam group, {tilde over (X)} V l is a set that comprises at least two column vectors, each column vector of {tilde over (X)} V l is a DFT vector, and a dimension of each column vector of {tilde over (X)} V l is a quantity of co-polarized antennas in the vertical direction; L is a quantity of beam groups in the vertical direction; and N V b is a quantity of vectors in a beam group in the vertical direction; and

wherein the first configuration information is configuration information of a codebook subset restriction corresponding to {tilde over (X)} H k , and the second configuration information is configuration information of a codebook subset restriction corresponding to {tilde over (X)} V l .

7. The method according to claim 1 , wherein a precoding matrix comprised in the codebook whose quantity of antenna ports is X is represented as W=W 1 (k,l)*W 2 , wherein

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{tilde over (X)} V l =[X V l′ X V l′+1 . . . X V l′+N V b −1 ], l=0, . . . , L,l′=f(l), {tilde over (X)} H k =[X H k′ X H k′+1 . . . X H k′+N H b −1 ], k=0, . . . , K,k′=f(k), and ⊗ represents a Kronecker product;

wherein {tilde over (X)} H k corresponds to a precoding matrix in a horizontal direction, {tilde over (X)} H k corresponds to a beam group, {tilde over (X)} H k is a set that comprises at least two column vectors, each column vector of {tilde over (X)} H k is a discrete Fourier transform (DFT) vector, and a dimension of each column vector of {tilde over (X)} H k is a quantity of co-polarized antennas in the horizontal direction; K is a quantity of beam groups in the horizontal direction; N H b is a quantity of vectors in a beam group in the horizontal direction; {tilde over (X)} V l corresponds to a precoding matrix in a vertical direction, {tilde over (X)} V l corresponds to a beam group, {tilde over (X)} V l is a set that comprises at least two column vectors, each column vector of {tilde over (X)} V l is a DFT vector, and a dimension of each column vector of {tilde over (X)} V l is a quantity of co-polarized antennas in the vertical direction; L is a quantity of beam groups in the vertical direction; N V b is a quantity of vectors in a beam group in the vertical direction; and W 2 is a matrix whose dimension comprises X rows and is used to perform column selection and/or phase adjustment on W 1 (k,l); and

wherein:

the first configuration information is configuration information of a codebook subset restriction corresponding to W 1 (k,l), and the second configuration information is configuration information of a codebook subset restriction corresponding to W 2 ; or

the first configuration information comprises fifth sub-configuration information and sixth sub-configuration information, wherein the fifth sub-configuration information is configuration information of a codebook subset restriction corresponding to {tilde over (X)} H k , and the sixth sub-configuration information is configuration information of a codebook subset restriction corresponding to {tilde over (X)} V l , and the second configuration information is configuration information of a codebook subset restriction corresponding to W 2 .

8. A user equipment (UE), comprising:

a receiver, configured to receive a reference signal that is of an antenna whose quantity of antenna ports is X and that is sent by a base station and configuration information of a codebook subset restriction for the quantity X of antenna ports, wherein the configuration information of the codebook subset restriction for the quantity X of antenna ports comprises first configuration information and second configuration information, and X is a positive integer greater than or equal to 2;

a processor, configured to:

determine, according to the configuration information of the codebook subset restriction for the quantity X of antenna ports, a precoding matrix on which channel measurement and feedback need to be performed, wherein the codebook subset restriction for the quantity X of antenna ports is for instructing the UE to select some precoding matrices from all precoding matrices in a codebook whose quantity of antenna ports is X for measurement and feedback; and

obtain, via measurement according to the reference signal of the antenna whose quantity of antenna ports is X, the precoding matrix on which channel measurement and feedback need to be performed.

9. The UE according to claim 8 , wherein the first configuration information is configuration information of a codebook subset restriction for a quantity X1 of antenna ports, and the second configuration information is configuration information of a codebook subset restriction for a quantity X2 of antenna ports, wherein X=X1×X2.

10. The UE according to claim 8 , wherein the first configuration information is configuration information of a codebook subset restriction for a quantity X1 of antenna ports, and the second configuration information is configuration information of a codebook subset restriction for a quantity X2 of antenna ports, wherein X=X1×X2×2.

11. The UE according to claim 9 , wherein the processor is further configured to:

perform a Kronecker product on a precoding matrix whose quantity of antenna ports is X1 and a precoding matrix whose quantity of antenna ports is X2 to obtain the precoding matrix on which channel measurement and feedback need to be performed.

12. The UE according to claim 11 , wherein the processor is further configured to:

perform the Kronecker product on the precoding matrix whose quantity of antenna ports is X1 and the precoding matrix whose quantity of antenna ports is X2 to obtain W 1 of a precoding matrix whose quantity of antenna ports is X; and

obtain, according to a formula W=W 1 *W 2 , the precoding matrix on which channel measurement and feedback need to be performed, wherein W 2 is a matrix whose dimension comprises X rows and is for performing column selection and/or phase adjustment on W 1 .

13. The UE according to claim 12 , wherein

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{tilde over (X)} V l =[X V l′ X V l′+1 . . . X V l′+N V b −1 ], l=0, . . . , L,l′=f(l), {tilde over (X)} H k =[X H k′ X H k′+1 . . . X H k′+N H b −1 ], k=0, . . . , K,k′=f(k), and ⊗ represents a Kronecker product:

wherein {tilde over (X)} H k corresponds to a precoding matrix in a horizontal direction in W 1 , {tilde over (X)} H k corresponds to a beam group, {tilde over (X)} H k is a set that comprises at least two column vectors, each column vector of {tilde over (X)} H k is a discrete Fourier transform (DFT) vector, and a dimension of each column vector of {tilde over (X)} H k is a quantity of co-polarized antennas in the horizontal direction; K is a quantity of beam groups in the horizontal direction; N H b is a quantity of vectors in a beam group in the horizontal direction; {tilde over (X)} V l corresponds to a precoding matrix in a vertical direction in W1, {tilde over (X)} V l corresponds to a beam group, {tilde over (X)} V l is a set that comprises at least two column vectors, each column vector of {tilde over (X)} V l is a DFT vector, and a dimension of each column vector of {tilde over (X)} V l is a quantity of co-polarized antennas in the vertical direction; L is a quantity of beam groups in the vertical direction; and N V b is a quantity of vectors in a beam group in the vertical direction; and

wherein the first configuration information is configuration information of a codebook subset restriction corresponding to {tilde over (X)} H k , and the second configuration information is configuration information of a codebook subset restriction corresponding to {tilde over (X)} V l .

14. The UE according to claim 8 , wherein a precoding matrix comprised in the codebook whose quantity of antenna ports is X is represented as W=W 1 (k,l)*W 2 , wherein

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{tilde over (X)} V l =[X V l′ X V l′+1 . . . X V l′+N V b −1 ], l=0, . . . , L,l′=f(l), {tilde over (X)} H k =[X H k′ X H k′+1 . . . X H k′+N H b −1 ], k=0, . . . , K,k′=f(k), and ⊗ represents a Kronecker product;

wherein {tilde over (X)} H k corresponds to a precoding matrix in a horizontal direction, {tilde over (X)} H k corresponds to a beam group, {tilde over (X)} H k is a set that comprises at least two column vectors, each column vector of {tilde over (X)} H k is a discrete Fourier transform (DFT) vector, and a dimension of each column vector of {tilde over (X)} H k is a quantity of co-polarized antennas in the horizontal direction; K is a quantity of beam groups in the horizontal direction; N H b is a quantity of vectors in a beam group in the horizontal direction; {tilde over (X)} V l corresponds to a precoding matrix in a vertical direction, {tilde over (X)} V l corresponds to a beam group, {tilde over (X)} V l is a set that comprises at least two column vectors, each column vector of {tilde over (X)} V l is a DFT vector, and a dimension of each column vector of {tilde over (X)} V l is a quantity of co-polarized antennas in the vertical direction; L is a quantity of beam groups in the vertical direction; N V b is a quantity of vectors in a beam group in the vertical direction; and W 2 is a matrix whose dimension comprises X rows and is for performing column selection and/or phase adjustment on W 1 (k,l); and

wherein:

the first configuration information is configuration information of a codebook subset restriction corresponding to W 1 (k,l), and the second configuration information is configuration information of a codebook subset restriction corresponding to W 2 ; or

the first configuration information comprises fifth sub-configuration information and sixth sub-configuration information, wherein the fifth sub-configuration information is configuration information of a codebook subset restriction corresponding to {tilde over (X)} H k , and the sixth sub-configuration information is configuration information of a codebook subset restriction corresponding to {tilde over (X)} V l , and the second configuration information is configuration information of a codebook subset restriction corresponding to W 2 .

15. The UE according to claim 8 , wherein:

both the first configuration information and the second configuration information are sent by using higher layer signaling; or

the first configuration information is sent by using higher layer signaling, and the second configuration information is sent by using dynamic signaling.

16. The UE according to claim 8 , wherein:

configuration information of a codebook subset restriction of antenna ports for a larger quantity of antenna ports in X1 and X2 is configured by using dynamic signaling, and configuration information of a codebook subset restriction of antenna ports for a smaller quantity of antenna ports in X1 and X2 is configured by using higher layer signaling; or configuration information of a codebook subset restriction of antenna ports for a larger quantity of antenna ports in X1 and X2 is configured by using higher layer signaling, and configuration information of a codebook subset restriction of antenna ports for a smaller quantity of antenna ports in X1 and X2 is configured by using dynamic signaling.