Method for determining precoding matrix indicator, receiving device, and sending device

1. A method for determining a precoding matrix indicator, comprising:

selecting, by a receive end, a precoding matrix W from a codebook based on a reference signal sent by a transmit end, wherein the precoding matrix W is a product of a matrix W 1 and a matrix W 2 wherein

the W 1 comprises N B block matrices X i , N B ≥1, and the W 1 is indicated as: W 1 =diag{X 1 , . . . , X N B }, wherein 1≤i≤N B , and a column x i,j of each block matrix X i is a Kronecker product of a first vector A ij and a second vector B ij , that is, x ij =A ij B ij ; and

sending, by the receive end, a precoding matrix indicator (PMI) corresponding to the precoding matrix W to the transmit end, so that the transmit end obtains the precoding matrix W according to the PMI.

2. The method according to claim 1 , wherein

all columns of the block matrix X i are obtained by pairwisely successively calculating Kronecker products of N 1 consecutive first vectors and N 2 consecutive second vectors.

3. The method according to claim 2 , wherein N 1 is greater than or equal to N 2 .

4. The method according to claim 1 , wherein

for any two adjacent block matrices X i and X i+1 , if second vectors that constitute the X i and the X i+1 are N 2 same consecutive second vectors, wherein N 2 is greater than 0, there are s 1 same first vectors in two groups of first vectors that constitute the X i and the X i+1 , and s 1 is greater than or equal to 0; and

for any two adjacent block matrices X i and X i+1 , if first vectors that constitute the X i and the X i+1 are N 1 same consecutive first vectors, wherein N 1 is greater than 0, there are s 2 same second vectors in two groups of second vectors that constitute the X i and the X i+1 , and s 2 is greater than or equal to 0.

5. The method according to claim 4 , wherein s 1 is greater than or equal to s 2 .

6. A receiving device, comprising:

a processor, configured to select a precoding matrix W from a codebook based on a reference signal sent by a sending device, wherein the precoding matrix W is a product of a matrix W 1 and a matrix W 2 , wherein

the W 1 comprises N B block matrices X i , N B ≥1, and the W 1 is indicated as: W 1 =diag{X 1 , . . . , X N B }, wherein 1≤i≤N B , and a column x i,j of each block matrix X i is a Kronecker product of a first vector A ij and a second vector B ij , that is , x ij =A ij B ij ; and

a transmitter, configured to send a precoding matrix indicator (PMI) corresponding to the precoding matrix W to the sending device, so that the sending device obtains the precoding matrix W according to the PMI.

7. The receiving device according to claim 6 , wherein

all columns of the block matrix X i are obtained by pairwisely successively calculating Kronecker products of N 1 consecutive first vectors and N 2 consecutive second vectors.

8. The receiving device according to claim 7 , wherein N 1 is greater than or equal to N 2 .

9. The receiving device according to claim 6 , wherein

for any two adjacent block matrices X i and X i+1 , if second vectors that constitute the X i and the X i+1 are N 2 same consecutive second vectors, wherein N 2 is greater than 0, there are s 1 same first vectors in two groups of first vectors that constitute the X i and the X i+1 , and s 1 is greater than or equal to 0; and

for any two adjacent block matrices X i and X i+1 , if first vectors that constitute the X i and the X i+1 are N 1 same consecutive first vectors, wherein N 1 is greater than 0, there are s 2 same second vectors in two groups of second vectors that constitute the X i and the X i+1 , and s 2 is greater than or equal to 0.

10. The receiving device according to claim 9 , wherein s 1 is greater than or equal to s 2 .

11. A sending device, comprising:

a transmitter, configured to send a reference signal to a receiving device;

a receiver, configured to receive a precoding matrix indicator (PMI) sent by the receiving device; and

a processor, configured to determine, according to the PMI, a precoding matrix W selected by the receiving device from a codebook based on the reference signal, wherein the precoding matrix W is a product of a matrix W 1 and a matrix W 2 , wherein

the W 1 comprises N B block matrices X i , N B ≥1, and the W 1 is indicated as: W 1 =diag{X 1 , . . . , X N B }, wherein 1≤i≤N B , and a column x i,j of each block matrix X i is a Kronecker product of a first vector A ij and a second vector B ij , that is, x ij =A ij B ij .

12. The sending device according to claim 11 , wherein

all columns of the block matrix X i are obtained by pairwisely successively calculating Kronecker products of N 1 consecutive first vectors and N 2 consecutive second vectors.

13. The sending device according to claim 12 , wherein N 1 is greater than or equal to N 2 .

14. The sending device according to claim 11 , wherein

for any two adjacent block matrices X i and X i+1 , if second vectors that constitute the X i and the X i+1 are N 2 same consecutive second vectors, wherein N 2 is greater than 0, there are s 1 same first vectors in two groups of first vectors that constitute the X i and the X i+1 , and s 1 is greater than or equal to 0; and

for any two adjacent block matrices X i and X i+1 , if first vectors that constitute the X i and the X i+1 are N 1 same consecutive first vectors, wherein N 1 is greater than 0, there are s 2 same second vectors in two groups of second vectors that constitute the X i and the X i+1 , and s 2 is greater than or equal to 0.

15. The sending device according to claim 14 , wherein s 1 is greater than or equal to s 2 .