Method for Precoding Matrix Indicator Feedback and Apparatus

• US 20190149206A1
• Filed: 01/15/2019
• Published: 05/16/2019
• Est. Priority Date: 04/01/2016
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: ZHANG, Ruiqi, LIU, Jianqin
• Granted Patent: US 10,454,546 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 7/0478 Special codebook structures directed to feedback optimisation
• CPC Class Codes: H04B 7/0639 Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
• CPC Class Codes: H04B 7/0658 Feedback reduction
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems

Abstract

A method and apparatus for precoding matrix indicator feedback reduce a quantity of bits in the feedback. In the method, a terminal device receive a reference signal from a base station and determines a precoding matrix W in a precoding matrix set corresponding to a rank indication. W satisfies W=W₁×W₂×W₃, where W₁, W₂ and W₃ are matrices and respectively corresponding to a first, second and third precoding matrix indicator. None of W₁, W₂, and W₃ is an identity matrix, and the 2M columns in W₁ comprise every column in W₁×W₂. The terminal device transmits the rank indication, the first precoding matrix indicator, the second precoding matrix indicator, and the third precoding matrix indicator to the base station.

Claims

1. A method, comprising:

receiving, by a terminal device, a reference signal from a base station;

based on the received reference signal, determining, by the terminal device, a precoding matrix W in a precoding matrix set,

wherein W satisfies W=W₁×

W₂×

W₃, wherein W is a matrix of N_t rows and R columns, wherein N_t is a quantity of antenna ports, wherein R is a rank value corresponding to a rank indication, wherein N_t is an even number, and wherein N_t is greater than or equal to R;

wherein W₁ is a matrix of N_t rows and 2M columns, wherein W₂ is a matrix of 2M rows and 2K columns, wherein W₃ is a matrix of 2K rows and R columns, wherein N_t, R, M, and K are all positive integers, wherein K is less than M, and wherein M is greater than or equal to 2; and

wherein none of W₁, W₂, and W₃ is an identity matrix, and wherein the 2M columns in W₁ comprise every column in W₁×

W₂, wherein the first precoding matrix W₁ corresponds to a first precoding matrix indicator, the second precoding matrix W₂ corresponds to a second precoding matrix indicator, and the third precoding matrix W₃ corresponds to a third precoding matrix indicator; and

sending, by the terminal device, the rank indication, the first precoding matrix indicator, the second precoding matrix indicator and the third precoding matrix indicator to the base station.

2. The method according to claim 1, wherein

W₂ satisfies

3. The method according to claim 1, wherein:

W₁ satisfies

4. The method according to claim 1, wherein a frequency domain resource corresponding to the first precoding matrix indicator is a downlink system bandwidth of the terminal device, wherein the downlink system bandwidth comprises A first sub-bands and B second sub-bands, wherein A and B are positive integers greater than 1, and wherein A is less than or equal to B;

and

wherein a frequency domain resource corresponding to the second precoding matrix indicator is one of the A first sub-bands, and wherein a frequency domain resource corresponding to the third precoding matrix indicator is one of the B second sub-bands.

5. The method according to claim 1, wherein a transmission period of the first precoding matrix indicator is P₁, wherein a transmission period of the second precoding matrix indicator is P₂, wherein a transmission period of the third precoding matrix indicator is P₃, wherein P₁ is greater than or equal to P₂, and wherein P₂ is greater than or equal to P₃.

6. The method according to claim 1, wherein T column vectors in 2K column vectors in W₂ are indicated by the first precoding matrix indicator, wherein T is an integer greater than or equal to 2, and wherein T is less than K;

and

wherein 2K−

T column vectors in W₂ except the T column vectors are indicated by the T column vectors and the second precoding matrix indicator.

7. The method according to claim 1, wherein 2K column vectors in W₂ are indicated by a configuration parameter delivered by the base station and the second precoding matrix indicator.

8. A terminal device, comprising:

a receiver, the receiver configured to receive a reference signal from a base station;

at least one processor, the at least one processor configured to, based on the received reference signal, determine a precoding matrix W in a precoding matrix set,

wherein W satisfies W=W₁×

W₂×

W₃, W is a matrix of N_t rows and R columns, wherein N_t is a quantity of antenna ports, wherein R is a rank value corresponding to a rank indication, wherein N_t is an even number, and wherein N_t is greater than or equal to R,

wherein W₁ is a matrix of N_t rows and 2M columns, wherein W₂ is a matrix of 2M rows and 2K columns, wherein W₃ is a matrix of 2K rows and R columns, wherein N_t, R, M, and K are all positive integers, wherein K is less than M, and wherein M is greater than or equal to 2,

wherein none of W₁, W₂, and W₃ is an identity matrix, and wherein the 2M columns in W₁ comprise every column in W₁×

W₂, wherein the first precoding matrix W₁ corresponds to a first precoding matrix indicator, the second precoding matrix W₂ corresponds to a second precoding matrix indicator, and the third precoding matrix W₃ corresponds to a third precoding matrix indicator; and

a transmitter, the transmitter configured to send the rank indication, the first precoding matrix indicator, the second precoding matrix indicator, and the third precoding matrix indicator to the base station.

9. The terminal device according to claim 8, wherein:

W₂ satisfies

10. The terminal device according to claim 8, wherein:

W₁ satisfies

11. The terminal device according to claim 8, wherein a frequency domain resource corresponding to the first precoding matrix indicator is a downlink system bandwidth of the terminal device, wherein the downlink system bandwidth comprises A first sub-bands and B second sub-bands, wherein A and B are positive integers greater than 1, and wherein A is less than or equal to B;

and

wherein a frequency domain resource corresponding to the second precoding matrix indicator is one of the A first sub-bands, and wherein a frequency domain resource corresponding to the third precoding matrix indicator is one of the B second sub-bands.

12. The terminal device according to claim 8, wherein a transmission period of the first precoding matrix indicator is P₁, wherein a transmission period of the second precoding matrix indicator is P₂, wherein a transmission period of the third precoding matrix indicator is P₃, wherein P₁ is greater than or equal to P₂, and wherein P₂ is greater than or equal to P₃.

13. The terminal device according to claim 8, wherein T column vectors in 2K column vectors in W₂ are indicated by the first precoding matrix indicator, wherein T is an integer greater than or equal to 2, and wherein T is less than K;

and

wherein 2K−

T column vectors in W₂ except the T column vectors are indicated by the T column vectors and the second precoding matrix indicator.

14. The terminal device according to claim 8, wherein the receiver is configured to receive a configuration parameter from the base station;

and

wherein 2K column vectors in W₂ are indicated by the configuration parameter and the second precoding matrix indicator.

15. A non-transitory computer readable medium having program instructions stored thereon which, when executed by at least one processor, cause the at least one processor to perform:

receiving a reference signal from a base station;

based on the received reference signal, determining a precoding matrix W in a precoding matrix set,

wherein W satisfies W=W₁×

W₂×

W₃, wherein W is a matrix of N_t rows and R columns, wherein N_t is a quantity of antenna ports, wherein R is a rank value corresponding to a rank indication, wherein N_t is an even number, and wherein N_t is greater than or equal to R,

wherein W₁ is a matrix of N_t rows and 2M columns, wherein W₂ is a matrix of 2M rows and 2K columns, wherein W₃ is a matrix of 2K rows and R columns, wherein N_t, R, M, and K are all positive integers, wherein K is less than M, and wherein M is greater than or equal to 2,

wherein none of W₁, W₂, and W₃ is an identity matrix, and wherein the 2M columns in W₁ comprise every column in W₁×

W₂, wherein the first precoding matrix W₁ corresponds to a first precoding matrix indicator, the second precoding matrix W₂ corresponds to a second precoding matrix indicator, and the third precoding matrix W₃ corresponds to a third precoding matrix indicator; and

transmitting the rank indication, the first precoding matrix indicator, the second precoding matrix indicator, and the third precoding matrix indicator to the base station.

16. The non-transitory computer readable medium according to claim 15, wherein

W₂ satisfies

17. The non-transitory computer readable medium according to claim 15, wherein

W₁ satisfies

18. The non-transitory computer readable medium according to claim 15, wherein a frequency domain resource corresponding to the first precoding matrix indicator is a downlink system bandwidth of a terminal device, wherein the downlink system bandwidth comprises A first sub-bands and B second sub-bands, wherein A and B are positive integers greater than 1, and wherein A is less than or equal to B;

and

wherein a frequency domain resource corresponding to the second precoding matrix indicator is one of the A first sub-bands, and wherein a frequency domain resource corresponding to the third precoding matrix indicator is one of the B second sub-bands.

19. The non-transitory computer readable medium according to claim 15, wherein a transmission period of the first precoding matrix indicator is P₁, wherein a transmission period of the second precoding matrix indicator is P₂, wherein a transmission period of the third precoding matrix indicator is P₃, wherein P₁ is greater than or equal to P₂, and wherein P₂ is greater than or equal to P₃.

20. The non-transitory computer readable medium according to claim 15, wherein T column vectors in 2K column vectors in W₂ are indicated by the first precoding matrix indicator, wherein T is an integer greater than or equal to 2, and wherein T is less than K;

and

wherein 2K−

T column vectors in W₂ except the T column vectors are indicated by the T column vectors and the second precoding matrix indicator.