Method for precoding matrix indicator feedback and apparatus

• US 10,454,546 B2
• Filed: 01/15/2019
• Issued: 10/22/2019
• 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
• Primary Examiner(s): Patel, Dhaval V
• Application Number:
  US16/248,344
• Publication Number:
  US 20190149206A1
• Time in Patent Office: 280 Days
• Field of Search: 375260, 375262, 375265, 375267, 375295, 375316, 375340, 375343, 375346, 370203, 370204, 370208, 370209
• 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 network device;

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

wherein W satisfies W=W₁×

W₂×

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

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

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

W₂, 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 network device.

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, 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 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, a transmission period of the second precoding matrix indicator is P₂, and a transmission period of the third precoding matrix indicator is P₃, wherein P₁ is greater than or equal to P₂, and 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, T is an integer greater than or equal to 2, and 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 network device the second precoding matrix indicator.

8. An apparatus, comprising:

a receiver, configured to receive a reference signal from a network device;

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

wherein W satisfies W=W₁×

W₂×

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

W₁ is a matrix of N_t rows and 2M columns, W₂ is a matrix of 2M rows and 2K columns, W₃ is a matrix of 2K rows and R columns, N_t, R, M and K are all positive integers, K is less than M and 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, the first precoding matrix W₁ corresponds to a first precoding matrix indicator, the second precoding matrix W₂ corresponds to a second precoding matrix indicator, the third precoding matrix W₃ corresponds to a third precoding matrix indicator; and

a 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 network device.

9. The apparatus according to claim 8, wherein:

W₂ satisfies

10. The apparatus according to claim 8, wherein:

W₁ satisfies

11. The apparatus according to claim 8, wherein a frequency domain resource corresponding to the first precoding matrix indicator is a downlink system bandwidth of the apparatus, 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 apparatus 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, and 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 apparatus according to claim 8, wherein T column vectors in 2K column vectors in W₂ are indicated by the first precoding matrix indicator, T is an integer greater than or equal to 2, and 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 apparatus according to claim 8, wherein the receiver is configured to receive a configuration parameter from the network device;

and

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