Method and apparatus for selection of linear combination coefficients for precoding in frequency-selective channels

Patent metadata

Field	Value
Publication number	US-11909472-B2
Application number	US-202217729457-A
Country	US
Kind code	B2
Filing date	Apr 26, 2022
Priority date	Nov 16, 2021
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

The disclosure provides a method of providing implicit channel state information (CSI) feedback from a user equipment (UE). The method includes determining a precoding matrix indicator (PMI) selection decision metric, selecting one of a sub-band (SB) linear combination coefficient (LCC) selection method, a wideband (WB) LCC selection method, or a sub-band group (SBG) LCC selection method, based on the determined PMI selection decision metric, determining, using the selected LCC selection method, PMI indices based on sub-bands configured by a base station, and transmitting the determined PMI indices to the base station.

First claim

What is claimed is:

1. A method performed by a user equipment (UE), the method comprising:
determining a precoding matrix indicator (PMI) selection decision metric;
selecting one of a sub-band (SB) linear combination coefficient (LCC) selection method, a wideband (WB) LCC selection method, or a sub-band group (SBG) LCC selection method, based on the determined PMI selection decision metric;
determining, using the selected LCC selection method, PMI indices based on sub-bands configured by a base station; and
transmitting the determined PMI indices to the base station.

2. The method of claim 1 , wherein the determined PMI selection decision metric includes a ratio between LCC energy after frequency domain (FD) compression and LCC energy before FD compression.

3. The method of claim 2 , wherein selecting one of the SB LCC selection method, the WB LCC selection method, or the SBG LCC selection method comprises:
comparing the ratio with a threshold;
selecting the SB LCC selection method, in response to the ratio being greater than the threshold; and
selecting one of the WB LCC selection method or the SBG LCC selection method, in response to the ratio being less than or equal to the threshold.

4. The method of claim 3 , wherein selecting one of the WB LCC selection method or the SBG LCC selection method comprises selecting the SBG LCC selection method, in response to an SB grouping achieving lossless compression.

5. The method of claim 3 , wherein selecting one of the WB LCC selection method or the SBG LCC selection method comprises:
determining a number of the sub-bands configured by the base station and a maximum number of sub-bands; and
selecting one of the WB LCC selection method or the SBG LCC selection method, based on a comparison of the number of the sub-bands configured by the base station and the maximum number of sub-bands, and whether the number of the sub-bands configured by the base station is odd or even.

6. The method of claim 5 , wherein selecting one of the WB LCC selection method or the SBG LCC selection method, based on the comparison of the number of the sub-bands configured by the base station and the maximum number of sub-bands, and whether the number of the sub-bands configured by the base station is odd or even comprises:
selecting the SBG LCC selection method, in response to the number of the sub-bands configured by the base station being less than the maximum number of sub-bands, and the number of the sub-bands configured by the base station being even; and
selecting the WB LCC selection method, in response to the number of the sub-bands configured by the base station being greater than or equal to the maximum number of sub-bands, or the number of the sub-bands configured by the base station being odd.

7. The method of claim 1 , wherein the determined PMI selection decision metric includes an average capacity difference.

8. The method of claim 7 , wherein selecting one of the SB LCC selection method, the WB LCC selection method, or the SBG LCC selection method comprises:
selecting the SB LCC selection method, in response to the average capacity difference being greater than 0; and
selecting one of the WB LCC selection method or the SBG LCC selection method, in response to the average capacity difference being less than or equal to 0.

9. The method of claim 8 , wherein selecting one of the WB LCC selection method or the SBG LCC selection comprises selecting the SBG LCC selection method, in response to an SB grouping achieving lossless compression.

10. The method of claim 8 , wherein selecting one of the WB LCC selection method or the SBG LCC selection method comprises:
determining a number of the sub-bands configured by the base station and a maximum number of sub-bands; and
selecting one of the WB LCC selection method or the SBG LCC selection method, based on a comparison of the number of the sub-bands configured by the base station and the maximum number of sub-bands, and whether the number of the sub-bands configured by the base station is odd or even.

11. The method of claim 10 , wherein selecting one of the WB LCC selection method or the SBG LCC selection method, based on the comparison of the number of the sub-bands configured by the base station and the maximum number of sub-bands, and whether the number of the sub-bands configured by the base station is odd or even comprises:
selecting the SBG LCC selection method, in response to the number of the sub-bands configured by the base station being less than the maximum number of sub-bands, and the number of the sub-bands configured by the base station being even; and
selecting the WB LCC selection method, in response to the number of the sub-bands configured by the base station being greater than or equal to the maximum number of sub-bands, or the number of the sub-bands configured by the base station being odd.

12. The method of claim 1 , wherein the WB LCC selection method comprises:
determining a single LCC matrix for an entire band; and
mapping the single matrix to PMI indices corresponding the SB LCC selection method.

13. The method of claim 1 , wherein the SBG LCC selection method comprises:
determining a set of LCC matrices, wherein a total number of matrices included in the set of the LCC matrices is less than a number of discrete Fourier transform (DFT) components utilized in the SB LCC selection method; and
mapping the set of LCC matrices to PMI indices corresponding the SB LCC selection method.

14. A user equipment (UE), comprising:
a transceiver; and
a processor configured to:
determine a precoding matrix indicator (PMI) selection decision metric,
select one of a sub-band (SB) linear combination coefficient (LCC) selection method, a wideband (WB) LCC selection method, or a sub-band group (SBG) LCC selection method, based on the determined PMI selection decision metric,
determine, using the selected LCC selection method, PMI indices based on sub-bands configured by a base station; and
transmit, via the transceiver, the determined PMI indices to the base station.

15. The UE of claim 14 , wherein the determined PMI selection decision metric includes a ratio between LCC energy after frequency domain (FD) compression and LCC energy before FD compression.

16. The UE of claim 15 , wherein the processor is further configured to:
compare the ratio with a threshold,
select the SB LCC selection method, in response to the ratio being greater than the threshold, and
select one of the WB LCC selection method or the SBG LCC selection method, in response to the ratio being less than or equal to the threshold.

17. The UE of claim 16 , wherein the processor is further configured to select the SBG LCC selection method, in response to an SB grouping achieving lossless compression.

18. The UE of claim 16 , wherein the processor is further configured to:
determine a number of the sub-bands configured by the base station and a maximum number of sub-bands, and
select one of the WB LCC selection method or the SBG LCC selection method, based on a comparison of the number of the sub-bands configured by the base station and the maximum number of sub-bands, and whether the number of the sub-bands configured by the base station is odd or even.

19. The UE of claim 18 , wherein the processor is further configured to:
select the SBG LCC selection method, in response to the number of the sub-bands configured by the base station being less than the maximum number of sub-bands, and the number of the sub-bands configured by the base statio

Assignees

• Samsung Electronics Co Ltd

Inventors

• Penna Federico
• Kwon Hyukjoon
• Bai Dongwoon
• Kim Jaein
• Lee Junho
• Je Hui Won

Classifications

• H04B7/0456 Primary

  Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting · CPC title

• H04B7/0632

  Channel quality parameters, e.g. channel quality indicator [CQI] · CPC title

• H04L5/0094

  Indication of how sub-channels of the path are allocated · CPC title

• H04B7/0639 Primary

  Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection · CPC title

• H04B7/048 Primary

  using three or more PMIs · CPC title