Closed loop MIMO systems and methods

Patent metadata

Field	Value
Publication number	US-10554272-B2
Application number	US-201715486060-A
Country	US
Kind code	B2
Filing date	Apr 12, 2017
Priority date	Jun 22, 2004
Publication date	Feb 4, 2020
Grant date	Feb 4, 2020

Abstract

Systems and methods for closed loop MIMO (multiple input and multiple output) wireless communication are provided. Various transmit formats including spatial multiplexing and STTD are defined in which vector or matrix weighting is employed using information fed back from receivers. The feedback information may include channel matrix or SVD-based feedback.

First claim

The invention claimed is:

1. A multiple input multiple output (MIMO) system comprising:
a receiver configured to:
analyze one or more channel conditions of a wireless communication channel between the receiver and a transmitter having a plurality of transmit antennas;
based on the analyzed one or more channel conditions, select one of a spatial-multiplexing (SM) format or a transmit diversity format and one or more transmission layers for use in transmission to the receiver, wherein the selected one of the SM format or the transmit diversity format are selected from a defined subset of available formats; and
generate, for transmission to the transmitter, feedback information indicating the selected one of the SM format or the transmit diversity format for transmission and the one or more transmission layers, wherein the one or more transmission layers are included in a rank indication in the feedback information.

2. The system of claim 1 , wherein the transmit diversity format includes a single data stream.

3. The system of claim 2 , wherein the single data stream comprises four transmission intervals during which four symbols are transmitted.

4. The system of claim 1 , wherein the transmit diversity format comprises a space time transmit diversity (STTD) format.

5. The system of claim 4 , wherein the STTD format is proportionally weighted.

6. The system of claim 1 , wherein the SM format includes two data streams.

7. The system of claim 6 , wherein a first stream of the two data streams is weighted.

8. The system of claim 1 , wherein the feedback information specifies beam-forming information usable by the transmitter.

9. The system of claim 1 , wherein power is increased for a first transmission layer of the one or more transmission layers based on the channel conditions.

10. A method, comprising:
at a receiver in a multiple input multiple output (MIMO) system:
analyzing one or more channel conditions of a wireless communication channel between the receiver and a transmitter having a plurality of transmit antennas;
based on the analyzed one or more channel conditions, selecting one of a spatial-multiplexing (SM) format or a transmit diversity format and one or more transmission layers for use in transmission to the receiver, wherein the selected one of the SM format or the transmit diversity format are selected from a defined subset of available formats; and
generating, for transmission to the transmitter, feedback information indicating the selected one of the SM format or the transmit diversity format for transmission and the one or more transmission layers, wherein the one or more transmission layers are included in a rank indication in the feedback information.

11. The method of claim 10 , wherein the transmit diversity format includes a single data stream.

12. The method of claim 11 , wherein the single data stream comprises four transmission intervals during which four symbols are transmitted.

13. The method of claim 10 , wherein the transmit diversity format comprises a space time transmit diversity (STTD) format.

14. The method of claim 13 , wherein the STTD format is proportionally weighted.

15. The method of claim 10 , wherein the SM format includes two data streams.

16. The method of claim 15 , wherein a first stream of the two data streams is weighted.

17. The method of claim 10 , wherein the feedback information specifies beam-forming information usable by the transmitter.

18. The method of claim 10 , wherein power is increased for a first transmission layer of the one or more transmission layers based on the channel conditions.

Assignees

• Apple Inc

Inventors

• Tong Wen
• Jia Ming
• Ma Jianglei
• Zhu Peiying
• Xu Hua
• Yu Dong-Sheng
• Zhang Hang
• Fong Mo-Han

Classifications

• H04L5/0007

  the frequencies being orthogonal, e.g. OFDM(A) or DMT · CPC title

• H04B7/0413

  MIMO systems · CPC title

• H04B7/0691

  using subgroups of transmit antennas · CPC title

• H04B7/0673

  using feedback from receiving side · CPC title

• H04L5/0028

  Variable division (indication of the divided channel H04L5/0092) · CPC title