Integrity and Quality Monitoring and Signaling for Sounding and Reduced Feedback

• US 20130058239A1
• Filed: 10/20/2011
• Published: 03/07/2013
• Est. Priority Date: 10/21/2010
• Status: Abandoned Application

• Current Assignee: MediaTek Singapore Pte. Ltd. (MediaTek, Inc.)
• Original Assignee: MediaTek Singapore Pte. Ltd. (MediaTek, Inc.)
• Inventors: Wang, James June-Ming, Ponnampalam, Vishakan, Wang, Chao-Chun, Ye, Huanchun, Liu, Jianhan
• Application Number:
  US13/635,360
• Publication Number:
  US 20130058239A1
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/063 Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04B 7/065 Variable contents, e.g. long-term or short-short
• CPC Class Codes: H04B 7/0658 Feedback reduction
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0028 Formatting
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 25/0228 with direct estimation from sounding signals

Abstract

A method of sounding and feedback with channel quality information and reduced overhead is provided. A receiving station receives a sounding signal transmitted from an access point over multiple sub-channels of a wide channel in a wireless network. The receiving station detects channel quality based on the received sounding signal for each sub-channel. The receiving station then performs channel estimation based on the received sounding signal and thereby determining feedback information. Finally, the receiving station transmits a feedback message to the access point, the feedback message contains NULL feedback information, reduced feedback information, or channel integrity/quality indicators based on the channel quality information for each sub-channel. Based on the feedback message, the access point may repeat the sounding process, narrow the transmission bandwidth, or select only stations who have indicated uncorrupted channel sounding for MU-MMO transmission.

Claims

1. A method comprising:

(a) receiving a sounding signal transmitted from an access point over a wide channel in a wireless network, wherein the sounding signal is transmitted over one or multiple sub-channels of the wide channel;

(b) detecting channel quality based on the received sounding signal for each sub-channel;

(c) performing channel estimation based on the received sounding signal and thereby determining feedback information; and

(d) transmitting a feedback message to the access point, wherein the feedback message contains NULL feedback information, or reduced feedback information, and/or indicators based on the channel quality information detected in (b) for each sub-channel.

2. The method of claim 1, wherein the detecting in (b) involves performing clear channel assessment (CCA) prior to the arrival of the sounding signal.

3. The method of claim 1, wherein the sounding signal contains a cyclic redundancy check (CRC), and wherein the detecting in (b) involves checking the CRC for each sub-channel.

4. The method of claim 1, wherein the sounding signal contains a fixed bit pattern, and wherein the detecting in (b) involves checking the fixed bit pattern for each sub-channel.

5. The method of claims 1 and 6, wherein the null feedback information does not include beamforming report if the channel suffers significant degradation.

6. The method of claim 1, wherein the reduced feedback information only includes beamforming report for the sub-channels that do not suffer significant degradation.

7. The method of claim 1, wherein the feedback message contains an integrity or quality indicator comprising a plurality of bits, each bit indicates whether each corresponding sub-channel suffers significant degradation.

8. The method of claim 1, wherein the sounding signal and feedback message are transmitted for MU-MIMO sounding and feedback, or for transmit beamforming sounding and feedback.

9. A device, comprising:

a receiver that receives a sounding signal transmitted from an access point over a wide channel in a wireless network, wherein the sounding signal is transmitted over one or multiple sub-channels of the wide channel;

a channel quality detecting module that detects channel quality based on the received sounding signal for each sub-channel;

a channel estimation module that performs channel estimation based on the received sounding signal and thereby determining feedback information; and

a transmitter that transmits a feedback message to the access point, wherein the feedback message contains NULL feedback information, or reduced feedback information, and/or indicators based on the detected channel quality information for each sub-channel.

10. The device of claim 9, wherein the feedback message contains an integrity or quality indicator comprising a plurality of bits, each bit indicates whether each corresponding sub-channel suffers degradation.

11. The device of claim 9, wherein the null feedback information does not include beamforming report if the channel suffers significant degradation.

12. The device of claim 9, wherein the reduced feedback information only includes beamforming report information for the sub-channels that do not suffer significant degradation.

13. A method, comprising:

(a) transmitting a sounding signal by an access point to a plurality of stations over a wide channel in a wireless network, wherein the sounding signal is transmitted over one or multiple sub-channels of the wide channel; and

(b) receiving feedback messages from the corresponding stations, wherein one or more feedback messages contain NULL feedback information, or reduced feedback information, and/or indicators that indicate channel quality information for each sub-channel of a corresponding station.

14. The method of claim 13, further comprising:

retransmitting the sounding signal to a first station if the feedback message from the first station indicates significant degradation.

15. The method of claim 13, further comprising:

transmitting multi-user multiple-input multiple-output (MU-MIMO) signals to a selected subset of the plurality of stations based on the channel quality information indicated in each feedback message.

16. The method of claim 13, further comprising:

transmitting multi-user multiple-input multiple-output (MU-MIMO) signals over a selected subset of the sub-channels based on the channel quality information indicated in each feedback message.

17. The method of claim 13, wherein the access point makes dynamic transmission bandwidth adjustments based on the channel quality information indicated in each feedback message.

18. A device, comprising:

a transmitter that transmits a sounding signal to a plurality of stations over a wide channel in a wireless system, wherein the sounding signal is transmitted over one or multiple sub-channels of the wide channel; and

a receiver that receives feedback messages from the corresponding stations, wherein one or more feedback messages contain NULL feedback information, or reduced feedback information, and/or indicators that indicate channel quality information for each sub-channel of a corresponding station.

19. The device of claim 18, wherein the device retransmits the sounding signal to a first station if the feedback message from the first station indicates significant degradation.

20. The device of claim 18, wherein the device transmits multi-user multiple-input multiple-output (MU-MIMO) signals to a selected subset of the plurality of stations based on the channel quality information indicated in each feedback message.

21. The device of claim 18, wherein the device transmits multi-user multiple-input multiple-output (MU-MIMO) signals over a selected subset of the sub-channels based on the channel quality information indicated in each feedback message.

22. The device of claim 18, wherein the device makes dynamic transmission bandwidth adjustments based on the channel quality information indicated in each feedback message.