Integrity and Quality Monitoring and Signaling for Sounding and Reduced Feedback
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.
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.