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 for enhancing the robustness of a channel sounding process comprising:
receiving a sounding signal transmitted from an access point over a wide channel in a wireless network, wherein the sounding signal is transmitted over at least one sub-channels of the wide channel, wherein the sounding signal contains a VHT-SIG-B field corresponding to the at least one sub-channels;
verifying whether a bit pattern of the VHT-SIG-B field equals to a fixed pattern of the at least one sub-channels;
determining whether interference occurs in a corresponding sub-channel according to the verified result;
transmitting a feedback message, wherein the feedback message comprises information for indicating whether interference occurs in the corresponding sub-channel.
2 . The method of claim 1 , wherein the at least one sub-channels comprises a plurality of sub-channels, the feedback message comprises quality information, and the quality information have a plurality of values corresponding to the plurality of sub-channels, respectively, wherein each value represents a quantitative measure of the extent that measurement of the corresponding sub-channel is corrupted by the interference.
3 . The method of claim 1 , wherein the at least one sub-channels comprises a plurality of sub-channels, the feedback message comprises integrity information, and the integrity information have a plurality of values corresponding to the plurality of sub-channels, respectively, each bit indicates whether interference occurs in the corresponding sub-channel.
4 . The method of claim 1 , wherein the feedback message comprises SNR information for indicating whether interference occurs in the corresponding sub-channel.
5 . The method of claim 1 , wherein the sounding signal and feedback message are transmitted for MU-MIMO sounding and feedback, or for beamforming sounding and feedback.
6 . A method for enhancing the robustness of a channel sounding process comprising:
receiving a sounding signal transmitted from an access point over a wide channel in a wireless network, wherein the sounding signal is transmitted over at least one sub-channels of the wide channel;
determining whether interference occurs in a corresponding sub-channel;
transmitting a feedback message, wherein the feedback message comprises SNR information for indicating whether interference occurs in the corresponding sub-channel.
7 . The method of claim 6 , wherein the step of determining whether interference occurs in the corresponding sub-channel comprising: performing clear channel assessment (CCA) prior to the arrival of the sounding signal in the at least one sub-channels, and determining whether interference occurs in a corresponding sub-channel in the at least one sub-channels according to the CCA.
8 . The method of claim 6 , wherein the step of determining whether interference occurs in the corresponding sub-channel comprising: checking a cyclic redundancy check (CRC) for each sub-channel of the at least one sub-channels, and determining whether interference occurs in a corresponding sub-channel according to the checked result.
9 . The method of claim 6 , wherein the sounding signal and feedback message are transmitted for MU-MIMO sounding and feedback, or for beamforming sounding and feedback.
10 . 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 at least one sub-channels of the wide channel, wherein the sounding signal contains a VHT-SIG-B field corresponding to the at least one sub-channels;
a processor that performs verifying whether a bit pattern of the VHT-SIG-B field equals to a fixed pattern of the at least one sub-channels, and determining whether interference occurs in a corresponding sub-channel according to the verified result; and
a transmitter that transmits a feedback message, wherein the feedback message comprises information for indicating whether interference occurs in the corresponding sub-channel.
11 . The method of claim 10 , wherein the at least one sub-channels comprises a plurality of sub-channels, the feedback message comprises quality information, and the quality information have a plurality of values corresponding to the plurality of sub-channels, respectively, wherein each value represents a quantitative measure of the extent that measurement of the corresponding sub-channel is corrupted by the interference.
12 . The method of claim 10 , wherein the at least one sub-channels comprises a plurality of sub-channels, the feedback message comprises integrity information, and the integrity information have a plurality of values corresponding to the plurality of sub-channels, respectively, each bit indicates whether interference occurs in the corresponding sub-channel.
13 . The method of claim 10 , wherein the feedback message comprises SNR information for indicating whether interference occurs in the corresponding sub-channel.
14 . The method of claim 10 , wherein the sounding signal and feedback message are transmitted for MU-MIMO sounding and feedback, or for beamforming sounding and feedback.