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 by a device, wherein the sounding signal is transmitted over at least one sub-channels of the wide channel, and the at least one sub-channels comprises a primary sub-channel and a secondary sub-channel; and
performing channel estimation based on the received sounding signal,
wherein the device does not transmit any beamforming report to the access point when a result of the channel estimation indicates that the primary sub-channel suffers significant degradation, regardless of whether the secondary sub-channel suffers degradation or not, and the device transmits a feedback message with a beamforming report to the access point when the result of the channel estimation indicates that the primary sub-channel does not suffer significant degradation and the secondary sub-channel suffers significant degradation.
2. The method of claim 1 , wherein the sounding signal and the feedback message are transmitted for MU-MIMO sounding and feedback, or for beamforming sounding and feedback.
3. The method of claim 1 , wherein performing channel estimation involves performing clear channel assessment (CCA) prior to the arrival of the sounding signal in the at least one sub-channels.
4. The method of claim 1 , wherein performing channel estimation involves checking a cyclic redundancy check (CRC) for each sub-channel of the at least one sub-channels.
5. The method of claim 1 , wherein the sounding signal contains a VHT-SIG-B field, and wherein performing channel estimation involves checking whether a bit pattern of the VHT-SIG-B field equals to a fixed pattern.
6. The method of claim 1 , wherein the feedback information only includes the beamforming report for one or more sub-channels that do not suffer significant degradation, wherein the one or more sub-channels that do not suffer significant degradation comprise the primary sub-channel.
7. The method of claim 1 , wherein the feedback message comprises an integrity indicator comprising a plurality of bits, each bit indicates whether or not each corresponding sub-channel suffers significant degradation.
8. The method of claim 1 , wherein the feedback message comprises quality indicator, and the quality indicator 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.
9. The method of claim 1 , wherein the device does not transmit any beamforming report to the access point when the result of the channel estimation indicates that the primary sub-channel suffers significant degradation and the secondary sub-channel does not suffer significant degradation.
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 at least one sub-channels comprises a primary sub-channel and a secondary sub-channel;
a processor that performs channel estimation based on the received sounding signal; and
a transmitter that does not transmit any beamforming report when a result of the channel estimation indicates that the primary sub-channel suffers significant degradation, regardless of whether the secondary sub-channel suffers degradation or not, and transmits a feedback message with a beamforming report to the access point when the result of the channel estimation indicates that the primary sub-channel does not suffer significant degradation and the secondary sub-channel suffers significant degradation.
11. The device of claim 10 , wherein the sounding signal and the feedback message are transmitted for MU-MIMO sounding and feedback, or for beamforming sounding and feedback.
12. The device of claim 10 , wherein the sounding signal contains a VHT-SIG-B field, wherein performing channel estimation involves verifying whether a bit pattern of the VHT-SIG-B field equals to a fixed pattern or not.
13. The device of claim 10 , wherein the feedback information only includes the beamforming report for one or more sub-channels that do not suffer significant degradation, wherein the one or more sub-channels that do not suffer significant degradation comprise the primary sub-channel.
14. The device of claim 10 , wherein the feedback message comprises an integrity indicator comprising a plurality of bits, each bit indicates whether each corresponding sub-channel suffers significant degradation or not.
15. The device of claim 10 , wherein the feedback message comprises quality indicator, and the quality indicator 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.
16. The device of claim 10 , wherein the transmitter does not transmit any beamforming report when the result of the channel estimation indicates that the primary sub-channel suffers significant degradation and the secondary sub-channel does not suffer significant degradation.
17. A method for enhancing the robustness of a channel sounding process, 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 at least one sub-channels of the wide channel, and the at least one sub-channels comprises a primary sub-channel and a secondary sub-channel; and
(b) the access point does not receive any beamforming report from a first station when a result of channel estimation of the first station is that the primary sub-channel suffers significant degradation, regardless of whether the secondary sub-channel suffers degradation or not, and the access point receives a first feedback message with a beamforming report from the first station when the result of channel estimation of the first station is that the primary sub-channel does not suffer significant degradation and the secondary sub-channel suffers significant degradation.
18. The method of claim 17 , wherein the first feedback message comprises the beamforming report only for one or more sub-channels that do not suffer significant degradation, wherein the one or more sub-channels that do not suffer significant degradation comprise the primary sub-channel.
19. The method of claim 17 , wherein the access point transmits multi-user multiple-input multiple-output (MU-MIMO) signals to a selected subset of the plurality of stations based on the first feedback message and a second feedback message from a second station.
20. The method of claim 17 , wherein the access point transmits multi-user multiple-input multiple-output (MU-MIMO) signals over a selected subset of the sub-channels based on the first feedback message and a second feedback message from a second station.