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 a beamformer over a wide channel in a wireless network by a device, wherein the wide channel comprises a primary 20 Mhz sub-channel and a secondary sub-channel, and the sounding signal comprises a front part and a later part; and
performing channel estimation based on the received sounding signal,
wherein the device does not transmit any beamforming report to the beamformer when a result of the channel estimation indicates that the primary 20 Mhz sub-channel carrying the front part of the sounding signal 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 beamformer when the result of the channel estimation indicates that the primary 20 Mhz sub-channel carrying the front part of the sounding signal does not suffer 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 the primary sub-channel only carrying the later part of the sounding signal comprises a plurality of RUs, and the secondary sub-channel only carrying the later part of the sounding signal comprises a plurality of RUs.
4. The method of claim 3 , wherein the beamforming report comprises a CQI report field, the CQI report field carries a respective average SNR for each space-time stream for each RU in the primary sub-channel only carrying the later part of the sounding signal and the secondary sub-channel only carrying the later part of the sounding signal.
5. The method of claim 3 , wherein the feedback message comprises quality indicator, and the quality indicator have a plurality of values corresponding to a plurality of RUs in the primary 20 Mhz sub-channel and the secondary sub-channel only carrying the later part of the sounding signal, respectively, wherein each value represents a quantitative measure of the extent that measurement of each corresponding RU for each space-time stream is corrupted by the interference.
6. The method of claim 1 , wherein the device does not transmit any beamforming report to the beamformer when the result of the channel estimation indicates that the front part of the primary 20 Mhz sub-channel suffers significant degradation and the secondary sub-channel do not suffer significant degradation.
7. A device, comprising:
a receiver, configured to receive a sounding signal transmitted from a beamformer over a wide channel in a wireless network, wherein the wide channel comprises a primary 20 Mhz sub-channel and a secondary sub-channel, and the sounding signal comprises a front part and a later part;
a processor, configured to perform channel estimation based on the received sounding signal; and
a transmitter, configured to not transmit any beamforming report when a result of the channel estimation indicates that the primary 20 Mhz sub-channel carrying the front part of the sounding signal suffers significant degradation, regardless of whether the secondary sub-channel suffers degradation or not, and to transmit a feedback message with a beamforming report to the beamformer when the result of the channel estimation indicates that the primary 20 Mhz sub-channel carrying the front of the sounding signal does not suffer significant degradation.
8. The device of claim 7 , wherein the sounding signal and the feedback message are transmitted for MU-MIMO sounding and feedback, or for beamforming sounding and feedback.
9. The device of claim 7 , wherein the primary sub-channel only carrying the later part of the sounding signal comprises a plurality of RUs, and the secondary sub-channel only carrying the later part of the sounding signal comprises a plurality of RUs.
10. The device of claim 9 , wherein the beamforming report comprises a CQI report field, the CQI report field carries a respective average SNR for each space-time stream for each RU in the 20 MHz primary sub-channel only carrying the later part of the sounding signal and the secondary sub-channel only carrying the later part of the sounding signal.
11. The device of claim 9 , wherein the feedback message comprises quality indicator, and the quality indicator have a plurality of values corresponding to the plurality of RUs in the primary 20 Mhz sub-channel and the secondary sub-channel only carrying the later part of the sounding signal, respectively, wherein each value represents a quantitative measure of the extent that measurement of each corresponding RU for each space-time stream is corrupted by the interference.
12. The device of claim 7 , wherein the transmitter does not transmit any beamforming report when the result of the channel estimation indicates that the primary 20 Mhz sub-channel suffers significant degradation and the secondary sub-channel does not suffer significant degradation.
13. A method for enhancing the robustness of a channel sounding process, comprising:
(a) transmitting a sounding signal by a beamformer to a plurality of beamformees over a wide channel in a wireless network, wherein the wide channel comprises a primary 20 Mhz sub-channel and a secondary sub-channel, and the sounding signal has a front part and a later part; and
(b) the beamformer does not receive any beamforming report from a first beamformee of the plurality of beamformees when a result of channel estimation of the first beamformee is that the primary 20 Mhz sub-channel carrying the front part of the sounding signal suffers significant degradation, regardless of whether the secondary sub-channel suffers degradation or not, and the beamformer receives a first feedback message with a beamforming report from the first beamformee when the result of channel estimation of the first beamformee is that the primary 20 Mhz sub-channel carrying the front part of the sounding signal does not suffer significant degradation.
14. The method of claim 13 , wherein the beamformer transmits multi-user multiple-input multiple-output (MU-MIMO) signals to a selected subset of the plurality of beamformees based on the first feedback message and a second feedback message from a second beamformee.
15. The method of claim 13 , wherein the beamformer transmits multi-user multiple-input multiple-output (MU-MIMO) signals over a selected subset of a plurality of RUs in the primary 20 Mhz sub-channel and the secondary sub-channel based on the first feedback message and a second feedback message from a second beamformee.