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Sounding Sequence for SU-only Beamformee. Authors:. Date: 2011-01-17. Motivation. SU-only beamformee [1] SU Beamformee Capable field = 1, and MU Rx Capable field = 0 No poll for SU-only beamformee
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Sounding Sequence for SU-only Beamformee Authors: Date: 2011-01-17 Yong Liu, Marvell
Motivation • SU-only beamformee [1] • SU Beamformee Capable field = 1, and • MU Rx Capable field = 0 • No poll for SU-only beamformee • The overhead of NDPA+NDP+FB sequence over Poll+FB sequence is around 84us (SIFS + NDP duration) for the worse case • For SU sounding with 100ms sounding interval, the overhead is only around 0.084% • Polling for sounding feedback adds extra complexity and interoperability issues Yong Liu, Marvell
Sounding Sequence for SU-only Beamformee • The NDP sounding sequence for a single beamformee shall be used for sounding a SU-only beamformee • NDP-A => RA = Beamformee’s MAC address • NDP-A => STA Info => sounding control => STA AID = Beamformee’s AID • NDP-A => STA Info => sounding control => SU/MU = SU • NDP-A => STA Info => sounding control => Recommended Dimension = Invalid Yong Liu, Marvell
Polling for missed segments • If the sounding feedback cannot fit in a MPDU with the max supported length, the beamformee needs to divide the sounding feedback into one or more segments/MPDUs, and transmit all segments/MPDUs using a single A-MPDU [2] • If the beamformer receives one or more segments correctly, it may choose to poll the missed segments only to reduce sounding feedback overhead • Note that this selective polling is optional to both beamformer and beamformee; if a beamformee does not support it, it can respond the poll with a complete feedback • If the beamformer does not receive any segment correctly, it can resound the beamformee for a complete/new sounding feedback • If a SU-only beamformee can always fit sounding feedback in a single MPDU, it does not need to support sounding feedback segmentation and polling Yong Liu, Marvell
Pre-motion 1 • Should the spec framework document be updated with the following rule for sounding SU-only beamformee • A beamformer shall sound a SU-only beamformee using a unicast NDPA with a single STA Info field as following • NDP-A => RA = Beamformee’s MAC address • NDP-A => STA Info => sounding control => STA AID = Beamformee’s AID • NDP-A => STA Info => sounding control => SU/MU = SU • NDP-A => STA Info => sounding control => Recommended Dimension = Invalid • Yes • No • Abstain Yong Liu, Marvell
Pre-motion 2 • Should the spec framework document be updated with the following rulefor sounding SU-only beamformee • A beamformer shall only poll a SU-only beamformee for sounding feedback if it received at least one segment of the feedback from the beamformee • Yes • No • Abstain Yong Liu, Marvell
Reference • 11-11-0050-00-00ac-VHT BF and MU Capabilities.ppt • 11-11-0041-00-00ac-Sounding-Protocol-Segmentation-and-Null-feedback.pptx Yong Liu, Marvell