Geonjung According to the subclass 27.11.6 Add Revised - Ko (SPATIAL_REUSE), when a STA "If the PHY-CCARESET.request Protection with SR transmits a Trigger frame, it is primitive is issued before the restricted is mostly recommended to set the end of the PPDU, and a TXOP is for the cascaded TXVECTOR parameter initiated within the duration of case (as in the SPATIAL_REUSE to SR_DELAY or the PPDU, then the TXOP should non-cascaded SR_RESTRICTED. Since a Trigger be limited to the duration of the case, the trigger frame is allowed to be sent in a HT PPDU if a Trigger frame is in the will mostly be for or VHT PPDU, there may be other PPDU." Acks and will set frames aggregated to the Trigger CS required to 0). frame in the same PPDU. If an Cascaded only inter-BSS STA transmits a frame applies to HE MU on the OBSS_PD-based SR PPDUs. on the PPDU, STAs solicited by the Now there could Trigger frame may not be able to be a single trigger respond to the Trigger frame after frame carried in the CCA. Therefore, we can define VHT of HT format the operation for a STA which that triggers a long received a Trigger frame, for PPDU and we want example, the similar operation to make sure that when the Spatial Reuse field is set the TB PPDu is to SR_DELAY or SR_RESTRICTED. protected. For HE, we set it to SR_DELAY. For HT format, the classification as inter-BSS PPDU can only be done at the end of the PPDU when decoding the MAC header, so the SR will effectively be delayed at the end of the PPDU, which will then naturally protect the TB PPDUs. For a trigger carried in VHT, it is true that a STA can classify it as BSS PPDU based on the VHT-SIG field, so we could have an issue here. But there does not seem to be any reason why we would use VHT PPDU to send a trigger frame. The proposed resolution is therefore to include a note to recommend the AP not to transmit trigger frames in VHT PPDU format.
Geonjung Ko According to the subclass 27.11.6 (SPATIAL_REUSE), when a STA transmits a Trigger frame, it is recommended to set the TXVECTOR parameter SPATIAL_REUSE to SR_DELAY or SR_RESTRICTED. Since a Trigger frame is allowed to be sent in a HT or VHT PPDU, there may be other frames aggregated to the Trigger frame in the same PPDU. If an inter-BSS STA transmits a frame on the OBSS_PD-based SR on the PPDU, STAs solicited by the Trigger frame may not be able to respond to the Trigger frame after the CCA. Therefore, we can define the operation for a STA which received a Trigger frame, for example, the similar operation when the Spatial Reuse field is set to SR_DELAY or SR_RESTRICTED. Add "If the PHY-CCARESET.request primitive is issued before the end of the PPDU, and a TXOP is initiated within the duration of the PPDU, then the TXOP should be limited to the duration of the PPDU if a Trigger frame is in the PPDU." Revised - Protection with SR restricted is mostly for the cascaded case (as in the non-cascaded case, the trigger will mostly be for Acks and will set CS required to 0). Cascaded only applies to HE MU PPDUs. Now there could be a single trigger frame carried in VHT of HT format that triggers a long PPDU and we want to make sure that the TB PPDu is protected. For HE, we set it to SR_DELAY. For HT format, the classification as inter-BSS PPDU can only be done at the end of the PPDU when decoding the MAC header, so the SR will effectively be delayed at the end of the PPDU, which will then naturally protect the TB PPDUs. For a trigger carried in VHT, it is true that a STA can classify it as PPDU based on the VHT-SIG field, so we could have an issue here. But there does not seem to be any reason why we would use VHT PPDU to send a trigger frame. The proposed resolution is therefore to include a note to recommend the AP not to transmit trigger frames in VHT PPDU format. BSS
11-17-1852-01-00ax-cr-for-27-9.docx