Slot-based Power Save without PS-Poll February 2008 doc.: IEEE 802.11-07/2376r0 Date: July, 2012 Slot-based Power Save without PS-Poll Date: 2012-07-12 Authors: Liwen Chu Etc. Liwen Chu, STMicroelectronics

Recap of Response Frame Rate Selection Date: July, 2012 Recap of Response Frame Rate Selection A frame from a TXOP holder decides the unique response frame from the TXOP responder, e.g. RTS + CTS, BlkAckReq + BlkAck, data MPDU + ACK… Without beamforming training, a TXOP holder can calculate the content of the Duration/ID field. The rate/MCS of the response frame is strictly defined. With TGac beamforming training, a TXOP responder can select rate/MCS of VHT Compressed Beamforming report without considering the rate/MCS of the preceding NAPA/Beamforming Report Poll. This July increase the chance of successful reception of VHT Compressed Beamforming report. The VHT TXOP holder can’t calculate the content of the Duration/ID field in this case. In TGah, similar rules should be defined: The same rate/MCS rules for the response frames should be used. But, these rules are not enough to calculate the duration. 2

TGah Possible New Frame Sequence Date: July, 2012 TGah Possible New Frame Sequence TGah defines new frame formats to decrease the MAC layer overhead: the data/management frames with compressed header (the compressed data/management frames), short-CTS, and short-ACK. The compressed data/management frames don’t have a Duration/Id field. But the STAs for indoor applications July not support the short control/data/management frames. The following new frame sequences are possible: compressed data/management frame + short-ACK, compressed data/management frame + ACK, Data/management frame + short-ACK, RTS + short-CTS, A-MPDU with compressed data/management frames + BlkAck. Should TGah allow all these frame sequences? 3

Why Definitive Frame Sequences are Important Date: July, 2012 Why Definitive Frame Sequences are Important Definitive frame sequences make medium access fair and efficient. The TXOP holder can calculate the content of the Duration/ID field. STA1 STA2 STA3 STA4 Compressed Data with ACK Ind Short-ACK Should I start backoff based on Short-ACK or normal ACK? STA1 can’t detect STA3’s transmission, and STA4 can’t detect STA4’s transmission. 4

TGah Possible Frame Sequence Discussion Date: July, 2012 TGah Possible Frame Sequence Discussion “compressed data/management frame + short-ACK”: There is no Duration/ID field in compressed data/management frame. The Duration/Id field in the following ACK/short-ACK should be defined. The Duration/Id field in ACK/short-ACK following compressed data/management frame shall be set to 0. “compressed data/management frame + ACK”: “compressed data/management frame + ACK” shall not be used since “compressed data/management frame + short-ACK” is more efficient. “A-MPDU with compressed data frames + BlkAck”: There is no Duration/ID field in A-MPDU with short data frames. The Duration/Id field in BlkAck “A-MPDU with short data frames + BlkAck” should be defined. The Duration/Id field in BlkAck “A-MPDU with short data frames + BlkAck” shall be set to 0. 5

TGah Possible Frame Sequence Discussion (Cont’d) Date: July, 2012 TGah Possible Frame Sequence Discussion (Cont’d) “RTS + short-CTS”: “RTS + short-CTS” is efficient than “RTS + CTS” and “RTS + short-CTS” can also provide NAV protection. But “RTS + short-CTS” can’t be used for link adaptation, beamforming training. “RTS + short-CTS” shall be used if link adaptation or beamforming training is not executed. “data/management frame + short-ACK”: “data/management frame + short-ACK” is efficient than “data/management frame + ACK”. But “data/management frame + short-ACK” can’t be used for link adaptation, beamforming training. data/management frame +short- ACK shall be used if link adaptation or beamforming training is not executed. Why is this required? In a TXOP after A-MPDU with data frame + BlkAck, the TXOP holder is easy to transmit unsuccessful data MPDU and the TXOP responder responds with short-ACK. If Duration/ID is added to compressed data/management frames, “data/management frame + short-ACK” is not necessary. 6

TGah Response Frame Rules Option 1 Date: July, 2012 TGah Response Frame Rules Option 1 This option assumes that all TGah STAs are able to transmit and receive compressed data/management frames and short control frames: Short-ACK shall follow a compressed data/management frame. Short-ACK shall not follow a data/management frame when the data/management frame is used for link adaptation. Otherwise, if the data/management frame is not used for link adaptation, Short-ACK shall be used. Short-CTS shall not follow RTS, if RTS is used for link adaptation. Otherwise, if RTS is not used for link adaptation, Short-CTS shall be used. 7

TGah Response Frame Rules Option 2 Date: July, 2012 TGah Response Frame Rules Option 2 This option assumes that some TGah STAs are not able to transmit and receive the compressed data/management frames and the short control frames. When a TXOP holder and the TXOP responder have the abilities to transmit and receive the compressed data/management frames and the short control frames as indicated by Extend Capabilities or other new IE: the TXOP responder shall respond Short-ACK if compressed data/management frame is received. the TXOP responder shall not respond Short-ACK if the received data/management frame is used for link adaptation. Otherwise, if the data/management frame is not used for link adaptation, Short-ACK shall be used. the TXOP responder shall not respond Short-CTS if the received RTS is used for link adaptation. Otherwise, if the RTS is not used for link adaptation, Short-CTS shall be used. 8

TGah Response Frame Rules Option 2 (cont’d.) Date: July, 2012 TGah Response Frame Rules Option 2 (cont’d.) When the TXOP responder supports transmitting and receiving compressed data/management frames and short control frames as indicated by Extend Capabilities (or other new IE), a TXOP holder July transmit compressed data/management frames. 9