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

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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