1. HCF Duration Field Set Rules
Month 1998
doc.: IEEE /xxx
July 2002
HCF Duration Field Set Rules
Sunghyun Choi*, Javier del Prado*
Srini Kandala+, Adrian Stephens-
*Philips Research USA, +Sharp Labs, -Mobilian
S. Choi, Philips, et al.

2. July 2002
Background
802.11e/D3.0 has inconsistent descriptions about Duration/ID field values in different frame types
This presentation will serve an illustrative explanation for the Duration/ID field set rule
The normative text is found in 02/444r0
S. Choi, Philips, et al.

3. July 2002
EDCF TXOP
S. Choi, Philips, et al.

4. July 2002
Comments
Any frame by TXOP holder within EDCF TXOP: covers till the end of the next MPDU transmission if any; can vary depending on the ACK policy of the MPDU
Any frame by receiver (e.g., ACK, CTS, QoS CF-ACK, and BurstAck): the Dur/ID value in the previous frame minus (the frame transmission time + SIFS)
Last frame by TXOP holder within EDCF TXOP: covers till the end of the corresponding ACK if any
S. Choi, Philips, et al.

5. HC’s Downlink Transmissions
July 2002
HC’s Downlink Transmissions
S. Choi, Philips, et al.

6. Comments The Duration/ID set rule is the same as EDCF TXOP July 2002
S. Choi, Philips, et al.

7. July 2002
Polled TXOP
S. Choi, Philips, et al.

8. Comments QoS (+)CF-Poll: Polled TXOP Limit + aSlotTime
July 2002
Comments
QoS (+)CF-Poll: Polled TXOP Limit + aSlotTime
Any frame by TXOP holder including RTS and CTS (except for last frame): the remaining time till the end of the polled TXOP + aSlotTime
Any frame by receiver (i.e., ACK, CTS, or QoS CF-ACK): the Dur/ID value in the previous frame minus (the frame transmission time + SIFS)
QoS Null as the last frame by TXOP holder : zero duration value to indicate returning the residual TXOP to the HC
S. Choi, Philips, et al.

9. RTS/CTS before Polled TXOP
July 2002
RTS/CTS before Polled TXOP
S. Choi, Philips, et al.

10. July 2002
Comments
RTS before QoS (+)CF-Poll: the remaining time till the end of the expected QoS (+)CF-Poll; conform with the HC downlink frame rule
The rest is the same as Polled TXOP rule
S. Choi, Philips, et al.

11. Special Cases in EDCF TXOP
July 2002
Special Cases in EDCF TXOP
BurstAckReq frame
Duration = ACK + SIFS
BurstAck frame transmitted when immediate policy is not used
CC frame?
S. Choi, Philips, et al.