1. Submission doc.: IEEE 802.11-12/0615r0 May 2012 Sudheer Grandhi, InterDigital CommunicationsSlide 1 Considerations for early NAV indication Date: 2012-05-11 Authors:

2. Submission doc.: IEEE 802.11-12/0615r0 May 2012 Sudheer Grandhi, InterDigital CommunicationsSlide 2 Abstract This document discusses possibility of additional packet protection using NAV indication in the ACK indication field.

3. Submission doc.: IEEE 802.11-12/0615r0 Early ACK indication ACK indication field (2 bits) In the SIG or SIGA field Indicate whether an immediate response is requested right after the PPDU, and also the type of the response (00: ACK; 01: BA; 10: No ACK; 11: reserved) If a STA decodes the SIG correctly, but 1) decides to skip the remaining fields after SIG for power saving, or 2) is not able to decode /verify the MAC header, it can determine whether to defer medium access for ACK protection based on the ACK Indication in SIG Slide 3Sudheer Grandhi, InterDigital Communications May 2012

4. Submission doc.: IEEE 802.11-12/0615r0 Issues in Packet Protection Due to hidden node problem, a STA cannot always hear all packets in a packet exchange Frames could have no ACK but contains NAV setting in the Duration Field of the MAC header RTS CTS Slide 4Sudheer Grandhi, InterDigital Communications May 2012

5. Submission doc.: IEEE 802.11-12/0615r0 Proposal: further NAV Indication using ACK Indication bits (1/2) Use the reserved “11” in the ACK indication bits in SIG field as NAV setting indicator for NAV settings other than Normal ACK or BA If there is NAV setting in the MAC header other than Normal ACK or BA, an unintended receiving STA should decode the MAC header to obtain the Duration Field and set NAV accordingly or if the STA cannot decode the MAC header, it can defer medium access by a default value (TBD) to prevent premature medium access that would interrupt ongoing packet transmission or receptions Slide 5Sudheer Grandhi, InterDigital Communications May 2012

6. Submission doc.: IEEE 802.11-12/0615r0 Summary The current ACK Indication may be extended for additional packet/NAV protection other than ACK or BA Proposal: Use of “11” value of ACK Indication bits to offer packet/NAV protection for frames other than Normal ACK or BA Slide 6Sudheer Grandhi, InterDigital Communications May 2012

7. Submission doc.: IEEE 802.11-12/0615r0 Questions / Comments ? Slide 7Sudheer Grandhi, InterDigital Communications May 2012 Thank You!

8. Submission doc.: IEEE 802.11-12/0615r0 Straw Poll 1 Do you think that the use of the reserved “11” value of the ACK Indication in the SIG field should be further studied to allow additional packet/NAV protection? Yes No Abstain Slide 8Sudheer Grandhi, InterDigital Communications May 2012

9. Submission doc.: IEEE 802.11-12/0615r0May 2012 Sudheer Grandhi, InterDigital Communications Slide 9 References [1] IEEE Std 802.11™-2012: Wireless LAN MAC and PHY Specifications [2] IEEE 802.11-11/1482r4, “Preamble Format for 1 MHz,” Qualcomm and et. al. [3] IEEE 802.11-12/0119r0, “Early ACK Indication,” Marvell and et. al.