1. doc.: IEEE 802.11-12/0617r0 Submission NDP sounding May 2012 Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)Slide 1 Date: 2012-05-14 Authors:

2. doc.: IEEE 802.11-12/0617r0 Submission May 2012 Slide 2Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)

3. doc.: IEEE 802.11-12/0617r0 Submission May 2012 Slide 3Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)

4. doc.: IEEE 802.11-12/0617r0 Submission Introduction IEEE 802.11ac Null Data Packet (NDP) sounding –SU: Only Immediate-SIFS feedback (after NDP) is allowed, not allow delayed or aggregated feedbacks. –MU: Feedback happens SIFS after NDP, or SIFS after polling frames. IEEE 802.11ac NDP sounding can be reused for 2>= MHz beam-forming in IEEE 802.11ah But, NDP sounding frame format (>=2MHz modes) is not defined yet May 2012 Slide 4Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)

5. doc.: IEEE 802.11-12/0617r0 Submission 11ac NDP sounding frame IEEE 802.11ac has a common frame structure for SU- MIMO, MU-MIMO and NDP Variable SIG contents in an 11ac NDP frame –The number of space-time streams (N STS ) –Channel bandwidth (20/40/80/160MHz) VHT-STFVHT-LTF1 VHT-LTFN … L-LTFL-SIG VHT-SIG-A (Symbol 1) VHT-SIG-A (Symbol 2) L-STF VHT-SIG-B May 2012 Slide 5Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)

6. doc.: IEEE 802.11-12/0617r0 Submission Proposed 11ah NDP sounding frame for >= 2MHz Modes Current 11ah spec framework supports two different frames for >= 2MH modes, short frame and long frame We have two options for 11ah NDP sounding frame –Option 1) Short frame It is the same with 2 MHz short frame format defined in 11ah spec framework R.3.2.1.1.A –Option 2) Long frame It is the same with 2 MHz long frame format defined in 11ah spec framework R.3.2.1.1.B – D-STFD-LTF1 D-LTF_N … LTF1 SIGA (2 symbols) STF SIG-B LTF2 LTF_N … LTF1 SIG (2 symbols) STF May 2012 Slide 6Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)

7. doc.: IEEE 802.11-12/0617r0 Submission Proposed 11ah NDP sounding frame for >= 2MHz Modes Option 1 (short frame) is more reasonable for IEEE 802.11ah NDP sounding frame –Pros : Less overhead –Cons : Less time budget, because there is no additional SIG after LTFs Immediate feedback time budget is 320us and it may be enough to compute V and prepare BF –The immediate feedback time budget of 11ac is about 50us NDP AH-LTFAH-STFAH-SIG…. Immediate FB frame Compute VCompress V and Prepare FB SIFS SIFS (80us) + PLCP Header (40*6us) = 320 us May 2012 Slide 7Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)

8. doc.: IEEE 802.11-12/0617r0 Submission Proposed 11ah NDP sounding frame for >= 2MHz Modes Proposed SIG field in NDP sounding frame includes following bits –MCS : set to 0 MCS values 0 – 9 are reserved for normal PPDU MCS values 10 – 15 are reserved for NDP PPDU –Length/Duration : set to 0 –BW : set to the same value as the TXVECTOR parameter CH_BANDWIDTH in the preceding VHT NDP Announcement frame –Nsts : indicates two or more space-time streams May 2012 Slide 8Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)

9. doc.: IEEE 802.11-12/0617r0 Submission Proposed 11ah NDP short MAC frame for >= 2MHz Modes 1MHz Short MAC frames is of the same format as the current 1MHz preamble But, all NDP short MAC frame sent in >=2MHz also has two options, short frame and long frame For making a consistency with NDP sounding frame, it makes sense to use a short frame format for Short-ACK, Short-CTS, and all future NDP short MAC frames –Meaning that SIG field is always modulated by {QBPSK, QBPSK} May 2012 Slide 9Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell) STFLTF1SIGRemaining LTFs

10. doc.: IEEE 802.11-12/0617r0 Submission Summary IEEE 802.11ac NDP sounding can be reused for 2/4/8/16MHz beam-forming in IEEE 802.11ah We propose Option 1 (in slide 6) as 11ah NDP sounding format We propose SIG field of 11ah NDP sounding format in slide 8 Also, we propose that all NDP short MAC frames in >=2MHz use the short frame format. May 2012 Slide 10Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)

11. doc.: IEEE 802.11-12/0617r0 Submission Straw Poll 1 Do you support the following 11ah NDP sounding format for >= 2MHz modes? It is the same with 2 MHz PHY short frame format defined in 11ah spec framework R.3.2.1.1.A May 2012 Slide 11Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell) LTF2 LTF_N … LTF1 SIG (2 symbols) STF

12. doc.: IEEE 802.11-12/0617r0 Submission Straw Poll 2 Do you support including the following fields described in slide 8 in the SIG field of 11ah NDP sounding format for >= 2MHz modes ? –MCS : set to 0 –Length/Duration : set to 0 –BW : set to the same value as the TXVECTOR parameter CH_BANDWIDTH in the preceding VHT NDP Announcement frame –Nsts : indicates two or more space-time streams May 2012 Slide 12Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)

13. doc.: IEEE 802.11-12/0617r0 Submission Straw Poll 3 Do you support that all NDP short MAC frames sent in >=2MHz use the short frame? –Include Short-ACK, Short-CTS, and all future NDP short MAC frames May 2012 Slide 13Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)

14. doc.: IEEE 802.11-12/0617r0 Submission References [1] Draft P802.11ac_D2.0 [2] Minyoung Park, “Proposed Specification Framework for TGah”, IEEE 802.11-11/1137r6 [3] Yong Liu, “Short ACK”, IEEE 802.11-12/324r2 Slide 14 May 2012 Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)