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doc.: IEEE 802.11-12/0617r0
Submission
NDP sounding
May 2012
Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)Slide 1
Date: 2012-05-14Authors:Name Affiliations Address Phone email Yongho Seok LG Electronics LG R&D Complex
Anyang-Shi, Kyungki-Do, Korea
+82-31-450-1947
Hongyuan Zhang Marvell Ron Porat Broadcom
Nihar Jindal Broadcom
Vinko Erceg Broadcom
Sameer Vermani Qualcomm
Eugene Baik Qualcomm
Lin Yang Qualcomm
Hemanth Sampath Qualcomm
VK Jones Qualcomm
Richard Van Nee Qualcomm
Jinsoo Choi LG Electronics
Jeongki Kim LG Electronics
Jin Sam Kwak LG Electronics
doc.: IEEE 802.11-12/0617r0
Submission
May 2012
Slide 2
Name Affiliations Address Phone email Yong Liu Marvell Raja Banerjea Marvell Eldad Perahia Intel Tom Tetzlaff Intel Tom Kenney Intel Jianhan Liu MediaTek Vish Ponnampalam MediaTek
ChaoChun Wang MediaTek James Wang MediaTek James Yee MediaTek George Calcev Huawei
Bin Chen Huawei
Young Hoon Kwon Huawei
Junghoon Suh Huawei
Tianyu Wu Huawei
Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)
doc.: IEEE 802.11-12/0617r0
Submission
May 2012
Slide 3
Name Affiliations Address Phone email Sun Bo ZTE Lv, Kaiying ZTE Huai-Rong Shao Samsung Chiu Ngo Samsung Minho Cheong ETRI Jae Seung Lee ETRI Heejung Yu ETRI Sayantan Choudhury Nokia
Taejoon Kim Nokia Klaus Doppler Nokia
Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)
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
NDP Annoncement
Sounding Feedback
VHT-NDP
SIFS SIFS
NDP Annoncement
Sounding Feedback
VHT-NDP
Sounding Feedback
SIFS
Poll Poll
Sounding Feedback
SIFS SIFS SIFS SIFS SIFS
May 2012
Slide 4 Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)
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 (NSTS)– Channel bandwidth (20/40/80/160MHz)
VHT-STF VHT-LTF1 VHT-LTFN…L-LTF L-SIG VHT-SIG-A
(Symbol 1)VHT-SIG-A(Symbol 2)L-STF VHT-SIG-B
May 2012
Slide 5 Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)
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-STF D-LTF1 D-LTF_N
…LTF1 SIGA(2 symbols)STF SIG-B
LTF2 LTF_N…LTF1 SIG
(2 symbols)STF
May 2012
Slide 6 Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)
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-STF AH-SIG ….
Immediate FB frame
Compute V Compress V and Prepare FB
SIFS
SIFS (80us) + PLCP Header (40*6us) = 320 us
May 2012
Slide 7 Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)
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 8 Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)
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 9 Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)
STF LTF1 SIG Remaining LTFs
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 10 Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)
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 11 Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)
LTF2 LTF_N…LTF1 SIG
(2 symbols)STF
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 12 Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)
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 13 Yongho Seok (LG Electronics), Hongyuan Zhang (Marvell)
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)