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

yongho.seok@lge.com

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)