1. 2200 Mission College Blvd., Santa Clara, CA 95054, USA
July 2008
doc.: IEEE /1021r0
MU-RTS/CTS PHY Format
Date:
Name
Affiliation
Address
Phone
Po-Kai Huang
Intel
2200 Mission College Blvd., Santa Clara, CA 95054, USA  
Robert Stacey
Qinghua Li
Shahrnaz Azizi
Xiaogang Chen
Chitto Ghosh
Laurent Cariou
Yaron Alpert
Assaf Gurevitz
Ilan Sutskover
Feng Jiang
Po-Kai Huang et al. (Intel)
Peter Loc

2. Authors (continued) Alice Chen Albert Van Zelst Alfred Asterjadhi
Name
Affiliation
Address
Phone
Alice Chen
Qualcomm
5775 Morehouse Dr. San Diego, CA, USA
Albert Van Zelst
Straatweg 66-S Breukelen, 3621 BR Netherlands
Alfred Asterjadhi
Bin Tian
Carlos Aldana
1700 Technology Drive San Jose, CA 95110, USA
George Cherian
Gwendolyn Barriac
Hemanth Sampath
Lin Yang
Lochan Verma
5775 Morehouse Dr. San Diego, CA USA
Menzo Wentink
Naveen Kakani
2100 Lakeside Boulevard Suite 475, Richardson TX 75082, USA
Raja Banerjea
1060 Rincon Circle San Jose CA 95131, USA
Richard Van Nee

3. Authors (continued) Rolf De Vegt Sameer Vermani Qualcomm Simone Merlin
Name
Affiliation
Address
Phone
Rolf De Vegt
Qualcomm
1700 Technology Drive San Jose, CA 95110, USA
Sameer Vermani
5775 Morehouse Dr. San Diego, CA, USA
Simone Merlin
Tevfik Yucek  
VK Jones
Youhan Kim

4. Authors (continued) Jianhan Liu Mediatek USA
Name
Affiliation
Address
Phone
Jianhan Liu
Mediatek
USA
2860 Junction Ave, San Jose, CA 95134, USA
Thomas Pare
ChaoChun Wang
James Wang
Tianyu Wu
Russell Huang
James Yee
No. 1 Dusing 1st Road, Hsinchu, Taiwan  
Alan Jauh
Frank Hsu

5. Authors (continued) Name Affiliation Ron Porat Broadcom
Address
Phone
Ron Porat
Broadcom
Sriram Venkateswaran
Matthew Fischer
Zhou Lan
Leo Montreuil
Andrew Blanksby
Vinko Erceg
Thomas Derham
Mingyue Ji
Po-Kai Huang et al. (Intel)

6. Authors (continued) Name Affiliation Address Phone Email David X. Yang
Huawei
F1-17, Huawei Base, Bantian, Shenzhen
Jiayin Zhang
5B-N8, No.2222 Xinjinqiao Road, Pudong, Shanghai
Jun Luo
Yi Luo
Yingpei Lin
Jiyong Pang
Zhigang Rong
10180 Telesis Court, Suite 365, San Diego, CA  NA
Jian Yu
Ming Gan
Yuchen Guo
Yunsong Yang
Junghoon Suh
303 Terry Fox, Suite 400 Kanata, Ottawa, Canada
Peter Loc
Edward Au
Teyan Chen
Yunbo Li

7. 5488 Marvell Lane, Santa Clara, CA, 95054
Authors (continued)
Name
Affiliation
Address
Phone
Hongyuan Zhang
Marvell
5488 Marvell Lane, Santa Clara, CA, 95054
Lei Wang
Liwen Chu
Jinjing Jiang
Yan Zhang
Rui Cao
Sudhir Srinivasa
Bo Yu
Saga Tamhane
Mao Yu
Xiayu Zheng
Christian Berger
Niranjan Grandhe
Hui-Ling Lou

8. Authors (continued) Jinmin Kim Kiseon Ryu Jinyoung Chun
Name
Affiliation
Address
Phone
Jinmin Kim
LG Electronics
19, Yangjae-daero 11gil, Seocho-gu, Seoul , Korea
Kiseon Ryu
Jinyoung Chun
Jinsoo Choi
Jeongki Kim
Dongguk Lim
Suhwook Kim
Eunsung Park
JayH Park
HanGyu Cho
Bo Sun
ZTE
#9 Wuxingduan, Xifeng Rd., Xi'an, China
Kaiying Lv
Yonggang Fang
Ke Yao
Weimin Xing
Brian Hart
Cisco Systems
170 W Tasman Dr, San Jose, CA 95134
Pooya Monajemi

9. Authors (continued) Fei Tong Samsung Hyunjeong Kang Kaushik Josiam
Name
Affiliation
Address
Phone
Fei Tong
Samsung
Innovation Park, Cambridge CB4 0DS (U.K.)
Hyunjeong Kang
Maetan 3-dong; Yongtong-Gu Suwon; South Korea
Kaushik Josiam
1301, E. Lookout Dr, Richardson TX 75070
(972)
Mark Rison
Rakesh Taori
(972)
Sanghyun Chang
Yasushi Takatori
NTT
1-1 Hikari-no-oka, Yokosuka, Kanagawa Japan  
Yasuhiko Inoue  
Shoko Shinohara
Yusuke Asai  
Koichi Ishihara  
Junichi Iwatani  
Akira Yamada
NTT DOCOMO
3-6, Hikarinooka, Yokosuka-shi, Kanagawa, , Japan
 3759

10. Authors (continued) Name Affiliation Address Phone Email Masahito Mori
Sony Corp.
Yusuke Tanaka
Yuichi Morioka
Kazuyuki Sakoda
William Carney
Narendar Madhavan
Toshiba
Masahiro Sekiya
Toshihisa Nabetani
Tsuguhide Aoki
Tomoko Adachi
Kentaro Taniguchi
Daisuke Taki
Koji Horisaki
David Halls
Filippo Tosato
Zubeir Bocus
Fengming Cao

11. Authors (continued) Name Affiliation Address Phone Email Minho Cheong
Newracom, Inc.
9008 Research Dr, Irvine, CA 92618
Reza Hedayat
Young Hoon Kwon
Yongho Seok
Daewon Lee
Yujin Noh
Sigurd Schelstraete
Quantenna
Huizhao Wang

12. Background
11ax has agreed to have MU-RTS/CTS procedure for protection of MU transmission [1]
The MAC format of MU-RTS is a variant of Trigger frame
CTS Response carried in non-HT or non-HT duplicate PPDU may be requested by MU-RTS for protection from legacy STAs
We discuss the PHY format of MU-RTS/CTS with further details in this presentation
Intel

13. MU-RTS PHY format
Since MU-RTS is a variant of Trigger frame, MU-RTS currently is also allowed to be carried in HE MU PPDU [2,3]
We may have multiple unicast MU-RTSs in HE MU PPDU. This complicates the rule for requesting same CTS response
We may have one MU-RTS requesting non-HT response and the trigger frame in other RUs requesting HE response. In this case, the preamble of UL MU transmission can not be decoded by neighboring STAs.
Expect that it is not useful to have MU-RTS carried in HE MU PPDU.
Propose that MU-RTS shall not be carried in an HE MU PPDU
Po-Kai Huang et al. (Intel)

14. PHY format of CTS Response
Like RTS, MU-RTS may be carried in non-HT PPDU, HT PPDU, VHT PPDU, or HE SU PPDU.
Expect that most of the time, MU-RTS is carried in
non-HT PPDU for legacy protection
HE SU PPDU for utilizing 11ax HE features or simply for transmission with large bandwidth to reduce overhead (See Appendix for overhead comparison)
When MU-RTS is carried in non-HT PPDU,
Similar to the VHT RTS procedure, CTS response should be carried in non-HT PPDU for legacy protection
When MU-RTS is carried in HE SU PPDU,
Soliciting HE trigger-based PPDU does not provide additional value because CTS response in HE trigger-based PPDU cannot be decoded by neighboring STAs
Soliciting HE trigger-based PPDU with feedback from STA can already be done by the basic trigger frame
Hence, CTS should be carried in non-HT PPDU for legacy protection
Note that CTS-to-self can be transmitted before MU-RTS for legacy protection if required
Intel

15. PHY format of CTS Response
When MU-RTS is carried in VHT PPDU,
Expect that MU-RTS will not be carried in this format most of the time
For RTS, if RTS is carried in VHT PPDU, then CTS is carried in VHT PPDU only if RTS is transmitted using control wrapper frame.
Since control wrapper frame is not widely supported, most of the time CTS response to RTS is carried in non-HT PPDU
Expect that control wrapper will not be widely supported by 11ax STAs as well. Hence, CTS response to MU-RTS should be carried in non-HT PPDU by following the 11ac rule.
When MU-RTS is carried in HT PPDU,
For simplicity, propose that the CTS response to an MU-RTS shall be carried in a non-HT or a non-HT duplicate PPDU
Intel

16. Conclusion
We discuss the PHY format of MU-RTS/CTS with further details in this presentation
To avoid possible complicated scenarios when MU-RTS is carried in HE MU PPDU, propose that MU-RTS shall not be carried in an HE MU PPDU
For simplicity, propose that the CTS response to an MU-RTS shall be carried in a non-HT or a non-HT duplicate PPDU
Intel

17. Reference 11-15-1325-00 MU-RTS/CTS Follow Up
Broadcast and Unicast (Trigger) in DL MU
Proposed draft specification
Po-Kai Huang et al. (Intel)

18. Straw Poll 1
Do you agree to add to the TG Specification Frame work document?
x.y.z. MU-RTS shall not be carried in an HE MU PPDU
Po-Kai Huang et al. (Intel)

19. Straw Poll 2
Do you agree to add to the TG Specification Frame work document?
x.y.z. The CTS response to an MU-RTS shall be carried in a non-HT or a non-HT duplicate PPDU
Po-Kai Huang et al. (Intel)

20. Appendix
Assume 178 bytes for MU-RTS frame [3] (2 bytes frame control + 2 bytes duration + 6 bytes TA +6 bytes RA+ 2 bytes common info + 5 bytes *32 per-user info)
Assume 80 MHz bandwidth and MCS0 for non-HT PPDU (6Mbps) and HE SU PPDU (36Mbps) [3]
Case 1: Overhead = = 313 us
Case 2: Overhead = = 131 us
MU-RTS
non-HT duplicate
CTS
non-HT duplicate
MU-RTS
HE SU
CTS
non-HT duplicate
Po-Kai Huang et al. (Intel)