1. Adaptive CCA and TPC Date: 2015-09-12 Authors: September, 2015
Name
Affiliation
Address
Phone
James Wang
Mediatek
USA
2860 Junction Ave, San Jose, CA 95134, USA
Thomas Pare
ChaoChun Wang
Jianhan Liu
Tianyu Wu
Russell Huang
James Yee
No. 1 Dusing 1st Road, Hsinchu, Taiwan  
Alan Jauh
Chingwa Hu
Frank Hsu
James Wang, Mediatek, et. al.

2. Authors (continued) September, 2015 Albert Van Zelst Alfred Asterjadhi
Name
Affiliation
Address
Phone
Albert Van Zelst
Qualcomm
Straatweg 66-S Breukelen, 3621 BR Netherlands
Alfred Asterjadhi
5775 Morehouse Dr. San Diego, CA, USA
Arjun Bharadwaj
Bin Tian
Carlos Aldana
1700 Technology Drive San Jose, CA 95110, USA
George Cherian
Gwendolyn Barriac
Hemanth Sampath
Menzo Wentink
Richard Van Nee
Rolf De Vegt
Sameer Vermani
Simone Merlin
Tevfik Yucek  
VK Jones
Youhan Kim
James Wang, Mediatek, et. al.

3. 2111 NE 25th Ave, Hillsboro OR 97124, USA
September, 2015
Authors (continued)
Name
Affiliation
Address
Phone
Robert Stacey
Intel
2111 NE 25th Ave, Hillsboro OR 97124, USA     
Eldad Perahia
Shahrnaz Azizi
Po-Kai Huang
Qinghua Li
Xiaogang Chen
Chitto Ghosh
Laurent cariou
Rongzhen Yang
Ron Porat
Broadcom
Matthew Fischer
Sriram Venkateswaran
Andrew Blanksby
Matthias Korb
Tu Nguyen
Vinko Erceg
James Wang, Mediatek, et. al.

4. Authors (continued) September, 2015 Phillip Barber Peter Loc Le Liu
Name
Affiliation
Address
Phone
Phillip Barber
Huawei
The Lone Star State, TX
Peter Loc
Le Liu
F1-17, Huawei Base, Bantian, Shenzhen
Jun (Rossi) Luo
5B-N8, No.2222 Xinjinqiao Road, Pudong, Shanghai
Yi Luo
Yingpei Lin
Jiyong Pang
Zhigang Rong
10180 Telesis Court, Suite 365, San Diego, CA  NA
Rob Sun
303 Terry Fox, Suite 400 Kanata, Ottawa, Canada
David X. Yang
Yunsong Yang
Zhou Lan
F1-17, Huawei Base, Bantian, SHenzhen
Junghoon Suh
Jiayin Zhang
James Wang, Mediatek, et. al.

5. Authors (continued): September, 2015 Hongyuan Zhang Marvell
Name
Affiliation
Address
Phone
Hongyuan Zhang
Marvell
5488 Marvell Lane, Santa Clara, CA, 95054
Yakun Sun
Lei Wang
Liwen Chu
Jinjing Jiang
Yan Zhang
Rui Cao
Bo Yu
Sudhir Srinivasa
Saga Tamhane
Mao Yu
Edward Au
Hui-Ling Lou
Joonsuk Kim
Apple
Aon Mujtaba  
Guoqing Li
Eric Wong
Chris Hartman
James Wang, Mediatek, et. al.

6. Authors (continued) September, 2015 Hyeyoung Choi LG Electronics
Name
Affiliation
Address
Phone
Hyeyoung Choi
LG Electronics
19, Yangjae-daero 11gil, Seocho-gu, Seoul , Korea
Kiseon Ryu
Jinyoung Chun
Jinsoo Choi
Jeongki Kim
Giwon Park
Dongguk Lim
Suhwook Kim
Eunsung Park
HanGyu Cho
Thomas Derham
Orange
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
James Wang, Mediatek, et. al.

7. Authors (continued) September, 2015 Fei Tong Samsung Hyunjeong Kang
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
Yusuke Asai
Koichi Ishihara
Akira Kishida
Akira Yamada
NTT DOCOMO
3-6, Hikarinooka, Yokosuka-shi, Kanagawa, , Japan
Fujio Watanabe
3240 Hillview Ave, Palo Alto, CA 94304
Haralabos Papadopoulos
James Wang, Mediatek, et. al.

8. Authors (continued) September, 2015 Masahito Mori Sony Corporation
Name
Affiliation
Address
Phone
Masahito Mori
Sony Corporation
1-7-1 Konan Minato-ku, Tokyo , Japan 
Takeshi Itagaki
James Wang, Mediatek, et. al.

9. Outline Interference problems for spatial reuse transmission
Adaptive CCA and TPC schemes
Conclusions
James Wang, Mediatek, et al

10. Interference Problem for Spatial Re-use
In Ref[11], a 4 BSSs/40STAs scenario is presented
CCA prevents high percentage of spatial re-use transmission (>90% for CCA=-82dBm)
Significant percentage of spatial re-use transmission (shaded area: >30%) will affect the MCSs of the on-going frame exchange
4BSSs/40STAs, all TX Power = 15 dBm
TPC needed to avoid collisions
Spatial Re-use Possible
Spatial re-use induced collision causes loss in throughput before link can adapt to lower MCSs.
Interference mitigation (such as
Higher MCS
Normalized distance (by that of MCS0) between primary nodes
transmit power control) should be employed during SR transmission to avoid collision with on-going frame exchange in a dense environment
James Wang, Mediatek, et al

11. Adaptive CCA/TPC Schemes
To achieve higher spatial re-use in a dense environment, the following step are needed.
Detect and identify whether a received PPDU is from inter-BSS or intra-BSS (e.g., via BSS Color)
for OBSS PPDUs, employ an OBSS specific channel access procedure for spatial re-use (such as employing a OBSS_PD CCA threshold)
initiate a spatial re-use transmission under specific conditions (such as employs transmit power adjustment)
Higher OBSS CCA threshold increases spatial re-use. However, to
avoid interference to OBSS transmission
maintain fairness to legacy STAs
the OBSS CCA threshold should be accompanied by a TXPWR value and a reduction in the TXPWR should be allowed to be accompanied by an increase in the OBSS CCA threshold value.
There are many contributions (e.g, Ref 1~12) on this subject. Specific methods (Ref 1~12) of adaptive CCA and TPC implementations are still subject to further investigation and comparison.
James Wang, Mediatek, et al

12. An Example of Adaptive CCA/PC Scheme
STA’s OBSS_PD threshold and transmit power are based on received RSSI (e.g, received RCPI of the beacon or path loss) and constants determined by AP
Adjusted_TX_Pwr = TX_Pwrnominal –RSSIAP +constant 1
Adjusted_OBSS_PD = OBSS_PDnominal + RSSIAP + constant 2
Limits the OBSS_PD threshold to be
-82dBm<Adj_CCA<-62 dBm
(Note: OBSS_PD for AP can be set to the value based on the farthest STA.)
Less adjustment
More adjustment
Higher SR,
Lower TX PWR
Lower SR,
Higher TX PWR
James Wang, Mediatek, et al

13. Simulation Results for the Example Adaptive CCA/TPC Scheme
Simulation Scenario 6, 11ax BSS
BSS B (middle) achieves the highest throughput improvement.
BSS A and BSS C (edge) also achieve significant throughput improvement.
BSS C
BSS B
BSS A
BSS
Adaptive CCA TPC Gput
(Mbps)
Baseline Gput
Gput Improvement
(%) A 32 B 57 C 30
Total 38
James Wang, Mediatek, et al

14. Simulation Results for the Example Adaptive CCA/TPC Scheme
Simulation results of a mixed 11ax BSS and legacy BSS (BSS B is legacy BSS)
Note that legacy BSS performance is not degraded
BSS
Adaptive CCA TPC Gput (Mbps)
Baseline Gput
(Mbps)
Gput Improvement
(%) A 29 B 10 C 28
Total 23
James Wang, Mediatek, et al

15. Sony’s Simulation Results – SS1 (All of STAs are Ax-STA)
September 2015
Sony’s Simulation Results – SS1 (All of STAs are Ax-STA)
(Offered DL load=60Mbps)
From Ref 12
Offered
UL load
When TPC and DCCA(DSC/DOCCA) are used together, larger gain can be obtained than when TPC/DCCA is used alone.
James Wang, Mediatek, et al

16. Sony’s Simulation Results for SS1 (All of STAs are Ax-STA)
September 2015
Sony’s Simulation Results for SS1 (All of STAs are Ax-STA)
From Ref 12
Uplink
Downlink
DCCA(DSC/DOCCA) can deteriorate the 5%tile throughput when used alone.
On the other hand, when TPC is used with DCCA, 5%tile throughput can be improved.
James Wang, Mediatek, et al

17. Conclusions
In this contribution, simulation results for adaptive CCA/TPC show that higher network throughput can be achieved while maintaining fairness to legacy STA and 5 percentile performance.
Propose that for adaptive CCA/TPC scheme, the OBSS CCA threshold in the adaptive CCA/TPC scheme should be accompanied by a TXPWR value and a reduction in the TXPWR should be accompanied by an increase in the OBSS CCA threshold value
James Wang, Mediatek, et al

18. Straw Poll
When an 11ax STA detects a valid OBSS PPDU it may discard the PPDU if the RXPWR of the received PPDU is below the OBSS_PD threshold and TBD conditions are met, noting that the OBSS_PD threshold is accompanied by a TXPWR value and a reduction in the TXPWR may be accompanied by an TBD increase in the OBSS_PD threshold value.
Yes:
No:
Abstain:
James Wang, Mediatek, et al

19. Backup Charts
Mediatek

20. Scenario Description (slides 12 and 13)
802.11ac Enterprise Network with OBSS, Scenario 6.
DCN: ac-tgac-functional-requirements-and-evaluation-methodology
Parameters:
ac 20MHz overlapped BSS
BSS A: 5 STAs
BSS B: 20 STAs
BSS C: 5 STAs
AP Tx power: 20 dBm
STA Tx power: 15 dBm
ED CCA threshold: -62 dBm
Fixed Rate: MCS5
EDCA, AC_BE, [CWmin = 15, CWmax = 1023], AIFSn = 3
MSDU Packet size: 1500 bytes
full buffer
BSS A
Station UL
STA3 Y
STA9
STA15
STA21
STA27
BSS B
Station UL
STA1 Y
STA2
STA4
STA5
STA7
STA8
STA10 N
STA11
STA13
STA14
STA16
STA17
STA19
STA20
STA22
STA23
STA25
STA26
STA28
STA29
BSS C
Station UL
STA6 Y
STA12
STA18
STA24
STA30
James Wang,Mediate,k et al

21. Reference
[1] DCN r1 “The Effect of Preamble Error Model on MAC Simulator”, Po-Kai Huang, Intel [2] DCN r0 “OBSS preamble detection”, Gwen Barriac , Qualcomm [3] DCN “Spatial Reuse and Coexistence with Legacy Devices” James Wang, Mediatek [4] DCN r1 “Improved Spatial Reuse Feasibility – Part I” Ron Porat, Broadcom [5] DCN “Link Aware CCA” Brian Hart, Cisco [6]DCN “Spatial Reuse and Coexistence with Legacy Devices” James Wang, Mediatek [7] DCN r1 “OBSS reuse mechanism which preserves fairness” Imad Jamil, Orange [8] DCN r1 “CCA Study in Residential Scenario - Part 2” Gwen Barriac, Qualcomm [9] DCN r0 “CCA Study in Residential Scenario”, Gwen Barriac, Qualcomm [10] DCN r2 “Considerations for Adaptive CCA” Reza Hedayat, Newracom [11] DCN r0 “CCA Revisited” Amin Jafarian, Newracom [12[ DCN r0 Sony Dynamic CCA control and TPC Simulation Results
James Wang,Mediate,k et al