doc.: ieee 802.11-12/0112r4 submission supporting authentication/association for large number of...

doc.: IEEE 802.11-12/0112r4

Submission

Supporting Authentication/Association for Large Number of Stations

September 2012

Slide 1 I2R

Date: 2012-09-12Name Affiliations Address Phone email Haiguang Wang

I2R 1 Fusionopolis Way, #21-01, Connexis South Tower, Singapore 138632

hwang@i2r.a-star.edu.sg

Jaya Shankar I2R jshankar@ i2r.a-star.edu.sg

Shoukang Zheng I2R skzheng@ i2r.a-star.edu.sg

Hoang Anh Tuan I2R athoang@ i2r.a-star.edu.sg

Zander Lei I2R leizd@ i2r.a-star.edu.sg

Yeow Wai Leong I2R wlyeow@ i2r.a-star.edu.sg

Joseph Teo Chee Ming

I2R cmteo@ i2r.a-star.edu.sg

Rojan Chitrakar Panasonic Rojan.Chitrakar@sg.panasonic.com

Ken Mori Panasonic Mori.ken1@jp.panasonic.com

ChaoChun Wang MediaTek chaochun.wang@mediatek.com

James Wang MediaTek james.wang@mediatek.com

Jianhan Liu MediaTek jianhan.liu@mediatek.com

Vish Ponnampalam MediaTek vish.ponnampalam@mediatek.com

James Yee MediaTek james.yee@mediatek.com

Thomas Pare MediaTek thomas.pare@mediatek.com

Kiran Uln MediaTek kiran.uln@mediatek.com

Huai-Rong Shao Samsung hr.shao@samsung.com

Chiu Ngo Samsung chiu.ngo@samsung.com

doc.: IEEE 802.11-12/0112r4

Submission

Authors:

September 2012

Name Affiliations Address Phone email Sayantan Choudhury Nokia

Taejoon Kim Nokia

Klaus Doppler Nokia

Chittabrata Ghosh Nokia

Esa Tuomaala Nokia

George Calcev Huawei Rolling Meadows, IL USA

George.Calcev@huawei.com

Osama Aboul Magd Huawei Osama.AboulMagd@huawei.com

Young Hoon Huawei Younghoon.Kwon@huawei.com

Betty Zhao Huawei Betty.Zhao@huawei.com

David Yangxun Huawei David.Yangxun@huawei.com

Bin Zhen Huawei ZhenBin@huawei.com

Minho Cheong ETRI 138 Gajeongno, Yuseong-gu, Dajeon, Korea

+82 42 860 5635

minho@etri.re.kr

Jae Seung Lee ETRI jasonlee@etri.re.kr

Hyoungjin Kwon ETRI kwonjin@etri.re.kr

Heejung Yu ETRI heejung@etri.re.kr

Jaewoo Park ETRI parkjw@etri.re.kr

Sok-kyu Lee ETRI Sk-lee@etri.re.kr

Sun, Bo ZTE sun.bo1@zte.com.cn

Lv, Kaiying ZTE lv.kaiying@zte.com.cn

Slide 2 I2R

doc.: IEEE 802.11-12/0112r4

Submission

Authors:

September 2012

Name Affiliations Address Phone email Minyoung Park Intel Corp. 2111 NE 25th Ave.

Hillsboro, OR +1 503 712 4705 minyoung.park@intel.com

Adrian Stephens Intel Corp. Adrian.P.Stephens@intel.com

Tom Tetzlaff Intel Corp. thomas.a.tetzlaff@intel.com

Emily Qi Intel Corp. emily.h.qi@intel.com

Yong Liu Marvell yongliu@marvell.com

Hongyuan Zhang Marvell Hongyuan@marvell.com

Sudhir Srinivasa Marvell sudhirs@marvell.com

Yongho Seok LG Electronics LG R&D Complex Anyang-Shi, Kyungki-Do, Korea

+82-31-450-1947 yongho.seok@lge.com

Jinsoo Choi LG Electronics

Jeongki Kim LG Electronics

Jin Sam Kwak LG Electronics

Matthew Fischer Broadcom 190 Mathilda Place, Sunnyvale, CA

+1 408 543 3370 mfischer@broadcom.com

Eric Wong Broadcom ewong@broadcom.com

Simone Merlin Qualcomm 5775 Morehouse Dr, San Diego, CA

8588451243 smerlin@qualcomm.com

Alfred Asterjadhi Qualcomm

Amin Jafarian Qualcomm

Santosh Abraham Qualcomm

Menzo Wentink Qualcomm

Hemanth Sampath Qualcomm

VK Jones Qualcomm

Slide 3 I2R

doc.: IEEE 802.11-12/0112r4

Submission

Introduction

• The concept has been presented in IEEE [3]

• This contribution is a follow-up that provides more details addressing questions and concerns raised after previous presentations

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doc.: IEEE 802.11-12/0112r4

Submission Slide 5

Motivation

• IEEE 802.11ah is required to support >6000 stations [1]• In smart grid (e.g. power meter), large number of STA

may try to authenticate/associate with AP simultaneously after power outage, leading to severe collision and authentication/association failure

• AP is required to handle a sudden burst of authentication/association requests from many STA within a short period.

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Submission

Authentication/Association Procedure

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doc.: IEEE 802.11-12/0112r4

Submission Slide 7

Simulation Parameters• Simulator

– Qualnet network simulator

• Simulation parameters• DCF mode with 1 MHz bandwidth as specified by 802.11ah frame work• With implemented power saving protocols. • PHY modulation: MCS0-REP2 • Transmission range: 1 km

• Basic parameters

Parameter Value Parameter Value

Data Rate 150 Kbps Backoff Win 15 - 1023

Number of Nodes 50- 3000 Maximum Short Retry 7

DIFS 250 us Maximum long Retry 4

SIFS 160 us Time slot 45 us

Beacon Interval 200 milliseconds DTIM Period 25 (5 seconds)

PS Mode Listen Interval 25 (5 seconds)

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doc.: IEEE 802.11-12/0112r4

Submission Slide 8

Topology

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Submission

Performance Results for Authentication/Association of Stations within 300 Seconds Limit

Slide 9 I2RI2R

doc.: IEEE 802.11-12/0112r4

Submission

Reason for Authentication/Association Failure

• STAs redo the authentication due to following reasons:– Authentication request transmission failure due to collision– Fail to receive authentication response

• Authentication response collide with transmission from other stations• Authentication reply timeout due to long queue at AP.

– Association request/response time out due to collision and severe transmission media contention

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doc.: IEEE 802.11-12/0112r4

Submission

Suggested Solution: Using Random Numbers

• Make use of random number to limit the number of stations that can authenticate/associate with AP at the same time– AP may broadcast a value V as an IE in the beacon– Each station generates a random number R, for example when it is initialized or

when it is required for authentication. – If a station receives V in the beacon from the AP, before sending out

authentication request, the station compares R with V, if R <= V , it can send authentication request to the AP. Else, it shall delay the transmission of authentication request.

– If a station does not receive V in the beacon, its authentication/association is not constrained by V.

– Stations that have already received authentication response are not constrained by value V.

– AP can adjust the value of V for every beacon. • More details see the following slides.

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doc.: IEEE 802.11-12/0112r4

Submission

Usage of Value V (1)

• When AP starts (no change to current spec)– AP does not need to broadcast value V in the beacon. – As per normal, any STA can send authentication/ association request to

AP

• When only a few STA want to associate with AP (no change to current spec)– E.g. Queue of management frame is very short – AP does not need to broadcast value V in the beacon. – As per normal, any STA can send authentication/ association request to

AP

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Submission

Usage of Value V (2)

• When many stations try to associate with AP – AP starts to broadcast Value V (e.g. set V=0)

• Larger V value = more STA is allowed to associate/authentication• e.g. Management frames building up at AP’s buffer• If queue length QL > Q0, AP may consider network is congested and set

value V to a smaller value such as 0. – AP continues sending out updated value V in subsequent beacons

• AP may regulate the number of STAs through adjust value V – STA compares value V with a random number R generated by STA

• If R <=V then STA is allowed to send authentication request– STA does not need to check value V after STA receiving authentication

response from AP

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Submission

Example: Updating V

• Before sending out a beacon, AP checks the Queue length of management frame– AP decreases Value V when the Queue length is above a threshold– AP increases Value V when the Queue length is below a threshold– Maximum Value V

• 255, if Value V in IE is one byte (good enough as in simulations)• Larger number is possible using more bits in IE

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Performance Results: Using Random Numbers

Slide 15 I2RI2R

doc.: IEEE 802.11-12/0112r4

Submission

Variation of Value V over Time

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Submission Slide 17

Conclusions

• Simulation results show that, it is necessary to control the number of

stations performing authentication/association at the same time to

improve the performance in scenario with large number of stations.

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Submission Slide 18

References

• [1] Chao-Chun Wang, “Supporting Large Number of STAs in 802.11ah”, IEEE 802.11-11/1019, July 2011.

• [2] Siyang Liu, Luo Zhengdong, Daning Gong, “DCF Enhancements for Large Number of STAs”, IEEE 802.11-11/1255, Sep 2011.

• [3] Haiguang Wang, et. al. “Supporting Authentication/Association for Large Number of Stations”, IEEE 802.11-12/0112r3, May 2012.

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doc.: IEEE 802.11-12/0112r4

Submission

Straw Poll 1

• Do you agree that AP should limit the number of STA to be authenticated/associated at the same time?

• Y: • N: • A:

Slide 19 I2RI2R

doc.: IEEE 802.11-12/0112r4

Submission

Straw Poll 2

• Do you agree that AP is allowed to broadcast a value in the beacon to control the authentication/association of STA?– Y– N– A

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