doc.: ieee 802.11-12/0112r4 submission supporting authentication/association for large number of...
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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
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 [email protected]
Ken Mori Panasonic [email protected]
ChaoChun Wang MediaTek [email protected]
James Wang MediaTek [email protected]
Jianhan Liu MediaTek [email protected]
Vish Ponnampalam MediaTek [email protected]
James Yee MediaTek [email protected]
Thomas Pare MediaTek [email protected]
Kiran Uln MediaTek [email protected]
Huai-Rong Shao Samsung [email protected]
Chiu Ngo Samsung [email protected]
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
Osama Aboul Magd Huawei [email protected]
Young Hoon Huawei [email protected]
Betty Zhao Huawei [email protected]
David Yangxun Huawei [email protected]
Bin Zhen Huawei [email protected]
Minho Cheong ETRI 138 Gajeongno, Yuseong-gu, Dajeon, Korea
+82 42 860 5635
Jae Seung Lee ETRI [email protected]
Hyoungjin Kwon ETRI [email protected]
Heejung Yu ETRI [email protected]
Jaewoo Park ETRI [email protected]
Sok-kyu Lee ETRI [email protected]
Sun, Bo ZTE [email protected]
Lv, Kaiying ZTE [email protected]
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 [email protected]
Adrian Stephens Intel Corp. [email protected]
Tom Tetzlaff Intel Corp. [email protected]
Emily Qi Intel Corp. [email protected]
Yong Liu Marvell [email protected]
Hongyuan Zhang Marvell [email protected]
Sudhir Srinivasa Marvell [email protected]
Yongho Seok LG Electronics LG R&D Complex Anyang-Shi, Kyungki-Do, Korea
+82-31-450-1947 [email protected]
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 [email protected]
Eric Wong Broadcom [email protected]
Simone Merlin Qualcomm 5775 Morehouse Dr, San Diego, CA
8588451243 [email protected]
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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doc.: IEEE 802.11-12/0112r4
Submission
Authentication/Association Procedure
Slide 6 I2RI2R
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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doc.: IEEE 802.11-12/0112r4
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.
Slide 11 I2RI2R
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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doc.: IEEE 802.11-12/0112r4
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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doc.: IEEE 802.11-12/0112r4
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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doc.: IEEE 802.11-12/0112r4
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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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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