Supporting Authentication/Association for Large Number of Stations Month Year doc.: IEEE 802.11-yy/xxxxr0 January 2012 Supporting Authentication/Association for Large Number of Stations Date: 2012-03-12 Authors: Haiguang Wang et. al, I2R, Singapore John Doe, Some Company

Month Year doc.: IEEE 802.11-yy/xxxxr0 January 2012 Abstract In this contribution, we present the performance of current Authentication/Association protocols for 802.11 networks with large number of nodes. We found that it is necessary to limit the number of stations that can perform the authentication/association simultaneously. Haiguang Wang et. al, I2R, Singapore John Doe, Some Company

January 2012 Motivation IEEE 802.11ah is required to support up to 6000 stations by a single AP [1]. It is necessary to examine performance of existing standard in supporting large number of nodes, including authentication/association. Haiguang Wang et. al, I2R, Singapore

January 2012 Usage Scenarios In smart grid application, when AP or stations experience power outage, the stations may try to authenticate/associate with AP simultaneously after recovery. The AP is required to handle a sudden burst of authentication/association requests from a few thousands stations within a short period. Haiguang Wang et. al, I2R, Singapore

Authentication/Association Procedure January 2012 Authentication/Association Procedure Haiguang Wang et. al, I2R, Singapore

Simulation Parameters January 2012 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 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 Haiguang Wang et. al, I2R, Singapore

January 2012 Topology Haiguang Wang et. al, I2R, Singapore

Month Year doc.: IEEE 802.11-yy/0112r0 Performance Results for Authentication/Association of Stations within 300 Seconds Limit Haiguang Wang et. al, I2R, Singapore Haiguang Wang et. al, I2R, Singapore

Suggested Solution: Using Random Numbers January 2012 Suggested Solution: Using Random Numbers Limit the number of stations that can authenticate/associate with AP at the same time. Make use of random number to limit the number of stations. AP broadcast a value V in the beacon. Stations with random number less than V are allowed to send authentication request. AP can adjust the value of V to control the number of stations performing authentication/association process. Haiguang Wang et. al, I2R, Singapore

Performance Results: Using Random Numbers January 2012 Performance Results: Using Random Numbers Haiguang Wang et. al, I2R, Singapore

Variation of Value V over Time January 2012 Variation of Value V over Time Haiguang Wang et. al, I2R, Singapore

January 2012 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. Haiguang Wang et. al, I2R, Singapore

January 2012 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. Haiguang Wang et. al, I2R, Singapore

January 2012 Straw Poll (1) Do you agree that AP should limit the number of stations to be authenticated/associated at the same time? Y: N: A: Haiguang Wang et. al, I2R, Singapore

January 2012 Straw Poll (2) Do you agree to use random number to limit the number of stations to be authenticated/associated at the same time? Y: N: A: Haiguang Wang et. al, I2R, Singapore