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

2. Month Year
doc.: IEEE yy/xxxxr0
January 2012
Abstract
In this contribution, we present the performance of current Authentication/Association protocols for 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

3. January 2012
Motivation
IEEE ah 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

4. 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

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

6. Simulation Parameters
January 2012
Simulation Parameters
Simulator
Qualnet network simulator
Simulation parameters
DCF mode with 1 MHz bandwidth as specified by ah 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
Number of Nodes
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

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

8. Month Year
doc.: IEEE yy/0112r0
Performance Results for Authentication/Association of Stations within 200 Seconds Limit
Haiguang Wang et. al, I2R, Singapore
Haiguang Wang et. al, I2R, Singapore

9. Suggested Solution: Using MAC Address
January 2012
Suggested Solution: Using MAC Address
Limit the number of stations that can authenticate/associate with AP at the same time.
Make use of the last byte of station’s MAC address to limit the number of stations.
AP broadcast a value V in the beacon.
Stations with last byte of MAC address 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.
Alternative solution to solve unfairness due to MAC address assignment;
AP broadcast two values, V1 and V2, to the stations
Stations with last byte of its MAC address falls in [V1, V2] are allowed to send authentication request.
AP adjust the value of V1 and V2 to control the number of stations performing authentication/association process.
Haiguang Wang et. al, I2R, Singapore

10. Performance Results Using Proposed Method
January 2012
Performance Results Using Proposed Method
Haiguang Wang et. al, I2R, Singapore

11. 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

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

13. 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

14. January 2012
References
[1] Chao-Chun Wang, “Supporting Large Number of STAs in ah”, IEEE /1019, July 2011.
[2] Siyang Liu, Luo Zhengdong, Daning Gong, “DCF Enhancements for Large Number of STAs”, IEEE /1255, Sep 2011.
Haiguang Wang et. al, I2R, Singapore

15. 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

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

17. January 2012
Straw Poll (3)
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