Robust SuperPoll Protocol for IEEE 802.11 Wireless LANs By Aura - PowerPoint PPT Presentation

Robust SuperPoll Protocol for IEEE 802.11 Wireless LANs By Aura Ganz*, Anan Phonphoem*, and Zvi Ganz** * ECE Department, University of Massachusetts, Amherst ** AIM Engineering Inc. 1

Presentation Outline ■ IEEE 802.11 PCF ■ Single Polling Concept in Noisy Environments ■ Proposed SuperPoll with Chaining Approach ■ Performance Results ■ Summary 2

IEEE 802.11 Point Coordination Function (PCF) CFP Repetition Interval CFP Repetition Interval CFP CP CFP CP B PCF DCF B PCF DCF 3

Single Polling AB PTS X PTS Y X Z PTS X Data Data Ack Ack Data Ack PTS Y Y Ack Data 4

Single Polling in Noisy Environment PTS(X) PTS(Y) PTS(Z) AB Time timeout X Data(X) Y Z Data(Z) 5

Proposed solution: SuperPoll with Chaining Approach AB sPTS X,Y,Z X Z Data Data sPTS X,Y,Z sPTS X,Y,Z Ack Ack 1st 3rd sPTS X,Y,Z Y 2nd 6

SuperPoll with Chaining 1 2 3 n AB Chance to n 1 2 3 hear sPTS 7

SuperPoll with Chaining AB sPTS X,Y,Z X Z Data XYZ Data XYZ Ack Ack sPTS X,Y,Z sPTS X,Y,Z 1st 3rd 3rd sPTS X,Y,Z Y Data XYZ 2nd 2nd 8

Average Probability that a station will not receive the SuperPoll P = 0.5 0.6 Average Probability (P*) 0.5 P = 0.5 0.4 0.3 P = 0.125 P = 0.3 0.2 0.1 P = 0.1 0.0 0 1 2 3 4 5 6 7 8 9 10 11 12 Group size 9

Efficiency Gain of SuperPoll over Single Poll 50.00 P = 0.5 40.00 30.00 % Gain P = 0.3 20.00 P = 0.1 10.00 0.00 0 1 2 3 4 5 6 7 8 9 10 11 12 Group size 10

Summary ■ SuperPoll is very robust and efficient in noisy environment ■ Group size can be adjusted according to station’s environment (location, etc.) ■ Easy integration within IEEE802.11 ■ SuperPoll algorithm is more complex than single poll 11