Simulation and Analysis of a Wireless Mac Protocol: MACAW.

MACAW Medium Access Collision Avoidance Wireless is a new MAC protocol for wireless LANs proposed by Bharghavan et al. Ref. 2 based on Karns MACA protocol Ref.3. In this thesis the performance characteristics and operational behavior of the protocol are investigated The approach taken was to simulate the protocol by OPNET 2.4c of MIL3, Inc. and determine the utilizations and mean delay times of the transmitters under various operational conditions. Also a new performance measure was defined in terms of utilization and mean delay time. Our investigation has shown that the optimum performance of the MACAW protocol occurs at approximately 50 channel load. We have also shown the importance of the backoff algorithm, and finally, we have shown that carrier sensing dramatically improves the performance of the protocol for high channel loads. Simulation results showed that decreasing the backoff increase rate by 15 gave twice as good performance results for the small number of transmitting nodes cases. When carrier sensing was introduced to the protocol, dramatic performance increases resulted under heavy loads 60 to 80 channel loads. Carrier sensing also pushed the optimum performance channel load threshold from 50 to 60.