Persistence based cooperative MAC protocol for Ad Hoc wireless networks

In this paper we propose a combined MAC protocol for wireless ad hoc networks that overcome some of the limitations of basic IEEE 802.11b MAC protocol. The proposed protocol involves the concept of cooperation along with persistence to avoid the negative effects caused by multi rate modulation employed by the 802.11b. Unlike basic MAC protocol, the proposed MAC also provides service distinction to real and non real time packets and also contains the provision for fair access of the channel. We introduce the concept of persistence after the exponential back-off to reduce collision. Simulation study shows that the throughput and delay performance are much better at 0.8 persistence rather than at 1 persistence after back-off which is being used by the standard 802.11b MAC. We also show through exhaustive simulations that there is a marked improvement on the performance of the MAC protocol when all the above provisions are combined together.