Study On Collision Resolving Algorithm In MAC Protocol In AD HOC Network

Ad Hoc network requires no infrastructure and nodes are free to enter, leave, or move inside the network without prior configuration. The media access control (MAC) protocol controls how the nodes access the wireless channel, influences the performance of the Ad Hoc network. Since there is not a specific MAC protocol focuses on the network with fast-moving nodes and mutative topology. Consequently this dissertation focuses on how to improve the performance and stability of the MAC protocol in such a network environment. The contributions of this paper are follows:1) Through the analysis on the probability model of backoff algorithm, this paper presents a novel algorithm called DABEB-M with an adaptive original contention window based on the real time neighbor nodes density.2) This paper presents a novel algorithm called FED, which sacrificed the fairness to improve the other performances as delay, throughput, collision avoid.3) This paper combines the two algorithms above and presents a novel algorithm called P-FED with adaptive contention window and adaptive decrease speed of backoff time.4) It's presented the modification and realization of the proposed algorithm, DABEB-M, FED and PFED by NS2 to verify the performance. By comparison with BEB, the simulation showed that the improved algorithms have better performance and have good potential in applications.