Survey Paper on Achieving MAC Layer Fairness using Back off Schemes in Wireless Ad hoc Networks?

A Wireless Adhoc Networks consists of wireless nodes that can be fashioned anywhere and anytime without any fixed infrastructure in which every node can act as both as a host or a router. Nodes that want to access the channel may participate in a distributed way via Carrier Sensing Multiple Access with Collision Avoidance (CSMA/CA) scheme in MAC (Medium Access Control) layer. Packet collisions among nodes cannot be fully eliminated due to the disseminated nature of the nodes. For this collision avoidance purpose MAC layer adopts Binary Exponential Backoff (BEB) scheme. In BEB scheme, the contention window of a node is reset to an initial value after each successful transmission of packets. In case of packet collision, window size is doubled. This unexpected alteration in window size may humiliate the performance of the network. There are several existing backoff algorithms which are discussed in this survey paper and an appropriate analysis of these existing algorithms is presented.