Contention Based MAC Collision Avoidance Technique for Mobile Adhoc Networks

Mobile ad hoc networks (MANETs) have transformed providing services for a variety of real-time applications. In a MANET, a collection of wireless mobile nodes powered by batteries is configured into a dynamic topology and operate independently without external infrastructure. In OSI model, the Medium Access Control (MAC) sub-layer of the data link layer has the primary responsibility of managing the devices that connects with the transmission channel. Mobility and resource limitations are the two main aspects that have an impact on MANET's operation. Frequent link failures occur due to nodes mobility and sharing of single channel during data transmission results is packet collision during nodes movement. Packet collision leads to retransmissions, higher delay, packet loss and more energy consumption. In this paper we propose a collision avoidance technique using contention window (CAD-CW) for MANET’s to handle nodes unique characteristics such as mobility, link constrain and energy. CAD utilises dynamic contention window to adapt network changes and high priority data is allowed to transmit first to minimize collision. Energy efficient path is selected for reliable data transmission to handle QoS.