Neighbourhood backoff algorithm for optimizing bandwidth in single hop wireless ad-hoc networks

When using a random access method, such as IEEE 802.11 CSMA/CA scheme, in mobile ad hoc networks, a large bandwidth capacity is wasted due to many collisions. To improve the channel capacity, we propose a new backoff algorithm named neighbourhood backoff algorithm (NBA). A novel feature of the NBA scheme is its neighbourhood consideration, in which every node modifies its backoff interval according to the number TV of its neighbours. In order to find the optimum parameters for NBA, we have studied the backoff intervals as fund on of different number of active nodes (N) in a single transmission area. We have found that the minimum contention window is proportional to the number of neighbours. Our experiments show a better behaviour of the NBA scheme in comparison to the BEB (binary exponential backoff) scheme defined in IEEE 802.11 CSMA/CA.