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.

[1]  Yuguang Fang,et al.  A novel MAC protocol with fast collision resolution for wireless LANs , 2003, IEEE INFOCOM 2003. Twenty-second Annual Joint Conference of the IEEE Computer and Communications Societies (IEEE Cat. No.03CH37428).

[2]  V. Bharghavan,et al.  MACAW: A media access protocol for wireless LANs , 1994 .

[3]  Luigi Fratta,et al.  Performance evaluation and enhancement of the CSMA/CA MAC protocol for 802.11 wireless LANs , 1996, Proceedings of PIMRC '96 - 7th International Symposium on Personal, Indoor, and Mobile Communications.

[4]  Pramod K. Varshney,et al.  A New Backoff Algorithm for the IEEE 802.11 Distributed Coordination Function , 2004 .

[5]  Haitao Wu,et al.  IEEE 802.11 distributed coordination function (DCF): analysis and enhancement , 2002, 2002 IEEE International Conference on Communications. Conference Proceedings. ICC 2002 (Cat. No.02CH37333).

[6]  Hend Koubaa,et al.  Enhanced routing-aware adaptive MAC with traffic differentiation and smoothed contention window in wireless ad-hoc networks , 2004, 24th International Conference on Distributed Computing Systems Workshops, 2004. Proceedings..

[7]  I. MacPhee,et al.  The Number of Packets Transmitted by Collision Detect Random Access Schemes , 1987 .

[8]  A. Girotra,et al.  Performance Analysis of the IEEE 802 . 11 Distributed Coordination Function , 2005 .

[9]  Marco Conti,et al.  Dynamic tuning of the IEEE 802.11 protocol to achieve a theoretical throughput limit , 2000, TNET.