Abstract:
MANET is a self-directed system consisting of mobile
nodes, which can be either routers and/or hosts. Nodes in
MANET are connected by wireless links without base stations.
The Backoff algorithm considered as a main element of Media
Access Control (MAC) protocol, which is used to avoid collision
in MANET?s. The Fibonacci Backoff algorithm and the
Pessimistic Fibonacci Backoff are proposed to improve network
performance depending on contention window size. This research
introduces a new hybrid Backoff algorithm called Pessimistic
Fibonacci Backoff (PFB) Algorithm which merges the two
previous algorithms in order to find the most proper contention
window sizes that reduce collisions as much as possible. This
research takes into consideration and evaluates each of the
following main measurements: Packet delivery ratio, normalized
routing load and end-to-end delay. Based on the extracted
simulation results, PFB algorithm outperforms Pessimistic
Linear-Exponential Backoff (PLEB) by up to 76%,40.41%,
31.88% in terms of Packet delivery ratio, end-to-end delay and
normalized routing load respectively, especially in the sparse
environments. All of the simulation results are obtained by the
well-known NS-2 Simulator, version 2.34, without any distance or
location measurements devices