Impact of Contention Window Cheating on Single-Hop IEEE 802.11e MANETs

This paper presents a work in progress which deals with the important and unresolved problem of node misbehavior. A realistic approach is used to determine the impact of contention window manipulation on IEEE 802.11e ad-hoc networks. It is explained why such networks are more prone to misbehavior. Novel results pertaining to the 802.11e standard are presented. Simulation analysis is done for several scenarios with a distinction made for uplink and downlink traffic. It is shown that a misbehaving node can jeopardize network performance, therefore, countermeasures to this problem need to be developed.

I. Introduction

MOBILE ad-hoc networks (MANETs) are based on the principle of cooperation, with each node acting as both terminal and router. The performance of the network depends on how well the participants of the network collaborate with each other. The threat of misbehavior arises when nodes (or rather: the users controlling them) decide to maximize their own benefit rather than work together as a group. These gains can be measured for example in terms of throughput or battery life. The detection and mitigation of such behavior is important for the functioning of the ad-hoc network.