Performance issues with IEEE 802.11 in ad hoc networking

Although 802.11 is initially designed for infrastructure-based networks, the distributed coordination function allows mobiles to access the radio medium without the need for a base station. Thus, studies in wireless multihop networks, also called ad hoc networks, often rely on the use of IEEE 802.11 for the physical and MAC layers. However, for a couple of years the use of 802.11 in ad hoc networks has been discussed. Different scenarios show serious performance issues. The performance offered by 802.11 is often low and directly impacts the performance of higher-layer protocols. In this article we provide a summary of the different performance issues extracted so far. We classify basic situations according to the main effects. We then present a quick survey of the possible solutions to these problems. This classification is intended to help design appropriate MAC protocols dedicated to ad hoc networks.