Dynamic tuning of the IEEE 802.11 protocol to achieve a theoretical throughput limit

In wireless LANs (WLANs), the medium access control (MAC) protocol is the m ain element that determines the efficiency in sharing the limited communica tion bandwidth of the wireless channel, In this paper we focus on the effic iency of the IEEE 802.11 standard for WLANs. Specifically, we analytically derive the average size of the contention window that maximizes the through put, hereafter theoretical throughout limit, and we show that: Ii depending on the network configuration, the standard can operate very far from the t heoretical throughput limit; and 2) an appropriate tuning of the backoff al gorithm can drive the IEEE 802.11 protocol close to the theoretical through put limit, Hence we propose a distributed algorithm that enables each stati on to tune its backoff algorithm at run-time, The performances of the IEEE 802.11 protocol, enhanced with our algorithm, are extensively investigated by simulation. Specifically, we investigate the sensitiveness of our algori thm to some network configuration parameters (number of active stations, pr esence of hidden terminals), Our results indicate that the capacity of the enhanced protocol is very close to the theoretical upper hound in all the c onfigurations analyzed.