Loss differentiation based back off strategy for correlated channels in 802.11

摘要

The paper proposes two schemes for contention resolution in 802.11 MAC namely modified back off strategy and estimation based back off strategy. The back off strategies provided a way to resolve contention for access to wireless channel which is continuously changing and difficult to model in a set of parameters. Differentiation between packet loss due to channel error and collision in 802.11 MAC is essential for the above two schemes to exist. Modified strategy tries to find the optimum back off period on loss due to channel error by taking the advantages of both the current strategy implemented in 802.11 MAC and the Return to Zero on channel error (ROCE) strategy. The Estimation based approach shows how by analyzing the channel for a period of time, we can predict the best back off interval in case of channel error. The aim is to maximize the throughput while being fair to all contending users. Simulation of the above two scheme suggest their superiority to the currently implemented scheme. Estimation based approach is better than other schemes for static correlated WLAN channel.