On the Smoothing Factor for Rate Adaptation in IEEE 802.11b/g Mobile Multi-Hop Networks

IEEE 802.11b/g networks support multiple rates and rate adaptation mechanisms provide the ability to select the adequate rate intelligently. Prior work on the rate-adaptation focuses on stationary scenarios, such as mesh networks. The effect of the smoothing of the rate adaptation is not a well-studied topic in the mobile scenarios such as IEEE 802.11 multi-hop networks. In this paper, we use an experimental method to evaluate the one-hop performance and the routing decisions of a well-known rate adaptation mechanism referred as the SampleRate algorithm. In the experiments, the impact of the smoothing factor on the rate adaptation is analyzed based on throughput comparison. Smaller smoothing factors lead to larger throughput improvement and faster response when the channel is dynamic.