Joint Adaptation of IEEE 802.11 Link Rate and Backoff Parameters: Prototyping Validation

In IEEE 802.11, DCF performs a binary exponential backoff mechanism to control channel access attempts, in order to reduce congestion. When transmission fails, both binary exponential backoff and rate reduction are performed, which may induce overly conservative transmission attempts. On the other hand, once transmission succeeds, rate adaptation may decide to increase the data rate and DCF resets the contention window to minimum value, which results in overly aggressive transmission attempts. Motivated by this, we propose a mechanism entitled Enhanced Adaptation of link Rate and Contention window, abbreviated as EARC. EARC is a receiver-assisted link rate adaptation protocol that jointly considers the backoff mechanism. We implement EARC in a real-life testbed to observe its performance. Empirical results validate that EARC enhances system throughput by judiciously adapting to both the link rate and backoff parameters.