Link Adaptation Scheme with Signal-to-Noise Ratio Feedback for IEEE 802.11 Networks

Rate adaptation is one of the key factors to improve the performance of the link layer of IEEE 802.11 WLAN. Yet most of the existing rate adaptation policies and algorithms do not consider the effect of the losses due to collisions. To mitigate the effect of collisions, a rate adaptation scheme based on the receiver´s SNR is proposed in this paper. It reflects the link condition correctly even when collisions exist, so that the unnecessary rate downshift caused by collisions can be avoided. The sender is informed about the adaptive rate by ACK frames from the receiver. The simulation results show that our scheme can improve the throughput and decrease the average delay over other rate adaptation algorithms, such as AARF.