A New Rate Adaptation Algorithm over Block-ACK of 802.11 Protocol

Abstract

Rate Adaptation is one important way to improve the throughput in the 802.11 networks. However, the previously proposed rate adaptation algorithms were based on the Basic-ACK mechanism. In IEEE 802.11e and 802.11n protocols, the Block-ACK was introduced to reduce the overhead caused by the ACKs so as to improve the system throughput. In this paper, we focus on the rate adaptation under the Block-ACK. Through a lot of simulation results, we find that the conventional rate adaption algorithms (e.g. ARF) under Block-ACK may cause the worse throughput than under Basic-ACK. Furthermore, we reveal that the main reason is that the channel quality information can’t be feedback timely and accurately, especially over the time-varying channel. Finally, we proposed a new rate adaption (B-ARF) algorithm to improve the throughput under the Block ACK mechanism. The simulation results validate that the B-ARF algorithm outperforms those traditional algorithms.