Performance analysis and enhancement for IEEE 802.11 MAC protocol

摘要

In the IEEE 802.11 MAC layer protocol, the basic access method is the DCF which is based on the CSMAICA. The IEEE 802.11 adopts exponential backoff. In this paper, we use the fixed contention window instead of the exponentially increased contention window. We employ the "linear feedback model" to compute the throughput and the delay for CSMA/CA. Based on our analytical equations, we can get the optimal contention window size. The results show that our optimal contention window scheme can greatly improve the performance compared to IEEE 802.11 CSMA/CA MAC protocol. This paper has also given the analytical results for the effect of RTS/CTS. It is shown that although RTS/CTS does add the overhead to the system by using additional bandwidth, it becomes essential when the hidden terminal problem is dominant, traffic is heavy, or the packet length is very large.