Abstract
In the IEEE 802.11 Distributed Coordination Function (DCF) protocol, there are two access modes: the basic access mode and request-to-send/clear-to-send (RTS/CTS) access mode. However, the effect of wireless channel, e.g., the channel signal-to-noise ratio (SNR), and the associated appropriate choice between these two access modes are hardly addressed in the existing literature. In this paper, we design a linear programming algorithm to reduce the complexity of the throughput optimization with respect to the minimum contention window size, which arises from a complicated and difficult nonlinear integer programming problem. Since the network performance of the DCF protocol has been shown to tremendously depend on the channel SNR and the number of competing stations, we propose a new algorithm which selects the access mode and the size of minimum contention window jointly by utilizing the estimated parameters from the feedback network information. We numerically evaluate our proposed new DCF protocol and the results show that our new MAC scheme significantly outperforms the original IEEE 802.11 protocol. Copyright © 2009 ACM.