Abstract
AbstractIn the Distributed Coordination Function (DCF) of IEEE 802.11, there are two access modes. The basic access mode is default. Another mechanism known as request-to-send/clear-to-send (RTS/CTS) is used to combat the hidden terminals problem, which occurs when some stations in the network are unable to detect each other. 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 theexisting 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 evaluate our proposed new DCF protocol using the NS-2 simulator and our new scheme outperforms other existing methods according tosimulations.