Optimal Contention Window Based on Performance Analysis for Full Duplex WLANs

Abstract

Wireless full-duplex (FD) communication enables one to double the throughput of any link in theory. To achieve such benefits for FD wireless networks, it is very beneficial to develop medium access control (MAC) protocols for wireless FD networks. A backoff mechanism for FD MAC is designed based on distributed coordination function (DCF). In a fundamental backoff operation for FD MAC, nodes transmit data frames as a secondary transmitter even when they have not counted up their backoff timer to zero, which is the difference between the conventional DCF and FD MAC. By considering such operation, several theoretical models to analyze the FD networks have been developed. Whereas, there are few works for deriving the throughput maximization for FD MAC because the FD MAC operation makes the analysis complex and difficult. This paper presents an optimal CW for FD MAC based on theoretical performance analysis regarding FD wireless local area networks (FD WLANs), As an essential contribution in this paper, a theoretical expression for the optimal value of the initial contention window ( $CW_{\min}$ ) is derived, which gives the maximum throughput in networks, from the analytical model for FD MAC. By applying the derived optimal $CW_{\min}$ in FD WLANs, the network throughput is improved significantly for any number of contention nodes.