Design and performance analysis of a full-duplex MAC protocol for wireless local area networks

In this paper, Synchronized Contention Window Full-Duplex (S-CW FD) protocol is presented as a medium access control (MAC) protocol that enables full-duplex (FD) in wireless local area networks (WLANs), while seamlessly operating together with legacy nodes. For performance analysis, a Markov chain model of S-CW FD is devised, using this model, the saturated throughput of S-CW FD is derived and the results are validated by comparisons with OPNET simulations. Later, through detailed simulations, S-CW FD is evaluated against standard half-duplex IEEE 802.11, considering realistic self-interference and channel models and the effect of hidden nodes. It is shown that S-CW FD MAC protocol can double the throughput of standard half duplex IEEE 802.11 without hidden nodes in the network, and its improvement can get as high as ten fold in the presence of hidden nodes. In this work, S-CW FD is also compared to two similar contention based FD MAC protocols from the literature, and it is shown that, under typical network loads, S-CW FD outperforms those protocols by up to 30%, despite much lower complexity. Overall, S-CW FD stands out as a promising candidate for implementing FD in WLANs due to significant performance improvements, simplicity and flexibility for application in different FD modes to support bidirectional, relaying and cellular scenarios.