Medium access control for full-duplex in wireless local area networks

Current wireless technologies strive to respond to the arising demand for the increase in mobile traffic. Recently, with the introduction of self-interference (SI) cancellation techniques, wireless full-duplex communication has become an attractive solution that doubles the spectral e ciency and enhances data rates. In this thesis, we present a medium access control (MAC) protocol, named Synchronized Contention Window Full-Duplex (S-CW FD) protocol for enabling full duplex communication in wireless local area networks (WLANs). The proposed S-CW FD protocol can not only work in ad hoc and infrastructure modes of IEEE 802.11 WLANs, but with the legacy nodes as well. In this work, saturated throughput of S-CW FD is derived based on a two dimensional Markov chain model, similar to Bianchi's, and those results are used to validate simulations in OPNET tool. Via detailed simulation experiments, the performance of S-CW FD is evaluated under different self-interference models and wireless network conditions. It is shown that when there are no hidden nodes in the network, the S-CW FD protocol can double the throughput of half-duplex IEEE 802.11, and in the presence of hidden nodes in the network, the throughput gain of full duplex over half-duplex can get as high as ten fold, even for moderate SI cancellation levels and heavy load. Comparisons with existing similar FD MAC protocols also indicate that the proposed S-CW FD protocol performs best under realistic network conditions and residual SI. Hence, S-CW FD stands out as a promising FD MAC protocol with a high chance of application in WLANs, not only for signiffcant performance improvements, but also for its exibility and backwards compatibility

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