Performance analysis of distributed coordination function with early collision detection in In-band Full-duplex wireless networks

In-band Full-duplex (IB-FD) wireless has the potential to double the spectral efficiency offering its innate capability to resolve conventional problems emerge owing to the imperfect medium access control (MAC) in In-band half-duplex (IB-HD) wireless networks. IEEE 802.11 distributed coordination function (DCF), a binary slotted exponential back-off with carrier sense multiple access scheme, has been used extensively in literature as the fundamental contention resolution technique to devise MAC protocols for IB-FD wireless networks. Unlike IB-HD, an IB-FD network can contain two simultaneously active transmission links within a single collision domain. This phenomenon invalidates the applicability of existing IB-HD models of the DCF to compute its performance (i.e., saturation throughput) accurately in IB-FD wireless networks. We have proposed two MAC protocols for two types of network scenarios taking early collision detection capability of an IB-FD wireless transceiver into consideration. This paper also presents a distinct analytical model to quantify the performance of the DCF in the context of IB-FD wireless assuming finite number of stations and idle channel conditions. We have applied the concept of primary-secondary transmission links and, thoroughly derived the probability that a station transmits either as primary or secondary in a randomly chosen time-slot taking secondary transmitter's back-off counter into account. We have also investigated the effect of inter-station interference free IB-FD link on the performance of the DCF. Our protocol, when applied to network without hidden stations, has obtained the highest throughput gain of 1.59, 1.61, 1.68 while the DCF is configured with CWmin of 16, 32, 64, respectively than IEEE 802.11 basic access scheme. We have observed increased throughput gain with hidden stations, thanks to inter-station interference free transmission region, and achieved 2.12, 2.14, 2.16 times higher throughput, respectively than that of IEEE rts-cts access scheme.