User-AP Association for Performance Gains in Dense Full Duplex CSMA/CA Networks

Abstract

The spectral efficiency of wireless LANs (WLANs) can be improved by allowing access points (APs) and stations (STAs) to transmit concurrently in a bidirectional mode using full duplex (FD) radio technology. However, the high density of today's WLANs necessitates the need to optimally coordinate the association of stations (STAs) or users with the access points (APs) to minimize the effect of interference among multiple pairs of FD transmissions, and to achieve better throughput gain. Hence, we seek a set of user-AP associations that improve throughput gain in FD WLAN based on spatial channel statistics. Using tools from stochastic geometry, this problem is formulated as an optimization problem with the objective of maximizing the mean rate utility and the sum rate. We perform the analysis of throughput gain when FD is used in dense WLAN with an optimized user-AP association and the assumption that self- interference (SI) is reduced close to the noise floor level. From our evaluation, we infer that FD WLAN yields potential significant gains over half duplex (HD) WLAN. Also, efficient distribution of users among APs further improves throughput gain in FD WLAN in the worst-case mean interference when compared with the legacy user-AP association. Overall, our analysis reveals that FD could at most double the throughput of WLAN and additional throughput gain is possible when FD is combined with an optimized user-AP association.