Balancing Hidden-node and Exposed-node Problems in Full-duplex Enabled CSMA Networks

In-band full-duplex (FD) technique can efficiently improve the network throughput of future wireless networks. However, the network throughput is significantly affected by the hidden-node (HN) problem and the exposed-node (EN) problem, both of which are closely associated with the carrier-sensing range, determined by the physical carrier-sensing (PCS) threshold. Specifically, decreasing one leads to the increase of the other one. Thus, setting the PCS threshold can achieve a tradeoff between HN and EN problems in FD networks. This paper investigates the optimal PCS setting for a homogeneous network with bidirectional FD links to achieve the maximum network throughput. In particular, we adopt the bicircle interference model and the bicircle carrier-sensing model to capture the interference region and the carrier-sensing region of a bidirectional FD link, respectively. Based on the bicircle models, we establish an analytical model to determine the optimal PCS setting via minimizing the total probability of HN and EN problems. Simulation results verify the derived probabilities of the HN problem and the EN problem, and show that setting the carrier-sensing range equal to the interference range can achieve the maximum network throughput in most cases.