Decoupled Rate-Optimal User Association for Full-Duplex Heterogeneous Networks

Full-duplex (FD) transmission in a point-to-point (P2P) link, wherein bidirectional traffic flows simultaneously share the same spectrum, has the capability of doubling the link throughput by completely removing self-interferences. However, the throughput gain of FD transmission in an interference-limited network is not as clear as a P2P link due to the interferences induced by complex FD and half- duplex (HD) transmission behaviors in the network. To thoroughly investigate the link throughputs of users and base stations (BSs) in a heterogeneous network (HetNet) with decoupled user association, a general approach is proposed to model a HetNet in which all BSs and users can perform HD or FD transmission depending on their traffic patterns. We first characterize the decoupled rate-optimal user association scheme and use it to define the downlink and uplink throughputs in the HetNet. The tight lower bounds on the link throughputs of the FD users and BSs are found in a neat form that characterizes general channel fading, user and BS intensities and imperfect self- interference cancellation. Numerical results validate that our analytical results are fairly accurate and the proposed decoupled rate-optimal user association indeed significantly improves the link throughputs.