Joint Backhaul-Access Optimization in Full-Duplex Heterogeneous Networks

In this paper, a joint downlink backhaul-access power and subchannel allocation problem is studied for a two-tier heterogeneous network with a full-duplex (FD) small-cell base station (SBS), a macro-cell base station (MBS), and multiple SBS users. To this end, a low-complexity two-stage optimization algorithm using matching theory framework is proposed, which maximizes the minimum user rate in the presence of inter-tier interference from the MBS and self-interference at the SBS FD transceiver. In the first stage, the algorithm adopts matching theory to allocate the SBS subchannels according to the users' preferences of maximizing their individual rates. Then, the SBS and MBS downlink power is solved by using successive convex approximation with geometric programming. In the second stage, a swap-matching approach is employed at the SBS to search through all pairwise swaps of user-subchannel matching to find the subchannel and power allocation that maximizes the minimum user rate. Numerical simulations show that our proposed algorithm converges to a near-optimal solution with low computational complexity and significantly outperforms conventional half-duplex (HD) backhaul-access schemes.