LAUSR

Network-assisted full duplex (NAFD) is a unified duplex technique for large-scale distributed antenna systems (DAS) with remote antenna units operating in either half-duplex mode or full-duplex mode and all connecting to central processing unit via backhaul links. Downlink sparse beamforming and uplink power control are effective methods to reduce cross-link interference involved in NAFD with finite-capacity backhaul. We study joint downlink beamforming and power control for NAFD by maximizing the aggregated uplink and downlink spectral efficiency subject to quality-of-service constraints and backhaul constraints. Two approaches have been proposed to solve the optimization problem, where the first approach converts the objective function to the difference of two convex functions with semi-definite relaxation, and then, an iterative SDR-block coordinate descent method is applied to solve the problem. The second method is based on sequential parametric convex approximation. Simulation results have shown that the proposed algorithms yield a higher spectral efficiency gain compared to the traditional time-division duplex scheme.