Robust Relay Beamforming for Two-Way Relay Networks
The authors study the design of robust relay beamforming for two-way relay networks by considering channel feedback errors. Their objective is to maximize the minimum worst-case Signal-to-Noise Ratios (SNRs) of two sources subject to a total relay power budget. They first decompose this non-convex problem into a series of relay power minimization problems under minimum SNR constraints by using bisection search. Then the relay power minimization problem is recast to a Semi-Definite programming Relaxation (SDR) problem. A suboptimal but efficient solution is finally obtained for the original design. A necessary condition for the power minimization problem to be feasible is also given.