Robust Beamforming Problem in Cognitive One-way Relay Networks

Abstract

The paper investigates the problem of a distributed robust relay beamforming in cognitive one-way relay networks with imperfect channel state information. We aim to the minimum the transmit power of relays, satisfying the SNR (signal-to-noise ratio) of the secondary users high a threshold and keeping the interference at primary users below an acceptable threshold. Because of the robust identity the optimal problem is a non-convex problem which is hard to be solved. In this paper we transform the non-convex problem into a convex one which can be solved efficiently by exploiting S-procedure and Schur complement theorem and relaxing the rank-one constrain. Then the robust beamforming vector can be obtained. Simulation results show that the proposed algorithm can solve the minimum problem with robust features efficiently and obtain satisfactory results. Keyword: Relay Networks, Robust, Cognitive Networks; SDP; Rank-one