Robust Distributed Beamforming for Relay Networks

We propose a worst-case based robust distributed beamforming method for half-duplex relay network which consists of one transmitter, one destination, and multiple relays. Assuming the estimation errors of the channel state information (CSI) at the destination are bounded by some known constants, we minimize the worst-case total relay transmit power subject to the destination signal-to-noise ratio (SNR) constraint. This distributed beamforming problem is shown to be convex and can be efficiently solved using interior point methods. Simulation results are presented to illustrate that the proposed technique is robust to the imperfect knowledge of the CSI and guarantees no SNR outage.