Pareto Optimality for the Single-Stream Transmission in Multiuser Relay Networks

In this paper, we study Pareto optimality for multiuser relay networks. We adopt single-stream transmission and amplify-and-forward relays. First, with fixed relay processing matrices and transmit and receive beamforming vectors, we study Pareto optimality with respect to the power of the transmitters. Based on the signal-to-noise-plus-interference ratio (SINR) balancing analysis, we give a necessary and sufficient condition for a set of SINRs to be Pareto optimal. Second, we consider Pareto optimality with respect to the relay processing matrices, where the power of the transmitters and the transmit and receive beamforming vectors is fixed. Taking advantage of multi-objective optimization analysis, we present a necessary and sufficient condition for a set of SINRs to be Pareto optimal. We also give a necessary condition to check whether Pareto optimality is fulfilled. Finally, with fixed relay processing matrices, we study Pareto optimality with respect to the transmit and receive beamforming vectors. Simulations show that our proposed algorithms outperform the compared schemes.