Joint Relay Beamforming Design for Multilevel Nondistributed and Distributed Amplify Amplify-and-Forward Relay Networks
Abstract: This paper considers both nondistributed and distributed multilevel amplify-andamplify forward (AF) wireless relay networks. For a fair comparison, the nondistributed multilevel AF relay network consists of a one-source–one-destination one destination pair and a relay at each level with multiple antennas, whereas the distributed network consists of a one-source––one-destination destination pair and multiple distributed relays at each level with a single antenna at each relay. In this paper, relay beamforming matrices are determined for both networks based on the minimum mean square error (MMSE) criterion. During data transmission, power is independently and individually constrained at the relays at each level. Finally, an iterative algorithm is proposed to solve the desired optimization problem.