Transmit Beamforming in Relayed Multicast Systems

In this work the gains from the addition of a single antenna relay in a multicasting system with transmitter beamforming are studied. Different solutions to the problem of maximizing the minimum user SNR with varying trade-offs between performance and complexity are taken from the literature and studied in two relaying scenarios. One scheme represents the classic setup without using the relay while the other combines the signal from the direct and relayed paths using Maximal Ratio Combining (MRC). The gain in received signal power from the relayed scheme comes at the expense of an additional transmission phase. The simulation results show gains on minimal SNR and those gains resulted in superior spectral efficiency and throughput even when using double as much transmission phases.