Optimum Power Allocation for Beamforming-Based Regenerative Dual-Hop MISO Relay Channels

We consider a power allocation strategy to maximize the end-to-end capacity of a regenerative dual-hop multiple-input single-output (MISO) relay channel with the use of transmit beamforming. In a dual-hop MISO relay channel, the optimum power allocation can be determined by means of a max-min technique with sum power constraints. The proposed scheme adaptively allocates the transmit power of the source and relay according to the achievable beamforming gain as well as the average channel gain to balance the capacity between the dual- hop MISO relay channels. Simulation results show that the proposed scheme can provide noticeable performance improvement over the average signal-to-noise ratio (SNR)-based power allocation scheme in a dual-hop MISO relay channel with the use of the transmit beamforming.