Optimum Power Allocation with Transmit Beamforming in Correlated MISO Relay Channels

Abstract

This paper proposes an optimum power allocation strategy to maximize the end-to-end capacity of regenerative relay channels with transmit beamforming. An achievable rate for this model is first derived, and is optimized in terms of spectral efficiency. This optimization is a max-min problem. A general technique for solving this max-min problem is applied to derive the optimum power allocation that satisfies the sum power constraints at the source and relay. The upper bound of the regenerative relay channels allocated by the proposed scheme is also derived. The analytic and simulation results show that the optimum power allocation highly depends on not only the average channel gain but also the achievable beamforming gain of the first hop and the second hop channel