Transmit power allocation for non-regenerative multi-relay system

By allowing multiple users to cooperate and share their antennas effectively, the multi-relay system based on multi-input-multi-output (MIMO) techniques realizes spatial diversity gain in a distributed manner. This paper analyzes the capacity of a two-hop non-regenerative system with multiple relay stations (RSs). Given a certain power constraint, an adaptive power allocation (APA) scheme is developed to maximize the end-to-end achievable rate. Numerical results show that the APA scheme can allocate fractional power efficiently to each hop and select the relaying intellectively based on the power allocation results, which improves the power efficiency and enhances the performance of the multi-relay system significantly.