Adaptive relay selection and power allocation for hybrid relay systems

In this paper, we propose an adaptive power allocation method for hybrid relay systems that employ the amplify-and-forward and decode-and-forward protocols simultaneously. The total transmission power is analytically allocated to a source and two selected relays by the proposed power allocation criterion to maximize the overall received signal-to-noise ratio at the destination. Simulation results show that the proposed scheme achieves better performance than that of conventional cooperative schemes or hybrid systems with equal power allocation.