Optimization of power allocation with simple relay selection

In this paper, we consider a dual-hop selective decode-and-forward relay system with multiple antennas at the destination. Using a simple relay selection strategy with the knowledge of channel gain magnitudes, we explore adaptive power allocation between the source and relay to minimize the system outage probability under a power constraint. Numerical results show that optimizing the allocation of power enhances the system performance. Moreover, more destination antennas bring more improvement and less power allocation at the relay. It is also shown that more candidate relays will further improve the outage performance of relay system under both uniform and adaptive power allocation.