On the Power Allocation for Decode-and-Forward Cooperative Transmission Over Rayleigh-Fading Channels

The efficient power allocation strategies for cooperative transmission applying Decode-and-Forward (DF) approach are further investigated in this paper. The cooperative ratio, defined as the ratio of the power used for cooperative-information transmission to the total power, is investigated in an attempt to minimize Bit Error Rate (BER) with a constraint of fixed total transmit power for each user. The authors' results show that efficient power allocation greatly depends on the cooperative method. The preferred cooperative ratio changes from low to high by using DF with no parity check, amplify-and-forward, DF with parity check. Simulation results show that with appropriate power allocation, BER performance of all cooperative schemes can achieve a significant gain over non-cooperative systems.