OFDM based link adaptive one-way DF relaying

OFDM based one-way DF relaying has recently received significant attention to improve the reliability and performance of wireless communication systems. In this paper, link adaptive relaying (LAR) approach which combats performance degradation due to error propagation in digital relaying has been applied to the OFDM based one-way DF relaying. It is shown that the power of sub-carriers can be scaled to reduce the error propagation to the destination which improves the BER performance of system. The power scaling is obtained from source-relay and relay-destination channel knowledge. The proposed system has the advantage of low complexity and it can help the relay use the power more efficiently. The error performance analysis of proposed system over frequency selective Nakagami-m fading channel is investigated. The results show that the proposed system outperforms the non-link adaptive based system. BER derivation is given for Rayleigh fading channel (m = 1) under high signal to noise ratio (SNR). Monte-Carlo simulation results are provided in order to confirm the obtained numerical results by considering various position of relay.