Outage and SER analysis of DF cooperative OFDM systems with nonlinear power amplifiers

In this paper, a performance analysis of decode-and-forward (DF) cooperative OFDM systems is presented by considering the nonlinear distortions inserted by PAs at the source and relay. In particular, a theoretical formulation for the symbol error rate (SER) and for upper and lower bounds of the outage probability are developed considering fixed and selective DF relaying protocols. In the considered system model, the receiver exploits the signal received directly from the source as well as the signal transmitted through the relay using the maximum ratio combining (MRC) technique. The proposed analysis also studies the effects of the nonlinearities on the diversity order and it shows in what situations the PA nonlinearities affect significantly the system performance. The proposed theoretical expressions are validated by means of computer simulations.