On the performance of ofdm-based amplify-and-forward relay networks in the presence of phase noise

We investigate the performance of orthogonal frequency division multiplexing (OFDM)-based dual-hop amplify-and-forward (AF) relay networks in the presence of phase noise (PHN). We show that the use of an AF relay may not be beneficial compared to a direct transmission in the presence of PHN. Using outage probability analysis, an upper bound on the allowable PHN level is derived which ensures that the dual-hop outperforms the direct transmission. To improve dual-hop transmission performance in the presence of PHN, we propose a reduced-complexity joint channel and PHN estimator using full-pilot OFDM symbols for AF relay transmission. The proposed approach achieves a lower mean squared error compared to the conventional channel estimator. In addition, we derive a joint data detection and PHN estimation scheme for comb-type data OFDM symbols by modifying the maximum ratio combining metric to account for the effect of PHN at the destination node.