Performance of OFDM-Based Dual-Hop Amplify-and-Forward Relaying

In this letter, the end-to-end BER performance of a dual-hop OFDM-based relay system is investigated. The relay terminal operates in the amplify-and-forward (AF) mode. We derive the bit error rate (BER) of AF relaying with average power scaling (APS) constraint valid for source-relay link high signal- to-noise ratio conditions. We also study a frequency diversity technique that improves the performance of single antenna AF-APS relaying. The theoretical BER expressions are verified by computer simulations for a 4-QAM modulated OFDM system.