Ergodic Capacity of OFDM AF Fixed Gain Relay System with Subcarrier Mapping

In this paper ergodic capacity of dual-hop OFDM amplify-and-forward (AF) fixed gain (FG) relay system, implementing capacity maximizing best-to-best subcarrier mapping (BTB SCM) scheme at the relay (R) station, is examined. Scenario without direct communication between the source of information (S) and destination terminal (D) is considered, with Rayleigh fading statistics on both hops. A closed form relation for the tight lower bound of the system ergodic capacity is derived. Comparisons of the obtained ergodic capacity results with the simulation results have confirmed the accuracy of the undertaken analytical approach. Thus, the derived analytical expression presents very useful and most accurate available tool for the performance assessment of the OFDM AF FG relay system with BTB SCM, considered to be interesting solution for the next generation of mobile cellular systems.