ABSTRACT
This chapter analyzes performances of orthogonal frequency division multiplexing (OFDM) amplify-and-forward, fixed gain (AF FG) relay systems with subcarrier permutation (SCP), obtained analytically, and verified through simulations. Identification of precise amounts for those performance improvements is necessary, in order to justify SCP incorporation at relay stations. Using the derived expressions for the moment generating function (MGF) of the end-to-end signal-to-noise ratio (SNR), as well as the MGF approach in bit error rate (BER) determination, it is possible to formulate an adequate BER determination algorithm for different input data modulation methods and the transmission over wireless fading channels. The presented analyses clearly show that the incorporation of the Best-to-Best SCP scheme significantly improves the ergodic capacity performance of the OFDM AF FG relay systems. The presented BER performance and their analyses for DPSK, BPSK and 4-QAM modulated OFDM AF FG relay system, clearly show the positive impact of subcarrier mapping applied at the relay station.
