On performance limits of coded asymmetric OFDM systems over multipath fading channels

We investigate performance limits of a coded asymmetric OFDM (A-OFDM) system in multipath fading channels when maximum-likelihood (ML) detection is deployed. Our A-OFDM formulation is general and the analysis extends to coded OFDM (COFDM), precoded COFDM and single carrier systems. At first, an exact pairwise error probability is evaluated based on Craig´s alternative form of the Q-function. Then we derive a tight union bound of bit error probability based on a code transfer function. The analysis shows that the coded A-OFDM system has improved diversity, whose order equals to the channel code´s Hamming distance times the fast Fourier transform (FFT) or inverse FFT (IFFT) size of the A-OFDM system. The simulation results support the analysis and demonstrate superior performance of the coded A-OFDM system with the high signal to noise ratio (SNR).