On the effectiveness of iterative demodulation algorithm for SEFDM signals

Abstract

This work is dedicated to researching demodulation algorithms of the nonorthogonal multifrequency spectrally efficient frequency division multiplexing (SEFDM) signals. Demodulation algorithms described in this article proposed for fixing bit-error rate (BER) degradation of received signal caused by inter-channel interference (ICI). Comparison of symmetrical, asymmetrical and standard demodulation algorithms was considered. Crossing points of iterative algorithms and standard algorithm, dependences of values of crossing points on number of subcarriers in signal, subcarriers used for feedback algorithm and factor of compressed bandwidth in order to evaluate efficiency limits of iterative feedback algorithm for subsequent use in signal-coding systems. It was shown that max value of crossing point when improving algorithm can give benefit with chosen parameters is 20.6 dB. Value of crossing point is the lowest when number of subcarriers in signal is the lowest, factor of compressed bandwidth is close to 1 and number of subcarriers used for feedback is large. For the best situation value of crossing point is 1.83 dB.