Trellis Demodulator for Pulse Shaped OFDM

Abstract

A trellis demodulator for spectrally efficient pulse shaped OFDM-signals is proposed. Its' performance is analyzed for a set of optimal pulses obtained as the solution of the optimization problem with restriction to a certain spectrum reduction rate. We consider the pulse shapes of general form with duration equal to OFDM-symbol duration. The iterative version of trellis demodulator for pulse shaped OFDM with FEC is also proposed. The BER performance of proposed iterative demodulator of spectrally efficient pulse shaped OFDM signals is comparable with the one of classic coded OFDM modulation with the same FEC. The performance of proposed algorithms does not depend on the number of subcarriers. They allow to introduce non-orthogonality into OFDM to achieve very good spectral characteristics with small BER degradation.