Near-Optimal Detection of CE-OFDM Signals with High Power Efficiency via GAMP-based Receivers

A quasi-optimum receiver based on the generalized approximate message passing (GAMP) concept is proposed for constant envelope orthogonal frequency division multiplexing (CE-OFDM) signals. Large modulation index results in large power efficiency for CE-OFDM, but the phase modulator introduces nonlinear distortion effects, precluding good performance for a simple phase detector. Our simulation results show that the GAMP receiver can achieve quasi-optimum performance and it can outperform the linear OFDM and CE-OFDM with phase detectors, for both additive white Gaussian noise (AWGN) and frequency selective channels.