A Soft Detector for Spectrally Efficient Systems With Non-Orthogonal Overlapped Sub-Carriers

Spectrally efficient frequency division multiplexing (SEFDM) improves spectral efficiency, relative to the well known orthogonal frequency division multiplexing (OFDM). A fast Fourier transform (FFT) detector working with a standard Bahl-Cocke-Jelinek-Raviv (BCJR) decoder based on the Turbo principle is proposed to improve iteratively the system performance. In the presence of multipath fading channel, system modelling results show that the new system with 1024 sub-carriers can save up to 40% of bandwidth compared to the OFDM system. In addition, this work proves that by using the FFT detector, complexity is reduced.