A Spectrally Efficient Frequency Division Multiplexing Based Communication System

In this paper we propose a spectrally efficient frequency division multiplexing (FDM) based communications system. This FDM system handles intercarrier frequency separations smaller than those of orthogonal frequency division multiplexing (OFDM) systems. The FDM transmitter consists of a bank of modulators that generate the different information conveying sub-carriers that compose the transmitted FDM signal. The FDM receiver consists of a bank correlators followed by a maximum likelihood (ML) detector. The demodulators extracts a set of sufficient statistics from the received FDM signal and the ML detector uses the sufficient statistics to estimate the transmitted symbols. To alleviate the complexity of ML detection alternative detection methods are examined including linear detectors and genetic algorithms (GA) based detectors. Finally, FDM system fundamental limitations are discussed.