Doubling the Rate of Spectrally Efficient FDM Systems Using Hilbert Pulse Pairs

Abstract

This paper proposes a new multi-carrier signal format for spectrally efficient frequency division multiplexing (SEFDM) system to further improve the spectral efficiency, where a Hilbert pair is utilised as pulse-shaping filters. In this work, the square-root raised cosine (SRRC) pulse is employed to generate the Hilbert pulse pair at the transmitter and an equivalent matched filter configuration is used to generate the receiver Hilbert pair. To verify the data rate gain of the proposed system, we generate the mathematical models and carry out simulations with varying compression factor of the SEFDM signals. The numerical modelling results show that the proposed system doubles the data rate relative to conventional SEFDM system with no bit error rate (BER) performance degradation. In addition, results are reported for un-coded transmission and also for system using turbo coding, showing significant BER improvement.