Design and Analysis of an OFDM-Based Short Reference Quadrature Chaos Shift Keying Communication System

Abstract

In this paper, a new non-coherent chaos-based digital communication system combined short reference Quadrature chaos shift keying with orthogonal frequency division multiplexing named (OFDM-SRQCSK) is presented. This system is an extension of short reference Quadrature chaos shift keying (SR-QCSK) modulation by sending parallel information sequences with one chaotic reference sequence over the selected subcarrier frequencies. The proposed system enhanced the spectral efficiency and the energy saving of the conventional QCSK and SR-QCSK systems. In the proposed system, the information rate and energy saving improvement factors are derived comparing with QCSK system. Furthermore, the bit error rate (BER) analytic expressions for OFDM-SRQCSK system are derived in additive white Gaussian noise (AWGN) and multipath Rayleigh fading channels. The simulation results proved that the BER analytics match the Monte-Carlo simulations with average relative differences about 0.07 and 0.1 dB under AWGN and multipath fading channel respectively.