A direct sampling receiver for communication of DCSK systems over flat fading channels

In this paper, we propose a direct sampling receiver which can exploit multipath characteristic of flat fading channels to improve Bit Error Rate (BER) performance of Differential Chaos-Shift Keying (DCSK) systems. Structure of the proposed receiver consists of a conventional correlator-type receiver and an oversampling block at the input. This oversampling helps the receiver to specifically determine the delayed-signal components from the channel, which can be combined together in order to increase the ratio of signal-to-noise (SNR) at the output. Discrete-time models for the conventional transmitter, flat Rayleigh fading channel with delay paths as well as the proposed receiver are built and described in detail. Dependence of BER performance on typical parameters of the system, i.e., ratio of Eb/N0, number of delay paths, spreading factor, number of samples per chip, fading coefficients, and path delays, are determined by means of numerical simulations. Interestingly, obtained results point out that the system performance is significantly improved when the number of delay paths increases.