I-DCSK: An Improved Noncoherent Communication System Architecture

This paper presents the design and performance analysis of an improved differential chaos-shift keying (I-DCSK) system. Instead of sending reference and data carrier signals in two time slots as in the conventional DCSK scheme, in the improved design, a time-reversal operation is used to generate an orthogonal reference signal to the data carrier signal and then sum up these two sequences into one time slot, prior to transmission. This operation reduces the bit duration to half, which doubles data rate and enhances spectral efficiency. At the receiver, the received signal is correlated to its time-reversed replica and is summed over the bit duration. The new system design proposed in this brief replaces the delay circuit used in conventional DCSK systems by time-reversal operations. Moreover, the theoretical bit-error-rate expressions for additive white Gaussian noise and multipath fading channels are analytically studied and derived. The proposed I-DCSK system is compared with the conventional DCSK and quadrature chaos-shift keying schemes. Finally, to validate accuracy, simulation results are compared with relevant theoretical expressions.