A Multilevel Code-Shifted Differential Chaos Shift Keying System With Reference Diversity

In this brief, a multilevel code-shifted differential chaos shift keying system with reference diversity (MCS-DCSK-RD) is proposed. In the proposed system, the reference signal with several replicated versions (called reference diversity) are transmitted to reduce the interference of channel noise on the reference signal. We derive the theoretical bit error rate (BER) of the proposed system over the AWGN and multipath Rayleigh channels, and verify its accuracy by simulations. Then, the optimal reference diversity quantity is determined via the theoretical BER. Compared with the multilevel code-shifted differential chaos shift keying (MCS-DCSK) system, the proposed scheme with optimal reference diversity quantity can effectively reduce noise, thus obtain much better BER performance over the additive white Gaussian noise (AWGN) and multipath Rayleigh channels. Also, we further reduce the noise by averaging the received demodulated signals at the receiver, thereby further improving the BER performance of the MCS-DCSK-RD system.