Design and analysis of an improved OMU-NRDCSK communication system

Aiming at the shortcomings of a low transmission rate in traditional Differential Chaos Shift Keying (DCSK) and a high bite error rate when transmitting multi-user information, an improved orthogonal multi-user noise reduction differential chaotic keying (OMU-NRDCSK) is proposed. The chaotic sequence generated at the sending end of the system is used as an information bearing signal after being duplicated, the multi-users’ information modulated by the Walsh codes are transmitted respectively through different delays. At the receiver, after passing through the moving average filter, the received signals are correlated with themselves to demodulate the initial information signals. The bit error rate formula for the system under the Rayleigh fading channel is derived and Monte Carlo simulation is carried out. Analytical and simulation results show that the OMU-NRDCSK system reduces the noise term variance by averaging the received signals and improves the bit error performance, with its transmission rate improved compared to the DCSK system, which effectively improves the bit error performance of the multi-user DCSK system.