Performance analysis of a chaos shift keying system with polarisation sensitivity under multipath channel

This study presents a spread-spectrum chaos-based communication system with polarisation diversity in a multipath channel. The propagation model takes into account the random direction angle of arrival and the polarisation orientation assigned to each version of the transmitted signal. To improve the performance of the proposed system, the receiver integrates monopoles with different orientations and no space diversity. Once the number of antennas is defined, many antenna positions are simulated, and then the optimal position is deduced to improve the performance of the system. To demodulate the received signal, a RAKE receiver is used for multi-antenna processing. An analysis is carried out leading to the analytical expression of the system bit error rate (BER). Simulation results show first that our system performance is improved with the use of this new receiver, and the perfect match observed between simulations and analytical BER expressions confirms the exactitude of our computation approach. Finally, the performance of our studied system is compared and discussed to that of a conventional spread-spectrum system using gold codes as spreading sequences.