On the effectiveness of noise reduction methods in DCSK systems

Many different methods to decontaminate noisy chaotic signals have been proposed over the past few years. A possible application of these techniques is chaotic communications, where an unwanted additive channel noise has to be removed from the received chaotic signal. Until now, the noise performance of differential chaos shift keying (DCSK) could not be improved significantly using these noise reduction algorithms. Recent investigations suggest that noise reduction techniques can be used only if the signal-to-noise ratio (SNR) of the received signal exceeds a certain threshold. The objective of this work is to introduce an adequate performance measure based on correlation. Using this performance measure the reason for the threshold effect is explained.