UNIVERSITY OF CALGARY A Novel Chaotic Estimation Technique and its Application to Spread Spectrum Communications

This thesis proposes a novel technique for estimating parameters of a noisy chaotic signal. By exploiting the ergodic property of a chaotic signal, the proposed technique is capable of estimating chaotic parameters efficiently in low signal-to-noise ratio (SNR). Simulations confirm that the proposed method outperforms other conventional chaotic parameter estimation techniques. Applying it to demodulator design for chaotic parameter modulation (CPM) spread spectnun (SS) digital communication, the new ergodic CPM (ECPM) system is shown to overcome the major handicap of current chaotic communication methods, that is, poor performance in noisy environments. The performances of ECPM and other major chaos based digital communication schemes are compared thoroughly in terms of noise performance, the effect of data rate, synchronization error and multipath channel. ECPM is found to have great performance and strong robustness under various conditions. The application of ECPM to SS analog communication is also investigated. The author wishes to thank Dr. H. Leung sincerely, for his guidance, advice, patience and encouragement throughout the course of this work, and for his constructive criticism offered during the writing of this thesis. The author wishes to thank the persons working in the Multimedia Signal Processing Laboratory. The author has a wonderful collaborating experience with V. Varadan, N. Xie, and S. Chan during the whole research process. The assistance of K. Murali, Y. Xia and W. Li is also greatly appreciated. Finally, the author wishes to thank all the staff within the Department of Electrical and Computer Engineering for their support and assistance.