Un système de communication à faible probabilité d'interception basé sur la modulation chaotique

Abstract

In a military environment, there are situations in which it is important to use methods o f communication with low probability o f interception (LPI) and low probability of detection (LPD). This thesis proposés an LPI communication system based on chaotic modulation. Unfortunately, signal resulting from digital communication system based on chaotic modulation are cyclostationary [1]. A phase randomization technique is investigated in order to modify the cyclostationary properties of the chaotically modulated signal. Second-order statistical cyclostationary analysis shows that phase randomization reduce the degree of cyclostationarity of the chaotic signal. The chaotic modulation scheme is based on symbolic dynamics. The receiver estimates the transmitted sequence using the Maximum Likelihood (ML) estimation approach. The resulting bit error-rate (BER) of the proposed communication system show a performance that is two decibels lower than a BPSK modulation. In addition, the overall feasibility of such a scheme is presented by an analysis of the receiver complexity using field programmable gate array (FPGA) technologies.

Date	20 Dec 2010
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	François Gagnon (Supervisor) & Claude Thibeault (Co-supervisor)