Geradores de seqüências pseudoaleatórias usando caos em sistemas de espalhamento espectral

• Autor(a) principal: Netto, Fábio Siqueira
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações do Mackenzie
• Texto Completo: http://dspace.mackenzie.br/handle/10899/24410
• topic: comunicação digital; espalhamento espectral; seqüências pseudoaleatórias; sinais caóticos; digital communication; spread spectrum; psudo-random sequences; chaotic signals; CNPQ::ENGENHARIAS::ENGENHARIA ELETRICA::TELECOMUNICACOES

Spread sprectrum is a modulation technique that uses a binary sequence to spread an information signal in frequency domain. Conventionally, the process of spreading uses pseudo-random sequences created by shift-registers. However, sequences created using chaotic signals can also be employed because they have compatible spectral and autocorrelation properties and their generation is easy. This work compares the pseudo-random sequences generated conventionally and using chaotic signals, which are used in communication systems based on spread spectrum. These comparisons are made in terms of autocorrelation and cross correlation functions, power spectral density estimated, computational complexity of generators and bit error rate. Our results confirm that the pseudo-random sequences created by chaotic signals can be used in spread spectrum systems. However, there is a critical point: the choice of non-linear map and its initial conditions affect their performance.