Um estudo comparativo do desempenho de algumas famílias de sequências de códigos lineares espalhados em um sistema DS-SSMA

Abstract

Based on the new Communications Services nowadays like, the Personal Communication Networks (PCN), the Cellular Telephone System and the Global Positioning System (GPS), huge spectrum saturation is foreseen and can be minimized through the use of modulation techniques based on Spread Spectrum (SS). Thus, the main subject of this dissertation was the study of the performance of method of Direct Sequence-Spread Spectrum Multiple Access (DS-SSMA) from the carrier, when families of sequence codes, linear spread, are used. It was done a review of the main concepts related to the sequences codes having their use on Spread Spectrum Multiple Access (SSMA) systems. Based on the fact that the DS-SS systems are mostly used in this application, it was possible to stablish some performance parameters that was employed to compare the variety of families of sequences codes, in this specific use. It is presented the generation process of the most important families of linear sequence codes, and a study of the signal to noise ratio (SNR) performance for all the families of sequence codes is done, via computation simulations. The parameters used when measuring the performance were non-periodic cross-correlation functions. The results of the simulations were shown and also analyzed.