Analyse de la capacite des systemes AMRC synchrone et asynchrone dans les reseaux de communications personnelles par satellites.

摘要

This work addresses the Coded Division Multiple Access (CDMA) capacity analysis for a satellite personal communications services (PCS) system. The study is also focused on the comparative performance analysis of two CDMA schemes: asynchronous CDMA and quasi-synchronous CDMA.;Several multiple-satellite systems for personal communications services using low, medium or high elliptical earth orbits have been proposed. Most of these systems will be operational at the beginning of the next century.;One of the problems facing these systems is the choice of the multiple access technique. Several studies have been conducted in order to demonstrate the superiority of one of these techniques. Obviously, they are not unanimous, specially in the case of satellite communications systems.;After a brief presentation of the principal parameters of some of these personal communications systems, the problem of the CDMA capacity evaluation for satellite-based systems is addressed. In this study, only the uplink (mobile user toward satellite), which is the critical link, will be taken into account.;Two forms of CDMA systems for the same satellite channel model are analysed: the asynchronous CDMA system and the quasi-synchronous CDMA system. (Abstract shortened by UMI.)