RELIABLE, POWER-EFFICIENT, AND COST-EFFECTIVE SATELLITE COMMUNICATION SYSTEM

摘要

A reliable, power-efficient and cost-effective satellite radio communication system for providing communication between one or more service centers and an ensemble of fixed and mobile user terminals (S, TR, T, UMR, DT). The system comprises one or more earth orbiting satellites (10), each satellite having a transmitter forming a down-link channel (10), including slow frequency hopping the down-link channel, and a mutli-beam antenna system with a single channel per beam to time division multiple broadcast signals to all user terminals covered by each beam, respectively. Each user terminal includes a transceiver for receiving a down-link channel broadcast from the one of the beams in whose path it lies, and a return link feature comprised of a dedicated narrow band broadcast channel with slow frequency hopping the down-link channel, there being a fixed set of frequencies through which the frequency hopping is carried out (S, TR, T, UMR, ST). The plurality of fixed and mobile user terminals are adapted to use the same set of frequency hopping frequencies. The transmissions from each user are mutually synchronized so that while the ensemble of users display the same set of frequency hopping frequencies, each user in the ensemble of fixed and mobile user terminals employs a unique frequency at each instant of time.