18-12-2012, 06:51 PM
Satellite Link Design
1Satellite Link.ppt (Size: 798 KB / Downloads: 32)
COMMUNICATION LINK DESIGN
A satellite comm. network consists of a number of earth stations interconnected via a satellite. The radio links are designed to deliver messages at the destination with acceptable fidelity.Factors for link design : operational frequency propagation effects acceptable spacecraft/ground terminal complexity (hence cost) effects of noise and regulatory requirements. The source-to-destination path can be partitioned as: the earth station-satellite link or uplink the satellite path the satellite-earth station link or downlink.
Channel quality
any comm. n/w should provide an signal at acceptable quality to the user. - The parameter for specifying signal quality is signal-to-noise ratio for analog signals bit error rate for digital signals. - VSATs are generally used for carrying digital signals. - BPSK or QPSK modulation schemes with FEC using Viterbi or sequential decoding technique are often used.