Error Control for Satellite and Hybrid Communication Networks

Title of Thesis: Error Control for Satellite and Hybrid Communication Networks Name of degree candidate: Daniel E. Friedman Degree and year: Master of Science, 1995 Thesis directed by: Professor Anthony Ephremides Department of Electrical Engineering Both forward-error-correction (FEC) and automatic-repeat-request (ARQ) error control schemes are used for assuring the accuracy of information transferred through imperfect channels. In satellite systems, in which propagation times are typically large, ARQ error control can result in poor throughput to the destination. Also, an ARQ protocol for satellite multicast communication must be carefully crafted to assure good throughput to all destinations regardless of which stations require retransmissions. Supplementing a satellite link with a parallel terrestrial link may allow mitigating some problems of using ARQ in satellite communication systems. ARQ acknowledgments, and possibly retransmissions as well, can be sent terrestrially in such a hybrid network, and so avoid the large satellite propagation delay. The satellite transmission capability of a receiving station which communicates with the transmitter exclusively by terrestrial means can be eliminated and the system cost correspondingly reduced. Further, multicasting with a hybrid network may allow retransmissions to be conducted without interrupting the ow of new information to all destinations, so throughput need not drastically su er if retransmissions are required. The degree to which throughput can be improved by adopting a hybrid network is not clear. A hybrid network's e ect on the delity of information delivered to the destination(s) is also not clear. An experiment is presented for investigating such error control issues of hybrid networking. Error Control for Satellite and Hybrid Communication Networks