ANALYSIS OF SYSTEM PARAMETERS FOR LEO ICO-SATELLITE COMMUNICATION-NETWORKS/

Currently many efforts are undertaken to develop and install communica tion networks based on low earth orbit (LEG) and intermediate circular orbit (ICO) satellites, However, many problems are to be solved until the final operation of such networks, This paper deals with basic des ign problems of LEO/ICO-based networks, In the first part, the topolog y of the satellite network is considered and estimates for the necessa ry number of satellites, orbits and number of communication channels p er satellite are derived. Features and consequences of intersatellite links are discussed. In the second part of the paper, the number of co mmunication channels per link is derived with a more elaborate model, This includes the radio links from the satellites to mobile users and to gateways, as well as intersatellite links and terrestrial lines, We introduce a formal model for LEO/ICO-based networks and propose a met hod for the evaluation of link capacities, given the network topology and the traffic requirements, As an example, two constellations are in vestigated in detail, One of these constellations is the Iridium syste m proposed by Motorola, the other one is the LEONET concept developed in an ESA study, Finally, the influence of unequal traffic distributio n is discussed.