Analysis of connectivity requirements for communication networks based on low Earth orbit satellites

Currently many efforts are undertaken to develop and install communication networks based on Low Earth Orbit (LEO) satellites. However, many problems are to be solved until the final operation of such networks. This paper deals with the dimensioning of the number of communication links and channels per link. This includes the radio links from the satellites to mobile users and to gateways, as well as intersatellite links and terrestrial lines. The dimensioning of these network elements is crucial, since they have influence on the satellite power and mass and thus directly on the system costs. The authors introduce a formal model for LEO-based networks and propose a method for the evaluation of link capabilities, given the network topology and the traffic requirements. As an example, two constellations are investigated. One of those constellations is the Iridium system proposed by Motorola