Mobility management in LEO/ICO satellite systems preliminary simulation results

Several proposals have been put forward to provide global handheld mobile communication based on a fleet of satellites in circular orbits: low Earth orbit (LEO ≈1000 km) and intermediate circular orbit (ICO >10000 km), each providing multispot coverage of the Earth surface. In these systems the satellite acts like a base station of the mobile ground cellular network, relaying data between mobile users and gateway stations. The key element to be considered for analysing the mobility management problem in this type of system, is the fast motion of the satellites with respect to both the mobile users and the gateways. Typical LEO and ICO cases are compared and preliminary simulation results of mobility management solutions are presented for a satellite to user link. A simulator, based on discrete events, has been developed to evaluate in each point of a traffic region the blocking probability of new calls and the dropping probability of calls in progress due to handover failure