Issues for the integration of satellite and terrestrial cellular networks for mobile communications

Satellite and terrestrial cellular systems naturally complement each other for land mobile communications, even though the present systems have been developed independently. The maim advantages of the integrated system are a faster wide area coverage, a better management of traffic overload, an extension to geographical areas not covered by the terrestrial network and, in perspective, the provision of only one integrated system for all mobile communications (Land/Aeronautical/Maritime). To achieve these goals, as far as possible the same protocols of the terrestrial network should be used also for the satellite network. This paper discusses the main issues arising from the requirements of the integrated system, illustrates some preliminary results and presents possible improvements for the technical solutions.