MOBILE SATELLITE SYSTEM/TERRESTRIAL WIRELESS SYSTEM INTERWORKING TECHNIQUES

摘要

Methods for switching a mobile between operation in an mobilesatellite system mode and a terrestrial wireless mode. When operating inthe terrestrial wireless mode, the mobile terminal will initiate an attempt toswitch into the MSS mode when it nears the boundary of the coverage areafor a terrestrial wireless system to which it is registered. Conversely, amobile terminal operating in the MSS mode will regularly attempt to switchinto the terrestrial wireless mode. For both, a switch between modes iscontingent on the mobile terminal identifying a suitable system forregistration therewith upon completing the switch between modes. Thecriteria for identifying a suitable system for selection purposes include thefollowing: (1) the selected system is available, i.e., the mobile terminal isphysically located within a coverage area for the selected system; (2) themobile terminal is compatible with the selected system; and (3) the selectedsystem is willing to accept the mobile terminal. If multiple systems meetthese criteria, the mobile terminal will utilize a stored list of preferredsystems to select therefrom. When switching into the terrestrial wirelessmode, the MSS system provides the mobile terminal with switch-overinformation for the underlying terrestrial wireless systems and, whenswitching into the MSS mode, the terrestrial wireless system provides themobile terminal with switch-over information for the overlying MSSsystems.