Abstract: Methods and systems for acquiring service for a user terminal with a satellite communications system are provided wherein geographic information is received via an electromagnetic transmission at the user terminal defining a location of the user terminal. A control channel is selected corresponding to one of the spot beams covering the location of the user terminal using the geographic information. The user terminal acquires service from the satellite communications system over the control channel. The geographic information enables the user terminal to shorten the search time by searching those channels which correspond to the geographic region determined from the geographic information.

Abstract: A multi-mode mobile terminal having a subscriber identity is provided which uses knowledge of communications network supported service levels to navigate to a communication mode allowing the greatest possible service availability when the subscriber identity in at least one of the network modes is invalid. The mobile terminal may not only provide the ability to switch communication service from a current mode to an alternative mode to process emergency calls but may also restrict user operations on a communications network based on the services available without a valid subscriber identity. Operations of the mobile terminal invention may be supported by service level information on various communication service providers contained in memory within the mobile terminal or be obtained by the mobile terminal from the networks.

Abstract: A system and method for improving communication between two user terminals in a telecommunication system is disclosed. When two user terminals, such as in a satellite-based system with a terrestrial network interface, switch from a double-hop connection with the network to a single-hop connection with each other, communication is established according to the present invention by synchronizing the protocol parameters between the two user terminals, which in the double-hop connection were separately synchronized with the network.

Abstract: The present invention provides a method for synchronizing transaction identifiers used by two mobile stations in a mobile communication system. A network station determines the transaction identifier used by each mobile station and sends a signalling message to each mobile station containing a counterpart transaction identifier element. The counterpart transaction identifier element which is sent to each mobile station contains the transaction identifier value which is used by the other mobile station to identify the connection. The counterpart transaction identifier is received and stored in each mobile station. When a signalling message containing a transaction identifier is sent from one mobile station to another, the mobile station inserts the counterpart transaction identifier rather than its own transaction identifier into the outgoing message. In this way, the receiving mobile station will recognize the signalling message as belonging to the connection.

Abstract: A multi-mode mobile station receives a subscriber identity module (SIM) card storing at least certain communications standard required subscription information that is common to a plurality of types of cellular telecommunications systems. The mobile station also includes an internal memory for storing communications standard required subscription information unique to each type of cellular telecommunications systems for which mobile station operations are supported. If a certain type of cellular telecommunications system is selected for mobile station operation, and the inserted SIM card fails to include the necessary communications standard required subscription information for that type of system, the common information is extracted from the SIM card and used in combination with the internal memory stored unique information specific to the selected type of system in effectuating mobile station operation.