Abstract: A dispatch system (10) uses satellites (40) to broadcast simultaneously to an individual remote unit (30), to a select group of remote units (30) or to all the remote units (30). The dispatch system (10) may assign a remote unit (30) to a unique channel if there are enough available channels, or may assign the remote units (30) to a shared channel when the number of available channels is limited. The remote units (30) are given a unique control code or a shared control code. Based on the channel and the control code, the remote unit (30) will be able to listen to the broadcast or ignore it.

Abstract: A system for increasing call-handling capacity employs a multi-tier satellite network which includes one or more geosynchronous (GEO) satellites (12) and non-geosynchronous satellites (14). The GEO satellites (12) transfer non delay-sensitive data through the system, while the non-geosynchronous satellites (14) predominantly transfer delay-sensitive data through the system. In a preferred embodiment, a non-geosynchronous satellite (14) receives (102) a data packet, determines (112) whether or not the data packet is delay-sensitive, routes (114) a delay-sensitive data packet through the LEO network, and routes (116) a non delay-sensitive data packet to a GEO satellite (12).

Abstract: Advanced subscriber outage notification methods (100) notify a user of a subscriber unit (30) that its call is going to be dropped. The subscriber unit (30), the satellite (20) or the mobile telecommunication system (10) first predicts whether an outage is going to occur and how much time there is before the outage. Second, the subscriber unit (30) notifies the user of the outage and the time remaining before the outage. Third, the subscriber unit (30) waits for whether the user wants to end the call. Next, the subscriber unit (30), the satellite (20) or the mobile telecommunication system (10) terminates the call if the user wants to end the call. Lastly, the mobile telecommunication system (10) drops the call once the time remaining before the outage expires.

Abstract: A communication system is established for providing dual-coverage areas using communication satellites, one or more terrestrial stations and one or more dual-coverage subscriber units (DCSU). The communication system determines when and where to establish dual-coverage areas. Dual-coverage areas are provided using separate beams from two or more satellites. The satellites can be located in a variety of orbits around the earth. DCSUs receive signals and process data from at least two satellites at one time. DCSUs can also transmit signals to at least two satellites at one time. Data packets which are missing from one channel are replaced by data packets on another channel. Path delays are compensated for on the transmit side to minimize processing requirements on the receive side.

Abstract: Private Global Networks (PGNs) between communication terminals (110, 114, 116, 118) are established within a satellite communication system (100). Each PGN provides to its users a network of dedicated communication paths which have durations that exceed the duration of a particular call. A dedicated communication path is established by determining (416, 424) hand-off schedules for satellite-to-terminal links for both a source and destination terminal, and also by determining (428) satellite cross-link schedules necessary to maintain the dedicated path for a duration which exceeds the duration of a particular call.

Abstract: An emergency handoff method (50) reroutes or redirects communications from one channel in a cell (105) to another channel in the same cell (105) or a different cell (107). Handoff is initiated by a subscriber unit (SU) (100) when the SU (100) determines that an emergency handoff is needed. Once a new channel is needed, the SU (100) chooses a new, available channel to transfer its communication. After selecting an available channel, the SU (100) acquires the available channel. The servicing satellite which is providing the available channel then makes the constellation of satellites reroute or redirect the call data or the communication packets across the new channel to the SU (100).