Ico Services Limited

Sze-Ching Lu

Jose Luiz Moraes

Eddy Ka Ping Young

Jose Luiz Albuquerque Moraes

Communications apparatus and method for mobile platforms having a plurality of users

In a satellite communication system where user terminals,communicate via satellites,A-E with earth stations,A-E to join with a terrestrial telephone network,, a controller,at a master earth station,A monitors all earth stations,A-E for a request for service received from a user terminal,, then calculates which earth station,A-E is best placed to service the request and instructs the best placed earth station,B to service the request. In servicing the request, the best placed earth station,B uses that earth station,C whereat the user terminal,is registered as a visitor as the gateway into the terrestrial system,by routing all voice grade messages thereto and therefrom via a voice link,. If the user terminal,is not registered at any earth station,A-E, the best placed earth station becomes the earth station of registration and acts as a gateway. The user terminal can store the identity of the last earth station,A-E whereat it was registered and can inform the controller,for direct use of that information.

Earth station acquisition system for satellite communications

In a satellite communication system, a user terminal (11) seeks response from a selected earth station (7A-E) for a request for service based analysing the signal quality of broadcasts from earth stations (7A-E). Whichever earth station (7A-E) responds calculates which earth station (7A-E) can best meet the request for service. If it is another earth station (7A-E), the user terminal (11) is intructed to redirect the request for service thereto and, once in contact, the user terminal (11) addresses all new requests directly thereto, until the best earth station (7A-E) calculates that there is a better earth station (7A-E), and instructs the user terminal (11) to address all future requests for service thereto. This continues ad infinitum, unless the best earth station (7A-E) is inaccessible for the request for service, in which case the user terminal (11) once again reverts to selecting an earth station (7A-E) based on signal quality analysis, any failed requests for service being intimated and ignored by the addressed earth station (7A-E) in any future calculation of the best earth station (7A-E).

Earth station and user terminal access control system for satellite

A satellite communications system comprises satellites 9A-C, earth stations 7A-E, user terminals 11 and controlling gateways 3 in the form of mobile satellite switching centers 5A-E. Access to and from a user terminal 11 may be gained from and to a terrestrial telephone system 1 by earth stations 7A-E contacting the satellites 9A-C and by the satellites contacting the user terminals 11. The satellites 9A-C periodically broadcast messages indicative of the earth station 7A-E with which they are instantly in contact. The user terminal 11 listens to these broadcasts, assesses the quality of the received signal, and keeps a league table based on an accumulated score allocated to each earth station 7A-E which can be heard. When calling into the system, the user terminal pages earth stations in descending order of score in the league table. When in contact, the user terminal 11 sends the league table to the system. When subsequently trying to contact the user terminal 11, the system uses earth stations in descending order of score in the league table, last received from the user terminal.

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Surrey, United Kingdom

Sze-Ching Lu