Alcatel

Alcatel N.v.

Didier Casasoprana

Philippe Voisin

Florence Dolmeta

Fr&eacute;d&eacute;ric Croq

Denis Rouffet

Anne Sauvageot

A telecommunications system antenna for communicating, in transmission and in reception, with a large area whose position relative to the antenna varies. The antenna has motors ( ) for pointing the antenna towards the area and radiating elements ( ) associated with a control device for modifying the antenna's radiation pattern according to the relative position of the antenna and the area. When the antenna is installed on a telecommunications satellite, as the antenna moves, the antenna can remain constantly in communication with an area of the Earth covering several hundred kilometers.

Telecommunication system antenna and method for transmitting and receiving using the antenna

The invention concerns a telecommunications system in which the Earth is divided into areas ( ) within which communications are effected by means of transmit and receive means on a spacecraft, such as a satellite, allocated to communication for a plurality of areas. Areas ( ) of a first category ( ) are allocated signals having respective polarizations (P , P ) and carrier frequencies (&Dgr;F , &Dgr;F ) such that two adjacent areas of the first category are allocated signals having different polarizations or carrier frequencies. Each area of a second category ( ) is allocated signals having all the available polarizations and all the available carrier frequencies.

Frequency and polarization allocation for satellite telecommunication systems

A communication system comprising a set of non-geostationary satellites provides communication links between ground stations and terminals, a communication link from a particular station via a satellite terminating at associated terminals in a limited geographical area including the station and providing a communication channel to at least some of the associated terminals. The communication link is switched to another satellite during the process of communication link handover. A communication link between a particular station and its associated terminals includes an additional communication channel which enables advance data to be transmitted between the particular station and a terminal before the latter executes a communication link handover. This data masks any interruption of communication caused by the communication link handover.

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Saint Germain-en-Laye, France

Didier Casasoprana