Societe Anonyme Dite : Alcatel Espace

Alcatel

Alcatel N.v.

Alcatel Espace

Thierry Quignon

Andre Marguinaud

Sylvain Fontanes

Brigitte Romann

Patrice Birot

Philippe R Sehier

Regis Lenormand

Emmanuel Lemois

Christian Rigal

Henri Favaro

Charles Villemur

Method and system for enhancing channel capacity in a Point-to Multipoint radio communications system that includes terminal stations () of different kinds, such as residential terminals and business terminals, with different link budget requirements i.e. different signal-to-noise ratio. The method is characterized by the selective use of different channel coding codes such as forward error correction (FEC) codes, in the different concurrent channels, depending on a pre-defined category of an addressed subscriber. The multiplexing method used may be CDMA (Code Division Multiple Access) and TDMA (Time Division Multiple Access). Each terminal station () is in turn equipped only with an appropriate decoder, depending on its kind, e.g. residential or business.

Method and system for enhancing channel capacity in a point to multipoint radio communications system having different kinds of terminals

A method and a system for locating ground equipment transmitting signals to a geostationary satellite, the method and the system being based on identifying the arrival directions of such signals within the coverage zone of the satellite. In the method, the arrival directions of the signals are identified by using a beam-forming active-module array antenna system on board the satellite, the system being controlled to define simultaneous beams in the radiation pattern of the antenna, the beams being superposed on one another with small offsets, the superposed beams corresponding to a limited analysis zone being illuminated within the coverage zone of the satellite, the system further being associated with a digital processing program which identifies the arrival directions of the signals which are received in the analysis zone.

Method and a system for locating ground equipment transmitting via

A method of digitally evaluating the frequency and the phase of signals in the form of digitized samples, the method being wherein it comprises in succession: a stage during which numbers corresponding to the samples of the signals to be analyzed are processed in order to convert them into the form of an analytic signal whose real portion coincides with said signal to be analyzed; and, in parallel therewith: a stage of estimating the parameters to be analyzed which is performed in an overall manner on the basis of estimators and of selection criteria by working on the phase of the signal without using any operator of the Fourrier transform type of any hypothesis test either separately or simultaneously; and a stage of estimating the differences between the real signal as taken in this way and the signal obtained from the estimated parameters, thereby making it possible to deliver data in digital form relating to the quality of the analyzed signal and to the reliability of the estimated values. The invention is applicable, in particular, to microwaves.

Method of digitally evaluating the frequency and the phase of signals,

A method of digitally evaluating the frequency and the phase of signals in the form of digitized samples, the method being wherein it comprises in succession:

A signal may be demodulated without using any analog components by using a digital processor. A digitizer delivers the amplitude of the signal to be demodulated at a sampling rate. The signal is acquired from the digitizer and stored in a common memory. The amplitude samples are converted to phase samples. Symbol rate phase hypotheses are generated for splitting the time signal into slices. The carrier phase for one symbol is then calculated for each symbol rate phase hypothesis so that the carrier phase can be estimated over a plurality of (S) symbols. The symbol phase is compared to the carrier phase so that the demodulated signal may be extracted and so that the quality of the demodulation may be estimated.

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Nanterre, France

Thierry Quignon