Abstract: The invention concerns a method of allocating a respective free radio beam channel to calling and called stations of a satellite telecommunication network. If there is no free channel on a beam forming the coverage including one given station, the method of the invention looks for free channels in each beam adjacent said beam, and allocates one of the adjacent beam free channels to the given station as soon as in an optimal subset of beams comprising all beams using the same channel as the free channel each level of isolation equal to the ratio of an antenna gain of a main lobe of a respective one of the beams of the optimal subset to the sum of the maximal antenna gains of secondary lobes of the other beams is greater than a given threshold.

Abstract: A telecommunications network comprises a constellation of orbiting satellites placed in low-altitude polar inclined orbits with two inter-satellite links per satellite, a network of earth-based centers enabling the management and the control of the local traffic and one or more high latitude centers to set up the interconnections between satellites that are not in one and the same orbit. Application to telephony by mobile and/or fixed terminals.

Abstract: This invention relates to a method for allocating a resource in a periodic frame of an asynchronous digital satellite network, to each of cell bursts of sporadic connections which are transmitted by earth stations. Allocation requests for resources, such as a time intervals in a data sub-frame of a frame, are respectively transmitted by an earth station to a central network management station, from beginnings of reception of the bursts and therefore well before the earth station has completely received said bursts coming from an user station. Each of the resource allocation requests relating to the bursts of a connection is satisfied since the request does not comprise any information on lengths of bursts. Thus, during a connection phase, acceptance or refusal of a connection request is decided as a function of an algorithm avoiding overloading of the network and slumping of its performances.

Abstract: A earth station calling another station sends a link setting-up a request to a control station. The control station memorizes in a transformed reference system the contour of a global geographical coverage including all the earth stations together with the earth positions of the latter. Subsequent to the request, the control station simulates the optimum evolution of the radioelectric coverages of the satellite so as to include, both on emitting and receiving, the calling and called stations in respective coverages with guaranteed minimum antenna gains. The total power of the satellite and the positions of the stations are notably considered in this simulation. If the result of simulation is positive, an emission authorization is sent by the control station to the calling station, and satellite antennae are reconfigured by phase shift and power control values emitted by the control station.

Abstract: The invention concerns a protocol for multiple access to a networked telecommunications channel. A current auxiliary terminal of a plurality of auxiliary terminals address reservation messages to a central terminal. The latter addresses to the current auxiliary terminal an allocation message of transmission capacity in terms of number of data packets of an information message of the current auxiliary terminal dedicated to another auxiliary terminal. The reservation messages are provided with an item of information relating to the number of data packets forming the information message of current auxiliary terminal, stored but not yet transmitted to the other auxiliary terminal, which are thus present between the last allocation message reception and the current reservation message transmission of given order, so that stability of the channel is improved.

Abstract: After sampling a multicarrier signal, groups of multiplex modulated carriers with identical bandwidths are separated by group filters. Clock frequencies of the carriers are then reduced by decimators depending on their respective bandwidths. To separate each of the modulated carriers in each of the groups, a polyphase network architecture is combined with a stage of delay lines for processing separate groups of multiplexed modulated carriers with identical bandwidth by programming a Fourier transform complex multiplying circuit. The demultiplexing devices is programmed to process evolutive traffics of groups of multiplexed carriers by a switching stage linking outputs of the decimation filters to inputs of the delay line stage.