Abstract: A data transmission system in a communication network comprising a data modulator comprises: a first part at the level of the collection point part comprising: an NCR module taking account of an external absolute time reference to reconstitute a network clock, a transmitter module receiving the value of a time reference to be inserted into the data packet to be transmitted and transmitting to the NCR module an information item on an instant of synchronization for the receiver, a second part at the level of the radiofrequency part of a gateway comprising; a receiver module, a module for reconstructing a clock locally, a module for inserting a time reference into a data packet received by the receiver before transmission of the data via the satellite, the first part and the second part exchange encapsulated data.

Abstract: A method, and associated equipment, for dynamically allocating resources in a satellite network comprising at least one satellite configured to form a plurality of satellite beams and terminals, comprises the steps of: clustering the beams into groups of beams, allocating frequency resources to each of the groups of beams, determining geographical zones in which these frequency resources can be used simultaneously, determining a hop frame comprising first timeslots, in which the frequency resources are allocated to the whole set of terminals of one of the beams of the group, and second timeslots, in which the frequency resources are allocated to a subset of terminals of at least one beam of the group, identifying the subset of terminals and allocating to the terminals of the frequency resources, and uploading of information relating to the overall loading of each of the beams.

Abstract: A soft handover method with gateway site diversity between a first nominal gateway to a relay satellite of a space telecommunication system and a second redundant gateway to the same satellite comprises a soft handover preparation phase, and a soft handover execution phase that are executed in succession. During the execution phase, a first switchover of the traffic at the ground segment level to the second redundant gateway, and a second switchover at the level of the segment on board the satellite between a first nominal access link of the first nominal gateway and a second redundant access link of the second redundant gateway are finely synchronized.

Abstract: A data transmission system in a communication network comprising a data modulator comprises: a first part at the level of the collection point part comprising: an NCR module taking account of an external absolute time reference to reconstitute a network clock, a transmitter module receiving the value of a time reference to be inserted into the data packet to be transmitted and transmitting to the NCR module an information item on an instant of synchronization for the receiver, a second part at the level of the radiofrequency part of a gateway comprising; a receiver module, a module for reconstructing a clock locally, a module for inserting a time reference into a data packet received by the receiver before transmission of the data via the satellite, the first part and the second part exchange encapsulated data.

Abstract: A soft handover method with gateway site diversity between a first nominal gateway to a relay satellite of a space telecommunication system and a second redundant gateway to the same satellite comprises a soft handover preparation phase, and a soft handover execution phase that are executed in succession. During the execution phase, a first switchover of the traffic at the ground segment level to the second redundant gateway, and a second switchover at the level of the segment on board the satellite between a first nominal access link of the first nominal gateway and a second redundant access link of the second redundant gateway are finely synchronized.

Abstract: A broadband multi-beam satellite radiocommunication system configured to implement a scheme for re-use of frequencies from a total band allocated to an uplink comprises a satellite with a multi-beam receive antenna that forms adjacent reception spots of a terrestrial coverage. Each reception spot consists of a central inner zone and a peripheral zone. Each central inner zone is a cellular pattern identical except for a scale factor to geographical cells wherein the principal frequency sub-bands of a bundle of separate or adjacent principal sub-bands are unitarily distributed and the combination of which is equal to a principal band, included in the total band.

Abstract: A method, and associated equipment, for dynamically allocating resources in a satellite network comprising at least one satellite configured to form a plurality of satellite beams and terminals, comprises the steps of: clustering the beams into groups of beams, allocating frequency resources to each of the groups of beams, determining geographical zones in which these frequency resources can be used simultaneously, determining a hop frame comprising first timeslots, in which the frequency resources are allocated to the whole set of terminals of one of the beams of the group, and second timeslots, in which the frequency resources are allocated to a subset of terminals of at least one beam of the group, identifying the subset of terminals and allocating to the terminals of the frequency resources, and uploading of information relating to the overall loading of each of the beams.

Abstract: A multibeam telecommunication satellite comprises a reconfigurable payload, at least one anchor spot access and a plurality of user spot accesses wherein, for a given mobile terminal, the anchor spot access is associated with a unique frequency channel and the user spot accesses are each associated with a frequency channel, and wherein the payload comprises at least one routing module configured to dynamically route the user spot access to the anchor spot access associated with the anchor station and vice versa depending on the position of the mobile terminal, and a transposition module configured to transpose the frequency of the RF signals that originate from the user spot accesses to the frequency associated with the frequency channel of the anchor spot access and vice versa, the transposition of the signals always being to the same frequency for a given mobile terminal.

Abstract: A broadband multi-beam satellite radiocommunication system configured to implement a scheme for re-use of frequencies from a total band allocated to an uplink comprises a satellite with a multi-beam receive antenna that forms adjacent reception spots of a terrestrial coverage. Each reception spot consists of a central inner zone and a peripheral zone. Each central inner zone is a cellular pattern identical except for a scale factor to geographical cells wherein the principal frequency sub-bands of a bundle of separate or adjacent principal sub-bands are unitarily distributed and the combination of which is equal to a principal band, included in the total band.

Abstract: An interleaver (ER) is dedicated to interleaving of interleaving units representing a selected number of services grouped into periodic frames within a long period time interleaving radio communication network. The said interleaver (ER) comprises processing means (MT1) responsible for decomposing each frame into a chosen number of group(s) of service of constant respective durations, and then for distributing the interleaving units of each group into so-called spreading time intervals of constant respective durations spaced apart within a time interleaving period according to a period equal to the period of the frames.

Abstract: A system for surveying aircraft present in an area covered by at least one communication satellite, the aircraft transmitting signals conveying surveillance messages. The coverage area consists of multiple spots, the satellite is configured to periodically apply a switching sequence, the sequence consisting of multiple switching phases, a switching phase corresponding to a duration during which the signals transmitted by the aircraft present in at least one spot are processed by the satellite in such a way as to detect surveillance messages, and the sequence is adapted to allow for the detection, during a predetermined period Tup, of at least one surveillance message by aircraft present in the coverage area.

Abstract: A technique for configuring, in real time, an equipment item receiving and processing primary signals which are transmitted to it by satellite link, the technique including transmitting secondary signals with frequencies spread over a band at least partially overlapping a frequency band occupied by the primary signals, the secondary signals including signalling parameters which are used, in real time, by the equipment item to configure processing applied to the primary signals. The technique is applicable to dynamic switching of beams in a multi-beam satellite and to dynamic switching of frames, for example in a time-division multiple access system.

Abstract: A device (D1) is dedicated to the processing of signals to be transmitted by waves, within a communication terminal (T). This device (D 1) includes i) memory (M1) for temporarily storing a sequence of digital samples of an analogue input signal according to a first sampling frequency and in a manner synchronized with respect to starts of periodic time slots, and ii) digital/analogue conversion (CV2) for generating, during each time slot and according to a second sampling frequency equal to N times the first sampling frequency, with N an integer strictly greater than 1, an analogue output signal, to be transmitted, representative of N repetitions of the sequence of digital samples that is stored in the memory (M1) during the time slot concerned, so as to output the analogue signal according to a symbol rate equal to N times a reference symbol rate.

Abstract: A system for surveying aircraft present in an area covered by at least one communication satellite, the aircraft transmitting signals conveying surveillance messages. The coverage area consists of multiple spots, the satellite is configured to periodically apply a switching sequence, the sequence consisting of multiple switching phases, a switching phase corresponding to a duration during which the signals transmitted by the aircraft present in at least one spot are processed by the satellite in such a way as to detect surveillance messages, and the sequence is adapted to allow for the detection, during a predetermined period Tup, of at least one surveillance message by aircraft present in the coverage area.

Abstract: A technique for configuring, in real time, an equipment item receiving and processing primary signals which are transmitted to it by satellite link, the technique including transmitting secondary signals with frequencies spread over a band at least partially overlapping a frequency band occupied by the primary signals, the secondary signals including signalling parameters which are used, in real time, by the equipment item to configure processing applied to the primary signals. The technique is applicable to dynamic switching of beams in a multi-beam satellite and to dynamic switching of frames, for example in a time-division multiple access system.

Abstract: Methods for controlling orthogonal frequency division multiple access (OFDMA) communications over satellite links. The methods include estimating a differential delay in a satellite spotbeam between a mean propagation delay in the spotbeam and a propagation delay between a user terminal in the spotbeam and a satellite, estimating an overlap between an OFDMA uplink frame and an OFDMA downlink frame as a result of the differential delay, and providing a guard band in the OFDMA uplink frame and/or the OFDMA downlink frame to reduce an overlap between remaining portions of the OFDMA uplink frame and the OFDMA downlink frame other than the guard band. Corresponding systems and devices are also disclosed.

Abstract: A device (D1) is dedicated to the processing of signals to be transmitted by waves, within a communication terminal (T). This device (D1) comprises i) memory means (M1) for temporarily storing a sequence of digital samples of an analogue input signal according to a first sampling frequency and in a manner synchronized with respect to starts of periodic time slots, and ii) digital/analogue conversion means (CV2) for generating, during each time slot and according to a second sampling frequency equal to N times the first sampling frequency, with N an integer strictly greater than 1, an analogue output signal, to be transmitted, representative of N repetitions of the sequence of digital samples that is stored in the memory means (M1) during the time slot concerned, so as to output the analogue signal according to a symbol rate equal to N times a reference symbol rate.

Abstract: An interleaver (ER) is dedicated to interleaving of interleaving units representing a selected number of services grouped into periodic frames within a long period time interleaving radio communication network. The said interleaver (ER) comprises processing means (MT1) responsible for decomposing each frame into a chosen number of group(s) of service of constant respective durations, and then for distributing the interleaving units of each group into so-called spreading time intervals of constant respective durations spaced apart within a time interleaving period according to a period equal to the period of the frames.

Abstract: A method of operating an optical transmission system is described. The transmission system is provided with a bit-to-bit polarization interleaved bitstream having a given bitrate. The transmission system comprises a birefringent element and/or a decision circuit. The birefringent element and/or the decision circuit are triggered by a trigger signal having a frequency of half of the bitrate.

Abstract: A device for processing a digital signal of an optical transmission system is described. The device comprises: a polarization beam splitter for receiving the signal, a phase shifter for shifting the phase of the signal at the orthogonal output of the polarization beam splitter, and means for combining the signal at the parallel output of the polarization beam splitter and the shifted signal.