Abstract: To reduce interferences in signals received by a receiver through a propagation channel, each including symbols distributed according to frequency and time dimensions and corresponding to a common emitted signal, the receiver weights an estimate of the emitted signal and the received signals by weighting vectors evolving in vector subspaces representing time variations and frequency variations of the channels for propagating the signals between an emitter and the receiver. These vector subspaces are defined by matrices, some columns of which are suppressed as a function of frequency and time constraints of the channel. The receiver minimizes a function of the difference between the sum of weighted received signals and the weighted estimate of the emitted signal in order to estimate the emitted signal as a function of the weighting vectors and the received signals.

Abstract: A radio communication emitter includes at least two antennas for emitting a signal including encoded bits that are converted into symbols distributed on subcarriers and in time intervals. The emitter includes a signal divider for distributing the set of the signal symbols into as many disjoined subsets of signal symbols as the antennas that the emitter comprises. Each subset is dedicated to one of the antennas. The union of the subsets is the set of the signal symbols. Symbols are distributed in at least two subsets for at least one time interval or for at least one subcarrier of the signal. The antennas synchronously emit the symbol subsets. The symbol subsets can comprise a substantially identical number of symbols to reduce a deviation between the power peaks and the average power of the signal emitted by each antenna.

Abstract: A method of management for operating a first system of communication of the broadband type communication system emitting over a first frequency range, and a second system of communication of the narrow band type communication system emitting over a second frequency range, the first system and the second system using all or part of a same frequency band, such common frequency band being called a crossover frequency band for both systems, the method including: embodying a scan operation from at least the crossover frequency band of the two systems using a scan device from the first communication system; identifying, after the scan operation, the frequency channels used by the second communication system; adapting the operating of the first communication system within the frequency channels identified as being used by the second communication system.

Abstract: A signal is received in a telecommunication network in the form of P signals received on P corresponding antennas, where P is greater than or equal to 1. The received signals correspond to a multi-carrier signal transmitted in the form of flames comprising symbols occupying corresponding positions distributed along a time axis and along a frequency axis; a frame comprising M blocks each having at least N reference symbols. The reference symbols in each of the blocks satisfy a first maximum spacing between each other along the time axis and a second maximum spacing between each other along the frequency axis, less than a first value and a second value respectively, M being an integer number equal to at least two. M estimated noise power values are determined at frame level, each related to one of the M emitted reference symbol blocks. Values of the estimated noise power for the other symbols in the frame are then obtained from the determined estimated noise power values.

Abstract: A signal is received by P antennas. It includes frames having symbols occupying respective positions distributed along an axis of time and of frequency, a frame including M blocks having N reference symbols M groups of P weighting coefficients are determined, each one of the groups relating to one of the blocks emitted, with the coefficients of a group being associated to the blocks which are received on the P antennas and which correspond to the block emitted relating to the group. The coefficients are determined so as to increase via a threshold value, an error value for each block emitted, between the reference symbols of the block emitted, and the symbols obtained using the symbols received on each antenna at the positions of reference symbols corresponding to the block emitted and the associated coefficients.

Abstract: A transmission chain comprises a power amplifier adapted for receiving as input a signal to be amplified Sw(t) and for providing as output an amplified signal Dw(t); a predistortion module comprising a linearization unit adapted for applying a predistortion coefficient W(t) to an input signal S(t), and a unit for determining said predistortion coefficient. The input signal S(t) is received and the amplified signal Dw(t) is received through a return pathway, at the level of the unit for determining the predistortion coefficient, and the predistortion coefficient is determined on the basis of a comparison between the input signal and the amplified signal. Next, at the level of the linearization unit, the predistortion coefficient is applied to the input signal to provide as output the signal to be amplified. The determining unit determines the predistortion coefficient on the basis of a first-order approximation of the input signal.

Abstract: To reduce interferences in signals received by a receiver through a propagation channel, each including symbols distributed according to frequency and time dimensions and corresponding to a common emitted signal, the receiver weights an estimate of the emitted signal and the received signals by weighting vectors evolving in vector subspaces representing time variations and frequency variations of the channels for propagating the signals between an emitter and the receiver. These vector subspaces are defined by matrices, some columns of which are suppressed as a function of frequency and time constraints of the channel. The receiver minimizes a function of the difference between the sum of weighted received signals and the weighted estimate of the emitted signal in order to estimate the emitted signal as a function of the weighting vectors and the received signals.

Abstract: A radio communication emitter includes at least two antennas for emitting a signal including encoded bits that are converted into symbols distributed on subcarriers and in time intervals. The emitter includes a signal divider for distributing the set of the signal symbols into as many disjoined subsets of signal symbols as the antennas that the emitter comprises. Each subset is dedicated to one of the antennas. The union of the subsets is the set of the signal symbols. Symbols are distributed in at least two subsets for at least one time interval or for at least one subcarrier of the signal. The antennas synchronously emit the symbol subsets. The symbol subsets can comprise a substantially identical number of symbols to reduce a deviation between the power peaks and the average power of the signal emitted by each antenna.

Abstract: A signal is received in a telecommunication network in the form of P signals received on P corresponding antennas, where P is greater than or equal to 1. The received signals correspond to a multi-carrier signal transmitted in the form of frames comprising symbols occupying corresponding positions distributed along a time axis and along a frequency axis; a frame comprising M blocks each having at least N reference symbols. The reference symbols in each of the blocks satisfy a first maximum spacing between each other along the time axis and a second maximum spacing between each other along the frequency axis, less than a first value and a second value respectively, M being an integer number equal to at least two. M estimated noise power values are determined at frame level, each related to one of the M emitted reference symbol blocks. Values of the estimated noise power for the other symbols in the frame are then obtained from the determined estimated noise power values.

Abstract: An emission chain is suitable for receiving an input signal and for providing a signal to be emitted. It comprises a processing pathway for the input signal which includes a digital signal decomposition according to N signal components, with N an integer greater than or equal to 2, said N signal components, on the one hand, being converted from a digital form into an analog form and, on the other hand, following respectively distinct physical pathways, said physical pathways inducing first respective delays on the N signal components. The input chain comprises a power amplifier. A delayed input signal is obtained by applying a second delay (?) having a value greater than or equal to the maximum value of the first delays. Next, N correction delays (???i) are applied respectively to the N signal components, this step being carried out on the basis of a comparison between said input signal delayed by the second delay and the signal to be emitted.

Abstract: The invention provides a multicarrier system constructed on a time-frequency lattice defined comprising frames having MxN symbols distributed over M subcarriers each of which is divided into N specific symbol times. Each frame comprises P pilot symbols distributed time-wise and frequency-wise so as to cover the frame in a meshed structure, so that, in particular, some at least of the M subcarriers contain no pilot symbol and/or that no pilot symbol should be transmitted to some at least of the N symbol times. The invention also relates to a method for tracking a transmission channel using such a signal, and a device for implementing the method.

Abstract: A method of synchronization on the uplink channel of a Simulcast network with a plurality of fixed receivers (BS1-BS4) and a selection unit (20), comprises the following steps. All the receivers are placed in a synchronization search mode (702), in which they search for a synchronization pattern sent by the mobile terminal over the uplink channel. When a receiver detects the synchronization pattern, it produces an initial synchronization context (SC3(0)), which indicates the delay of the radio signal relative to a time reference of the network, and transmits it (705) to the selection unit. The latter broadcasts it (707) to all the receivers that use it to start processing the radio signal. Then, each receiver maintains its synchronization context and transmits it (708-712) to the selection unit on each frame. At regular intervals, the value of an updated synchronization context (SC2(i)) is broadcast (714) to the receivers.

Abstract: A signal of OFDM type received in a radio receiver via a propagation channel includes symbols distributed according to frequency and time. The receiver determines likelihoods of the symbols, decodes the received signal to yield a decoded signal as a function of the likelihoods of the symbols, and estimates an instantaneous noise power of the received signal as a function of a difference between the received signal and a reconstructed noise-free signal derived from the decoded signal. A filtering module determines a bounded distribution of the instantaneous noise power as a function of frequency and/or time, and filters the distribution to yield a filtered noise variance as a function of a frequency and/or time parameter of the propagation channel. A corrector weights the likelihoods of the symbols of the received signal to be decoded as a function of the filtered noise variance.

Abstract: A transmission chain comprises a power amplifier adapted for receiving as input a signal to be amplified Sw(t) and for providing as output an amplified signal Dw(t); a predistortion module comprising, on the one hand, a linearization unit adapted for applying a predistortion coefficient W(t) to an input signal S(t), and, on the other hand, a unit for determining said predistortion coefficient. On the one hand, the input signal S(t) is received and, on the other hand, the amplified signal Dw(t) is received through a return pathway, at the level of the unit for determining the predistortion coefficient, and the predistortion coefficient is determined on the basis of a comparison between the input signal and the amplified signal. Next, at the level of the linearization unit, the predistortion coefficient is applied to the input signal, so as to provide as output the signal to be amplified.

Abstract: A signal is received by P antennas. It includes frames having symbols occupying respective positions distributed along an axis of time and of frequency, a frame including M blocks having N reference symbols M groups of P weighting coefficients are determined, each one of the groups relating to one of the blocks emitted, with the coefficients of a group being associated to the blocks which are received on the P antennas and which correspond to the block emitted relating to the group. The coefficients are determined so as to increase via a threshold value, an error value for each block emitted, between the reference symbols of the block emitted, and the symbols obtained using the symbols received on each antenna at the positions of reference symbols corresponding to the block emitted and the associated coefficients.

Abstract: A method for estimating a transmission channel from a multicarrier signal transmitted through said transmission channel, comprising real pilot symbols and so-called pure imaginary pilot symbols, consists in selecting one or several values zk of the received signal corresponding respectively to one or several real pilot symbols, and one or several values zl of the received signal corresponding respectively to one or several pure imaginary pilot symbols. The pilot symbols are sufficiently close both in frequency and in time such that it can be assumed that the fading of the signal through the transmission channel has a complex value ? substantially identical for the symbols. An estimated value {circumflex over (?)} of ? for the pilot symbols concerned is then determined by minimizing a least square equation involving the values zk and the values zl.

Abstract: A method of synchronization on the uplink channel of a Simulcast network with a plurality of fixed receivers (BS1-BS4) and a selection unit (20), comprises the following steps. All the receivers are placed in a synchronization search mode (702), in which they search for a synchronization pattern sent by the mobile terminal over the uplink channel. When a receiver detects the synchronization pattern, it produces an initial synchronization context (SC3(0)), which indicates the delay of the radio signal relative to a time reference of the network, and transmits it (705) to the selection unit. The latter broadcasts it (707) to all the receivers that use it to start processing the radio signal. Then, each receiver maintains its synchronization context and transmits it (708-712) to the selection unit on each frame. At regular intervals, the value of an updated synchronization context (SC2(i)) is broadcast (714) to the receivers.

Abstract: An elongate reaction vessel and process includes at least two stages in the vertical direction in which an endothermic or exothermic catalytic reaction is carried out and comprises: a catalytic reaction zone (12a, 12b) per stage (6, 7); introducing (2) a reaction fluid to a stage adapted for transverse motion of the fluid across the whole vertical extent of the reaction zone; introducing and extracting the catalyst; a heat exchanger (5a) for reaction fluids located inside the vessel between two successive reaction zones; means (6) for transporting reaction fluids from one stage to another preferably connected to the exchanger of the stage under consideration and to the inlet for reaction fluids of the subsequent stage; and means for recovering reaction fluids downstream of the last stage. The temperature variation in each zone and the temperature level are respectively adjusted by the thickness of each zone and by heat exchange.

Abstract: A method for estimating a transmission channel from a multicarrier signal transmitted through said transmission channel, comprising real pilot symbols and so-called pure imaginary pilot symbols, consists in selecting one or several values zk of the received signal corresponding respectively to one or several real pilot symbols, and one or several values zl of the received signal corresponding respectively to one or several pure imaginary pilot symbols. The pilot symbols are sufficiently close both in frequency and in time such that it can be assumed that the fading of the signal through the transmission channel has a complex value &agr; substantially identical for the symbols. An estimated value {circumflex over (&agr;)} of &agr; for the pilot symbols concerned is then determined by minimizing a least square equation involving the values zk and the values zl.

Abstract: A transmitter outputs a radio signal formed from a first baseband signal incorporating a synchronization signal. The recipient obtains a second baseband signal from the received radio signal, detects the synchronization signal in a portion of the second baseband signal in order to compute synchronization parameters and/or parameters for estimating a radio transmission channel, and uses the computed parameters to demodulate another portion of the second baseband signal and extract the transmitted information from it. The synchronization signal contains a synchronization pattern selected by the transmitter on the basis of signalling information to be supplied to the second station. The receiver searches several patterns in the second baseband signal in order to obtain the signalling information depending on the detected pattern.