Thales

Thomson-csf

Thomson Licensing S.a.

Ferreol, Anne

Pascal Chevalier

Anne Ferreol

Jean-Jacques Monot

Laurent Albera

François Pipon

François Delaveau

Gilbert Multedo

Fran&ccedil;ois Pipon

Christophe Donnet

Marc Chenu-Tournier

Pierre Vila

Pascal Larzabal

Francedillaois Pipon

Eric Moulines

Florian Dupuy

Jo&euml;l Thibault

Thierry Aste

Claude Adnet

Philippe Loubaton

Jean-Marie Chaufray

Pierre Comon

Lisa Perros-Meilhac

Fréderique Lasnier

Béatrice Col

Pipon Francois

François Van De Wiele

Sonja Hiltunen

Hanna Becker

Cécile Germont

Method and system for separating a plurality of users in a communication system including two transmitter antennas and N receiver antennas, said signals transmitted by said users containing symbols a, x( ) corresponding to the vector of the envelopes of the output signals of the 1 to N receiver antennas after a shaping filtering operation, characterized in that it uses a linear mean square filter extended over an observation vector {tilde over (x)}=[x(2n&#x2212;1)x(2n)x(2n&#x2212;1)x(2n)]where x(2n&#x2212;1) and x(2n) correspond to the (N&#xd7;1) (N&#x2267;1) observations at the symbol times 2n&#x2212;1 and 2n.

Method and device for mono- and multi-antenna reception for Alamouti-type links

A method for measuring certain parameters of the impulse response of a propagation channel involving emitters and reflectors that are fixed or mobile, and for detecting and determining the parameters regarding the position and kinematics of the emitters and reflectors, or for auto-locating the reception system implementing the invention, in a system comprising N sensors receiving signals from the emitters or from the reflection on the reflectors. The method determines an ambiguity function which couples the spatial analysis and the delay-distance/Doppler-kinematic analysis, and determines at least one sufficient statistic &#x108;(l,m,K) corresponding to the correlation between the known signal s(kTe) corresponding to the complex envelope of the signal emitted and the output of a filter w(l,m) where l corresponds to a temporal assumption and m corresponds to a frequency assumption. The method also determines the values of the pair (l,m) by comparing the value of the statistic for the pair (l,m) with a threshold value.

Methods and devices for determining the impulse response of propagation channels involving emitters, reflectors and sensors that are fixed or mobile

A method of fighting interference in a frequency-hopping communication system is disclosed. The system has at least one main sensor and one or more auxiliary sensors. According to at least one embodiment, frequency-hopping signals are received. The frequency-hopping signals are arranged to include useful bands and one or more guard bands inserted between the useful bands, and a ratio of the useful bands to the guard bands being chosen according to a predetermined value of probability of interference interception. Signals of the inserted guard bands having a signal level greater than a predetermined threshold are selected. A set of spatial-filtering weightings are calculated according to a correlation matrix of noise plus jammers alone on the signals selected. Baseband signals of the received frequency-hopping signals are filtered by the set of the calculated spatial-filtering weightings.

Method and device for anti-interference fighting in a telecommunications system

Method of high-resolution direction finding to an arbitrary even order, 2q (q&#x3e;2), for an array comprising N narrowband antennas each receiving the contribution from P sources characterized in that the algebraic properties of a matrix of cumulants of order 2q, C(l), whose coefficients are the circular cumulants of order 2q, Cum[x(t), . . . , x(t), x(t)*, . . . , x(t)*], of the observations received on each antenna, for cumulant rankings indexed by l, are utilized to define a signal subspace and a noise subspace.

High resolution, arbitrary-even-order direction finding method and device

A method of synchronizing a substantially rectilinear signal being propagated through an unknown channel, in the presence of unknown substantially rectilinear interferences, received by an array of N sensors, in which a known training sequence s(nT) is used comprising K symbols and sampled at the symbol rate T (s(nT), 0&#x2266;n&#x2266;{tilde over (K)}1), characterized in that, based on observations x((n+l/p)T) over the duration of the training sequence, where p=T/Te is an integer and Te the sampling period, a virtual observation vector X((n+l/p)T)=[x((n+l/p)T), x((n+l/p)T)]is defined, as well as a decision criterion or decision statistic taking into account the second-order non-circular nature of the interferences, by using the first and second correlation matrices of the virtual observation vector X((n+l/p)T).

Method and device for synchronizing rectilinear or quasi-rectilinear links in the presence of interference

An antenna processing method for centered or potentially non-centered cyclostationary signals, comprises at least one step in which one or more nth order estimators are obtained from r-order statistics, with r=1 to n&#x2212;1, and for one or more values of r, it comprises a step for the correction of the estimator by means of r-order detected cyclic frequencies. The method can be applied to the separation of the emitter sources of the signals received by using the estimator or estimators.

Antenna processing method for potentially non-centered cyclostationary signals

A method for the verification of anti-jamming in a communications system comprises several sensors or adaptive antennas, comprising at least the following steps: 

Method for verifying anti-scrambling efficiency of a communication system

A method for the fourth-order, blind identification of at least two sources in a system comprising a number of sources P and a number N or reception sensors receiving the observations, said sources having different tri-spectra. The method comprises at least the following steps: a step for the fourth-order whitening of the observations received on the reception sensors in order to orthonormalize the direction vectors of the sources in the matrices of quadricovariance of the observations used; a step for the joint diagonalizing of several whitened matrices of quadricovariance in order to identify the spatial signatures of the sources. Application to a communication network. to be published.

Method and device for the fourth-order, blind identification of an under-determined mixture of sources

Blind or partially blind process to determine characteristic space-time parameters of a propagation channel in a system comprising at least one reception sensor receiving a signal y(t). It comprises at least one step in which the specular type structure of the channel is used and a step for the joint determination of parameters such as antenna vectors (a) and/or time vectors (&#x3c4;) starting from second order statistics of the received signals. Application for monitoring the spectrum of a propagation channel for positioning purposes starting from one or several HF stations or for standard communication links with equalization or positioning or spatial filtering.

Blind process and receiver to determine space-time parameters of a propagation channel

A device and method for the calibration and equalization of reception chains of an antenna processing system comprises several RF chains, each associated with a radiating element, a set of sensors Ci formed out of the outputs of the preceding RF chains, a channel for the injection of a calibration signal, means to couple the calibration signal to the sensor signals and several reception-digitization chains. The device comprises at least one processor adapted to managing all the devices; a means used to adjust the value of the gain of an RF chain to a minimum value Gmin; a means for deflecting the sensors, adapted to minimizing their directivity toward the interference sources; a means adapted to adjusting the level of the injected calibration signal ST relative to the signal of the sensors, an RF chain having a gain adjusted to a minimum value Gmin.

Method and device for the calibration-equalization of a reception system

A method for the blind identification of sources within a system having P sources and N receivers comprises at least one step for the identification of the matrix of the direction vectors of the sources from the information proper to the direction vectors aof the sources contained redundantly in the m=2q order circular statistics of the vector of the observations received by the N receivers. Application to a communications network.

Method for the higher-order blind identification of mixtures of sources

A method and device to estimate the impulse response h of a propagation channel in a system comprising at least one or more sensors, comprising at least one step for estimating the statistics of the additive noise resulting from the interference and from the thermal noise on the basis of the statistics of the received signal

Method and device for the estimation of a propagation channel from its statistics

Process for estimating the correlation matrix of signals of unknown characteristics in an array of N sensor. The process determines the correlation matrix {circumflex over (R)}s of the signals of known characteristics, estimates the correlation matrix {circumflex over (R)}x of the sensor signals, forms a matrix A equal to A={circumflex over (R)}s{circumflex over (R)}x {circumflex over (R)}sand decomposes the matrix A into eigenelements, constructs a matrix B based on the eigenelements of the matrix A, and determines the estimated correlation matrix {circumflex over (R)}b of the interfering signals based on the estimated matrix {circumflex over (R)}s and of the matrix B, such that {circumflex over (R)}b={circumflex over (R)}sB {circumflex over (R)}s. Such a process may find application to antenna processing.

Method for estimating a correlation matrix of interfering signals received through a sensor array

A method for estimating one or more parameters of a propagation channel, with a priori knowledge of at least one signal, in a system having one or more sensors. The method includes correlating one or more signals received by the sensors with the known signal, sampling the received signals at a sampling period and selecting a number of samples per concatenation, and determining at least one parameter of the propagation channel which enables the most efficient reconstruction of the signals via a maximum likelihood method.

Method to estimate the parameters of a propagation channel

A method and apparatus for spatial multiplexing and demultiplexing of radio signals. A multichannel transmitter and receiver is integrated in a base station and coupled to an antenna array. Using digital radio signals containing previously known or non-Gaussian sequences and arranged in frames, the spatial information about each mobile unit is estimated on the basis of the signal received by the receiver for the reception and transmission frequencies. This is done by known sequences or by blind source separation methods. The respective paths of each mobile unit with the power above a predetermined threshold is isolated by spatial filtering in the presence of multiple channel paths in order to provide spatial demultiplexing. Simultaneously, the intended signal is transmitted in the direction of the main path of each mobile unit while protecting each mobile unit from signals transmitted in the direction of other mobile units by spatial filtering with cancelling constraints in order to provide spatial multiplexing.

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Courbevoie, France

Pascal Chevalier