Thomson-Csf

Thales

Thomson Licensing S.a.

Jean-Jacques Monot

Pascal Chevalier

Gilbert Multedo

Anne Ferreol

Fran&ccedil;ois Pipon

Philippe Morgand

Robert Berranger

Laurent Bernardot

Fr&eacute;d&eacute;rique Lasnier

Thierry Aste

Jo&euml;l Thibault

A method and system for detecting and locating at least one mobile in a standby mode using a search device located at a certain altitude above the at least one mobile. A simulation of a cellular network activates the at least one mobile within range of the simulated network. At least one parameter representative of at least one signal transmitted by the activated at least one mobile is determined.

System and method to locate radiomobiles outside the coverage of a cellular network

A process for locating radio sources by a two-channel high resolution radiogoniometer including a network of a specified number N of sensors. The process multiplexes the signals supplied by the N sensors on the inputs of only two receivers. Then, with the aid of a calculation device coupled to the outputs of the two receivers, the angles of arrival of the waves emitted by the sources are estimated on the basis of an estimation of the covariance matrix of the signals supplied by the two receivers.

Method for locating radioelectric sources using two-channel high resolution radiogoniometer

The disclosure relates to methods and devices for the real-time localization of terrestrial transmitters belonging to a TDMA type cellular radiocommunications network. The device comprises an antenna array, a multichannel receiver and a digital processor. The method consists of the interception, from an aircraft, of radioelectric signal and the detection of these signal by the implementation of a multichannel synchronization to determine the various sources of transmission, the simultaneous computation of an elevation angle &Dgr; and an azimuth angle &thgr; to instantaneously determine the direction of arrival of the radioelectric signal from the determined transmission sources and the building of track in the geographical areas in which the transmission sources are located in order to estimate the position of the transmitters.

Method for the localizing of terrestrial mobile radio from an aircraft

A system for analyzing interference caused by neighboring cells in a cellular communication system. A multipath synchronization is performed on the learning sequences of the beacon frequencies in order to determine the number of base stations using the analysis frequency as a beacon frequency. The identifiers of the base stations which are transmitting the beacon frequencies on which a synchronization has been made are demodulated after spatial filtering. A multipath synchronization is performed on learning sequences of the traffic frequencies so as to determine the number of base stations using the analysis frequency as a traffic frequency.

Method and device for analyzing interference in a cellular radiocommunication system

A process for managing intercellular transfers of communication in a cellular radio communication system. A specified number of microcells inside umbrella cells each respectively possess a base station for allowing the routing of the communications. Radio direction finding is used to pinpoint at least two successive virtual positions of the mobile stations in communication in relation to the base station of the umbrella cell in order to deduce therefrom a speed of movement of each mobile station in the time interval which separates the pinpointing of their positions. The speeds of movement which are obtained are compared to the specified speed values so as to entrust the management of the communication from a mobile station to the base station of the umbrella cell in which it lies when its speed is greater than the specified speed value, or to the base station of the microcells when it is not greater than the specified speed value.

Process and device for managing intercellular transfers of radio communications in a cellular radio communication system by measuring virtual speeds of cellular devices

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.

Method and device for space division multiplexing of radio signals transmitted in cellular radio communications

A process and device related to multisensor radio direction finding receivers usable in radio communication systems including several emission sources. The process and device isolate the contribution of each emission source in sensor signals so as to perform direction finding on a single emission source only, based on learning sequences inserted into waveforms emitted by each of the emission sources. Such a process and device may find particular application to cellular communication networks.

Radiogoniometry method and device co-operating in transmission

A process which adjusts the transmission and reception chains of the paths formed by a base station of a system for radio communication between mobiles which after calibration of the antenna base adjusts the reception chains relating to each path by distributing a first specified adjustment signal synchronously over each of the reception chains and calculating an equalization filter which inverts the transfer functions related to each reception chain. The process next adjusts the transmission chains related to each path by distributing a second specified adjustment signal synchronously over each of the transmission chains, by extracting from each of the paths a part of a transmission signal before the transmission signal is sent to the antenna base so as to re-inject that part of the transmission signal into the reception chains, and by calculating an equalization filter which inverts the transfer functions related to each transmission chain. Finally, the process receives via the equalization filters previously calculated for the reception chains reception signals originating from the antenna base, or transmits via the equalization filters previously calculated for the transmission chains the transmission signals originating from the multipath transmission/reception device.

Process for adjusting the transmission and reception chains of the paths by a base station of a system for radio communication between mobiles

Disclosed is a method enabling the improvement of the multisensor reception of a system of radiocommunications exchanging signals between at least one fixed base station providing for multisensor reception by means of a network of sensors, and the processing of the signals. This method consists, in a transparent manner perceived from the base station, in computing a weighting vector W for the formation of channels at reception. The weighting vector W is estimated by an adaptive algorithm leading to a maximization of the signal-to-noise ratio. Application: mobile radiocommunications. FIG. 1

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Courdimanche, France

Jean-Jacques Monot