Universite Du Luxembourg

Nokia Corporation

Iee International Electronics and Engineering S.a.

European Space Agency

Ses S.a.

Bjorn Ottersten

Udo Schroder

Bhavani Shankar Mysore Rama Rao

Christian Hammes

Martin Kristensson

Yogesh Nijsure

Alberto Ginesi

Thiemo Spielmann

Farbod Kayhan

Giorgio Taricco

Ana Isabel Perez-Neira

Pantelis-Daniel Arapoglou

David Astély

Symeon Chatzinotas

Roberto Piazza

Bhavani Shankar Bysore Rama Rao

Astel David

Dimitrios Christopoulos

Miguel Angel Vazquez

Stefano Andrenacci

Alessandro Vanelli Coralli

A method for obtaining an adaptive angle-Doppler ambiguity function (AF) for a target using multiple-input-multiple-output (MIMO) radar that includes a transmit antenna array having a plurality of antenna elements. The method includes generating transmit signals for transmission by the transmit antenna array, the transmit signals defining at least a first transmit trajectory of a phase center within the transmit antenna array; transmitting the transmit signals using the transmit antenna array and receiving receive signals from the target, the receive signals resulting from the incidence of the transmit signals upon the target; and obtaining at least an angle-Doppler ambiguity function (AF) from the receive signals. The first transmit trajectory is such that, in operation, the phase center undergoes random phase center motion (PCM), such that a phase center position within the transmit antenna array varies randomly with time. A system for obtaining an AF is also disclosed.

Method and system for obtaining an adaptive angle-doppler ambiguity function in MIMO radars

A method for obtaining an angle-Doppler signature for a target using sparse arrays in multiple-input-multiple-output (MIMO) radar, the MIMO radar including a transmit antenna array, the transmit antenna array being at least one-dimensional (e.g. 2-D, 3-D or 4-D) and having a plurality of antenna elements. The method includes generating transmit signals for transmission by the transmit antenna array, the transmit signals defining at least a first transmit trajectory (e.g. circular) of a phase center within the transmit antenna array, and transmitting the transmit signals using Amplitude Modulation on the transmit antenna array. The method further includes receiving receive signals from the target, the receive signals resulting from the incidence of the transmit signals upon the target, and determining the angle-Doppler signature from the receive signals. The first transmit trajectory is such that, in operation, the phase center undergoes non-linear motion within the transmit antenna array.

Method and system for obtaining angle-doppler signatures in MIMO radars

A simple construction for a family of non-uniform APSK constellations by the radial isomorphism between squares to circles is provided. The mutual information values indicate gains of at least 0.5 dB up to 1.5 dB with respect to the state of the art, such as the DVB-S2X constellations with 256 symbols. The invention also provides for a low-complexity detector of high-order modulated signals.

Data transmission method and device using non-uniform APSK constellations

A, method and apparatus for wirelessly transmitting data to a plurality of terminals in each of a plurality of beams through a plurality of transmit feeds includes selecting, for each beam, two or more terminals among the plurality of terminals in the beam as a subgroup of terminals, on the basis of channel state information of the plurality of terminals; determining, for each beam, equivalent channel state information representing the subgroup of terminals in the beam on the basis of the channel state information of the terminals of at least one of the plural subgroups of terminals; and determining a set of weight coefficients that relate the plurality of transmit feeds to a plurality of signals that are intended for transmission in the plurality of beams on the basis of the equivalent channel state information representing the plural subgroups of terminals. Also disclosed is a method and apparatus for receiving data transmitted via wireless transmission to a plurality of beams through a plurality of transmit feeds and estimating a channel on the basis of the received data. The present disclosure is advantageously applicable to satellite communication systems.

Joint transmitter signal processing in multi-beam satellite systems

A method, carried out by a gateway transmitter (), aims at compensating the nonlinearities of a communication channel () comprising a repeater (). A plurality of digital signals is modulated (s) on a plurality of carriers, wherein symbols of the constellation diagram used for modulation of each carrier are distorted in accordance with a pre-distortion function. The modulated signals are then frequency division multiplexed (s), and sent (s) for transmission, through the communication channel (), to at least one receiver (). The pre-distortion function involves a plurality of polynomial functions, each of which taking as input the symbols from all the carriers. The polynomial functions' coefficients, called 'pre-distortion coefficients', are computed according to a direct learning approach, performed jointly for the plurality of carriers. The pre-distortion coefficients are iteratively updated based on received signals being fed back from a receiver (). The invention also relates to transmitters and computer programs.

Methods, devices, and computer programs for compensating nonlinearities of a communication channel

The present invention relates to a method for a digital receiver and a receiver exploiting second order statistics for adaptive co-channel interference rejection in wireless communication. It uses digitally I, in phase, and Q, quadrature, branches of a received transmitted signal as input to the receiver, a coarse synchronization and a coarse frequency offset compensation have being performed on the signal. It comprises a means for derotation, means for separation, means for filtering, means for estimating and means for detecting transmitted symbols in the received signal. The invention thereby improving co-channel rejection in wireless communication, thus making it possible to increase the number of communication channels for frequencies used.

Receiver

Co-channel interference rejection in a digital receiver

Growing community of inventors

Luxembourg, Luxembourg

Bjorn Ottersten