Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Alain Ducasse is active.

Publication


Featured researches published by Alain Ducasse.


International Journal of Satellite Communications and Networking | 2007

Iterative interference cancellation and channel estimation in multibeam satellite systems

Jean-Pierre Millerioux; Marie-Laure Boucheret; Caroline Bazile; Alain Ducasse

This paper deals with the use of non-linear multiuser detection techniques to mitigate co-channel interference on the reverse link of multibeam satellite systems. These techniques allow more capacity efficient frequency reuse strategies than classical ones, as they make possible to cope with lower C/I. The considered system takes as a starting point the DVB-RCS standard, with the use of convolutional coding, and the use of the Ka-band. We propose different iterative interference cancellation schemes, which operate at the beamformer outputs, and which use information from decoders. The proposed receivers assume an initial single-user synchronization step: frame synchronization and timing recovery, and then perform channel estimation: beamformer coefficients; signal carrier phases and signal amplitudes. In a first step, these receivers are evaluated by simulation in terms of bit error rate and of channel estimation error on two interference configurations. For one of these receivers, sensitivity to imperfect timing recovery and to low-frequency offsets from user terminals is evaluated. In a second step, since the receiver performances highly depend on the interference configuration, we propose an approach to evaluate performances on a multibeam coverage (by taking into account the variability of interference configurations on the coverage). This method is used to compare different receivers on an example based on a coverage designed on a digital focal array feed reflector antenna. Copyright


international conference on information and communication technologies | 2004

Continuous phase modulation for future satellite communication systems in Ka band

Ridha Chaggara; Marie-Laure Boucheret; Caroline Bazile; Emmanuel Bouisson; Alain Ducasse; J. D. Gayrard

In this paper, a CPM (continuous phase modulation) based waveform is proposed. CPM is an efficient waveform for future satellite communication systems. It yields good power and spectral performance and provides a constant envelope signal. This class of modulation yields a constant envelope signal so that SSPA (solid state power amplifier) terminal amplifier can operate near saturation. These systems operate in Ka-band with MF-TDMA access method on the uplink with the requirements of future satellite communication systems. The system will overcome specific difficulties that may affect the quality of service. The brief summary of the main CPM signal properties and the receiver complexity, serially coded CPM with iterative decoding process is presented. Simulation results are presented in the paper such that coding and decoding schemes achieve good power performance.


international workshop on signal processing advances in wireless communications | 2005

A soft decision directed phase detector suited to satellite communications at very low signal to noise ratio

Mathieu Dervin; Marie-Laure Boucheret; G. Mesnager; Alain Ducasse

The introduction of data redundancy for the purpose of carrier synchronization over a Gaussian channel may be a profitable operation. We present in this paper the performance of a phase detector suited to 8 PSK receivers, based on the soft decoding of a single parity-check code. It is shown that in presence of phase noise and a quite important frequency error, the proposed synchronization scheme outperforms the classical non-data-aided and decision-directed algorithms, reducing the phase jitter in considerable proportions.


international workshop on signal processing advances in wireless communications | 2006

Iterative Multiuser Detection and Channel Estimation in a Multibeam Satellite Communication System

J.P Millerioux; Marie-Laure Boucheret; C. Bazile; Alain Ducasse

This paper deals with the use of non-linear multiuser detection techniques to mitigate co-channel interference on the reverse link of multibeam satellite systems. The considered system is inspired by the DVB-RCS standard, with the use of convolutional coding. The proposed scheme consists of an iterative parallel interference cancellation algorithm with semi-blind channel estimation. The main contributions of this paper are the assumption of unknown beamformer coefficients for the receiver design, the introduction a low complexity scheme for a symbol asynchronous channel, and sensitivity evaluations with imperfect timing recoveries or reduced frequency offsets. The proposed algorithm allows close to single user performance on configurations characterized by very low C/I


Eurasip Journal on Wireless Communications and Networking | 2007

Frequency estimation in iterative interference cancellation applied to multibeam satellite systems

Jean-Pierre Millerioux; Marie-Laure Boucheret; Caroline Bazile; Alain Ducasse

This paper deals with interference cancellation techniques to mitigate cochannel interference on the reverse link of multibeam satellite communication systems. The considered system takes as a starting point the DVB-RCS standard with the use of convolutional coding. The considered algorithm consists of an iterative parallel interference cancellation scheme which includes estimation of beamforming coefficients. This algorithm is first derived in the case of a symbol asynchronous channel with time-invariant carrier phases. The aim of this article is then to study possible extensions of this algorithm to the case of frequency offsets affecting user terminals. The two main approaches evaluated and discussed here are based on (1) the use of block processing for estimation of beamforming coefficients in order to follow carrier phase variations and (2) the use of single-user frequency offset estimations.


global communications conference | 2006

SAT02-1: Iterative Frequency and Channel Estimation Coupled with Multiuser Detection in Multibeam Satellite Communications

Jean-Pierre Millerioux; Marie-Laure Boucheret; Caroline Bazile; Alain Ducasse

This paper introduces an iterative multiuser detection scheme, including channel estimation, for the reverse link of (narrowband) multibeam satellite communication systems with convolutional coding. After a derivation of the algorithm on a symbol-asynchronous time-invariant channel, we discuss and evaluate possible adaptations to the more realistic case of frequency offsets affecting user terminals.


global communications conference | 2005

A soft detection directed phase estimator suited to satellite burst transmissions

Mathieu Dervin; Marie-Laure Boucheret; Gilles Mesnager; Alain Ducasse

In this paper, we present a phase synchronization algorithm which exploits the data redundancy brought by a single parity-check code. The symbol decoding of a parity equation is discussed first. Then, a soft detection directed (SDD) estimation technique is derived for any modulation scheme. The performance of the developed SDD phase estimator is evaluated with 8PSK modulation in very low SNR condition. It appears to greatly outperform the non data aided Viterbi and Viterbi estimator. Quite robust to phase noise, it seems well suited to the context of satellite burst transmissions


international workshop on signal processing advances in wireless communications | 2004

Adaptive waveform based on continuous phase modulations design and performance

R. Chaggara; Marie-Laure Boucheret; C. Bazile; E. Bouisson; Alain Ducasse; J.-D. Gayrard

Performance of serially coded binary and quaternary CPM (continuous phase modulations) with iterative decoding are explored. Such system shows high power performance when reasonable interleaver sizes (less than 1024) are considered. The effect of the modulation index variation on waveform efficiency is emphasized. Effect of ACI (adjacent channel interference) on waveform performance is also assessed. Simulation results will represent a guideline to select the best fitted CPM for future satellite communications systems in Ka band. The choice takes into account power and spectral performance, complexity as well as adaptive aspects. The latter criterion is justified by the significant channel fluctuations in Ka band. In such circumstances, non adaptive waveform leads automatically either to a non efficient channel exploitation or weak system availability.


european signal processing conference | 2006

Iterative multiuser detection performance evaluation on a satellite multibeam coverage

Jean-Pierre Millerioux; Marie-Laure Boucheret; Caroline Bazile; Alain Ducasse


20° Colloque sur le traitement du signal et des images, 2005 ; p. 1068-1071 | 2006

Détection de phase à très faible rapport signal à bruit à l’aide d’un code de parité

Mathieu Dervin; Marie-Laure Boucheret; Gilles Mesnager; Alain Ducasse

Collaboration


Dive into the Alain Ducasse's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar

Caroline Bazile

Centre National D'Etudes Spatiales

View shared research outputs
Top Co-Authors

Avatar

Jean-Pierre Millerioux

Centre National D'Etudes Spatiales

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge