CNRS / LIGM (UMR 8049)
Université Gustave Eiffel

Bât. Copernic,
bureau 4B190.
5, blvd. Descartes,
Champs-sur-Marne,
77454, Marne-la-Vallée Cedex 2.
France.

Phone: +33 1 60 95 77 42

E-mail:
firstname
(dot) lastname
(at) univ-eiffel (dot) fr


Useful links:


Walid Hachem


Researcher at the Centre national de la recherche scientifique (CNRS).

Université Gustave Eiffel
Laboratoire d'informatique Gaspard Monge (LIGM)
Equipe Méthodes et modèles pour le signal, les images et les données (MMSID)









Biography


I was born in Bhamdoun, Lebanon, in 1967. I received the Engineering degree in telecommunications from St Joseph University, faculté d'ingénierie (ESIB), Beirut, Lebanon, in 1989, the Masters degree from Telecom Paris in 1990, the PhD in signal processing from Université Paris-Est Marne-la-Vallée (now part of Université Gustave Eiffel) in 2000 and the "Habilitation à diriger des recherches" from Université Paris-Sud (now part of Université Paris Saclay) in 2006.
Between 1990 and 2000, I worked in the telecommunications industry as a signal processing engineer. In 2001, I joined the academia as a faculty member at Supélec. In 2006, I joined the CNRS, where I am a research director. After being based at Telecom Paris between 2006 and 2016, I am now a CNRS member of the laboratoire d'informatique Gaspard Monge (LIGM) at the Gustave Eiffel University.
My research and teaching activities are devoted to the mathematical tools for signal processing and statistical estimation. My research themes mainly consist in the large random matrix theory and its applications in the above fields, in the optimization algorithms in random environments, and more recently, in the large dimensional probability applied to the mathematical biology and ecology.




Publications


JOURNAL PAPERS



CONFERENCE PAPERS

  • M.-Y. Gueddari, W. Hachem and J. Najim, A Linear Complementarity Problem based on non-Symmetric Large Random Matrices , GRETSI 2023, Grenoble, France.
  • W. Hachem, "Les grandes matrices aléatoires : un aperçu historique", GRETSI 2022, Nancy, France.
  • W. Hachem et J. Najim, "Approximate Message Passing et solutions de grands systèmes dynamiques écologiques de Lotka-Volterra", GRETSI 2022, Nancy, France.
  • A. Bose and W. Hachem, "A whiteness test based on the spectral measure of large non-Hermitian random matrices", ICASSP 2020, Barcelona, Spain. Slides.
  • H. Nikbacht, M. Wigger, W. Hachem and Sh. Shamai (Shitz), "Mixed Delay Constraints on a Fading C-RAN Uplink", ITW 2019, Visby, Gotland, Sweden.
  • W. Hachem, A. Hardy et Sh. Shamai (Shitz), "Information mutuelle de canaux radio et opérateurs de Jacobi ergodiques", GRETSI 2019, Lille, France. Présentation.
  • A. Salim, P. Bianchi, and W. Hachem, "A Constant Step Stochastic Douglas-Rachford Algorithm with Application to Non Separable Regularizations", ICASSP 2018, Calgary, Canada.
  • A. Salim, P. Bianchi, and W. Hachem, "Convergence d'un algorithme du gradient proximal stochastique à pas constant et généralisation aux opérateurs monotones aléatoires", GRETSI 2017, Juan-les-Pins, France.
  • A. Salim, P. Bianchi, and W. Hachem, "Snake: a Stochastic Proximal Gradient Algorithm for Regularized Problems over Large Graphs", CAP 2017, Grenoble, France.
  • C. Meillier, P. Bianchi, and W. Hachem, "Two distributed algorithms for the deconvolution of large radio-interferometric multispectral images", EUSIPCO 2016, Budapest, Hungary.
  • A. Salim, P. Bianchi, W. Hachem and J. Jakubowicz, "A Stochastic Proximal Point Algorithm for Total Variation Regularization over Large Scale Graphs", IEEE CDC 2016, Las Vegas, USA. Accompanying document.
  • P. Bianchi, W. Hachem and A. Salim, "Building Stochastic Optimization Algorithms with Random Monotone Operators", European Conference on Computational Optimization (EUCCO) 2016, Leuven, Belgium.
  • W. Hachem, A.L. Moustakas and L.A. Pastur, "Time and frequency selective Ricean MIMO capacity: an ergodic operator approach", IEEE ISIT 2016, Barcelona, Spain.
  • X. Mestre, P. Vallet and W. Hachem, "Asymptotic Analysis of Linear Spectral Statistics of the Sample Coherence Matrix", IEEE ICASSP 2015.
  • P. Bianchi W. Hachem and F. Iutzeler, "Linear Convergence of an Asynchronous Distributed Optimization Algorithm based on the Alternating Direction Method of Multipliers", IEEE GlobalSIP 2014, Atlanta, USA.
  • P. Bianchi, W. Hachem and F. Iutzeler "A Stochastic Coordinate Descent Primal-Dual Algorithm And Applications", IEEE MLSP 2014, Reims, France.
  • P. Bianchi and W. Hachem, "A Primal-Dual Algorithm for Distributed Optimization", IEEE Conference on Decision and Control 2014, Los Angeles, USA.
  • F. Iutzeler, P. Bianchi, Ph. Ciblat, and W. Hachem, "Linear Convergence Rate for Distributed Optimization with the Alternating Direction Method of Multipliers", IEEE Conference on Decision and Control 2014, Los Angeles, USA.
  • J. Vinogradova, R. Couillet, and W. Hachem, "Estimation of large Toeplitz covariance matrices and application to source detection", EUSIPCO 2014, Lisbon, Portugal.
  • X. Mestre, P. Vallet, and W. Hachem, "Correlation Test for High Dimensional Data with Application to Signal Detection in Distributed Sensor Networks", EUSIPCO 2014, Lisbon, Portugal.
  • F. Iutzeler, P. Bianchi, Ph. Ciblat and W. Hachem, "Asynchronous Distributed Optimization using a Randomized Alternating Direction Method of Multipliers", IEEE Conference on Decision and Control 2013, Florence, Italy.
  • J. Vinogradova, R. Couillet and W. Hachem, "A new method for source detection, power estimation, and localization in large sensor networks under noise with unknown statistics" , IEEE ICASSP 2013.
  • J. Vinogradova, R. Couillet, W. Hachem, "Nouvelle méthode de détection de sources, d'estimation de puissances et de localisation dans un système de communication sans fil avec des statistiques de bruit inconnues", Actes du colloque GRETSI, 2013.
  • F. Iutzeler, P. Ciblat, W. Hachem, and J. Jakubowicz, New broadcast based distributed averaging algorithm over wireless sensor networks, IEEE ICASSP 2012.
  • R. Couillet and W. Hachem, "Local Failure Localization in Large Sensor Networks", 45th Asilomar Conference on Signals, Systems and Computers 2011, Pacific Grove.
  • F. Iutzeler, J. Jakubowicz, W. Hachem and Ph. Ciblat, "Distributed Estimation of the Maximum Value Over a Wireless Sensor Network", 45th Asilomar Conference on Signals, Systems and Computers 2011, Pacific Grove.
  • P. Bianchi, G. Fort, W. Hachem, and J. Jakubowicz, "Sur un algorithme de Robbins-Monro distribué", GRETSI 2011, Bordeaux, France.
  • F. Iutzeler, Ph. Ciblat, W. Hachem, et J. Jakubowicz, "Estimation distribuée du maximum dans un réseau de capteurs", GRETSI 2011, Bordeaux, France.
  • P. Bianchi, G. Fort, W. Hachem, and J. Jakubowicz, "Performance Analysis of a Distributed Robbins-Monro Algorithm for Sensor Networks", EUSIPCO 2011, Barcelona, Spain.
  • P. Vallet, W. Hachem, P. Loubaton, X. Mestre and J.Najim, "On the Consistency of the G-MUSIC DoA Estimator", SSP 2011, Nice, France.
  • P. Vallet, W. Hachem, P. Loubaton, X. Mestre and J.Najim, "An improved MUSIC algorithm based on low rank perturbation of large random matrices", SSP 2011, Nice, France.
  • X. Mestre, P. Vallet, P. Loubaton, and W. Hachem, "Asymptotic Analysis of a Consistent Subspace Estimator for Observations of Increasing Dimensions", SSP 2011, Nice, France.
  • P. Bianchi, G. Fort, W. Hachem, and J. Jakubowicz, "Convergence of a Distributed Parameter Estimator for Sensor Networks with Local Averaging of the Estimates", ICASSP 2011, Prague, Czech Republic.
  • F. Rubio, X. Mestre and W. Hachem, "A CLT on the SINR of the Diagonally Loaded Capon/MVDR Beamformer, ICASSP 2011, Prague, Czech Republic.
  • A. Kammoun, M. Kharouf, W. Hachem, J. Najim, and A. El Kharroubi, "On the Fluctuations of the Mutual Information for Non Centered MIMO Channels: The Non Gaussian Case", IEEE SPAWC, Marrakech, Morocco, June 2010.
  • D. Gregoratti, W. Hachem and X. Mestre, "Orthogonal Matrix Precoding for Relay Networks", IEEE ISWPC, Modena, Italy, May 2010.
  • E. Bouton, N. Ksairi, P. Ciblat, P. Bianchi and W. Hachem, "On outage probability optimization in Rician MISO channels" IEEE WiMob, Marrakech, Morocco, October 2009.
  • N. Ksairi, P. Ciblat, P. Bianchi et W. Hachem, "Compromis diversité-multiplexage pour un protocole de relayage DF non-orthogonal", accepté au colloque GRETSI, Dijon (France), Septembre 2009.
  • N. Ksairi, P. Bianchi, Ph. ciblat and W. Hachem, "A Static Protocol to Achieve Optimal Diversity-Multiplexing Tradeoff for High Diversity Gains in Half-Duplex Relay Channels", accepted in ITW 2009, Taormina, Italy.
  • M. Nahas, A. Saadani and W. Hachem, "Performance of Asynchronous Amplify-and-Forward Cooperative Relay Networks", Globecom 2009.
  • W. Hachem, E. Moulines, J. Najim and F. Roueff, "On the Error Exponents for Detecting Randomly Sampled Noisy Diffusion Processes" ICASSP 2009, Taipei, Taiwan.
  • N. Ksairi, P. Bianchi, W. Hachem and Ph. Ciblat, "Resource Allocation for Downlink OFDMA 2D-Cellular Networks with partial frequency reuse", ISITA 2008, Auckland, New Zealand.
  • P. Bianchi, Ph. Ciblat and W. Hachem, "Outage Performance of a Novel Relaying Protocol: Decode or Quantize and Forward", ISITA 2008, Auckland, New Zealand.
  • M. Nahas, A. Saadani and W. Hachem, "On the Outage Probability of Asynchronous Wireless Cooperative Networks", VTC Fall 2008.
  • A. Kammoun, M. Kharouf, W. Hachem and J. Najim, "Fluctuations of the SNR at the Wiener Filter Output for Large Dimensional Signals", SPAWC 2008.
  • A. Kammoun, M. Kharouf, W. Hachem and J. Najim, "Outage Probability Approximation for the Wiener Filter SINR in MIMO Systems", SPAWC 2008.
  • N. Ksairi, P. Bianchi, Ph. Ciblat, and W. Hachem, "Optimal Reuse Factor and Resource Allocation for Downlink OFDMA with Multicell Interference", SPAWC 2008.
  • W. Hachem, P. Bianchi and Ph. Ciblat, "Outage Probability Optimization of Certain Wireless Relaying Protocols", ITW 2008.
  • W. Hachem, Ph. Loubaton and J. Najim, "On the Fluctuations of the Mutual Information of Large Dimensional MIMO Channels", ITW 2008.
  • W. Hachem, Ph. Loubaton et J. Najim, " Sur les fluctuations de l'information mutuelle des canaux MIMO de grandes dimensions ", Colloque GRETSI 2007, Troyes, France.
  • J. Dumont, W. Hachem, S. Lasaulce, Ph. Loubaton et J. Najim, " Quelques propriétés d'un approximant de l'information mutuelle des canaux MIMO de Rice bi-corrélés ", Colloque GRETSI 2007, Troyes, France.
  • J. Dumont, W. Hachem, S. Lasaulce, Ph. Loubaton and J. Najim, "High SNR approximations of the capacity of MIMO correlated Rician channels: a large system approach", ISIT'2007, Nice, France.
  • S. Gault, W. Hachem and Ph. Ciblat, "Performance of a Resource Allocation Strategy for an FH-OFDMA based System in a multi-cell environment", SPAWC'2006, Cannes, France.
  • A.M. Cipriano, Ph. Ciblat, S. Gault and W. Hachem, "Balanced allocation strategy in multi-user OFDM with Channel State Information at the transmitter", EUSIPCO'2006, Florence, Italy.
  • W. Hachem, Ph. Loubaton and J. Najim, "The Mutual Information of a MIMO Channel: A Survey", ISCCSP'2006, Marrakech, Morocco.
  • J. Dumont, W. Hachem, Ph. Loubaton and J. Najim, "On the Asymptotic Analysis of Mutual Information of MIMO Rician Correlated Channels", ISCCSP'2006, Marrakech, Morocco.
  • S. Gault, Ph. Ciblat, and W. Hachem, "An OFDMA Based Modem for Powerline Communication Over the Low Voltage Distribution Network", ISPLC'2005, Vancouver, Canada.
  • J. Fiorina and W. Hachem, "Trade-off between repetition factor and frame length in Time-Hopping Impulse Radio Ultra Wide Band", PIMRC'2005, Berlin, Germany.
  • J. Fiorina and W. Hachem, "Central Limit Results for the Multiple User Interference at the SUMF Output for UWB Signals", ISITA'2004, Parma, Italy.
  • B. Mouhouche, Ph. Loubaton and W. Hachem, "Asymptotic Analysis of Reduced Rank Chip-Level MMSE Equalizers in the Downlink of CDMA Systems", SPAWC'2004, Lisboa, Portugal.
  • B. Mouhouche, Ph. Loubaton, W. Hachem and N. Ibrahim, "Asymptotic Analysis of Reduced Rank Downlink CDMA Wiener Receivers", EUSIPCO'2004, Vienna, Austria.
  • A. Wautier, S. Ammari and W. Hachem, "Low Complexity Linear Detection for Asynchronous CDMA Signals Over Frequency Selective Channels", EUSIPCO'2004, Vienna, Austria.
  • S. Gault, W. Hachem and Ph. Ciblat, "Cramér-Rao Bounds for Data-Aided Sampling Clock Offset and Channel Estimation",ICASSP'2004, Montreal, Canada.
  • B. Mouhouche, P. Loubaton, W.Hachem, K. Abed-Meraim et N. Ibrahim, "Analyse asymptotique de certains filtres de Wiener à rang réduit", proposé au colloque GRETSI'2003, Paris.
  • Ph. Loubaton and W. Hachem, "Asymptotic Analysis of Reduced Rank Wiener Filters", ITW'2003, Paris, France.
  • W. Hachem, "Low Complexity Polynomial Receivers for Downlink CDMA", Asilomar Conference on Signals, Systems and Computers 2002, Pacific Grove, California.
  • L. Ouvry , W. Hachem, D. Lattard, M. Laugeois, B. Piaget, "A DSSS-CDMA Based Implementation For Powerline Communications", WTC'02, Paris, France.
  • J.-M. Chaufray, Ph. Loubaton and W. Hachem, "Asymptotical Analysis of Optimum and Sub-Optimum CDMA Downlink MMSE Receivers", ISIT'2002, Lausanne.
  • M. Debbah, W. Hachem, Ph. Loubaton and Marc de Courville, "Asymptotic Performance Analysis for Redundant Block Precoded OFDM Systems with MMSE Equalization", SSP'2001, Singapore, October 2001.
  • M. Debbah, W. Hachem, Ph. Loubaton and Marc de Courville, "MMSE Analysis of Certain Large Isometric Random Precoded Systems", ITW'2001, Cairns, Australia, September 2001.
  • W. Hachem, Ph. Loubaton, S. Marcos and R. Samy, "Multiple Access Communication Over the PowerLine Channel: a CDMA Approach", GLOBECOM'01, San Antonio, Texas, November 2001.
  • W. Hachem, F. Desbouvries and Ph. Loubaton, "Blind Channel Estimation for CDMA Systems: An Induced Cyclostationarity Approach", ICASSP'2000, Istanbul, Turkey, June 2000.
  • W. Hachem, F. Desbouvries and Ph. Loubaton, "Un algorithme d'identification autodidacte multi entrée / multi sortie en présence de bruit corrélé spatialement", Actes du Colloque GRETSI'99, Vannes, France, September 1999.
  • W. Hachem, F. Desbouvries and Ph. Loubaton, "On the Identification of Certain Noisy FIR Convolutive Mixtures", ICA'99, Aussois, France, January 1999.




Some presentations


Les grandes matrices aléatoires : un aperçu historique, GRETSI, Nancy, 2022.

Information mutuelle de canaux radio et opérateurs de Jacobi ergodiques, GRETSI, Lille, août 2019.

Spectres de grandes matrices aléatoires non hermitiennes : bases et quelques applications, Journées MAS, Dijon, août 2018.

Opérateurs monotones maximaux et approximation stochastique, GdR ISIS, journée sur l'optimisation en milieu aléatoire, Paris, novembre 2017.

The mutual information of a MIMO non-centered time and frequency selective channel: an ergodic operator approach, Random matrix theory and statistical physics workshop, Institut Henri Poincaré, Paris, November 2014.

Grandes matrices aléatoires de Wishart : fluctuations et indépendance asymptotique aux bords du spectre, Journées MAS, Toulouse, septembre 2014.

Asynchronous distributed optimization using a randomized ADMM algorithm, November 2013.

Fixed Rank Perturbations of Large Random Matrices: Methodology and Some Statistical Applications, Institut Henri Poincaré, Paris, March 2012.

A mini course on the "Applications of Large Random Matrices to Digital Communications and Statistical Signal Processing" given at EUSIPCO 2011, Barcelona, with Ph. Loubaton and J. Najim.


LIGM| ORCID iD iconorcid.org/0000-0001-8499-2761