Archives des séminaires

Le 01/02/2018 Séminaire général Comelec : Ali Khalighi (Institut Fresnel)

Auteur(s) & Affilliation(s) du séminaire :

Ali Khakighi, Ecole Centrale Marseille & Institut Fresnel

Présentation du séminaire :

Potential of Optical Wireless Technology in Addressing Spectrum Requirements in Future Smart environments

Jeudi 1er février 2018, 14 H, Amphi Emeraude, télécom ParisTech, 46 rue Barrault, Paris 13

Optical wireless communications (OWC) in the infrared and visible spectra have recently received particular attention due to their potential in providing very high-rate data transmission in various indoor and outdoor application scenarios. This seminar provides an overview on this transmission technology and the challenges in the deployment of such links. We start by briefly presenting the principles of free-space optical communications (FSO) in outdoor applications and reviewing their most important practical limitations. We then consider the emerging field of visible-light communications (VLC) and explain their potential in enabling wireless connectivity in indoor and underwater applications. For the former context (e.g. in smart home applications), the main challenge concerns the limited modulation bandwidth and dynamic range of the commercial LEDs, which are supposed to replace the traditional luminaries in the near future. In the underwater context, on the other hand, the main limitation arises from the high attenuation of the aquatic channel, which seriously affects the attainable transmission range. We discuss the other factors affecting the data transmission rate and the link robustness, and the existing implementation challenges.

Contact(s) :

Sibille Alain

Document(s) :

Le 19/01/2018 [ComNum's seminar] Bent functions and difference sets

Auteur(s) & Affilliation(s) du séminaire :

Prof. Jim Davis

Présentation du séminaire :

in C46 at 11am

Abstract:

There are 99,270,589,265,934,370,305,785,861,242,880 8-variable bent functions. Current construction methods only explain about 1 in a million of these. I will give a gentle introduction to bent functions and difference sets, and I will describe a construction method from difference sets that can be applied to bent functions to achieve “new” 8-variable bent functions (bent functions that don’t currently have a known construction method). We will conclude with many open questions

Bio:

Jim Davis, Professor of Mathematics at the University of Richmond since 1988, does research in combinatorics and error correcting codes. He spent two years working for Hewlett-Packard and he has 15 patents stemming from that work. He has published more than 50 papers, including several with undergraduates as coauthors (one of those also has Sihem Mesnager as coauthor). Outside of mathematics, he is an avid squash and bridge player.

Contact(s) :

Le 18/01/2018  [ComNum PhD's seminar] Understanding and Designing Interaction from an Information-Theoretic Perspe

Auteur(s) & Affilliation(s) du séminaire :

Liu Wanyu

Présentation du séminaire :

in A301 at 1.30pm


Abstract :

My research lies in Human-Computer Interaction (HCI). In my thesis, I design interaction techniques and study user performance from an information-theoretic perspective, by capturing the uncertainty in the communication process and exploring the notion of combining human intelligence with machine power. Using the concepts from Information Theory and Bayesian Experimental Design, I propose BIG (Bayesian Information Gain), a framework to quantify the information sent by the user to the computer to express her intention. Two applications, BIGnav for multiscale navigation and BIGFile for hierarchical file retrieval, demonstrate how the computer can play a more active role and work together with the user to achieve shared goals. I also explore the concept of user information capacity to inform generalizable interaction designs.

Contact(s) :

Ciblat Philippe

Du 21/12/2017 au 21/12/2017 Séminaire général Comelec : the butterfly effect in semiconductor lasers: what and why ?

Auteur(s) & Affilliation(s) du séminaire :

Grillot Frédéric

Présentation du séminaire :

14H, Amphi B312, Télécom paristech, 46 rue Barrault, Paris 13

Semi-conductor lasers invented in 1962 are vital to our modern daily life. For example, they generate the optical impulses that carry ever-greater amounts of information in fiber-optic networks over great distances. The emergence of irregular and unpredictable pulsations and dynamical instabilities from a laser were first noted during the very early stages of the development of lasers. Pulses with amplitude varying in an erratic manner were reported in the output of the ruby solid-state laser. However, the lack of knowledge of what would later be termed butterfly effect i.e. deterministic chaos resulted in these initial observations being either left unexplained or wrongly attributed to noise.

This presentation will highlight the fundamental physics underpinning the butterfly effect in semiconductor lasers and also the opportunities in harnessing it for potential applications. The availability and ease of operation of semiconductor lasers, in a wide range of configurations, make them a convenient test-bed for exploring basic aspects of nonlinear and chaotic dynamics. Avenues for future research and development of quantum cascade lasers and nanoscale devices will be also discussed.

Contact(s) :

Sibille Alain

Document(s) :

Le 14/12/2017 Approche structurelle décrite en IP-XACT pour la conception basse consommation au niveau transaction

Auteur(s) & Affilliation(s) du séminaire :

Emna Gharbi

Présentation du séminaire :

Avec la complexité croissante des systèmes embarqués, la consommation d’énergie demeure un
critère crucial pour évaluer l’efficacité d’un système sur puce. Choisir une stratégie de gestion
de puissance convenable implique l’évaluation préalable de plusieurs techniques. Le niveau
ESL (Electronic System Level) semble bien approprié pour intégrer une stratégie de gestion
de puissance au modèle fonctionnel et effectuer ce type d’exploration. Toutefois, cette étape
d’extension représente une source potentielle d’erreurs qui peut altérer le comportement du
modèle initial. Nous proposons une approche structurelle pour décrire un power/clock intent
au niveau transactionnel et automatiser la génération du code de simulation SystemC-TLM/C
++ d’une stratégie de gestion de puissance. La spécification du modèle fonctionnel et des
informations relatives à la stratégie de gestion de puissance est basée sur des outils exploitant
le standard IEEE-1685 IP-XACT.

Contact(s) :

Le 14/12/2017 [ComNum PhD's seminar] Bits through queues with feedback

Auteur(s) & Affilliation(s) du séminaire :

Laure Aptel

Présentation du séminaire :

in A301 at 1pm

Abstract :

In their 1996 paper Anantharam and Verdù showed that feedback does not increase the capacity of a queue when the service time is exponentially distributed. Whether this conclusion holds for general service times has remained an open question which we address.
We will establish two main results for both the discrete-time and the continuous-time models. First, a sufficient condition on the service distribution for feedback to increase capacity under FIFO service policy. Underlying this condition is a notion of weak feedback wherein instead of the queue departure times the transmitter is informed about the instants when packets start to be served. Second, a condition in terms of output entropy rate under which feedback does not increase capacity. This condition is general in that it depends on the output entropy rate of the queue but explicitly depends neither on the queue policy nor on the service time distribution. This condition is satisfied, for instance, by queues with LCFS service policies and bounded service times.

Contact(s) :

Ciblat Philippe

Le 23/11/2017 [ComNum PhD's seminar] Energy-Latency Tradeoff in URLLC with Short-Length packets

Auteur(s) & Affilliation(s) du séminaire :

Avranas Apostolos

Présentation du séminaire :

in A301 at 1.30pm


Abstract: Emerging mobile networks (5G new radio) are envisioned to support mission-critical Internet-of-Things (IoT) applications (e.g., industrial control, automated transportation and robotics) and ultra-reliable low-latency communication (URLLC) scenarios with strict requirements in terms of latency (ranging from 1 ms and below to few milliseconds) and reliability (higher than 99.999%). This entails a fundamental paradigm shift from throughput-oriented system design towards holistic designs for guaranteed and reliable end-to-end latency. In this talk, we consider a URLLC system with short packets employing hybrid automatic repeat request (HARQ). We study the fundamental energy-latency tradeoff and analyze the energy consumption for incremental redundancy (IR) HARQ and compare it to the no HARQ case. Moreover, we derive closed-form expressions for the outage probability of IR-HARQ with both variable finite-length codewords and power. Our results show that when the feedback delay is more than half the latency constraint, it is beneficial in terms of energy to use one-shot transmission (no HARQ). This is joint work with Marios Kountouris (Huawei France) and Philippe Ciblat (Telecom ParisTech).

Contact(s) :

Ciblat Philippe

Le 16/11/2017 Séminaire général Comelec : Introduction à la chaîne de blocs (blockchain)

Auteur(s) & Affilliation(s) du séminaire :

Duc Guillaume

Présentation du séminaire :

Jeudi 16 novembre 2017, Télécom ParisTech, amphi Grenat, 46 rue Barrault, 75013 Paris

Depuis sa première utilisation en 2009 dans le Bitcoin pour empêcher la double dépense et ainsi lui permettre de devenir la première monnaie virtuelle décentralisée fonctionnelle, la chaîne de blocs (blockchain) est présentée, parfois exagérément, comme une technologie qui va révolutionner de nombreux secteurs, de l'industrie aux marchés financiers, en passant par la citoyenneté.

Ce séminaire présente le fonctionnement de base de la chaîne de blocs (liste de blocs sécurisés cryptographiquement, notion de preuve de travail et d'enjeu pour obtenir un consensus distribué sur une chaîne unique).

Contact(s) :

Document(s) :

Le 19/10/2017 [ComNum PhD's seminar] Distributed Hypothesis Testing with Collaborative Detection

Auteur(s) & Affilliation(s) du séminaire :

Escamilla Pierre

Présentation du séminaire :

in A301 at 1.30pm

Abstract:

A detection system with a single sensor and two detectors is considered, where each of the terminals observes a memoryless source sequence and where the sensor can send a message to both detectors and the first detector can send a message to the second detector. Communication of these messages is assumed error-free but rate-limited. The joint probability mass function of the source sequences observed at the three terminals depends on a binary hypothesis. The goal of the communication is that each of the two detectors can guess the underlying hypothesis. A set of achievable Type-II error exponent pairs is proposed, under the constraint that the Type-I error probabilities at both receivers are bounded by small values. The proposed set of achievable Type-II error exponents is optimal in special cases. For example when both rates of communication are 0, or when only the rate of communication from the first detector to the second is 0, the detectors have independent observations and one is testing against independence

Contact(s) :

Ciblat Philippe

Le 11/10/2017 [ComNum seminar] Layered Secrecy on Broadcast Networks

Auteur(s) & Affilliation(s) du séminaire :

Prof. Shlomo Shamaï

Présentation du séminaire :

11am in Amphi Rubis

Abstract:

We review the setting of layered secrecy, addressing the degraded broadcast channel. The basic framework facilitates for a legitimate receiver who enjoys a better channel quality (channel state information, unavailable to the transmitter)
to decode more secret messages, while the  eavesdroppers with worse channel quality are kept ignorant of more messages. While this layered based secrecy coding approach (variable-to-fixed rate secrecy coding) is evaluated for degraded channels, the strategy is relevant to general settings, though not necessarily optimal. Examples of the approach for fading channels, where the legitimate and eavesdropping channels are corrupted by multiplicative random fading gains are presented.

We use a similar paradigm of a layered approach to address secret sharing problem, where groups of users are able to determine certain secrets by sharing their channel outputs, and other groups of users are kept ignorant of certain secrets even if they share their outputs.

We also present secret capacity region results for secrecy outside of a bounded range, focusing on simple models, for which it is shown that the secret capacity requires combinations of superposition coding, binning, and embedded codes, as well as sharing designs (as rate splitting). Specific capacity results are demonstrated for the K-user degraded broadcast channel with a two level secrecy range. For this case an induction approach for the Fourier-Motzkin elimination is developed yielding the closed form capacity results.

In the concluding outlook we discuss secret communication designs for different models.

The talk is based on joint studies with S. Zou, Y. Liang, L. Lai and H.V. Poor.

Contact(s) :

Wigger Michele

Le 28/09/2017 "Controlling waves in complex media: from time reversal to wave front shaping"

Auteur(s) & Affilliation(s) du séminaire :

Geoffroy LEROSEY

Institut LANGEVIN, ESPCI Paris

Présentation du séminaire :

Séminaire général Comelec : Jeudi 28 septembre, 14 H, Télécom ParisTech, Amphi B312, 46 rue Barrault, Paris 13

In this talk I will discuss how waves can be controlled in complex media for imaging, communication or energy deposition purposes. After a brief introduction on waves in complex media, I will start by describing the concept of time reversal, a technique first developed in acoustics by Mathias Fink and later on transposed to the electromagnetic domain during my PhD. Particularly, I will explain the notion of spatial and temporal degrees of freedom offered by complex media, which are as many levers one can use to manipulate waves using arrays of sources. This will allow me to briefly review experimental works we have performed in the microwave and acoustic domains, which prove that it is possible to beat the diffraction limit from the far field using time reversal in a special subset of complex media: metamaterials. Then I will rapidly introduce the idea of wave front shaping originally proposed in the optical domain to reproduce the results obtained using time reversal at lower frequencies. This will lead me to show how, using the knowledge acquired throughout the previous works, we have proposed to move from an active control of microwaves in complex media to a passive one, using electronically reconfigurable metasurfaces as spatial microwave modulators. Finally I will rapidly discuss applications related to wireless communications, reconfigurable cavities, energy harvesting, radar and imaging.

Contact(s) :

Sibille Alain

Document(s) :

Le 31/08/2017 Securing tomorrow’s quantum computer world

Auteur(s) & Affilliation(s) du séminaire :

Adrien FACON
Secure-IC, Paris et Ecole Normale Supérieure de Paris (département d'informatique, Information Security Group)

Présentation du séminaire :

Modern information and communication systems, including cloud computing, global payment systems, e-Health, blockchain, global communications and IoT, all rely fundamentally on cryptographic. Quantum computers will decimate the cryptography we currently depend on for identification, authentication, confidentiality - and confidence. Henceforth, substantial technical development changes must occur over the following years and represent an astounding source of innovation at the crossroads of numerous scientific fields viz. Quantum Physics, Mathematics, Informatics, Electronics & Security Science, as well as new business opportunities. Although disruptive, this change of paradigm has however to be conducted in a safe and sound transition to guarantee a sufficient security level. This presentation will describe the ins and outs of this major change in the cyber security arena and present the way French academic, industrial and governmental actors are moving together for turning France into a significant international player in the post-quantum transition.

Contact(s) :

Danger Jean-luc

Document(s) :

Le 05/07/2017 [ComNum Seminar] The Gaussian Z-interference channel - To Mux or not to Mux

Auteur(s) & Affilliation(s) du séminaire :

Max Costa

Présentation du séminaire :

A301 at 10.30 am

Abstract :

We investigate the Gaussian Z-Interference channel and consider an efficient scheme to transmit information based on water filling and power controlled Gaussian signaling. In the proposed scheme, the notion of noisebergs arises, where noise power floats above signal power providing "prime space" underneath for signal power. This scheme has been shown to be the Han and Kobayashi region restricted to Gaussian signaling. We also look at the slopes at the two corner points of the region and consider the conditions when pure superposition coding is superior to multiplexing in time or frequency.


Bio:

——

Max H. M. Costa graduated in Electrical Engineering in 1974 at the University of Brasília. He received a Master degree in Electrical Engineering from the University of Campinas (Unicamp) in 1977, a Master degree in Statistics from Stanford University in 1979, and his Ph.D. in Electrical Engineering from Stanford University in 1983. 

He was a researcher at the Brazilian Institute of Space Research (INPE) from 1983 to 1988 and a member of technical staff at the General Electric Corporate Research and Development Center in Schenectady, NY, from 1988 to 1993. From 1993 to 1994 he was a senior research associate at NASA’s Jet Propulsion Laboratory. Since 1995 he has been a faculty member of the School of Electrical and Computer Engineering (FEEC) of Unicamp, currently as a professor. He was the director of FEEC from 2007 to 2011. 

He has been a visiting professor or researcher at the Katholieke Universiteit Leuven, Microsoft Research, the University of New Mexico, the Technische Universität München (TUM), the Chinese University of Hong Kong, and the Massachusetts Institute of Technology (MIT). 

He is a Life Fellow of the IEEE, a Senior Member of the Brazilian Telecommunications Society (SBrT) and a member of the IEEE Fellows Committee. He is a Senior Editor of the IEEE Journal of Selected Areas in Communications (JSAC) and an Associate Editor (Shannon Theory) of the IEEE Transactions on information Theory. He was a member of the Board of Governors (BoG) of the IEEE Information Theory Society (2010-2012) and a Distinguished Lecturer of the society (2011-2012). In the triennium 1997-2000, he was the Editor of the Journal of the Brazilian Telecommunications Society (SBrT). 

His teaching and research interests are in the areas of information theory, communications and digital signal processing with emphasis in Shannon theory, multiple user channels, information geometry, source and channel coding, digital video and optical communications. 

 

 

Contact(s) :

Wigger Michele

Le 15/06/2017 [ComNum PhD seminar] Certify the Security of Cryptographic Components with Claude Shannon

Auteur(s) & Affilliation(s) du séminaire :

De Cherisey Eloi

Présentation du séminaire :

2pm in A301


Abstract

The encryption algorithms most commonly used today (RSA, AES ...) have
been designed to be the most resistant possible against attacks such as differen-
tial analysis. In fact, an algorithm like AES is still reputed today as extremely
resistant since the only known attack to date is only five times more effective
than an exhaustive search that would take billions of years with the best proces-
sors . However, there is another way to attack a device. It is possible to exploit
temporal or electrical leaks to deduce key pieces. These attacks are known as
side-channel attacks.
The aim of our work is to make the link between side-channel and the theory
of information invented by Claude Shannon, and to study whether the usual
encryption algorithms are strong enough to deal with such attacks. We show
that the encrypting algorithms are not as appropriate as would be desired in
the face of such a threat.

Contact(s) :

Ciblat Philippe

Le 01/06/2017 Séminaire général Comelec : Décodeurs MIMO à faible complexité

Auteur(s) & Affilliation(s) du séminaire :

Rekaya - Ben Othman Ghaya

Présentation du séminaire :

 Jeudi 1er juin, 14 H, Télécom ParisTech, Amphi B312, 46 rue Barrault, Paris 13

La première partie de ce séminaire sera consacrée à un retour d’expérience sur le projet «Patent Factory MIMO», un projet en collaboration avec France Brevet. Ce projet a pour objectif l’élaboration d’un portefeuille brevet autour des décodeurs MIMO à faible complexité. C'est un sujet d’actualité étant donnée l’augmentation considérable des dimensions des systèmes d’aujourd’hui tels que le nombre d’antennes dans les systèmes sans fils, le nombre de modes et  de cœurs utilisés dans une fibre otique, et le nombre de nœuds ou capteurs dans un réseaux.

La seconde partie de ce séminaire sera dédiée à un travail réalisé dans le cadre de ce projet. Il s’agit d’un nouveau décodeur récursif, appelé « Semi-Exhaustive block MIMO decoder ». L’idée étant de diviser le système à décoder en blocs afin de réduire la dimension et par conséquent réduire de manière significative la complexité totale de décodage. A travers la dérivation de la probabilité d’erreurs, nous fixons les paramètres de notre décodeur afin d’atteindre la diversité désirée. 

Contact(s) :

Document(s) :

Le 01/06/2017 Using Event B: experiences, questions

Auteur(s) & Affilliation(s) du séminaire :

Coudert Sophie

Présentation du séminaire :

Using Event B: experiences, questions

Les méthodes formelles sont de plus en plus utilisées pour augmenter la fiabilité (sûreté, sécurité,etc) des systemes.

Ce séminaire montrera les apports, enjeux, difficultés et solutions de ces approches. Une présentation générale

sera illustrée au travers de l'exemple de la méthode "event-B" qui pose ces problématiques de façon large et

intéressante. Divers exemples d'applications seront présentés avant un bilan et quelques prospectives sur le futur.

Contact(s) :

Coudert Sophie

Le 22/05/2017 [ComNum Seminar] Coordination in Networks: An Information-Theoretic Approach

Auteur(s) & Affilliation(s) du séminaire :

Prof. Joerg Kliewer, New Jersey Institute of Technology

Présentation du séminaire :

11am in A301


Abstract:

One fundamental problem in decentralized networked systems is to coordinate activities of different nodes so that they reach a state of agreement. This global objective is typically obtained by local operations, for example, by employing gossip algorithms to achieve consensus over a set of agents, where several data exchanges are iteratively carried out between pairs of adjacent nodes. In these works the consensus is often given as a global function of all local observations, as for example an average of the same random process over all observing nodes. In contrast, we are interested in a generalization of this problem where consensus is meant in a broader sense of achieving coordinated actions by the network nodes, and therefore can be seen as an instance of distributed control in networks. This cooperative behavior is useful in a host of applications, for example in multi-agent systems for exploration of an unknown terrain, distributed surveillance applications, automatic vehicle control applications, or load balancing with divisible tasks in a large computer networks or power grids.

In this talk we address the coordination of multiagent systems over  point-to-point channels and line networks. We first investigate the problem of strong coordination over point-to-point noisy communication channels. Note that strong coordination requires that the L1 distance between the induced joint distribution of action sequences at the two nodes (A and B) by a coordination code and a prescribed joint distribution specified by the system designer must vanish exponentially fast with the block length. To this end, we first propose a joint coordination-channel coding scheme that implicitly uses channel randomness to reduce the randomness required in generating the action sequence at node B. We compare this scheme with a separate coordination-channel coding scheme which extracts channel randomness after the channel decoding stage and observe that the joint scheme is able to provide a lower communication rate compared to the separate scheme under the same amount of total injected randomness into the system. After that inner and outer bounds for the coordination capacity region for the coordination of agents along a line and in a broadcast setting are constructed. We show that for a given coordination demand the choice of the communication topology has a direct effect on the achievable rate. Finally, for point-to-point coordination a low complexity construction is presented based on polar codes which achieves a subset of the (strong) coordination capacity region.

Bio:
Dr. Joerg Kliewer received the Dipl.-Ing. (MSEE) degree in Electrical Engineering from the Hamburg University of Technology, Hamburg, Germany, in 1993 and the Dr.-Ing. degree (Ph.D.) in Electrical Engineering from the University of Kiel, Kiel,  Germany, in 1999, respectively. From 1993 to 1998 he was a Research Assistant at the University of Kiel, Germany, and from 1999 to 2004, he was a Senior Researcher and Lecturer with the same institution. In 2004, he visited the University of Southampton, Southampton, U.K., for one year, and from 2005 until 2007, he was with the University of Notre Dame, Notre Dame, IN, as a Visiting Assistant Professor. From August 2007 until December 2013 he was with New Mexico State University, Las Cruces, NM, as an as an Assistant and most recently as an Associate Professor. In January 2014 he joined the New Jersey Institute of Technology, Newark, NJ, as an Associate Professor.  His research interests span coding and information theory, graphical models, and statistical algorithms, which includes application to networked communication and security, data storage, and biology. Dr. Kliewer was the recipient of a Leverhulme Trust Award and a German Research Foundation Fellowship Award in 2003 and 2004, respectively. He was Associate Editor of the IEEE Transactions on Communications from 2008-2014 and now serves as an area editor for the same journal since 2015. He is also member of the editorial board of the IEEE Information Theory Society Newsletter since 2010 and serves as chair of the outreach committee for the same society since 2012. 

Contact(s) :

Wigger Michele

Le 05/05/2017 Flexible and cognitive optical networks enabled by coherent technologies and filterless

Auteur(s) & Affilliation(s) du séminaire :

Tremblay Christine

Professor, École de technologie supérieure, Montréal (Canada)

Présentation du séminaire :

Filterless optical networks based on coherent transceivers and passive broadcast-and-select nodes can be considered as a cost-effective and simpler alternative to active optical switching networks based on Reconfigurable Optical Add/Drop Multiplexers (ROADMs). Filterless networks are increasingly seen as very serious candidate architectures for future networks because of their main attributes (cost-effectiveness, energy efficiency), as well as its inherent gridless, elastic, multicast and cognition capabilities. Furthermore, coherent receivers equipped with digital signal processing (DSP) are foundational technologies for flexible and cognitive optical networking owing to their dynamic impairment compensation, performance monitoring and reconfiguration capabilities.

In this talk, we will review the recent progress on the design of elastic and agile filterless optical networks for terrestrial and submarine applications and present an overview of the current research activities at the Network Technology Lab aiming at leveraging the performance monitoring capability of coherent receivers for characterizing the performance dynamics in coherent optical networks and developing performance predictive models.

Biography

Christine Tremblay is a Professor in the Electrical Engineering Department of the École de technologie supérieure (ÉTS) since 2004. She is the founding researcher and head of the Network Technology Lab, an optical layer test bed composed of 19 network nodes fully equipped with 10G-100G transmission systems for research and teaching in optical communications. Her research interests include cognitive optical networks, optical performance monitoring, as well as optical layer characterization and silicon photonics. Her team introduced the filterless network concept, a step towards more flexible cost-effective and energy-efficient WDM network architectures for core and submarine network applications. Before joining ÉTS, she held senior R&D and technology management positions at Nortel, EXFO, Roctest and the National Optics Institute (INO). She has been co-instructor for two OFC hands-on short courses on fiber characterization and polarization measurements from 2009 to 2015. She is a member of two Quebec FRQNT Strategic Clusters (Center for Advanced Systems and Communications, SYTACom; Center for Optics, Photonics and Lasers (COPL), the Optical Society of America (OSA) and the IEEE Photonics Society.

Contact(s) :

Ware Cedric

Le 05/05/2017 Model-based programming of network electronic systems

Auteur(s) & Affilliation(s) du séminaire :

Andrea Enrici, Nokia)

Présentation du séminaire :

To meet the computational requirements of future 5G networks, the signal-processing functions 
of baseband stations and user equipments will be accelerated onto programmable, configurable 
and hard-wired components (e.g., CPUs, FPGAs, hardware accelerators). This urges the need to 
generate efficient implementations for such mixed architectures. Existing model-based approaches
 generate executable implementations of Systems-on-Chip (SoCs) by translating models into 
multiple SoC-programming languages (e.g., C/C++, OpenCL, Verilog/VHDL). However, these 
translations do not typically consider the optimization of non-functional properties 
(e.g., memory footprint, scheduling). This paper proposes a novel approach where 
system-level models are optimized and compiled into multiple implementations for 
different SoC architectures. We show the effectiveness of our approach with the 
compilation of UML/SysML models of a 5G decoder. Our solution generates, from a single 
Platform-Specific model, both a software implementation for a Digital Signal Processor 
platform and a hardware-software implementation for a platform based on hardware 
Intellectual Property (IP) blocks. Overall, we achieve a memory footprint reduction 
of 62% in the first case and 30% in the second case.

Contact(s) :

Apvrille Ludovic

Du 04/05/2017 au 04/05/2017 Séminaire général Comelec : Physical layer Security – technologies and perspectives

Auteur(s) & Affilliation(s) du séminaire :

François Delaveau (Thales Communications and Security)

Présentation du séminaire :

14 H, Télécom ParisTech, Amphi B312, 46 rue Barrault, Paris 13

Physical Layer Security (PHYSEC) provides means to protect the radio layer of wireless networks without pre-distributed keys, by exploiting the source of randomness built by the propagation and the reception noise of radio-communication signals. The Phylaws project (ICT-FP7 2013-16) proved that this physical source offers good randomness quality, while remaining exclusively shared among legitimate communication nodes and terminals. During this project, three PHYSEC schemes were studied, experimentally demonstrated on Wifi 802.11n/ac à 2.4 et 5 GHz, patented and published:

-    Secure Pairing (SP) of nodes and terminals, which Technology Readiness Level estimated for Wifi is 3,
-    Secret Key Generation SKG, which Technology Readiness Level estimated for Wifi is 5,
-    Secrecy Coding SC, which Technology Readiness Level estimated for Wifi is 5.

The specific interest of PHYSEC processing relies in their limited impact at the upper protocol layers of the OSI model: operating at the radio interface only, they are quite easy to implant. Thus, SKG and SC processing demonstrated in the Phylaws project for transec(*) and netsec(**) protection of 4G and WLAN nodes and terminals have been proposed for 5G standardization: they achieve a better protection of early negotiation and access protocol, enhancement of authentication, better security of messages relevant to subscriber’s identity, location, ciphering capability, etc. Nevertheless, when needed and relevant, the secret extracted at the radio interface can be propagated and exploited into higher protocol layers for further comsec(***) protections.

After a short introduction to security lacks of wireless networks and principle+theoretical performances of Physical Layer Security, this synthetic talk exposes the main processing developed and demonstrated in the Phylaws project. We also illustrate some practical application cases and performances at Wifi links.

(*) TRANSEC (Transmission Security): protection of the radio-communication signal.
(**) NETSEC (Network Security): protection of signaling messages
(***) COMSEC (Communication Security): protection of data messages.

Contact(s) :

Sibille Alain

Document(s) :

Le 20/04/2017 [ComNum PhD's seminar] Dispersion in Bursty Communication

Auteur(s) & Affilliation(s) du séminaire :

Li Longguang

Présentation du séminaire :

in A301 at 1.30pm

Abstract:

The energy and sampling constrained capacity was recently derived for bursty communication when the information is available infrequently at random times at the transmitter. Since the result depends on the asymptotical analysis, it's natural to doubt whether we can get similar conclusions in the finite length regime. In such regime, dispersion plays a key role in assessing the backoff from capacity due to finite length. We investigate the dispersion under different asynchronism settings, and establishes non-asymptotic tradeoffs between detection delay, output sampling rate, and communication rate for bursty communication. These tradeoffs imply regimes where the gap to capacity is captured by the inverse of the sampling rate rather than the usual dispersion.

Contact(s) :

Ciblat Philippe

Le 13/04/2017 [ComNum Seminar] Graph Information Ratio

Auteur(s) & Affilliation(s) du séminaire :

Prof. Ofer Shayevitz

Présentation du séminaire :

in A301 at 11am

Abstract:

Inspired by a problem of list decoding with structural constraints, we introduce a new notion of similarity between graphs, termed graph information ratio. We discuss various properties of this measure, including in particular metric structure and partial ordering of graphs, an information ratio power inequality, relations to graph homomorphism, algebraic identities and inequalities, and more. Joint work with Lele Wang (Stanford).

Contact(s) :

Wigger Michele

Le 06/04/2017 Ballooning technique enhanced with memory hotplug for QEMU/KVM guests

Auteur(s) & Affilliation(s) du séminaire :

Bielski Maciej

Présentation du séminaire :

"Ballooning technique enhanced with memory hotplug for QEMU/KVM guests"

During the seminarI will present current developments done within my PhD thesis, that is an improved memoryvirtualization in Linux/KVM, which enables dynamic regulation of diaggregated RAM resources - without guest VM restart.At the beginning the disaggregation subject will be shortlydescribed in the context of the EC H2020 DREDBOX project and then I will focus more on myinvolvement: memory ballooning and memory hotplug. Also, at the end I will probably presentshort demo.

Contact(s) :

Bielski Maciej

Du 30/03/2017 au 30/03/2017 Séminaire général Comelec : Artificial Intelligence for 5G : Challenges and Opportunities

Auteur(s) & Affilliation(s) du séminaire :

Mérouane Debbah, Mathematical and Algorithmic Sciences Lab, Huawei

Présentation du séminaire :

Jeudi 30 mars, 14H, Amphi B312, Télécom parisTech, 46 rue Barrault, paris 13

Mobile cellular networks are becoming increasingly complex to manage while classical deployment/optimization techniques  are cost-ineffective and thus seen as stopgaps. This is all the more difficult considering the extreme constraints of 5G networks  in terms of data rate (more than 10 Gb/s), massive connectivity (more than 1000000 devices per km2), latency (under 1ms) and energy efficiency (a reduction by a factor of 100 with respect to 4G network). Unfortunately, the development of adequate solutions is severely limited by the scarcity of the actual ressrouces (energy, bandwidth and space). Recently, the community has turned to a new ressource known as Artificial  Intelligence at all layers of the network to exploit the increasing computing power afforded by the improvement in Moore's law in combination with the availability of huge data in 5G networks. This is an important paradigm shift which considers the increasing data flood/huge number of nodes as an opportunity rather than a curse. In this talk, we will discuss through various examples how the recent advances in big data algorithms can provide an efficient framework for the design of 5G Intelligent Networks.

 

 

Contact(s) :

Sibille Alain

Document(s) :

Le 23/03/2017 [ComNum PhD's seminar] Relay assisted Hybrid Automatic Repeat Request (HARQ)

Auteur(s) & Affilliation(s) du séminaire :

Khreis Alaa

Présentation du séminaire :

1.30pm in A301

Abstract :

Wireless communication systems use retransmission protocols to achieve more reliable communication. The source retransmits the packets that were not successfully decoded at the destination. Another option is to use a relay for packet retransmissions. We introduce "Cooperative HARQ-II" and compare it with existing relay assisted HARQ protocols. The comparison includes performance evaluation by simulation and theoretical analysis.

 

 

Contact(s) :

Ciblat Philippe

Du 02/03/2017 au 02/03/2017 Séminaire général Comelec : RF power transmitters with high power efficiency and linearity

Auteur(s) & Affilliation(s) du séminaire :

Geneviève BAUDOIN

ESYCOM, ESIEE-Paris

Présentation du séminaire :

Jeudi 2 mars, 14 H, Télécom ParisTech, Amphi B312, 46 rue Barrault, Paris 13

RF power transmitters with high power efficiency and linearity: architectures and linearization by digital predistortion

Power Amplifiers (PA) are critical elements of radiocommunication systems because their power efficiency conditions the autonomy and cost of equipments and their linearity influences on performance of the communication. With the emergence of 5G systems, achieving a good trade-off between linearity and efficiency is becoming more crucial. New post-OFDM waveforms are proposed for 5G networks in order to improve spectral occupancy, decrease latency and facilitate asynchronous communications. However, these waveforms exhibit very high crest factors and are very sensitive to the PA non-linearities. Morever, carrier aggregation allows for very high data rate but creates new challenges for transmitters in terms of bandwidth, intermodulation, harmonics and filtering.

In that context, the presentation will be dedicated to architectures and linearization techniques for high efficiency linear transmitters.
After a short discussion on the impact of the evolution of communication systems and standards on transmitter architectures, it will give an overview of the architectures of power transmitters (Doherty, Envelop tracking, sampled architectures ...) in the context of 3G/4G/5G systems. Then it will focuss on linearization by digital predistortion: basic principles and challenges.

Contact(s) :

Sibille Alain

Document(s) :

Le 23/02/2017 [ComNum PhD's seminar] Distributed stochastic optimization

Auteur(s) & Affilliation(s) du séminaire :

Salim Adill

Présentation du séminaire :

at 1.30pm in A301

 

Abstract

This talk will be in two parts. First, I will introduce two optimization algorithms, the gradient algorithm and the proximal point algorithm from an unified point of view. Then, I will derive their stochastic version.

Contact(s) :

Ciblat Philippe

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