Flexible Multicarrier Waveforms for Future Communications Wireless Networks

Organizers: Dr Faouzi Bader (SUPELEC),  Dr Adrian Kliks (PUT)

Where and When: 21-23 May 2014 SUPELEC, Campus of Rennes-France

Dear All

It is our greatest pleasure to invite every interested Researchers and students to participate in the upcoming NEWCOM# summer school that will take place in beautiful and famous French city, Rennes, at the SUPELEC premises. 

The goal of that event is to discuss and investigate recent achievements in the very important and vivid research area devoted for future multicarrier systems. Currently, OFDM plays a role of the leader in practical realizations of multicarrier signaling, however it suffers from various limitations, raised by the researchers and manufacturers for many years. Filter Bank Multicarrier based solutions tend to become the successor of OFDM in the context of future wireless and even wired communications systems. During the three days long event all Participants will be acquainted with the arcane of the new modulations formats, covering not only the theoretical analysis and discussion, but also the debate on the hardware implementation issues.

You are kindly invited to read through this flyer, where you will find all answers to any bothering question regarding the organizational aspects of the school. However, if you have any other questions, do not hesitate and send us an email ( faouzi.bader@supelec.fr, and akliks@et.put.poznan.pl) 

We are looking forward to seeing you in Rennes this May!

Faouzi Bader and Adrian Kliks

TITLES of the talks

Tutorial1  – Faouzi Bader, Adrian Kliks – New modulation formats for future wireless systems

Tutorial2  – Jerome Louveaux – Single and multi-antenna receivers for FBMC transmission

Lecture 1 –  “5G New Air Interface based on Non-Orthogonal Waveforms” by Dr. Gehard Wunder, Fraunhofer Heinrich-Hertz-Ins!tut in Berlin-Germany

Lecture 2 – “An overview of mul!carrier modula!ons: From OFDM to its many variants” by Dr. Pierre Siohan, Orange-Labs, Rennes-France

Lecture 3 – “Fast-Convolu!on Based Flexible Mul!mode Communica!on Waveform Processing” by Prof. Markku Renfors, Tampere University of Technology, Tampere-Finland

Lecture 4 – “Filter bank techniques in communica!ons: deployment issues and perspec!ves” by Prof. Maurice Bellanger, CNAM, FRANCE

Lecture 5 – “Effect of channel frequency selec!vity on filterbank mul!carrier modula!ons” by Dr. Xavier Mastre, CTTC, Barcelona, Spain

Lecture 6 – “Flexible multicarrier waveforms: implementa!on issues and baseband processing technologies” by Dr. Nikolaos Bartzoudis, CTTC, Barcelona-Spain

Lecture 7 – Hao Lin, Marc Lanoiselée, Pierre Siohan, ” FBMC/OQAM Orange Labs Pla$orms” , Rennes-France


N# Spring School will be organized at SUPELEC Rennes:

École Supérieur d’Électricité- SUPELEC

Avenue de la Boulaie CS 47601

F-35576 Cession-Sévigné

Rennes- France


About Rennes 

Rennes, a city in northwestern France, is the capital of the Brittany region as well as the Ille-et-Vilaine department. It has a long history due to its location at the confluence of the Ille and the Vilaine rivers. With about 220,000 inhabitants, Rennes has virtually the same population as its sister city, Rochester, NY. According to the 2010 census, Rennes is the third fastest-growing metropolitan area in France. The city’s residents are known as Rennais. There are many museums, fine art galleries, churches and cathedrals, historical buildings, parks, and shopping opportunities to please anyone who visits this beautiful city.

For more information about Rennes, visit:

www.metropole.rennes.fr      http://www.tourisme-rennes.com/en/home.aspx

Accommodation information:

Novotel Rennes(Near to Rail station)***,

Mercure Hotel Rennes Center***

Hotes des Lices (downtown) ***,

Mercure Rennes Place Bretagne (near to Republic Square)*

For additional Hotels, please click on the following link:*



By Train:

Rennes has well-developed national road, rail, and air links and a metro line that opened in 2002. The city’s train station offers high-speed train (TGV) service to and from Paris’s Montparnasse Rail Station. Once at Rennes rail station you can either take a taxi to SUPELEC (approximative rate is about 15€ to 20€ depending on the traffic jam), or you can take the Subway located in the proper rail station, direction “J.F. Kennedy” , and stop  at “Place de la République”. Then at “Place de la République” (Republic Square) take the bus “N° 4” or “N° 40 express” direction  “Beaulieu Atalante” and stop at the last bus station ” Clos Courtel” see the entrace of SUPELEC in attached. 

By Plane

Rennes–Saint-Jacques Airport or Aéroport de Rennes–Saint-Jacques is an airport about 6 km southwest of Rennes. It is a national and international airport, open to regular and irregular flights, and to both private and passenger plans. The main runway can handle airplanes with up to around 180 passengers. You can take a taxi directly to SUPELEC or your Hotel destination.

By Car

Rennes–Saint-Jacques Airport or Aéroport de Rennes–Saint-Jacques is an airport about 6 km southwest of Rennes. It is a national and international airport, open to regular and irregular flights, and to both private and passenger plans. The main runway can handle airplanes with up to around 180 passengers. You can take a taxi directly to SUPELEC or your Hotel destination.


European Credit Transfer and Accumulation System (ECTS) is a standard for comparing the study attainment and performance of students of higher education across the European Union and other collaborating European countries. Two (2) ECTS credits will be awarded by SUPELEC (France) to students provided that they actually attended the NEWCOM# Spring School. 

In order to receive the two ECTS credits, besides the every day attendance, each student have to pass a test. The test consist in writing a report (at least 4 pages including your Name and Surname and your institution information) where he/she expose his/her synthesis on topics presented during the tutorial days (you can focus your report on selected topics) and explain how it can help you in your own research by exposing some potential new contributions.


Etudiant/Student (avant/before 25th Avril/April): 110,00 €
Non étudiants/Non Student (avant/before 25th Avril/April): 130,00 € 
Etudiant/Student (apr?s/after 25th April): 130,00 €
Non étudiants/Non Student (Apr?s le/After 25th Avril/April) 150,00 €
VAT included 

The registration file must be sent signed, scanned, with a copy of the bank transfer receipt in case the applicant chose the bank transfer procedure to: Karine Bernard < Karine.Bernard@supelec.fr>.

Registration Form (pdf version)

Registration Form (word version)

Abstracts and Bios of the lecturers:

Faouzi Bader, SUPELEC – Campus of Rennes, Brittany-France

 New modulation formats for future wireless systems

Faouzi Bader received the PhD degree (with Honours) in Telecommunications in 2002 from Universidad Politécnica de Madrid (UPM), Madrid, Spain. He joined the Centre Technologic de Telecomunicacions de Catalunya (CTTC), Barcelona-Spain as research associate in 2002. From 2006 to May 2013, he has been Senior Research Associate at CTTC. Since June 2013, he is Associate Professor at Supélec in Rennes-France. His research activities mainly focus on IMT-Advanced systems, cross layer system design, multicarrier waveforms (OFDM(A), (non-) uniform multimode filter based multicarrier schemes) and frequency allocation in relay cognitive environment. He has been involved in several European projects from the 5th-7th EC research framework, dealing with resource management in multicarrier transmission techniques for integrated broadband in cellular systems, and physical layer for dynamic spectrum access and cognitive radio.

He has published over 90 papers in peer-reviewed journals and international conferences, and more than 13 book chapters. He served as Technical Program Committee member in major IEEE ComSoc and VTS conferences. He acts as reviewer for several journals and magazines among them; IEEE Communications Magazine, IEEE Vehicular Technology Magazine (VTM), IEEE Transactions on Vehicular Technology, IET Communications, EURASIP journal on Wireless Communications and Networking, and EURASIP Journal on Advances in Signal Processing, and Transactions on Emerging Telecommunications -ET T. He is IEEE Senior Member  from 2007.

Adrian Kliks, Poznan University of Technology

New modulation formats for future wireless systems

Adrian Kliks received his M.Sc. and PhD degree in Telecommunication from Pozna? University of Technology in 2005 and 2011, respectively. Since 2005 he was employed at the Institute of Electronics and Telecommunications, and since 2011 he works in the position of assistant professor.

His research interests cover the wide spectrum of wireless communications. In particular he is interested in multicarrier (both orthogonal and non-orthogonal) systems, in the area of cognitive radios, small-cells and in radio-planning. He was involved in preparation of national and international conferences, such as European Wireless 2012 conference (April 2012, Poznan, Poland), as well as workshops like CRAFT workshop at ISWCS 2013 and MACNET workshop at PIMRC2013. Currently he acts as one of the organizers of the workshop at IEEE WCNC 2014 (Istanbul, Turkey) on Interference and Design Issues for Future Heterogeneous Networks. For 9 years dr Adrian Kliks is a member of IEEE, and from 2012 he reached the status of IEEE Senior Member. He was/is involved in industrial and international projects (like ICT-URANUS, NoE NEWCOM++, NEWCOM#, COGEU, ACROPOLIS, COST Action IC-0902, COST-Terra), where he also acts/acted as the task leader. Within these projects he was awarded with international exchange grants (realized in University of Pisa and CTTC in Barcelona). He acts/acted also as a reviewer for various journals (e.g., IEEE Transactions on Wireless Communications, Wireless Personal Communications) and conference papers (e.g. IEEE Globecom, IEEE PIMRC, IEEE ICC, IEEE VTC). He organized various special sessions at international conferences (like CrownCom, WSA, Eusipco). Currently, he participates actively in working groups established for definition of IEEE 1900.x standards on cognitive radio. He is also the leading guest editor of the Special Issue on future heterogeneous networks that will be published at EURASIP Journal on Wireless Communications and Networking. From 2014 he acts as the Membership Development/Web Visibility Chair at the IEEE ComSoc Europe Middle East Africa (EMEA) region.

Gerhard Wunder – Fraunhofer Heinrich-Hertz-Ins!tut in Berlin-Germany

5G New Air Interface based on Non-Orthogonal Waveforms

This seminar/talk discusses the latest findings on new waveforms for the phyiscal layer of a 5G New Air Interface summarizing also the latest results of the EC FP7 project 5GNOW. We start with an overview of potential scenarios where new waveforms will really make a difference for 5G. This will include massive machine-type or ultra-low delay communication which are intriguing new scenarios for the Internet of Things market or other new applications. In the second part we will discuss new waveforms and their specific advantages and disadvantages and relate them also to the application requirements introduces before. Specifically, we will discuss actual receiver implementations for these settings. This will serve as an overview of current proposals for 5G (and who is proposing it). In the third part we will find common ground for these waveforms by introducing the Gabor time-frequency signaling context. In this course we will re-discover the waveforms and corresponding properties in this general context. In particular we will present approaches to deal with pulse-shaping, spectral and temporal fragmentation, performance estimation etc. from a theoretical point of view and apply it to the specific settings. Thereby we introduce known and new techniques for performance evaluation. In the final part we elaborate on system aspects of new waveforms particularly link-to-system interfaces for system simulation and draw conclusions regarding the roadmap to 5G.

Gerhard Wunder (M’05, Editor IEEE TWC) studied electrical engineering at the University of Hannover, Germany, and the Technical University (TU) Berlin, Germany, and received his graduate degree in electrical engineering (Dipl.-Ing.) with highest honors in 1999 and the PhD degree (Dr.-Ing.) in communication engineering on the peak-to-average power ratio (PAPR) problem in OFDM with distinction (summa cum laude) in 2003 from TU Berlin. In 2007, he also received the habilitation degree (venia legendi) and became a Privatdozent at the TU Berlin in the field of detection/estimation theory, stochastic processes and information theory. Since 2003 he is heading a research group at the Fraunhofer Heinrich-Hertz-Institut in Berlin working in close collaboration with industry on theoretical and practical problems in wireless communication networks particularly in the field of LTE-A systems. He is a recipient of research fellowships from the German national research foundation (DFG). Currently, Dr. Wunder is coordinator and principal investigator both in the FP7 Call 8 project 5GNOW (www.5gnow.eu) supported by the European Commission as well as PROPHYLAXE (www.ict-prophylaxe.de) the largest IoT physical layer security project supported by the German Ministry of Education and Research. He also receives currently funding in the DFG Schwerpunktprogramm 1397 COIN (Communications in Interference Limited Networks). 

In 2000 and 2005, he was a visiting professor at the Georgia Institute of Technology (Prof. Jayant) in Atlanta (USA, GA), and the Stanford University (Prof. Paulraj) in Palo Alto/USA (CA). In 2009 he was a consultant at Alcatel-Lucent Bell Labs (USA, NJ), both in Murray Hill (S. Stolyar) and Crawford Hill (R. Valenzuela). He was a general co-chair of the 2009 International ITG Workshop on Smart Antennas (WSA 2009) and a lead guest editor in 2011 for a special issue of the Journal of Advances on Signal Processing regarding the PAPR problem of the European Association for Signal Processing. Since 2011, he is also an editor for the IEEE Transactions on Wireless Communications (TWireless) in the area of Wireless Communications Theory and Systems (WCTS). In 2011 Dr. Wunder received the 2011 award for outstanding scientific publication in the field of communication engineering by the German communication engineering society (ITG Award 2011). He is the author of the two recent articles in the IEEE Signal Processing Magazine, on the PAPR problem, and the IEEE Comm. Magazine, 5G special issue which is to appear in Feb. 2014.

Dr. Pierre Siohan – Orange-Labs, Rennes-France

 An overview of multicarrier modulations: From OFDM to its many variants

OFDM has become an essential technological component in the beginning of the nineties. Since then, due to its nice features: fast implementation algorithms and simple equalization scheme, it has been adopted in various wired and wireless standards, including leading applications: ADSL, DVB-T, WiFi, Wimax, LTE, etc. However, OFDM leaves room to some potential improvements, particularly with respect to its poor frequency localization. The aim of this lecture is to provide an overview of the large set of OFDM variants that can keep its initial advantages and limit its drawbacks.  The Gabor formalism offers an appropriate framework to study these different schemes. It tells us that an ideal scheme providing complex orthogonality, maximum spectral efficiency and good time-frequency localization does not exist.  Therefore the game is to achieve a better compromise than the one provided with Cyclic Prefix OFDM (CP-OFDM). In this regard, we will first review the two most important alternatives, namely the OFDM combined with Offset QAM constellation and the oversampled OFDM also known as Filtered MultiTone (FMT). In practice, both systems can be built using filter banks, hence the acronym Filter Bank MultiCarrier (FBMC). These FBMC schemes take advantage of polyphase network (PPN) implementations of their prototype filters. Until recently the current practice for this filtering operation was based on the linear convolution form. Since the recent introduction of the Generalized Frequency Division Multiplexing (GFDM) scheme and its circular convolution implementation, things have changed. In this respect, in addition to the CP-OFDM, FBMC/OQAM and FMT schemes, our analysis will include circular convolution-based schemes with GFDM, coded-block FMT (CB-FMT) and weighted cyclic-prefix circular OFDM/OQAM (WCP-OQAM). Furthermore, we will also take into account a very recent proposal named Universal Filtered MultiCarrier (UFMC). Not all these different schemes have yet acquired the degree of maturity required by the high level requirements of future communication systems, as e.g. those related to the Internet of Things for the 5G. Nevertheless, we can already draw up a first comparison of all these multicarrier modulation schemes.  Our, non exhaustive, list of relevant comparison criteria will include the orthogonality features, for back-to-back systems and also in the presence of a multipath transmission, the waveform flexibility, the spectral efficiency, the power spectral density.  This first global picture will illustrate the strength and weaknesses of each scheme and will help to emphasize some open problems to solve to get as close as possible from the non-existing universal ideal scheme. 

Dr. Pierre Siohan (IEEE SM 1999) received the PhD degree from the École Nationale Supérieure des Télécommunications (ENST), Paris, France, in 1989. In 1977 he joined the Centre Commun d’Études de Télédiffusion et Télécommunications (CCETT), Rennes, where his activities were first concerned with the communication theory and its application to the design of broadcasting systems. Afterwards, he was in charge of the CCETT Mathematical and Signal Processing Group.  From September 2001 to September 2003, he took a two-year sabbatical leave, being directeur de recherche with the Institut National de Recherche en Informatique et Automatique (INRIA), Rennes. Now, he is Expert in Access Networks at Orange. His current research interests are in signal processing for communication, especially for radio and power line communication systems. Dr. Siohan has authored 31 papers in refereed international journals, 30 patents and 90 papers in international conferences. Recently, he was a guest editor of the special issue on “Filter Banks for Cognitive Next Generation Multicarrier Wireless Communications,” which appeared in 2010 EURASIP ASP journal.

Jerome Louveaux – Professor at ICTEAM, Université catholique de Louvain

 Single and multi-antenna receivers for FBMC transmission

FBMC (filter-bank based multicarrier) modulations, and in particular FBMC/OQAM (Offset quadrature amplitude modulation), are considered as a potential candidate for 5G as well as cognitive radio applications. FBMC/OQAM offers high spectral efficiency and a very low out of band emission which is particularly useful when considering the coexistence of multiple asynchronous systems. On the other hand, it generates a specific interference structure which may  require complex receivers to be dealt with, especiall in the MIMO (multiple input multiple output) case. In this tutorial, we present an overview of the state-of-the-art equalizers for FBMC/OQAM both in single antenna and multi-antenna cases. Then, we provide a comparison of the interference between asynchronous systems for OFDM and FBMC systems, showing the advantage of the latter.  The first part addresses the issue of equalization. Starting with single antenna receiver, we present different equalization structures with various levels of complexity to deal with various levels of channel frequency selectivity: simple one-tap equalization,  frequency sampling approach, MMSE fractionnaly spaced equalizer, decision-feedback equalizer, and multi-stage interference cancellation. We then show how these  methods can be extended to the multi-antenna case when dealing with spatial multiplexing transmission. The issue with Alamouti coding (or in space-time coding in general) for FBMC is explained, and an overview is given of currently available alternatives. Then, the influence of asynchronous coexitsing systems is analyzed in more detail for both OFDM and FBMC modulations. A unified framework is presented, using a family of interference tables that model the correlation between a given interfering subcarrier and the victim one. The tables are shown for OFDM and FBMC, then the impact of the  asynchronous interference on the average error rate and the average spectral efficiency is addressed. Simple new expressions for the exact evaluation of the average error rate and the average spectral efficiency are derived that significantly reduce the computational complexity for performance evaluation.

Jerome Louveaux received the electrical engineering degree and the Ph. D. degree from the Université catholique de Louvain (UCL), Louvain-la-Neuve, Belgium in 1996 and 2000 respectively.  From 2000 to 2001, he was a visiting scholar in the Electrical Engineering department at Stanford University, CA. From 2004 to 2005, he was a postdoctoral researcher at the Delft University of technology, Netherlands. Since 2006, he has been an Associate Professor in the ICTEAM institute at UCL.  His research interests are in signal processing for digital communications, and in particular: multicarrier modulations, xDSL systems, resource allocation and synchronization/estimation. Prof. Louveaux was a co-recipient of the “Prix biennal Siemens 2000” for a contribution on filter-bank based multi-carrier transmission and co-recipient of the the “Prix Scientifique Alcatel 2005” for a contribution in the field of powerline communications.

Markku Renfors – Tampere University of Technology, Tampere-Finland

 Fast-Convolution Based Flexible Multimode Communication Waveform Processing

This presentation focuses on a special implementation scheme for multirate filter banks which is based on fast-convolution (FC) processing. The basic idea of fast convolution is that a high-order filter can be implemented effectively through multiplication of sequences in frequency domain, after taking DFT’s of the input sequence and the filter impulse response. Eventually, the time domain output is obtained by IDFT. Commonly, efficient implementation techniques, like FFT/IFFT, are used for the transforms, and overlap-save processing is adopted for processing long sequences.

The application of FC to multirate filters is rather well known in the literature and FC implementations of channelization filters for wireless communication systems have been considered in a few papers. The idea of FC-implementation of nearly perfect-reconstruction filter bank systems, with applications in filter bank multicarrier waveforms, has been introduced only recently. This fast-convolution filter bank (FC-FB) idea appears competitive in terms of computational complexity when compared to the polyphase and other traditional implementation structures of uniform filter banks. Furthermore, FC-FB offers high degree of flexibility to support simultaneous processing of different or differently parametrized communication waveforms. FC processing can also be used for implementing the synchronization functions needed to support simultaneous processing of non-synchronized communication waveforms. This is an important feature since asynchronous FDMA operation has abeen seen as an important ingredient in the future wireless system developments.

The lecture starts by introducing the fast-convolution principle for multirate filtering and filter banks. Then a linear periodically time-variant (LPTV) model is introduces as an efficient tool for analysis and optimization of FC-filters and filter banks. Also possibilities to combine channel equalization and synchronization functions with FC-processing structure are described. Along the way, examples about the use of FC-FB for multimode waveform processing are given, considering a fragmented spectrum use scenario with coexisting broadband and narrowband communication systems.

Markku Renfors received the Dr. Tech. degree from Tampere University of Technology (TUT), Tampere, Finland, in 1982. Since 1992, he has been a Professor with the Department of Electronics and Communications Engineering, TUT, where he was Department Head from 1992 to 2010. Dr. Renfors is a Fellow of IEEE and recipient of the 1987 IEEE Circuits and Systems Society’s Guillemin-Cauer Award (together with Tapio Saramäki). His research interests include filter bank based multicarrier systems and signal processing algorithms for flexible communications receivers and transmitters. In 2008-10 he participated actively in the EU FP7 project PHYDYAS developing FBMC techniques for dynamic spectrum access and cognitive radio. Currently he the Technical manager of the European Union 7th Framework Programme project Enhanced Multicarrier Techniques for Professional Ad-Hoc and Cell-Based Communications (EMPhAtiC)  developing advanced filter bank based waveforms and signal processing  techniques for dynamic spectrum access and heterogenous radio environments.

Maurice Bellanger – CNAM, FRANCE

Filter bank techniques in communications: deployment  issues and perspectives

The potential of filter bank multicarrier (FBMC) as an alternative and/or complement to OFDM in some scenarios of future communication networks is discussed. In a first part, the relative merits of the two multicarrier schemes are reviewed and  deployment issues are detailed. Delay, equalization, complexity, MIMO, asynchronous access and multiuser scenarios are considered. Then, the frequency domain approach for the FBMC receiver is presented, with emphasis on its capabilities for channel equalization and carrier frequency offset compensation. In a second part, the specific aspects of the introduction of FBMC in wireless networks are reviewed: bursts, pilots, single carrier mode, coordinated multipoint. Some opportunities in future mobile networks are pointed out, such as lean carrier and direct mode. Standardization is part of the process and a strategy for FBMC is proposed. To conclude, research needs are summarized and future directions are suggested.

Maurice Bellanger graduated from ENST (Ecole Nationale Supérieure des Télé-communications), Paris, in 1965 and received the doctorate degree from the university of Paris in 1981. He joined the company Philips Communications in France in 1967 and, since then, he has worked on digital signal processing and applications in telecommunications. 

In 1991, he joined CNAM (Conservatoire National des Arts et Métiers), a public education and research institute, as a professor of electronics. He is now emeritus professor.

From 2008 to 2010, he was the coordinator of the European Research FP7-project “Physical Layer for Dynamic Spectrum Access and Cognitive Radio”-PHYDYAS (http://www.ict-phydyas.org/).

Elected a Fellow member of the IEEE in 1984, for contributions to the theory of digital filtering and the applications to communication systems, he was the technical program chairman of the conference ICASSP’82 in Paris. He was the president of EURASIP, the European Association for Signal Processing, from 1987 to 1994 and the chairman of the France section of URSI (Union Radio Scientifique Internationale) from 2006 to 2008. He is a member of the French Academy of Technology.

Xavier Mestre – CTTC, Barcelona, Spain

 Effect of channel frequency selectivity on filterbank multicarrier modulations

Filterbank multicarrier modulations are typically designed so that the transmission channel is approximately flat inside each subcarrier bandwidth. When this is the case, classical single-tap per-subcarrier equalization can be used to recover the originally transmitted signal with very little effort and complexity. However, when the channel becomes strongly frequency selective, the flatness hypothesis inside each subcarrier bandwidth can no longer be sustained, and the signal recovered with a single-tap per-subcarrier equalizer becomes seriously distorted.

In this talk we will show how to characterize this distortion in practical scenarios, and we will study the relationship between this distortion, the channel frequency response and the pulse shape used as prototype in the FBMC modulator/demodulator. The concepts can be applied to a wide range of FBMC modulations, our focus will mainly be on OQAM/FBMC. In particular, for this type of modulation we will show that, when perfect reconstruction conditions hold, the residual distortion becomes proportional to a pulse-specific quantity that can be optimized regardless of the channel response. Conversely, when perfect reconstruction conditions do not hold, we will see that the distortion depends on several quantities related to the channel frequency response.

In the second part of this talk, we will study several equalization schemes that have traditionally been proposed in the literature in order to overcome the effect of the strong channel frequency selectivity, including multi-tap per-subcarrier equalizers and multi-tap multi-band equalizers. We will also present a multi-stage equalization scheme based on a Taylor approximation of the system frequency response that can achieve an extremely good performance with moderate computational complexity.

In the last part of the talk, we will generalize the above concepts to multi-antenna spatial multiplexing configurations, where several symbol streams are transmitted in parallel using frequency-selective precoding at the transmitter and linear receivers at the receiver. For this particular scenario, we will show how the distortion effect caused by the strong channel frequency selectivity becomes especially harmful due to the superposition of the multiple parallel streams, and we will present generalized pre-coding/equalization architectures that specifically deal with this MIMO setting. 

Xavier Mestre received the MS and PhD in Electrical Engineering from the Technical University of Catalonia (UPC) in 1997 and 2002 respectively and the Licenciate Degree in Mathematics in 2011. During the pursuit of his PhD, he was awarded the 2002 Rosina Ribalta second prize for the best doctoral thesis project within areas of Information Technologies and Communications by the Epson Iberica foundation. From January 1998 to December 2002, he was with UPC’s Communications Signal Processing Group, where he has worked as a Research Assistant and has participated actively in the European-funded projects. In January 2003 he joined the Telecommunications Technological Center of Catalonia (CTTC), where he currently holds a position as a Senior Research Associate and is head of the Advanced Signal and Information Processing Department. During this time, he has actively participated in multiple European projects and several contracts with the local industry. He is currently the coordinator of the ICT project EMPhAtiC, which deals with enhanced multicarrier techniques for professional mobile radiocommunications. He has been associate editor of IEEE Transactions on Signal Processing, 2007-2011 and he is currently a member of the IEEE Sensor Array and Multichannel Technical Committee

Nikolaos Bartzoudis – CTTC, Barcelona-Spain

Flexible multicarrier waveforms: implementation issues and baseband processing technologies

The forthcoming generation of wireless communication systems, usually denoted as 5G, promises to resolve the ever increasing data traffic demand and exploit more efficiently the available spectrum at a lower energy cost. A number of technological innovations will have to be introduced at the PHY-layer of 5G wireless communication systems, in order to yield the required performance and adaptivity at a low-energy footprint. This talk will focus on implementation and technology aspects of 5G systems with special attention to new flexible multicarrier waveforms that are candidates for 5G systems. Such waveforms are typically based on bit-intensive digital signal processing algorithms (e.g., filter banks) and are currently developed and evaluated in the framework of EC-funded projects (e.g., “5Gnow” and “EMPhAtiC”). In order to leverage the benefits of such broadband communications making opportunistic use of fragmented spectrum, it is required to achieve software-like adaptation with hardware-like performance (using dedicated co-processors). Different baseband processing ICs and design methodologies are available towards this end. System-on-Chips (SoCs) enclose in the same silicon die hardware co-processors together with embedded multi-core processors, memory resources and hardware-accelerated peripheral I/O cores. Hence SoCs are able to combine software-defined radio (SDR) flexibility and hardware accelerated performance, satisfying likewise a trade-off of the mentioned requirements at an affordable energy cost. A review of SoC technologies and solutions suitable for prototyping and validating flexible multicarrier waveforms will be covered in this talk.

Nikolaos Bartzoudis obtained his B.S.C.. in Electronic Engineering at the Technical Educational Institute of Thessaloniki (Greece, 2000). He then pursued postgraduate studies in the UK and received his M.Sc. degree (in Digital Communication Systems) and Ph.D. degree (in dependable embedded systems) from Loughborough University in 2001 and 2006 respectively. Nikolaos has worked as a Research Assistant (Loughborough University, 2001-2003) and Senior Research Officer (University of Essex, UK, 2005-2007) in FPGA-based embedded processing for high-end communication systems, before joining CTTC (January 2008) to work as a senior engineer in real-time baseband implementations for OFDM-based systems. At CTTC, Nikolaos was promoted to Research Associate (October 2008) and to Senior Researcher (April 2013) and served as coordinator of the GEDOMIS testbed (04/2008 to 04/2013). Nikolaos was nominated head of CTTC’s PHYCOM department in April 2013. His duties as technical team leader include FPGA-based baseband prototyping and lab-testing of spectral and energy efficient communication systems. On top of that, Nikolaos is involved with project management, supervising (1 PhD thesis) and various other academic activities (writing and reviewing scientific articles, conference TPC member, PhD thesis examiner). Nikolaos has coordinated 2 R&D projects and participated in 10 others over the past 12 years.

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