Energy-efficient design of (5G and beyond 5G) wireless networks

The exponential increase of wireless devices and the demand for higher communication rates has put forward the issue of sustainable growth of modern wireless communication systems. All key players in the wireless community agree that future wireless networks will be required to provide much higher datarates, but at a similar power consumption as present networks. As a consequence, a crucial challenge in future wireless networks will be the maximization of the network energy efficiency, defined as the amount of information which can be transmitted per Joule of consumed energy.

The tutorial is divided into two parts. In the first part, it will be shown how energy efficiency radio resource allocation problems are naturally modeled as a particular class of optimization problems, namely fractional problems. Next, a comprehensive overview on fractional programming theory is provided, presenting classical methods as well as the most recent advances in the field.
The second part of the tutorial will show how fractional programming can be used to develop a general optimization framework which can be applied to optimize the energy efficiency of generic wireless networks. Several practical applications of the framework will be discussed, including the main candidate technologies for 5G networks: heterogeneous networks, massive MIMO systems, multi-hop communications, multi-carrier transmissions. The talk will also show how the framework is general enough to be applied to additional settings, such systems employing physical layer security techniques. Preliminary experimental results performed by the 5G lab Germany will be presented.
Finally, the latest research directions and open issues are discussed, describing the challenges that future cellular networks pose as far as energy-efficient designs are concerned.

zapponeAlessio Zappone is a research associate at the Technische Universität Dresden, Dresden, Germany. Alessio received his M.Sc. and Ph.D. both from the University of Cassino and Southern Lazio. Afterwards, he worked with Consorzio Nazionale Interuniversitario per le Telecomunicazioni (CNIT) in the framework of the FP7 EU-funded project TREND, which focused on energy efficiency in communication networks. Since 2012, Alessio is the project leader of the project CEMRIN on energy-efficient resource allocation in wireless networks, funded by the German research foundation (DFG).
His research interests lie in the area of communication theory and signal processing, with main focus on optimization techniques for resource allocation and energy efficiency maximization. He was the recipient of a Newcom # mobility grant in 2014. Alessio currently serves as associate editor for the IEEE SIGNAL PROCESSING LETTERS and has been a guest editor for the IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS (Special Issue on Energy-Efficient Techniques for 5G Wireless Communication Systems).

jorswieckEduard A. Jorswieck received the Diplom-Ingenieur (M.S.) degree and Doktor-Ingenieur (Ph.D.) degree, both in electrical engineering and computer science, from the Technische Universität Berlin, Germany, in 2000 and 2004, respectively. He was with the Broadband Mobile Communication Networks Department, Fraunhofer Institute for Telecommunications, Heinrich-Hertz-Institut, Berlin, from 2000 to 2006. From 2006 to 2008, he was with the Department of Signals, Sensors and Systems, Royal Institute of Technology, as a Post-Doctoral Researcher and an Assistant Professor. Since 2008, he has been Professor for Communications Theory with the Technische Universität Dresden, Germany. Currently, he is principal investigator in the excellence cluster center for Advancing Electronics Dresden (cfAED) and founding member of the 5G lab Germany (

His main research interests are in the area of signal processing for communications and networks, applied information theory, and communications theory. He has authored over 85 journal papers, 11 book chapters, some 225 conference papers and 3 monographs on his research topics. Eduard was a co-recipient of the IEEE Signal Processing Society Best Paper Award in 2006 and co-authored papers that won the Best Paper or Best Student Paper Awards at IEEE WPMC 2002, Chinacom 2010, IEEE CAMSAP 2011, IEEE SPAWC 2012, and IEEE WCSP 2012. He was a member of the IEEE SPCOM Technical Committee (2008– 2013), and has been a member of the IEEE SAM Technical Committee since 2015. Since 2011 until 2015, he has been an Associate Editor of the IEEE TRANSACTIONS ON SIGNAL PROCESSING. Since 2008, continuing until 2011, he has served as an Associate Editor of the IEEE SIGNAL PROCESSING LETTERS, and until 2013, as a Senior Associate Editor. Since 2013, he has served as an Editor of the IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS.



The Massive MIMO Paradigm – Fundamentals and State-of-the-Art

The next generation wireless networks need to accommodate 1000x more data traffic and 50x more devices than contemporary networks. Since the spectral resources are scarce, particularly in bands suitable for coverage, the main improvements need to come from spatial reuse of spectrum; that is, many more concurrent transmissions are required per unit area. This is achieved by the Massive MIMO (massive multi-user multiple-input multiple output) technology, where the access points are equipped with hundreds of antennas and can serve tens of users on each time-frequency resource by spatial multiplexing.

In recent years, Massive MIMO has gone from being a mind-blowing theoretical concept to one of the most promising 5G-enabling technologies. Everybody seems to talk about Massive MIMO, but do they really mean the same thing? What is the canonical definition of Massive MIMO? What are the differences from classical multi-user MIMO technology? What are the key characteristics of the transmission protocol and why is it designed in that way? Are there any widespread misunderstandings?

This tutorial provides answers to these questions and other doubts that you might have. We begin by covering the motivation and main properties of Massive MIMO. Next, we describe basic communication theoretic results that are useful to understand the fundamental gains and limits of the technology. This is followed by a survey of the state-of-the-art on spectral efficiency, radio resource management, energy efficient network design, and the impact of hardware impairments.

bjornsonEmil Björnson has a 10-years research experience on the multi-user MIMO technology and 5 related best paper awards. He received the Ph.D. degree from the KTH Royal Institute of Technology, Sweden, in 2011. From 2012 to July 2014, he was a joint postdoc at Supélec, France, and KTH Royal Institute of Technology. He joined Linköping University, Sweden, in 2014 and is currently an Associate Professor and Docent at the Division of Communication Systems.

Dr. Björnson received the 2014 Outstanding Young Researcher Award from IEEE ComSoc EMEA and the 2015 Ingvar Carlsson Award. He is the first author of the magazine paper “Massive MIMO: Ten Myths and One Critical Question” (2016) and the textbook “Optimal Resource Allocation in Coordinated Multi-Cell Systems” (2013). He is dedicated to reproducible research and has made a large amount of simulation code publicly available.

His research interests include multi-antenna cellular communications, Massive MIMO technology, radio resource allocation, energy efficient communication, and network topology design. Since 2015 he is on the editorial board of IEEE Journal on Selected Areas in Communications (JSAC): Series on Green Communications and Networking.



Engineering wireless full-duplex nodes and networks.

A full-duplex wireless transceiver node can transmit and receive at same time and in the same frequency band. In contrast, a half-duplex wireless transceiver node cannot realize simultaneous bidirectional in-band communication. Consequently, networks where all or some of the nodes are full-duplex capable can potentially achieve higher spectral efficiency than networks were all the nodes are half-duplex. This is the main motivation for the deployment of full-duplex nodes. However, implementing full-duplex capable transceivers requires the mitigation of the self-interference signal, with a power level several orders of magnitude larger than the received power of the signal of interest coming from a distant node. Recently, different research groups have demonstrated the feasibility of substantial self-interference mitigation that enables the realization of full-duplex communications with higher spectral efficiency than half-duplex systems. These demonstrations have motivated research in the area of full-duplex wireless communications and have made full-duplex a candidate technology for next generation wireless networks. The recent increasing amount of research on full-duplex systems has resulted in a variety of methods for self-interference mitigation and of protocol designs for networks with full-duplex nodes. In this tutorial, we will present the state-of-the-art of full-duplex technology and give some insight about potential applications in future communications systems, in particular in the context of fifth-generation (5G) cellular networks and 802.11ax WLAN. The attendees will learn about the challenges that need to be overcome at the RF level, physical layer level, and network level, and about the trade-offs between performance gains and hardware complexity associated with full-duplex. The tutorial is targeted to a broad audience with the aim that attendees with different backgrounds can understand the overall challenges of full-duplex system design as well as potential benefits. There are still improvements to be made to current proposed full-duplex solutions before they can be integrated into commercial networks. Our goal is that our tutorial will familiarize the attendees with the main to-date results and will highlight some of the aspects that need to be addressed by future research.

duarteMelissa Duarte received her B.Sc. degree in Electrical Engineering from the Pontificia Universidad Javeriana, Bogota, Colombia, in 2005. She received her M.Sc. and Ph.D. degrees in Electrical and Computer Engineering from Rice University, Houston, TX, in 2007 and 2012 respectively. From 2012 to 2013 she was a postdoctoral researcher at the School of Computer and Communication Sciences, EPFL, Lausanne, Switzerland. She is currently a research engineer at the Mathematical and Algorithmic Sciences Lab, France Research Center, Huawei Technologies Co. Ltd. Her Ph.D. thesis entitled `Full-duplex Wireless: Design, Implementation and Characterization’ received the Rice University Electrical and Computer Engineering Department Best Dissertation Award, 2012. She holds two US Patents, one of them on a `System and Method for Full-Duplex Cancellation’. She received the ACM MobiHoc 2013 Best Paper Award. Her research interests include the design and implementation of architectures for next-generation wireless communications. Specific interests and expertise include the areas of full-duplex wireless systems, cooperative relaying based networks, Multiple Input Multiple Output antenna (MIMO) systems, multi-carrier systems (OFDM), Software-Defined Radio (SDR), channel modeling for wireless systems, over-the-air measurements and experiments for the evaluation of wireless networks.


guillaudMaxime Guillaud received the M.Sc. degree in Electrical Engineering from ENSEA, Cergy, France, in 2000, and the Ph.D. in Electrical Engineering and Communications from Telecom ParisTech, Paris, France, in 2005. From 2000 to 2001 he was a research engineer at Lucent Bell Laboratories in Holmdel, NJ, USA. From 2006 to 2010, he was a Senior Researcher at the FTW in Vienna, Austria. From 2010 to 2014, he was a researcher with Vienna University of Technology, Vienna, Austria. Since 2014, he is a principal researcher in Huawei Technologies’ France Research Center.

Dr. Guillaud is the author of over 50 research papers and holds two patents. He is the recipient of a SPAWC 2005 student paper award, and co-recipient of the Mario Boella Business Idea prize of the NEWCOM NoE in 2005. He worked on the transceiver architecture of multi-user cellular systems, as well as on various aspects of wireless channel modeling, including sparse representations and channel state inference methods. He introduced the principle of relative calibration for the exploitation of channel reciprocity. His recent interests include interference management in dense wireless systems. Dr. Guillaud is a Senior Member of IEEE.


On System-Level Analysis & Design of Cellular Networks: The Magic of Stochastic Geometry

This tutorial is aimed to provide a comprehensive crash course on the critical and essential importance of spatial models for an accurate system-level analysis and optimization of emerging 5G ultra-dense and heterogeneous cellular networks. Due to the increased heterogeneity and deployment density, new flexible and scalable approaches for modeling, simulating, analyzing and optimizing cellular networks are needed. Recently, a new approach has been proposed: it is based on the theory of point processes and it leverages tools from stochastic geometry for tractable system-level modeling, performance evaluation and optimization. The potential of stochastic geometry for modeling and analyzing cellular networks will be investigated for application to several emerging case studies, including massive MIMO, mmWave communication, and wireless power transfer. In addition, the accuracy of this emerging abstraction for modeling cellular networks will be experimentally validated by using base station locations and building footprints from two publicly available databases in the United Kingdom (OFCOM and Ordnance Survey). This topic is highly relevant to graduate students and researchers from academia and industry, who are highly interested in understanding the potential of a variety of candidate communication technologies for 5G networks.


Marco Di Renzo received the Laurea (cum laude) and the Ph.D. degrees in electrical engineering from the University of L’Aquila, L’Aquila, Italy, in 2003 and in 2007, respectively, and the Habilitation à Diriger des Recherches (Doctor of Science) degree from University Paris-Sud, France, in 2013. He has held various research and academic positions in Italy at the University of L’Aquila, in the United States at Virginia Tech, in Spain at CTTC, and in the United Kingdom at The University of Edinburgh. Since 2010, he has been a CNRS Associate Professor (“Chargé de Recherche Titulaire CNRS”) in the Laboratory of Signals and Systems of Paris-Saclay University—CNRS, CentraleSupélec, University Paris Sud, France. He is a Distinguished Visiting Fellow of the Royal Academy of Engineering, U.K. He is a co-founder of the university spin-off company WEST Aquila s.r.l. Italy. He is a recipient of several awards, including Best Paper Awards at IEEECAMAD (2012 and 2014), IEEE-VTCfall (2013), IEEE-ATC (2014), IEEE ComManTel (2015), the 2013 Network of Excellence NEWCOM# Best Paper Award, the 2013 IEEE-COMSOC Best Young Researcher Award for Europe, Middle East and Africa (EMEA Region), the 2015 IEEE Jack Neubauer Memorial Best System Paper Award, and the 2015-2018 CNRS Award for Excellence in Research and in Advising Doctoral Students. Currently, he serves as an Editor of the IEEE COMMUNICATIONS LETTER and IEEE TRANSACTIONS ON COMMUNICATIONS, where is the Editor for Heterogeneous Networks Modeling and Analysis of the IEEE Communications Society. He is a Senior Member of the IEEE (COMSOC and VTS) and a Member of the European Association for Communications and Networking (EURACON).