IEEE SIGNAL PROCESSING MAGAZINE

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[VOLUME 31 NUMBER 6 NOVEMBER 2014]

IEEE SIGNAL PROCESSING MAGAZINE [1] NOVEMBER 2014

Digital Object Identifier 10.1109/MSP.2014.2350051

12 FROM THE GUEST EDITORSRobert W. Heath, Jr., Geert Leus, Tony Q.S. Quek, Shilpa Talwar, and Peiying Zhou

14 MULTIOBJECTIVE SIGNAL PROCESSING OPTIMIZATIONEmil Björnson, Eduard Jorswieck, Mérouane Debbah, and Björn Ottersten

24 TOWARD ENERGY-EFFICIENT 5G WIRELESS COMMUNICATIONS TECHNOLOGIESRenato L.G. Cavalcante, Slawomir Stanczak, Martin Schubert, Andreas Eisenblätter, and Ulrich Türke

35 BENEFITS AND IMPACT OF CLOUD COMPUTING ON 5G SIGNAL PROCESSINGDirk Wübben, Peter Rost, Jens Bartelt, Massinissa Lalam, Valentin Savin, Matteo Gorgoglione, Armin Dekorsy, and Gerhard Fettweis

45 COMMUNICATING WHILE COMPUTINGSergio Barbarossa, Stefania Sardellitti, and Paolo Di Lorenzo

56 CROSS-LAYER PROVISION OF FUTURE CELLULAR NETWORKSHadi Baligh, Mingyi Hong, Wei-Cheng Liao, Zhi-Quan Luo, Meisam Razaviyayn, Maziar Sanjabi, and Ruoyu Sun

69 FRONTHAUL COMPRESSION FOR CLOUD RADIO ACCESS NETWORKSSeok-Hwan Park, Osvaldo Simeone, Onur Sahin, and Shlomo Shamai (Shitz)

80 MODULATION FORMATS AND WAVEFORMS FOR 5G NETWORKS: WHO WILL BE THE HEIR OF OFDM?Paolo Banelli, Stefano Buzzi, Giulio Colavolpe, Andrea Modenini, Fredrik Rusek, and Alessandro Ugolini

94 THREE-DIMENSIONAL BEAMFORMINGS. Mohammad Razavizadeh, Minki Ahn, and Inkyu Lee

102 LOCATION-AWARE COMMUNICATIONS FOR 5G NETWORKSRocco Di Taranto, Srikar Muppirisetty, Ronald Raulefs, Dirk T.M. Slock, Tommy Svensson, and Henk Wymeersch

[COLUMNS] 4 FROM THE EDITORS

A New Era of IEEE Signal Processing MagazineAbdelhak Zoubir

Inside Signal Processing e-NewsletterChristian Debes

8 PRESIDENT’S MESSAGEA Chapter’s Role in Networking and Continuing EducationAlex Acero

9 SPECIAL REPORTSLooking at Machine VisionJohn Edwards

114 SP HISTORYThe Origins of Miniature Global Positioning System-Based Navigation SystemsLarry B. Stotts, Sherman Karp, and Joseph M. Aein

118 APPLICATIONS CORNERTeleimmersive Audio-Visual Communication Using Commodity HardwareViet Anh Nguyen, Jiangbo Lu, Shengkui Zhao, Douglas L. Jones, and Minh N. Do

124 LECTURE NOTESStochastic Approximation vis-à-vis Online Learning for Big Data AnalyticsKonstantinos Slavakis, Seung-Jun Kim, Gonzalo Mateos, and Georgios B. Giannakis

130 LIFE SCIENCESUltrawideband Signals in MedicineRaúl Chávez-Santiago and Ilangko Balasingham

138 REFLECTIONSReflections on Excellence in Research and Education in Signal ProcessingH. Vincent Poor

[DEPARTMENT] 142 DATES AHEAD

[CONTENTS] [VOLUME 31 NUMBER 6]

[ SPECIAL SECTION—THE 5G REVOLUTION]

Robert W. Heath, Jr., Geert Leus, Tony Q.S. Quek, Shilpa Talwar,

and Peiying Zhou

[from the GUEST EDITORS]

IEEE SIGNAL PROCESSING MAGAZINE [12] NOVEMBER 2014

Signal Processing for the 5G Revolution

C ellular communication sys-tems are continuing to in-corporate advanced signal processing techniques. Third-generation cellular

systems are already widely deployed and are being followed by fourth-generation (4G) systems. Since 4G cellular technolo-gy development is considered to have concluded in 2011, the attention of the research community is shifting toward what will be the next set of innovations in wireless communication technologies that are now broadly known as fifth-gen-eration (5G) technologies.

Given a historical ten-year cycle for ev-ery generation of cellular advancement, it is expected that networks with 5G tech-nologies will be deployed around 2020. While 4G standards were designed to meet requirements issued by the International Telecommunication Union-Radio, no defi-nition for 5G is currently available. Ex-perts vary in opinion whether the next generation of cellular networks will con-tinue to enhance (peak) service rates further, focus on spectral efficiency en-hancements, or move to newer metrics such as energy efficiency, cost- and utiliza-tion-efficiency, or even define new metrics around service quality experience. There is also the possibility that 5G will enable digital sensing, communication, and pro-cessing capabilities to be ubiquitously embedded into everyday objects, turning them into the Internet of Things (IoT) or machine-to-machine (M2M). In this new paradigm, smart devices will collect data, relay the information or context to each other, and process the information collab-oratively over the 5G cellular networks. No matter what the eventual metric or

system, it is certain that signal processing will play an important role in the features that define 5G.

This issue of IEEE Signal Processing Magazine (SPM) provides an overview of recent advances in signal processing for communication with an emphasis on sig-nal processing techniques that will be rel-evant for 5G cellular systems. It covers a wide range of topics including modula-tion, beamforming, cross-layer optimiza-tion based on different performance metrics, location-aware communication, cloud computing, and cloud radio access networks. The articles provide a diverse perspective on the potential challenges in 5G cellular systems.

The first set of articles addresses challenges related to the optimization of 5G systems.

The article by Björnson et al. considers the problem of operating a 5G system with conflicting performance metrics including higher peak rates, improved coverage with uniform user experience, higher reliabili-ty, lower latency, and better energy effi-ciency. The authors review a mathematical framework known as multiobjective opti-mization that can be used to solve prob-lems with multiple competing objectives. The article concludes with an example ap-plication to massive multiple-input, multi-ple-output (MIMO) systems.

Cavalcante et al. consider optimizations related to energy efficiency, arguing that reducing the transmit energy per bit may increase the total energy consumption in the network. Traffic patterns and interfer-ence calculus are used to suggest algo-rithms for energy efficiency. The article concludes with a detailed example where an interference calculus approach is used to adaptively select a subset of active base stations based on prior traffic history, using the majorization–minimization algorithm.

The second set of articles addresses challenges related to cloud computing and cloud radio access networks.

The article by Wübben et al. reviews the benefits that cloud computing can offer in 5G cellular networks. Signal processing is-sues related to the cloud implementation of three representative parts of the signal pro-cessing chain are described in detail: hybrid automatic repeat request, forward error correction, and multiuser detection.

In the article by Barbarossa et al., the authors approach cloud computing from the perspective of offloading computations. They provide a mathematical formulation of a computation offloading problem aimed at jointly optimizing the communi-cation and computation resources subject to latency and energy constraints. They consider computation offloading strategies and different ways to jointly optimize com-munication and computation resources.

Baligh et al. look at cloud computing from the perspective of interference manage-ment and network provisioning. They pro-pose a cross-layer optimization framework for joint user admission, user base station association, power control, user grouping, transceiver design as well as routing and flow control, suggesting that they should be treated in a unified way for 5G networks.

Park et al. consider the topic of fron-thaul compression for cloud radio access

Digital Object Identifier 10.1109/MSP.2014.2345430

Date of publication: 15 October 2014

NO MATTER WHAT THE EVENTUAL METRIC

OR SYSTEM, IT IS CERTAIN THAT SIGNAL PROCESSING WILL PLAY AN IMPORTANT

ROLE IN THE FEATURES THAT DEFINE 5G.

IEEE SIGNAL PROCESSING MAGAZINE [13] NOVEMBER 2014

networks. The fronthaul is the connection between remote radio heads and the cen-tralized control unit with cloud comput-ing technology. This article surveys work on fronthaul compression, especially mul-titerminal compression and structured coding, leveraging insights derived from network information theory.

The third set of articles focuses on more traditional physical-layer signal processing techniques relevant to 5G cel-lular systems.

The article by Banelli et al. considers the topic of modulation, speculating that 5G may employ another modulation strat-egy besides orthogonal frequency-division multiplexing. It reviews other competing modulation strategies including filter bank multicarrier, faster-than-Nyquist/time-fre-quency packing, and single-carrier modu-lations. The article concludes with a review

of the potential interactions between the choice of modulation and other 5G re-quirements: high data rates, small cells, IoT, low latency, and energy efficiency.

Razavizadeh et al. examine a multiple antenna technique known as three-dimen-sional beamforming, where antenna ele-ments in both horizontal and vertical directions are used. It reviews the concepts of two- and three-dimensional beamform-ing and discusses various challenges includ-ing channel modeling and array design.

The final article by Di Taranto et al. considers how 5G networks might ben-efit from precise location information at different layers of the protocol stack. Different applications of location are discussed including radio channel pre-diction and the ways that it can be used at the physical, medium access control, and higher layers.

In summary, we received many contri-butions in response to the call for papers of this special issue. Based on relevance and fit, many high-quality papers were not in-vited for full-paper submission. We would like to express our appreciation to all the authors who submitted white papers and full articles to this special issue. We would also like to thank all the reviewers who provided critical reviews of the diverse set of papers that we received. Finally, we would like to acknowledge Abdelhak Zou-bir, SPM’s editor-in-chief, who was very supportive of our issue, and Fulvio Gini, the special issues area editor who provided assistance and encouragement along with countless reminders, and, of course, Re-becca Wollman for her assistance with the entire process. We hope that you will enjoy the articles in this special issue of SPM.

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