Wei Xiang · Kan Zheng Xuemin (Sherman) Shen Editors 5G Mobile Communications 5G Mobile Communications Wei Xiang • Kan Zheng Xuemin (Sherman) Shen Editors 5G Mobile Communications 123 Editors WeiXiang KanZheng JamesCookUniversity BeijingUniversityofPosts Cairns,QLD,Australia andTelecommunications Beijing,China Xuemin(Sherman)Shen UniversityofWaterloo Waterloo,ON,Canada ISBN978-3-319-34206-1 ISBN978-3-319-34208-5 (eBook) DOI10.1007/978-3-319-34208-5 LibraryofCongressControlNumber:2016950231 ©SpringerInternationalPublishingSwitzerland 2017 Chapter21wascreatedwithinthecapacityofanUSgovernmentalemployment.UScopyrightprotection does notapply. Chapter 21is published with kindpermission ofHerMajesty the QueeninRight of Canada,Australia,andUnitedKingdom. 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Printedonacid-freepaper ThisSpringerimprintispublishedbySpringerNature TheregisteredcompanyisSpringerInternationalPublishingAGSwitzerland Preface Mobilecommunicationshavebeeninstrumentalintransformingourcontemporary societies in the past decades. From the first-generation (1G) of analogue mobile phonesystemtothenewestcommercialfourth-generation(4G)long-termevolution (LTE) networks deployed widely across the global, mobile communications have fundamentallychangedthe ways as to how humansin the modernsociety access, exchange, and share information with each other. Currently, we are at an era of mobile Internet with explosive big data. The growing demand for mobile data traffic and the proliferationof applicationsrequiring high data rates have raised a significantinterestinthedefinitionofnewstandardsinthemobilemarket.Thiscalls fornext-generationmobilecommunicationsystems,whichshouldhavetorespond toanavalancheoftraffic,anexplosioninthenumberofconnecteddevices,andthe largediversityofusecasesandrequirements. Against the above backdrop, the fifth-generation (5G) mobile communications are fast emerging to tackle the challenges brought by an exponential increase in wireless data traffic. On top of the massive increase in data volumes and rates, a formidable challenge for the 5G networks to deal with is how to connectbillions ofsmartdevicessuchassurveillancecameras,smart-home/griddevices,connected sensors, etc. The primary goals of 5G networks are to support a 1000-fold gain in capacity, connections for at least 100 billion devices, and 10 Gb/s delivered to individual users. Furthermore, new 5G networks will be able to provide mass low-latencyand ultrareliableconnectivitybetween people,machines,and devices, whichwillultimatelyusherintheeraoftheInternetofThings(IoT).Tomeetthese enormouschallenges, disruptiveinnovationsand drastic improvementsneed to be made in the mobile network architecture design in both the physical and upper layers. The International Telecommunications Union (ITU) has stipulated 2020 to be the targetyear of standardisingfuture 5G mobile networks.Althoughthe detailed technicalapproachestoimplementing5Gmobilenetworksremainuncertainatthe timeofthiswriting,severalbreakthrough5Gtechniquesstandoutsuchasmassive MIMOandmillimetre-wave(mmWave)communications.Thisbookaimstobeone of the first comprehensive books to reveal the enabling techniques underpinning v vi Preface next-generation 5G networks and to address the challenges and opportunities broughtby5Gmobilecommunications.Specifically,thebookisdividedintothree major parts: Part I Overview of 5G Networks, Part II Transmission and Design Techniquesfor5GNetworks,andPartIIINetworkingTechniquesandApplications for5GNetworks. PartIofthisbookprovidesacomprehensiveintroductiontoandoverviewof5G networks.Itconsistsofthreechapters. Thechapter“AnOverviewof5GRequirements”presentsanoverviewofnext- generation 5G mobile networks. To facilitate the study of 5G requirements and to provide guidance to 5G technical design, this chapter discusses several typical deployment scenarios including indoor hotspot, dense urban, urban macro, rural, and high-speed scenarios. It also presents high-levelkey capabilities and detailed technicalrequirementsfor5Gnetworks.Sometechnicalperformancemetricsof5G networksarealsodiscussed. The chapter “Spectrum Analysis and Regulations for 5G” discusses various aspectsof5Gspectrumissues.Itisexpectedthat5Grequiresmuchmorebandwidth as well as more flexibility in spectrum usage and management. The suitable frequencyranges of 5G will include those bands below 6 GHz such as re-farmed 2G/3Gspectrum,identifiedfrequencybandsforIMT,andalsoWRC-15candidate bands. However, due to the scarcity of spectrum below 6 GHz, it is imperative to seek potential frequency ranges above 6 GHz. Controlled spectrum sharing is an important way of reusing spectrum to complement current licensed dedicated spectrum,whichisstillthefoundationfortheoperationof5Gsystems. The chapter “Spectrum Sharing for 5G” first introduces spectrum sharing for 5G systems, which consists of multiple spectrum types with different scenarios. Then, spectrum sharing techniques mapped into different scenarios are intro- duced,i.e.coordinationprotocol,GLDBsupport,cognitive/DSA,andMAC-based coexistence. Besides, current applications of these techniques in real systems are described. Finally, spectrum sharing directions for 5G systems are analysed for different spectrum sharing techniques. It is concluded that licensed dedicated spectrumwillcontinuetobethedominantspectrumusagemethodfor5Gsystems due to the possibility to control interference and guarantee coverage, while other spectrum sharing scenarios will act as complementary spectrum usage methods whenbeneficial. Part II of this book presents new transmission and design techniques for 5G networks with a focus on physical-layer enabling techniques. It contains 11 chapters. Thechapter“MassiveMIMOCommunications”arguesthateverynewnetwork generation needs to make a leap in area data throughput, to manage the growing wirelessdatatraffic.MassiveMIMOtechnologycanbringatleasttenfoldimprove- mentsinareathroughputbyincreasingthespectralefficiency(bit/s/Hz/cell)while using the same bandwidth and density of base stations as in current networks. These extraordinarygainsare achievedby equippingthe base stationswith arrays of a hundred antennas to enable spatial multiplexing of tens of user terminals. Preface vii Thischapter explainsthe basic motivationsand communicationtheorybehindthe massiveMIMOtechnologyandprovidesimplementation-relateddesignguidelines. The chapter “Millimeter-Wave Mobile Communications” introduces key tech- nologiesofmmWavecommunications.ChannelmeasurementsshowthatmmWave signals suffer from much larger propagationlosses and are suitable for small cell coverage. A hybrid network is presented where mmWave is used for capacity enhancement in hotspots, and a low-frequency network is applied for seamless coverage. Uniform air interface is a consequence to simplify the design between mmWave bandsand low-frequencybands. Unified access and backhaultechnique not only reduces the cost of backhaul but also can meet the requirement of 1000 timescapacityenhancementoverLTEsystems. The chapter “Non-Orthogonal Multiple Access (NOMA) for Cellular Future RadioAccess”introducesstate-of-the-artNOMAtechniquesandevaluatesthelow density spreading (LDS)-based system, which is a strong candidate for the next generation of mobile networks due to its well-known advantages compared to state-of-the-arttechniquesbasedonorthogonalfrequencydivisionmultipleaccess (OFDMA). Furthermore,the effect of LDS parameters such as density factor and maximumnumberofusersateachtimeinstanceonthesumrateisevaluated.The effectofirregularityonthecomplexityisalsodiscussed.Moreover,itisshownthat thelossofachievablerateswhichiscausedbymodulationcanbecompensatedby usingasuitablechannelcodingscheme. The chapter “New Multicarrier Modulations for 5G” presents recent advances in filter bank multicarrier (FBMC) techniques and compares them with the con- ventional cyclic prefix (CP)-OFDM approach, in the context of 5G. After a brief description of some adaptations of CP-OFDM, FBMC combined with offset- QAM is considered, pointing out the crucial issue of subchannel equalisation. Then,analternativeapproachisproposed,FBMCcombinedwithpulse amplitude modulation (PAM). FBMC-PAM is an attractive option whenever asynchronous access and high level of out-of-band rejection are required. Finally, the case of nonoverlapping emitted symbols is considered, and a CP-less OFDM scheme with frequency domain equaliser in the receiver is included in the performance comparison. The chapter “Fundamentals of Faster-than-Nyquist Signaling” presents the fundamentals of Faster-than-Nyquist (FTN) signalling. As originally introduced, FTN increases the bit rate in the signalling bandwidth by packing symbolscloser intime,atthecostofintroducingintersymbolinterference(ISI).Thechapterbegins with the Euclidean distance properties of bandwidth-efficientpulses at FTN rates anddescribesreceiversthatmitigatethesevereISI.TheFTNachievableinformation rate is compared with the Nyquist information rate for practical pulses. It then discusses the FTN extension to multicarrier systems with not only time packing butalsosubcarrier,optimisingboththetimeandfrequencypacking. The chapter “Generalized Frequency Division Multiplexing:A Flexible Multi- Carrier Waveform for 5G” aims to develop a unified air interface that can be configured on-the-fly to address emerging 5G applications. Apart from an ever- increasing demand for data rates, 5G is facing new applications such as Tactile viii Preface Internet and the Internet of Things. Being aligned with the whole concept of software-defined networking, this chapter introduces the multicarrier waveform termed generalised frequency division multiplexing (GFDM) as the basis for realisingsuchaflexiblephysicaldesign. The chapter “Spectrally Efficient Frequency Division Multiplexing for 5G” focuses on novel multicarrier communication techniques, which share the com- mon goal of increasing spectrum efficiency in future communication systems. In particular,atechnologytermedspectrallyefficientfrequencydivisionmultiplexing (SEFDM) is described in detail outlining its benefits, challenges, and trade-offs whencomparedtothecurrentstateoftheart.Adecadeofresearchhasbeendevoted to examining SEFDM from different angles: mathematical modelling, algorithm optimisation, hardware implementation, and system experimentation. The aim of this chapter is to therefore give a taste of this technology, and in doing so, the chapterconcludesbyoutlininganumberofexperimentaltestbedswhichhavebeen developed for the purpose of evaluating the performance of SEFDM in practical scenarios. The chapter “Full-Duplex Wireless Communications for 5G” introduces full- duplex (FD) wireless communications for 5G, which enables simultaneous trans- mission and reception over the same frequency band. In this way, the spectral efficiencycanbeimprovedsignificantlycomparedwithhalf-duplex(HD).However, there exists severe self-interference (SI), signal leakage from the local trans- mitter to its own receiver. Three different classes of SI mitigation techniques are presented in this chapter, i.e. propagation-domain SI suppression, analogue- domainSIcancellation,anddigital-domainSIcancellation.Furthermore,thesystem performance of several FD schemes in several different application scenarios is presented.Theoretically,thespectralefficiencyofFDbidirectionalandcooperative communicationscanbedoubled,whileforcognitiveradionetworks,theFD-based protocol can achieve much better sensing performance than the traditional HD- basedcognitiveradioschemes. Thechapter“Device-to-DeviceCommunicationsover5GSystems:Standardiza- tion,ChallengesandOpenIssues”introducesoneofthekeyenablingtechnologies at the heart of the 5G systems, namely, device-to-device (D2D) communications. The potential of D2D communicationparadigm holding the promise to overcome thelimitationsofconventionalcellularsystemswithveryhighbitrates,lowdelay, and low power consumption is illustrated. Starting from an overview of D2D communicationtechnology,thischapterwillbrowsethroughthemainaspectsthat characterisetheproximityservices,withaviewonthestandardisationprocess,the challenges,andtheopenissues. Thechapter“M2MCommunicationsin5G” providesanoverviewofmachine- type communications (MTC) within the context of 5G networks. The Internet of EverythingforeseesahyperconnectedWorldwherehumans,things,andmachines willneedtocoexisttogether.TheywillbeinterconnectedandInternet-connectedvia communicationnetworks. In specific, the authorsreview the key novelchallenges ofMTC:whatisnewwithregardtohuman-typetraffic(HTC).Theythenanalyse existingcommunicationtechnologiesand howsuitable theyare for MTC. Finally, Preface ix theauthorsidentifykeytechnologyenablersbeingconsideredforthedesignof5G networksandprovideanoutlookforthefuture. The chapter “Design Techniques of 5G Mobile Devices in the Dark Silicon Era” is concerned with the design of the prospected 5G mobile communication system,whichneedswideskillsinwirelesscommunication,analoguecircuitdesign, embedded system, microwave technology, and so forth. System-level analyses, designspaceexploration,andperformancetrade-offsaresomekeystepsthatenable the design of low-cost, energy-efficient, ubiquitous, and flexible transceiver. This chapter providescomprehensivedesign techniquesfor 5G mobile communication inthedarksiliconerausingMorethanMooretechnology(MtM). Part III of this book focuses primarilyon the networkingand application layer techniquesfor5Gnetworks,whichincludes12chapters. The chapter “Ultra-Dense Network Architecture and Technologies for 5G” presentstheultra-densitynetwork(UDN),whichisthemostpromisingwaytomeet theultrahighareacapacityrequirementfor5G.Thecontentofthischapterincludes characters of UDN scenarios, network architecture design, and key technologies like flexible networking, wireless backhauling, multi-RAT coordination, mobility management,interferencemanagement,andradioresourcemanagement. Thechapter“5GRANArchitecture:C-RANwithNGFI”describescloudradio accessnetworks(C-RAN),whichareviewedasoneofthekeyRANarchitectures for 5G networks, with evolved architecture based on a newly designed fronthaul interface,dubbedthenext-generationfronthaulinterface(NGFI).Thedesignprin- ciplesandthechallengesofNGFIareintroduced.Aprototypeisfurtherdeveloped toverifytheapplicabilityofNGFI-basedC-RAN. The chapter “User-Centric Wireless Network for 5G” addresses the conceptof user-centricwirelessnetworkfor5Gfromtheperspectiveoffulfillingmultipleuser experiencerequirementsin5G.Fourkeytechnicaldirectionsarestudiedbasedon a gapanalysisbetween LTE technologyand 5G requirements,i.e. user-centric5G access network architecture design, flexible functionality and deployment, smart user and traffic awareness and management, and high-efficient low-cost network operation. These key technologies work together with cross-layer and end-to-end solutionstoprovidetheuser-centric5Gecosystem. The chapter “Energy Harvesting Based Green HeterogeneousWireless Access for 5G” is concerned with the issues of energy harvesting for future 5G cel- lular systems. A feasible and efficient method to tackle this issue is to let the communicationsystems harvestenergy from renewable energysources instead of fossil fuels. However, by employing the energy harvesting (EH) technique, the instabilityof renewableenergyresourcesintroducesnewchallengesonthe design of the upcoming5G systems. This chapter focuses on uplink access schemes and power allocations for EH-based heterogeneous networks. First, a heterogeneous access model incorporating EH-based mobile users is proposed and followed by a throughputmaximisation framework.Then, by classifying transmission policies into two main categories (i.e. single-channel vs. multichannel scenarios), the proposed framework is concretised under various practical conditions, including