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LTE BACKHAUL

LTE BACKHAULPLANNING AND OPTIMIZATION

Edited by

Esa Markus Metsälä

Juha T.T. SalmelinNokia Networks, Espoo, Finland

This edition first published 2016© 2016 John Wiley & Sons, Ltd

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Library of Congress Cataloging‐in‐Publication Data

LTE backhaul : planning and optimization / edited by Esa Markus Metsälä and Juha T.T. Salmelin. pages cm Includes bibliographical references and index. ISBN 978-1-118-92464-8 (hardback)1. Long-Term Evolution (Telecommunications) 2. Telecommunication–Traffic. I. Metsälä, Esa Markus. II. Salmelin, Juha T.T. TK5103.48325.L7345 2015 621.3845′6–dc23

2015021968

A catalogue record for this book is available from the British Library.

Set in 10/12pt Times by SPi Global, Pondicherry, India

1 2016

http://www.wiley.com

Contents

List of Contributors xiForeword xiiiAcknowledgments xvList of Abbreviations xvii

1 Introduction 1Esa Markus Metsälä and Juha T.T. Salmelin1.1 To the reader 11.2 Content 21.3 Scope 2reference 2

2 LTE Backhaul 3Gerald Bedürftig, Jouko Kapanen, Esa Markus Metsälä and Juha T.T. Salmelin2.1 Introduction 32.2 LTE Backhaul Planes 5

2.2.1 3GPP Planes and Protocol Stacks 52.2.2 Synchronization Plane 72.2.3 Management Plane 92.2.4 Active Monitoring Plane 92.2.5 Security Control Plane 102.2.6 Control and User Plane of Additional Proprietary Applications 10

2.3 radio Features of LTE and LTE‐A 112.3.1 LTE 112.3.2 LTE‐A 12

2.4 requirements for LTE Backhaul (SLAs) 172.4.1 Capacity 172.4.2 Latency and Loss 182.4.3 QoS Capabilities 212.4.4 Synchronization 212.4.5 Availability 22

vi Contents

2.4.6 Security 222.4.7 Examples 23

2.5 Transport Services 262.6 Planning Problems 272.7 LTE Backhaul Technologies 29

2.7.1 Access 302.7.2 Aggregation and Backbone Network 34

2.8 Small Cell Backhaul 342.9 Future radio Features Affecting Backhaul 35

2.9.1 Inter NodeB CoMP (eCoMP) 352.9.2 Dual Connectivity 362.9.3 Dynamic eICIC 38

2.10 related Standards and Industry Forums 392.10.1 3GPP 392.10.2 ITU‐T SG15 402.10.3 IEEE 802 402.10.4 IETF 402.10.5 MEF 402.10.6 NGMN 412.10.7 BBF 412.10.8 SCF 41

2.11 Operator Example 42references 42

3 Economic Modeling and Strategic Input for LTE Backhaul 45Gabriel Waller and Esa Markus Metsälä3.1 Introduction 45

3.1.1 Role of Backhaul Within LTE 463.1.2 Why and What to Model 48

3.2 Strategic Input for Planning 493.2.1 Physical Infrastructure 493.2.2 Transmission Media 503.2.3 Capacity and Interfaces 503.2.4 Network Technologies 513.2.5 Network Topology 513.2.6 Make or Buy 513.2.7 Backhaul Security Aspects 52

3.3 Quantifying Benefits 533.3.1 Revenue from LTE Backhaul 533.3.2 Contribution to Mobile Service Revenue 543.3.3 Cost Savings 54

3.4 Quantifying Costs 553.4.1 Equipment Purchases 553.4.2 Economic Lifetime 553.4.3 Operational Costs 563.4.4 Other Costs 57

Contents vii

3.5 Case router 583.5.1 Cash Flow 583.5.2 Payback Period 593.5.3 Net Present Value (NPV) 613.5.4 Selection of the Interest Rate 633.5.5 Internal Rate of Return 643.5.6 Return on Investment and Further Metrics 64

3.6 Wireless Backhaul Case Study 663.6.1 Case Definition 663.6.2 Payback Period 683.6.3 NPV 69

references 70Further reading 71

4 Dimensioning Aspects and Analytical Models of LTE MBH Networks 73Csaba Vulkán and Juha T.T. Salmelin4.1 Introduction 734.2 Dimensioning Paradigm 764.3 Applications and QoE: Considerations 78

4.3.1 Transmission Control Protocol 794.3.2 Web Browsing 834.3.3 Video Download 85

4.4 Dimensioning requirements 874.5 Traffic Models 88

4.5.1 Peak Load or Busy Hour Load 924.5.2 Geographic Diversity and Daily Load Profile/Distribution 934.5.3 Session Level User Behavior 954.5.4 Burst Level User Behavior 994.5.5 Packet Level Behavior 1024.5.6 Transmission Control Protocol Models 106

4.6 Network Models 1124.6.1 Queuing Methods 1134.6.2 Fluid Network Models 1174.6.3 Network Model 1184.6.4 Routing and Requirement Allocations 119

4.7 Dimensioning 1224.7.1 QoS‐Driven Dimensioning 1224.7.2 Reliability Requirement Based Dimensioning 124

references 127

5 Planning and Optimizing Mobile Backhaul for LTE 129Raija Lilius, Jari Salo, José Manuel Tapia Pérez and Esa Markus Metsälä5.1 Introduction 129

5.1.1 Planning and Optimization Process 1305.1.2 High‐Level Design Overview 131

5.2 Backhaul Network Deployment Scenarios 1325.2.1 Connectivity Requirements 132

viii Contents

5.2.2 Differences Between Ethernet and IP Connectivity 1335.2.3 Implications to Backhaul Scenarios 1345.2.4 Ethernet Services 1345.2.5 L3 VPN Service 1365.2.6 Scenario 1: IP Access 1375.2.7 Scenario 2: Ethernet Service in the Access 137

5.3 Network Topology and Transport Media 1385.3.1 Access Network Topologies and Media 1385.3.2 Aggregation Network Topologies 139

5.4 Availability and resiliency Schemes 1395.4.1 Availability Calculation 1405.4.2 Link Resiliency and its Impact on Availability 1415.4.3 Routing Gateway Redundancy 1445.4.4 Ethernet Ring Protection (ERP) 1475.4.5 IP and MPLS Rerouting 1485.4.6 SCTP Multi‐Homing 1495.4.7 Connectivity Toward Multiple S‐GWs and MMEs 1495.4.8 Synchronization Protection 1505.4.9 OSS Resiliency 1505.4.10 End‐to‐End Performance of Multilayer Redundancy 151

5.5 QoS Planning 1525.5.1 QoS in an Access Transport Node 1525.5.2 Packet Classification 1535.5.3 Scheduling 1565.5.4 Traffic Shaping 1585.5.5 Active Queue Management and Bufferbloat 1605.5.6 Connection Admission Control 161

5.6 Link Bandwidth Dimensioning 1635.6.1 Obtaining Input Parameters for User Plane

Bandwidth Dimensioning 1645.6.2 Obtaining Input Parameters for Control Plane

Bandwidth Dimensioning 1695.6.3 Link Bandwidth Dimensioning: Single Queue 1725.6.4 Link Bandwidth Dimensioning: Multiple Queues 1805.6.5 Combining Signaling, Voice and Data Traffic 1835.6.6 Comparison of Bandwidth Dimensioning Formulas 186

5.7 Dimensioning Other Traffic Types 1875.7.1 Management Traffic 1875.7.2 Synchronization Traffic 1875.7.3 Other Traffic Types 188

5.8 Base Station Site Solutions 1885.9 Security Solutions 189

5.9.1 Network Element Hardening 1905.9.2 Network Security High‐Level Architecture 1905.9.3 Security Gateway High Availability 1925.9.4 IPsec Parameter Planning 196

Contents ix

5.9.5 Public Key Infrastructure (PKI) 2015.9.6 Self‐Organizing Networks (SONs) and Security 203

5.10 IP Planning 2035.10.1 IP Addressing Alternatives for eNB 2045.10.2 VLAN Planning 2065.10.3 IP Addressing 2085.10.4 Dynamic Versus Static Routing 2115.10.5 Examples 211

5.11 Synchronization Planning 2145.11.1 Global Navigation Satellite System (GNSS) 2155.11.2 Synchronous Ethernet (SyncE) 2155.11.3 IEEE1588 (2008) Frequency Synchronization 2185.11.4 IEEE1588 (2008) Phase Synchronization 222

5.12 Self‐Organizing Networks (SON) and Management System Connectivity 2265.12.1 Planning for SON 2265.12.2 Data Communications Network (DCN) Planning for Transport

Network and the Base Stations 2275.13 LTE Backhaul Optimization 227

5.13.1 Introduction to LTE Backhaul Optimization 2275.13.2 Proactive Methods 2285.13.3 Reactive Methods 2315.13.4 Active vs. Passive Methods 232

references 236

6 Design Examples 239Jari Salo and Esa Markus Metsälä6.1 Introduction 2396.2 Scenario #1: Microwave 239

6.2.1 Synchronization 2406.2.2 IP Planning 2426.2.3 Availability 245

6.3 Scenario #2: Leased Line 2546.3.1 Assumptions for the Use Case 2546.3.2 Comparing Transport Providers 2546.3.3 The Solution Summary 258

reference 258

7 Network Management 259Raimo Kangas and Esa Markus Metsälä7.1 Introduction 2597.2 NMS Architecture 2607.3 Fault Management 2627.4 Performance Management 2637.5 Configuration Management (CM) 263

7.5.1 Maintaining an Up‐to‐Date Picture of the Network 2647.5.2 Configuration History 264

x Contents

7.5.3 Configuring Network 2657.5.4 Policy‐Based Configuration Management 2657.5.5 Planning Interfaces 2667.5.6 Network Configuration Discovery 2677.5.7 Configuration Management of Backhaul Network 267

7.6 Optimization 2687.7 Self‐Organizing Network (SON) 2707.8 O&M Protocols 272

7.8.1 SNMP 2737.8.2 NETCONF 275

7.9 Planning of Network Management System 2757.9.1 Strategic Planning 2767.9.2 Analysis 2767.9.3 Design 2777.9.4 Implementation 2787.9.5 Maintenance 278

references 278

8 Summary 279Esa Markus Metsälä and Juha T.T. Salmelin

Index 281

List of Contributors

Gerald BedürftigNokia NetworksBerlin, Germany

Raimo KangasNokia NetworksTampere, Finland

Jouko KapanenNokia NetworksEspoo, Finland

Raija LiliusNokia NetworksEspoo, Finland

Esa Markus MetsäläNokia NetworksEspoo, Finland

José Manuel Tapia PérezNokia NetworksEspoo, Finland

Juha T.T. SalmelinNokia NetworksEspoo, Finland

Jari SaloNokia NetworksDoha, Qatar

Csaba VulkánNokia NetworksBudapest, Hungary

Gabriel WallerNokia NetworksEspoo, Finland

Foreword

With LTE, the mobile network has evolved into a 150+ Mbps per user high‐speed always‐on packet network. Next we will see high‐speed LTE networks becoming available for even larger populations, and solving capacity and speed bottlenecks that users currently experience. For many of us, mobile broadband is the preferred and primary access to the Internet.

The competition for the hearts and minds of LTE subscribers makes the user experience increasingly critical. Understanding the technology behind the service is the key to business success. Delving into the details of LTE technology soon reveals many items that affect performance, allowing room for optimization—and differentiation—in the market.

In general, operators today have more choice and support than ever in choosing their strategy for LTE planning and optimization tasks, including IP and backhaul tasks. The myriad challenges operators face can be addressed by specific professional services, purchased from an expert organization, or issues can be solved by in‐house professionals. Many large networks are operated as a service, and a continuum of possibilities exists, from traditional in‐house operation to fully managed service operations, and everything in between.

Whatever the technology and business strategy of the operator, high‐bandwidth LTE radio needs to be reflected in the IP backhaul. For the LTE backhaul, a number of new areas call for special attention, namely security, synchronization, availability, end‐user QoS and dimen-sioning, to name a few.

LTE IP planning professionals depend on both LTE and IP knowledge, and greatly benefit from realistic guidance for their projects. This book is of great help when assessing technical and economical alternatives and when creating solid and reliable real‐life backhaul designs for LTE success.

Igor LeprinceExecutive Vice President, Global Services

Nokia

Acknowledgments

The editors would first like to acknowledge the contributing authors, who are our colleagues at Nokia Networks: Gerald Bedürftig, Raimo Kangas, Jouko Kapanen, Raija Lilius, José Manuel Tapia Pérez, Jari Salo, Csaba Vulkán and Gabriel Waller. Your knowledge has been the most essential ingredient in this project.

For specific review comments and for bigger and smaller suggestions and contributions we would like to thank: Heikki Almay, Antti Pietiläinen, Jyri Putkonen, Eugen Wallmeier, Raimo Karhula, Pekka Koivistoinen, Zoltán Vincze, Péter Szilágyi, Balázs Héder, Attila Rákos, Gábor Horváth, Lajos Bajzik, Dominik Dulas, Michal Malcher, Puripong Thepchatri, Lasse Oka, Steve Sleiman, Taufik Siswanto, Matti Manninen (Elisa), Timo Liuska (Juniper Networks) and Mika Kivimäki.

Also, we would like to thank the team at John Wiley & Sons for very good cooperation and an easy editing process, especially Mark Hammond, Tiina Wigley, Sandra Grayson, Teresa Netzler, Tim Bettsworth and Victoria Taylor.

We appreciate the patience and support of our families and our authors’ families during the writing period.

We are grateful for comments and suggestions for improvements or changes that could be implemented in forthcoming editions of this book. This feedback can be sent to the editors’ email addresses: esa.metsala@nokia.com and juha.salmelin@nokia.com.

Esa Markus Metsälä and Juha T.T. SalmelinEspoo, Finland

mailto:esa.metsala@nokia.commailto:juha.salmelin@nokia.com

List of Abbreviations

2G second generation (mobile system)3G third generation (mobile system)3GPP Third Generation Partnership ProgramASN.1 Abstract Syntax Notation OneABS almost blank subframeACK acknowledgement signalAFxx assured forwarding behavior group xxAH Authentication HeaderAM acknowledged modeAMBR Aggregate Maximum Bit RateAMR adaptive multi‐rate codingANR automatic neighbor relationAOM administration of measurementsAP Application ProtocolAPN‐AMBR Access Point Name–Aggregate Maximum Bit RateAQM active queue managementARP Address Resolution ProtocolATM asynchronous transfer modeBBF Broadband ForumBC boundary clockBCMP Baskett, Chandy, Muntz and PalaciosBE best effortBFD bidirectional forwarding detectionBH Backhaul, Busy HourBITW bump in the wireBMAP batch Markovian arrival processesBMCA best master clock algorithmBSC base station controllerBSHR bidirectional self‐healing ring

xviii List of Abbreviations

BTS base stationCA carrier aggregation, certification authorityCAC connection admission controlcapex capital expenditureCBS committed burst sizeCDF cumulative distribution functionCDMA Code Division Multiple AccessCE customer equipmentCET carrier EthernetCIR committed information rateCLI command line interfaceCM configuration managementCMP Certificate Management ProtocolCoDel controlled delayCoMP coordinated multi‐pointCORBA Common Object Request Broker ArchitectureCoS class of serviceC‐plane control planeCPE customer premises equipmentCPU central processing unitCRC cyclic redundancy checkCRL certificate revocation listCRS common reference signalsCSFB Compact Small Form‐factor PluggableCSV comma‐separated valuesCUBIC TCP with cubic window increases functionCWDM coarse wavelength division multiplexingDC dual connectivityDCF discounted cash flowsDCH dedicated channelDCN data communications networkDHCP Dynamic Host Configuration ProtocolDL downlinkDNS domain name systemDNU do not useDOCSIS data over cable service interface specificationDoS denial of serviceDPD dead peer detectionDSCP differentiated services code pointDSL digital subscriber lineDWDM dense wavelength division multiplexingDWRR deficit weighted round robinEAPS Ethernet Automatic Protection SwitchingEBS excess burst sizeECMP equal cost multipatheCoMP enhanced CoMP

List of Abbreviations xix

EDGE enhanced data rates for GSM evolutionEF expedited forwardingeICIC enhanced inter‐cell interference coordinationEIR excess information rateE‐LAN Ethernet service, multipoint‐to‐multipointE‐line Ethernet service, point‐to‐pointEMS element management systemeNB evolved NodeBe2e end‐to‐endEPC evolved packet coreERP Ethernet ring protectionESM EPS session managementESP Encapsulating Security PayloadE‐tree Ethernet service, point‐to‐multipointE‐UTRAN Evolved Universal Terrestrial Radio Access NetworkEXP experimental bitsFCAPS fault, configuration, accounting, performance, securityFCFS first come, first servedFDD frequency division duplexFD‐LTE full duplex LTEFeICIC further enhanced inter‐cell interference coordinationFIFO first in, first outFTP File Transfer ProtocolGbE gigabit EthernetGBR guaranteed bit rateGE gigabit EthernetG.Fast up to Gigabit/s fast short distance digital subscriber lineGLONASS Global Navigation Satellite System, RussiaGNSS global navigation satellite systemGPON gigabit‐capable passive optical networkGPRS general packet radio serviceGPS Global Positioning SystemGSM Global System for Mobile communicationsGTP general packet radio service Tunneling ProtocolGTP‐U general packet radio service Tunneling Protocol userHARQ hybrid automatic repeat requestHetNet heterogeneous networksHRM hypothetical reference modelHSPA high‐speed packed accessHSRP Hot Standby Router ProtocolHTML Hypertext Markup LanguageHTTP Hypertext Transfer ProtocolICIC inter‐cell interference coordinationICMP Internet Control Message ProtocolIEEE Institute of Electrical and Electronics EngineersIETF Internet Engineering Task Force

xx List of Abbreviations

IKE Internet key exchangeIMS IP Multimedia SubsystemIMT‐A international mobile telecommunications advancedimpex implementation expenditureIP Internet protocolIPsec Internet Protocol Security architectureIRC interference rejection combiningIRR internal rate of returnISD inter‐site distanceitag video parameter classificationITU International Telecommunication UnionITU‐T ITU Telecommunication Standardization SectorIU indoor unitKPI key performance indicatorL1 Layer 1 in Open Systems Interconnection data link layerL2 Layer 2 in Open Systems Interconnection data link layerL2 VPN Layer 2 virtual private networkL3 VPN Layer 3 virtual private networkLAG link aggregation groupLAN local area networkLDF load distribution factorLFA loop‐free alternateLOS line of sightLSP label switched pathLTE long‐term evolutionLTE‐A long term evolution advancedM/G/R‐PS M/G/R Processor Sharing modelMAC media access controlMAN metropolitan area networkMAP Markovian arrival processesMBH mobile backhaulMBMS Multimedia Broadcast Multicast ServiceMEF Metro Ethernet ForumMeNB master eNBMGW media gatewayMIB management information baseMIMO multiple input, multiple outputMLO multilayer optimizationML‐PPP multilayer point‐to‐point protocolMME mobile management entityMPEG4 Moving Pictures Experts GroupM‐plane management planeMPLS multiprotocol label switchingMPLS TC multiprotocol label switching traffic classMPLS‐TP multiprotocol label switching traffic profileMSP multiplex section protection

List of Abbreviations xxi

MS‐SPRING multiplex section protection ringMSTP Multiple Spanning Tree ProtocolMTBF mean time between failuresMTTR mean time to repairMTU maximum transfer unitMVI multi‐vendor interfaceMWR microwave radioNaaS network management system as a serviceNAS network application serverNETCONF Network Configuration ProtocolNGMN Next Generation Mobile NetworkNG‐SDH Next Generation Synchronous Digital HierarchynLOS near line of sightNLOS non line of sightNMS network management systemnon‐GBR non‐guaranteed bit rateNP non‐protectedNPV net present valueNTP Network Time ProtocolO&M operation and maintenanceOAM operations administration and maintenanceOC‐3 optical carrier level 3ODU outdoor unitOID object identifieropex operational expenditureOSPF Open Shortest Path FirstOSS operation support systemOTDOA observed time difference of arrivalOTT over the topOU outdoor unitP protected (IPsec)PDF probability distribution functionPDH plesiochronous digital hierarchyPDN public data networkPDP packet data protocolPDU protocol data unitPE provider edgePE–PE provider edge to provider edgeP‐GW packet data network gatewayPHB per‐hop behaviorsPHY physical layerPKI public key infrastructurePLMN public land mobile networkPM performance monitoringPON passive optical networkppb parts per billion

xxii List of Abbreviations

PPP point‐to‐point protocolppm pulse per minutepps pulse per secondPRC primary reference clockPS HO packet service handoverPSK pre‐shared keyPTP Precision Time ProtocolQCI quality of service class indicatorQNA queuing network analyzerQoE quality of experienceQoS quality of serviceRA radio accessRBID radio bearer identificationRC resource coordinationRE range extensionRED random early detectionRF radio frequencyRFCs request for commentsRLC radio link controlRN relay nodeRNC radio network controllerROI return on investmentRRC radio resource controlRRH remote radio headRRM radio resource managementRSTP Rapid Spanning Tree ProtocolRTO retransmission timeout timerRTP Real‐time Transport ProtocolRTT round trip timeRX receive, receiverS1 Interface between eNB and MME/S‐GWS1‐AP S1 Application ProtocolS1‐MME interface between eNB and MMES1‐U interface between eNB and S‐GWSA security associationSACK selective acknowledgmentSCEP Simple Certificate Enrollment ProtocolSCF Small Cell ForumSCTP Stream Control Transmission ProtocolSDH synchronous digital hierarchySEG security gatewaySeNB slave eNBS‐GW serving gatewaySLA service level agreementSMS short message service

List of Abbreviations xxiii

SMTP Simple Mail Transfer ProtocolSNMP Single Network Management ProtocolSOA service‐oriented architectureSOAP Simple Object Oriented Access ProtocolSON self‐organizing networkSONET synchronous optical networkSP strict priority schedulingSP‐GW combined node of S‐GW and P‐GWS‐plane synchronization planeSPQ strict priority queuingSRLG shared risk link groupSRVCC single radio‐voice call continuitySS7 signaling system 7SSH secure shellSSL secure sockets layerSSM synchronization status messagesSTM synchronous transport moduleSTP Spanning Tree ProtocolSyncE Synchronous EthernetTCP Transmission Control ProtocolTDD time division duplexTD‐LTE time division duplex LTETDM eICIC time domain enhanced inter‐cell interference coordinationTFRC Transmission Control Protocol‐friendly rate controlTLS Transport Layer Security protocolTMN Telecom Management NetworkTTI transmission time intervalTTL Time to LiveTWAMP Two‐Way Active Measurement ProtocolTX transmit, transmitterUDP User Datagram ProtocolUE user equipmentUL UplinkU‐plane user planeUSB universal serial busVDSL very high bit rate digital subscriber lineVLAN virtual local area networkVLL virtual leased lineVoIP voice over Internet protocolVoLTE voice over long‐term evolutionVPLS virtual private local area network serviceVPN virtual private networkVPWS virtual private wire serviceVRF virtual routing and forwardingVRRP Virtual Router Redundancy Protocol

xxiv List of Abbreviations

WACC weighted average cost of capitalW‐CDMA Wideband Code Division Multiple AccessWDM wavelength division multiplexingWFQ weighted fair queuingWRR weighted round robinX2‐AP X2 application protocolX2‐U interface between eNB and eNBxDSL “any kind of” digital subscriber lineXG‐PON 10 gigabits/passive optical networkXML Extensible Markup LanguageXPIC cross‐polarization interference cancellation

LTE Backhaul: Planning and Optimization, First Edition. Edited by Esa Markus Metsälä and Juha T.T. Salmelin. © 2016 John Wiley & Sons, Ltd. Published 2016 by John Wiley & Sons, Ltd.

Introduction

Esa Markus Metsälä and Juha T.T. SalmelinNokia Networks, Espoo, Finland

1.1 To the reader

This book intends to offer guidelines and insight for long‐term evolution (LTE) backhaul planning and optimization tasks and is aimed at technical professionals working in the field of network planning and operations. With LTE backhaul, several functional areas like synchroni-zation, Quality of Service (QoS) and security, to name a few, require major new analysis, when designing for a high‐performing and well‐protected network. And in addition, the capacity needs of the LTE and LTE Advanced (LTE‐A) radio typically mandate a major upgrade to the currently supported backhaul capacity, which often means introducing new backhaul links and technologies.

As with any network design project, several feasible and technically sound approaches exist. Many of the examples given in this text highlight topics that the authors find especially important. For every design, high‐level goals are unique, as are the boundaries set for the project, and the examples should be tailored where necessary to match the individual design target. All of the views presented reflect the authors’ personal opinions and are not necessarily that of their employers.

The book aims to give an objective, standards‐based view of the topics covered. Many of the LTE backhaul related aspects are, however, not written as binding standards. As such, there is room for different implementations, dependent on the capabilities of mobile network elements such as evolved NodeB (eNB), security gateways, backhaul elements and related management systems.

A basic command of LTE and Internet Protocol (IP) networking is useful for getting the most out of this book. Mobile backhaul, and its key services and functions, is discussed in greater detail in Metsälä and Salmelin (2012), which can be used as a reading companion.

1

2 LTE Backhaul

The book’s chapters approach each major topic of LTE with illustrations, complementing these with both short examples, including questions with model answers, and a few longer case studies.

Network designs are also influenced by non‐technical drivers, such as the budget available for the project. Strategic input and comparing alternative designs from the financial side is important, which is why these topics are covered in a separate chapter.

1.2 Content

The book is divided into eight chapters. Chapter 2 is a bird’s‐eye view of LTE backhaul: what is it all about? While the book’s focus is on technical matters and planning advice, the finan-cial modeling of LTE backhaul is discussed in Chapter  3. Backhaul dimensioning is a challenge, and the theoretical basis for backhaul dimensioning and end user application behavior is covered in Chapter 4. Chapter 5 covers planning advice in the form of guidelines and examples, while Chapter 6 focuses on two bigger walk‐through network design cases. Network management of the backhaul network and its relation to the LTE radio network management is the topic of Chapter 7 and the book is summarized in Chapter 8.

1.3 Scope

The essential scope of the book is the planning of the LTE IP backhaul, with focus on the LTE‐specific design requirements and how to meet these requirements using Ethernet, IP and other packet protocols, with security of the backhaul taken into account in all phases of the design.

In order to help dimensioning LTE backhaul, the theoretical basis for analyzing backhaul capacity needs is given. As well, several end user aspects related to Transmission Control Protocol (TCP) behavior over the LTE network are investigated, since these may heavily affect end user perception of the LTE service.

Network management systems are traditionally separate for the backhaul and for the LTE radio network; however, several benefits can be exploited from the integration of these tools, as discussed in a Chapter 7.

Detailed planning of backhaul physical layer technologies—like optical links, wavelength division multiplexing and wireless (microwave) links—would all need a book of their own to be properly covered, and such reference books exist, and those should be used as additional sources of knowledge for detailed planning with those technologies.

The standards for the radio technologies discussed in this book in relation to the evolution of LTE‐A are those finalized by the Third Generation Partnership Program (3GPP) at the spring of 2015. Constructing design guidelines for functionalities where standardization is in progress is difficult; however, key LTE advanced functions and their foreseen impact to backhaul are included in section 2.7.

reference

Metsälä E. and Salmelin J. (eds) (2012) Mobile Backhaul. John Wiley & Sons, Ltd, Chichester, UK, doi: 10.1002/ 9781119941019.

LTE Backhaul: Planning and Optimization, First Edition. Edited by Esa Markus Metsälä and Juha T.T. Salmelin. © 2016 John Wiley & Sons, Ltd. Published 2016 by John Wiley & Sons, Ltd.

LTE Backhaul

Gerald Bedürftig1, Jouko Kapanen2, Esa Markus Metsälä2 and Juha T.T. Salmelin21 Nokia Networks, Berlin, Germany2 Nokia Networks, Espoo, Finland

2.1 Introduction

This chapter gives an overview of different aspects of LTE backhaul. An introduction about the different elements of a backhaul network, the different end‐to‐end (e2e) services and the requirements of the LTE Mobile Access network are given. A short explanation of the different L1 possibilities for the defined network areas is also included. In addition, a prospective of future requirements and an overview of the relevant standards are provided. A general under-standing of packet‐based backhaul networks is a prerequisite for an understanding of this chapter. More detailed information can be found in Metsälä and Salmelin (2012).

With LTE, the backhaul network will be further extended toward the core network. For second‐generation (2G) networks the backhaul consisted of an access part and in most cases one level of aggregation until the base station controller (BSC) was reached. Third generation (3G) further concentrated the radio network controller (RNC) site locations and so additional aggregation layers needed to be considered. With the elimination of the RNC in the LTE architecture, a further concentration of the mobility management entity (MME), serving gateway (S‐GW) and packet data network gateway (P‐GW)—which in most cases were combined as a serving and packet data network gateway (SP‐GW)—was the consequence. In addition to multiple aggregation levels, parts of the IP backbone network may be passed to connect the eNBs with the core network elements. Figure 2.1 gives an overview of the nomen-clature and Figure 2.2 shows the different network areas used in this book.

As seen in Figure 2.2 the network that is the focus of this book will be the network between eNB and the respective core network elements. Backhaul elements are the network elements which are located between eNB and core network elements. Their purpose is simply to provide the relevant e2e services (see Section 2.2) by closing the geographic distance between the mobile nodes in a secure and cost‐efficient manner.

2

4 LTE Backhaul

In the future, “fronthaul” will be relevant for remote radio heads (RRH) or distributed antenna systems and “small cell” backhaul, which is about the backhauling of high‐density base stations in urban areas. Currently, fronthaul still requires dedicated fibers. Other wireless technologies or even fronthaul via a shared switching network are being considered but are not yet ready. Section 2.8 gives a short overview of small cell backhaul planning. Additionally, in the future functionality like caching and distributed security features may become relevant.

eNB Switch/router

Certificationauthority

WDM

Electrical GbE Optical GbEDSLconnectionMWR link with

two ODUs

Securitygateway

Timingmaster

MME S-GW P-GW NMS

Figure 2.1 Network element symbols

Access

Firstmile

Pre-aggregation

Certificationauthority

IP core

NMS

S-GW

P-GWMME

Aggregation

Securitygateway

Timingmaster

Timingmaster

Securitygateway

Figure 2.2 Definition of network areas