Hybrid PtP/LTE Infrastructure planning focusing on CAPEX-based migration

AALBORG UNIVERSITY

NETWORKS AND DISTRIBUTED SYSTEMS

MASTER THESIS

Hybrid PtP/LTE Infrastructure planningfocusing on CAPEX-based migration

Authors:Konstantinos PAPAEPTHIMIOUDimitar MIHAYLOVYonas TEFERA

Supervisors:Jose GUTIERREZ

Nuno PRATAS

June 6, 2013

School of Information and Communication TechnologyNetworks and Distributed SystemsFrederik Bajers Vej 7Telefon +45 99 40 86 00http://www.sict.aau.dkE-mail [email protected]

Title:Hybrid PtP/LTE Infrastructure planning fo-cusing on CAPEX-based migration

Project Period:P10, Spring semester 2013

Project group:13gr1024

Group members:Yonas Yehualaeshet TeferaDimitar Mihaylov MihaylovKonstantinos Thomas Papaefthimiou

Supervisor:Jose Manuel GutierrezNuno Killerich Pratas

Number of copies: 6

Number of pages: 129

Appended documents: appendix + CD-ROM

Finished: 26-06-13

Abstract:

Fiber, currently and for the next 40 years, is pre-dicted to be the highest bandwidth offering wire-line technology.Long Term Evolution (LTE) is a very promisingwireless technology, already commercialized andcurrently targeting the mobile market.This project integrates both technologies into a hy-brid broadband network infrastructure for providingfixed connectivity, focusing on the network designpart. Algorithms for minimizing the total CapitalExpenditure (CAPEX) in both deployments are im-plemented. A way for migrating from LTE towardsFiber to the home (FTTH) within 8-year time inter-val, until 2020, is proposed, pointing out the areaswhere one technology is preferable over the otheras well as how these two technologies can be com-bined to achieve a low-cost network deployment.Several programming tools have been used duringthe technical phase. The hybrid network architec-ture is designed, using as a test case Aalborg com-mune, Denmark.

The content of this report is freely available, but may only (with source indication) be published after agreement with the authors.

PrefaceThis report is made by a group of 4th semester students of the Network and Distributed Systems mastersprogramme at Aalborg University.

This report consists of four parts: Preliminary Analysis, Design and Implementation, Conclusion and As-sessment, and Appendix. The Preliminary phase will contain an analysis of the project and the existingtechnologies that has an influence on the current survey. The goal of this part is to end up with a completedescription of what should be developed during the rest of the project. The Design and Implementationpart will contain the development and implementation of the system described in the Preliminary Analy-sis. The Conclusion and Assessment is used to conclude on the entire project, as well as discussing whatwas achieved, and what should be included as a future work.

Throughout the report external references will be displayed as numbers, an example of this is: [1]. If thereport is read digitally these references will be interactive, and they can be used to jump directly to thereference in the reference list.

The report also contains a glossary list where acronyms and abbreviations used in the report can be found.These glossaries will be interactive in the same manner as the references.

As a part of the project is a CD. This CD contains Geographical information system (GIS) related data,the developed software and a digital copy of the report.

Yonas Tefera Dimitar Mihaylov

Konstantinos Papaefthimiou

Table of contents

1 Introduction 12

I Pre-analysis 14

2 Problem statement 15

3 Previous related work 17

4 Technologies 194.1 Fiber Optics Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194.2 Long Term Evolution(LTE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

5 Network Planning 325.1 Fiber Access Network Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325.2 LTE Cellular Network Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

6 Aalborg Commune 546.1 Information about Aalborg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 556.2 Statistical information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

II Design and Implementation 61

7 Access network Design 627.1 Planning of the fiber access network . . . . . . . . . . . . . . . . . . . . . . . . . . . . 627.2 Planning of the fixed LTE Access Network . . . . . . . . . . . . . . . . . . . . . . . . . 77

8 Economic Analysis 928.1 Fiber access network cost Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . 938.2 LTE Cellular Network Cost Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . 1008.3 Migration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

1

TABLE OF CONTENTS

III Conclusion and Future work 110

9 Conclusion 111

10 Future work 112

IV Appendix 118

2

Acronyms

3GPP Third Generation Partnership Project. 1, 4, 16, 17

AGI Association for Geographic Information. 1

AON Active Optical Network. 1, 9, 24, 2729, 54

BCNIS Battlefield Command Network Integration and Simulation. 1

BS Base Station. 1, 4, 5, 21, 31, 3638, 43, 44, 48, 67, 6971, 7375, 7883, 9294, 97100, 103105,107

CAD Computer Aided Design. 1

CAPEX Capital Expenditure. I, 1, 5, 79, 28, 34, 35, 44, 46, 85, 88, 89, 91, 92, 94, 100

CDF Cumulative Distribution Function. 1, 95

CDMA Code Division Multiple Access. 1, 14, 16

CN Communication Node. 1

CNP Center for Network Planning. 1, 9, 55

CO Central office. 1, 9, 10, 2429, 33, 34, 44, 48, 55, 56, 58, 59, 6167, 7981, 85, 8794, 97, 100,101, 104, 105

CPE Customer Premises Equipment. 1, 24, 59

DBMS DataBase Management Systems. 1

DFS Depth First Search. 1, 85

DL Downlink. 1, 107

DN Distribution Node. 1

DSL Digital Subscriber Line. 1, 5, 7, 52, 93, 105

3

Acronyms

EDGE Enhanced Data for Global Evolution. 1, 16

EPON Ethernet Passive optical network. 1, 34

EU Europian Union. 1, 10

EV-DO Evolution Data Optimized. 1, 14

FDD Frequency division duplex. 1, 42, 107

FDMA Frequency Division Multiple Access. 1

FTTC Fiber to the curb. 1, 5, 93

FTTH Fiber to the home. I, 1, 5, 710, 15, 26, 35, 52, 54, 59, 68, 85, 89, 93, 94, 103, 105

GIS Geographical information system. I, 1, 9, 31, 37, 5456, 74

GPON Gigabit Passive optical network. 1, 34

GPRS General Packet Radio Service. 1

GRASS Geographic Resources Analysis Support System. 1

GSM Global System for Mobile Communications. 1, 4, 16, 92

HDTV High Definition Television. 1, 4, 7

HSDPA High Speed Downlink Packet Access. 1

HSPA High Speed Packet Access. 1, 14, 1620, 22

HSUPA High Speed Uplink Packet Access. 1

ICT Information and Communications Technology. 1

IMS Internet Map Server. 1

IP Internet Protocol. 1, 4, 16, 19

ISI Information Scienses Institute. 1

ISP Internet service provider. 1, 7, 16, 25, 44

ISPs Internet service providers. 1

JTRS Joint Tactical Radio System. 1

KPI Key performance indicators. 1, 36

LAN Local Area Network. 1, 24, 30, 35, 55

LED Light emitting diode. 1, 11

LOS Line of Sight. 1, 38, 43

4

Acronyms

LP Linear Programming. 1

LTE Long Term Evolution. I, 1, 4, 5, 7, 8, 1423, 36, 37, 4145, 48, 52, 70, 72, 78, 79, 8183, 85, 89,9295, 97, 98, 100, 101, 103105, 107

MIMO Multiple Input Multiple Output. 1, 16, 17, 21, 22, 37, 38, 69, 72

MN Main Node. 1

MPLS MultiProtocol label Switching. 1

MST Minimum Spanning Tree. 1, 58

NC Network Consumer. 1

NLOS None Line of Sight. 1, 38

NP Network planning. 1

NRA NetRule Agent. 1

NS Network Simulator. 1, 71

NT Network Termination point. 1, 10, 25, 32, 33, 47, 5457, 62, 6468, 7074, 78, 79, 81, 82, 85,8798, 100, 103105

ODN Optical Distribution Network. 1

OECD Organization for Economic Co-operation and Development. 1, 41

OFDMA Orthogonal Frequency Division Multiple Access. 1, 16, 20

OGC Open Geospatial Consortium. 1

OLT Optical line terminator. 1, 25, 58

ONT Optical network terminal. 1, 25

ONU Optical Network Unit. 1

OPEX Operational Expenditure. 1, 16, 34, 35, 45

OSPF Open Shortest Path First. 1

P2MP Point-to-Multi-Point. 1, 43

PCP Primary Concentration Point. 1, 10, 55, 56, 58, 59, 62, 6467, 85, 8891, 96, 97, 105

PL Path loss. 1, 37, 71

PON Passive optical network. 1, 9, 2429, 34, 54

PtP Point-To-Point. 1, 9, 10, 2426, 28, 29, 34, 43, 54, 59, 97

QoS Quality of Service. 1, 39

5

Acronyms

R&D Research and Development. 1

RF Radio Frequency. 1, 107

SC-FDMA Single-Carrier Frequency Division Multiple Access. 1, 16, 20

SDTV Standard Definition Television. 1

SIMO Single Input Multiple Output. 1

SIS Spatial information System. 1

SMT Minimal Steiner Tree. 1, 9, 58

SNR Signal-noise-ratio. 1, 70, 72

SP Segment Point. 1, 3134, 56, 57, 63, 64, 66, 67, 81, 8791, 96, 97, 104

SPoF Single point of failure. 1, 105

SQoS Structural Quality of Service. 1

TCP Transmission Control Protocol. 1, 19

TDD Time division duplex. 1, 42, 107

TDMA Time Division Multiple Access. 1

telco Telecommunication company. 1, 5, 7, 10, 40, 47, 52, 84, 93, 94, 105

TSP Travelling Salesman Problem. 1

UE User Equipment. 1, 2022, 38, 107

UL uplink. 1, 107

UMTS Universal Mobile Telecommunications Service. 1, 4, 16, 20, 21, 43, 92, 93

USC University of South California. 1

VARs Value Added Resellers. 1

VAT4Net Visualization and Animation Tool for Network simulations. 1

VoIP Voice over IP. 1, 21

WCDMA Wideband Code Division Multiple Access. 1, 14, 16

WDM Wavelength division-multiplexing. 1, 34

WFS Web Feature Service. 1

WMS Web Map Service. 1

6

List of Figures

3.1 PON vs. PtP CAPEX comparison in Lolland[11] . . . . . . . . . . . . . . . . . . . . . 18

4.1 Fiber optic cable [13] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.2 Pig tail [13] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.3 Single mode fiber structure [14] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.4 Cellular Network Technology Speed Comparison[16] . . . . . . . . . . . . . . . . . . . 22

4.5 The evolution of LTE beyond LTE-A[19] . . . . . . . . . . . . . . . . . . . . . . . . . 24

4.6 Comparison of current cellular technologies average spectral efficiency . . . . . . . . . 26

4.7 Comparision of LTEs peak theoretical throughput . . . . . . . . . . . . . . . . . . . . 26

4.8 Comparision of LTEs Latency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.9 Downlink spectral efficiency of a Release 8 LTE FDD system with 4x2 SU-MIMO in theITU-R deployment scenarios. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

4.10 Relative spectral efficiency compared to 10MHz bandwidth in macro cells . . . . . . . . 31

5.1 PON architecture [25] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

5.2 Point-To-Point architecture [26] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

5.3 Cost breakdown for Point-to-Point[11] . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

5.4 Active Architecture [25] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

5.5 Energy consumption in Access network [28] . . . . . . . . . . . . . . . . . . . . . . . . 37

5.6 General wired planning method structure including Data preparation and planning algorithms[11] 38

5.7 General wired planning method structure including documentation presentation[11] . . . 39

5.8 Aalborg commune drew in MapInfo . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.9 Part of an optical fiber network[11] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

7

LIST OF FIGURES

5.10 Deleting SPs of degree 2 and all the segments interconnecting them[11] . . . . . . . . . 41

5.11 Normalized network[11] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

5.12 FTTH price breakdown[30] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

5.13 OPEX cost breakdown for keeping the network up and running[30] . . . . . . . . . . . . 43

5.14 Network planning process steps[32] . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

5.15 LTE dimensioning example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

5.16 LTE typical CAPEX breakdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

5.17 LTE typical OPEX breakdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

6.1 Aalborg area presented in terms of density . . . . . . . . . . . . . . . . . . . . . . . . . 55

6.2 Aalborg population by age . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

6.3 Aalborg population projection by age and time . . . . . . . . . . . . . . . . . . . . . . 57

6.4 Aalborg households with respect to size and time . . . . . . . . . . . . . . . . . . . . . 58

6.5 Activity and Employment rates by age . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

6.6 Use of Internet for communication activities by communication activity, time, type, re-gion, age category and employment status . . . . . . . . . . . . . . . . . . . . . . . . . 59

7.1 Point-To-Point architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

7.2 Data Preparation[11] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

7.3 k-means clustering: [47] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

7.4 Planning Algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

7.5 Digital representation of Aalborg area including road map, NT distribution and CO location 70

7.6 NT color notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

7.7 Astar algorithm vs Euclidean Distance algorithm in allocating SPs to the nearest CO[11] 71

7.8 Nodes not connected to the main node network . . . . . . . . . . . . . . . . . . . . . . 71

7.9 PCPs location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

7.10 PCPs with the corresponding to them NTs . . . . . . . . . . . . . . . . . . . . . . . . . 74

7.11 Applied A* algorithm in CO1 region . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

7.12 Base Station Honeycomb Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

7.13 NT Cumulative Distribution in Aalborg commune . . . . . . . . . . . . . . . . . . . . . 83

7.14 Possible BS Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

7.15 Flowchart for the Selection of BS Locations . . . . . . . . . . . . . . . . . . . . . . . . 85

7.16 Digital representation of 95% coverage of Aalborg NTs achieved by 180 BSs . . . . . . 87

8

LIST OF FIGURES

7.17 Matplot digital representation of the area served by CO4 and the corresponding trenchingpaths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

7.18 Digital representation of 95% coverage of Aalborg NTs achieved by 20 BSs . . . . . . . 90

8.1 Algorithm for calculating cost per NT(s) added to the fiber access network . . . . . . . . 94

8.2 Example of the algorithm run in a small part of south-west part of Aalborg area . . . . . 96

8.3 Algorithm 2 for calculating cost per NT(s) . . . . . . . . . . . . . . . . . . . . . . . . . 98

8.4 Average total cost per household in whole area . . . . . . . . . . . . . . . . . . . . . . 99

8.5 Average LTE deployment Cost-per-User in Urban, Suburban and Rural . . . . . . . . . . 101

8.6 LTE users migration towards 35-50-65% FTTH coverage using Algorithm 1 . . . . . . 103

8.7 Cost CDF plot for designed Fiber and LTE access networks . . . . . . . . . . . . . . . . 104

8.8 K-means clustering influence on calculation of shared NTs cost with Algorithm 2 . . . . 104

8.9 The decline in number of NTs connected to fixed LTE . . . . . . . . . . . . . . . . . . . 105

8.10 Rise in number of fiber connected NTs in deployment phases . . . . . . . . . . . . . . . 105

8.11 Migrating users between overlapping LTE BSs . . . . . . . . . . . . . . . . . . . . . . 106

8.12 LTE users migration towards 35-50-65% FTTH coverage using algorithm 2 . . . . . . . 107

8.13 Migration of users from LTE to Fiber . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

10.1 LTE FDD Frequency Bands and Channel Numbers . . . . . . . . . . . . . . . . . . . . 119

10.2 LTE TDD Frequency Bands and Channel Numbers . . . . . . . . . . . . . . . . . . . . 120

10.3 WINNER II Path Loss Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

10.4 Aalborg normalized table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

10.5 Node termination table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

10.6 Number of NTs connected to specific SP . . . . . . . . . . . . . . . . . . . . . . . . . . 126

10.7 ID of each NT, SP, PCP, CO and their coordinates respectively as well as the length andthe density of each NT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

10.8 SPs IDs and their coordinates respectively as well as the length and to which CO they areconnected to . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

10.9 NT, SP and BS IDs and their coordinates respectively as well as the CO they are connectedto and how much it costs to connect each NT to the network . . . . . . . . . . . . . . . 129

9

List of Tables

4.1 Characteristics of Different Cellular Networks[18] . . . . . . . . . . . . . . . . . . . . . 23

5.1 Advantages and disadvantages of the different technologies[11] . . . . . . . . . . . . . . 36

5.2 Consumer Internet Traffic, 2011-2016 . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

5.3 Regional Fixed Broadband Penetration for Western Europe . . . . . . . . . . . . . . . . 48

5.4 Average monthly Download Volume of Fixed Broadband Subscriber . . . . . . . . . . . 48

5.5 Terminal Catagories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

5.6 Comparison of mentioned high data rate technologies for cellular backbone networkimplementation[43] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

7.1 Number of SPs and NTs connected . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

7.2 Comparison between the total Fiber, Digging length and Costs using the Astar algorithmfor the PtP architecture, with respect to each CO . . . . . . . . . . . . . . . . . . . . . . 76

7.3 Input parameters for PL calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

7.4 Average Data Rate of Fixed Broadband Subscriber . . . . . . . . . . . . . . . . . . . . 81

7.5 Number of Subscribers per Site that can be served by the proposed LTE Technology . . 81

7.6 Average Population density of Urban, Sub-urban and Rural Denmark . . . . . . . . . . 82

7.7 NT density of Urban, Sub-urban and Rural Denmark . . . . . . . . . . . . . . . . . . . 82

7.8 Total number of BSs connected to each CO . . . . . . . . . . . . . . . . . . . . . . . . 89

7.9 Total number of NTs connected to each BS . . . . . . . . . . . . . . . . . . . . . . . . 90

8.1 Average CAPEX per household for Rural, Suburban and Urban areas in Aalborg returnedby the cost calculation algorithm 8.1 on page 94 . . . . . . . . . . . . . . . . . . . . . . 97

8.2 Capex elements cost assumptions for LTE network design . . . . . . . . . . . . . . . . . 100

10

LIST OF TABLES

8.3 Total cost of LTE deployment in each CO . . . . . . . . . . . . . . . . . . . . . . . . . 100

8.4 Total number of BSs in the three deployment phases . . . . . . . . . . . . . . . . . . . . 106

8.5 Three Phase Theoretical* Coverage of Fiber and LTE . . . . . . . . . . . . . . . . . . . 108

8.6 Total CAPEX in Fiber, LTE and Hybrid architectures . . . . . . . . . . . . . . . . . . . 109

11

Chapter 1Introduction

In the last decade bandwidth requirements have grown tremendously. Bandwidth hungry services suchas file sharing, video streaming, online gaming, High Definition Television (HDTV) and cloud-basedservices are becoming immensely popular and have been gaining popularity over the last few years.These combination of services continue to put pressure on the existing network infrastructure. As a re-sult, a high-speed affordable broadband connectivity to Internet is essential, offering widely recognizedeconomic and social benefits. To achieve this in todays competitive markets, it is crucial for network op-erators to look for different wire-line and wireless high-speed broadband technologies, to ensure best userexperience and provide service differentiation. The wire-line network is enabling a rapid convergence ofInternet Protocol (IP) video, audio and data into completely new applications, while broadband wirelessnetworks promise to provide access to these any time, anywhere. In recent years, a number of studiesare carried out on hybrid optical-wireless access technologies[2][3][4], which are believed to be the maintechnologies for next generation networks.

The ever growing need of higher bandwidth and offered capacity from the network side to meet usersdemands, gave birth to ever-increasing capacity wireless networks. Shortly after the establishment of2G wireless networks in the market, launched on the Global System for Mobile Communications (GSM)standard, 3G networks were developed, mostly known from the Universal Mobile TelecommunicationsService (UMTS) standard, and 4G-LTE network has been already standardized and is taking a bigger mar-ket share. LTE describes the standardization work by the Third Generation Partnership Project (3GPP)to define a new high-speed radio access method for mobile communication systems [5]. It is standard-ized so that it will be compatible with previous generation network infrastructures and can be establishedeasily both as a green-field 1 and brown-field 2 network, utilizing already built Base Station (BS)s afterundertaking specific modifications. It also has sufficient capacity to support IP based streaming videoand multimedia services to a large number of consumers simultaneously[6], with a quality that most willfind attractive. In addition, LTE offers significantly higher capacity at a lower cost per bit[7], leading toimproved commercial viability for operators and subscribers.

1Installation and configuration of a brand new network where no telecommunication infrastructure exists2Upgrade/expansion of already existing network infrastructure

12

CHAPTER 1. INTRODUCTION

In the fixed wire-line access networks, the increasing demand of traffic due to bandwidth intensive ser-vices is putting pressure on the currently vast deployed traditional networks, like Digital SubscriberLine (DSL). As legacy, copper-based access networks continue their inevitable decline in deployment,Telecommunication company (telco)s are investing in fibre access networks, which is a future prooftechnology. The strength of fiber optical technology comes from its ability to displace electronics andsimplify the network by combining network tiers[8]. The access networks for this technology have differ-ent deployment architectures, with FTTH as an all fiber access network architecture or Fiber to the curb(FTTC) which can also be deployed in combination with copper. Even though FTTH has higher initialdeployment cost, it has obvious advantages for the consumer because it provides a better performancethan broadband services delivered primarily over copper networks and hybrid ones both now and in theforeseeable future.

As data, voice and video gradually converge, wireless and wire-line networks are also converging. Cur-rently, with its high capacity throughput achievable, LTE offers an option for deploying high speed cellu-lar wireless networks even as an alternative for fixed wire-line broadband networks, where there deploy-ment is too expensive. This does not always mean that wireless networks are used only as an alternative tofixed wire-line access networks, rather they are complementary for fixed broadband. This kind of hybridnetwork is very much related to the nature of the area the network infrastructure is built, the competitionfrom other telcos in the same region, the cost of investment and the risk of replacing xDSL if necessary,which is a temporary, though established solution for fixed broadband connectivity.

In this project a hybrid access network infrastructure is proposed , which integrates LTE(supported by afiber backhaul network) and FTTH architectures. The geographical area targeted for the deployment ofthis network is Aalborg Commune, Denmark. The main focus of this project is on the infrastructural partof the network, which starts with a general discussion about the access technologies that can be applied.Thereafter, LTE and FTTH networks, as standalone entities, are designed. An optimization algorithm forminimizing the total number of BSs, preceded by graph algorithms for the CAPEX minimization are usedin the LTE and fiber network design, respectively. Algorithms for calculating the total deployment cost,in terms of cost per user, are implemented for the fiber case. Based on the obtained results, an economicanalysis is done to compare and contrast which technology is preferable over the other and where todeploy it. Based on the future traffic estimations and the digital agenda targets set by the Europeancommission[9], a time plan is set to show a migration of users towards FTTH in the upcoming years.Finally, all the obtained results are presented and a conclusion is made.

13

Part I

Pre-analysis

14

Chapter 2Problem statement

The worldwide demand for higher speed access to current and new technological breakthroughs is everincreasing. Smart phone devices have already flooded the market and new bandwidth-hungry applicationsare continuously becoming available. HDTV is already a reality, and with promising technologies such astele-medicine and tele-conference becoming part of ordinary peoples lives, the need for higher capacityis unquestionable. The downloading, streaming, entertainment and in general high speed connectivity tothe worldwide web, all need the existence of high capacity network infrastructures.

The current DSL infrastructure, which penetrates the market by far, has faced a difficulty to cope withthe forecasted users needs for high speed services in the following years due to the limited throughputit offers[10]. In order to meet such needs, Internet service provider (ISP)s and telcos are showing a ten-dency of migrating to future high-speed broadband network infrastructures. In mobile cellular networks,the trend shows a migration towards LTE technology. In wire-line networks, focus is mainly shown inVDSL, due to the already wide existing copper infrastructure in the last-mile access part, and in FTTH,mainly in developed countries. In fiber connectivity, the initial deployment cost (CAPEX) is high, beingan inhibiting factor for investment. However, as fiber networks are designed with a lifespan of 30-40years, and the users traffic demands will continue rising, FTTH will prove to be essential until the end-users premise.

Facing this high cost expenditure of designing and implementing green-field network infrastructures,most telcos are trying to exploit and reutilize their existing one, mainly wireless. Leasing parts of net-works is a common practice for ISPs to keep up with the fierce competition in the telecommunicationsmarket. In many cases, this financial weakness from the operators side has an impact on the users qual-ity of offered services. In that cases, hybrid network formations can prove to be a cost-wise solution.

In this project we propose a hybrid broadband network planning process, comprising of both FTTH andLTE in the local loop. We exemplify how such process would occur in a real scenario, by applying it toAalborg commune in Nordylland, Denmark.

How does a green-field deployment of such a hybrid network looks like nowadays?

15

CHAPTER 2. PROBLEM STATEMENT

What is the total CAPEX of deploying such a network? How can migration from LTE towards FTTH be achieved until year 2020 and what is the price for

that transition?

Which areas (Rural, Suburban, Urban) are the most suitable for the technologies discussed fromcost and deployment ease perspective?

All these questions will be thoroughly discussed throughout the present project report, ending up with aproposed planning solution for the current test-case, also applicable in diverse geographical areas. f

16

Chapter 3Previous related work

Related work on the network planning field has been previously carried out by the same members of thegroup as part of the 9th semester MSc project work. The project, titled - PON and Point-to-Point FTTHbased infrastructure planning in Lolland municipality - focused only on the fiber optics technology for agreen-field implementation of the access network in the fourth biggest island of Denmark.

Both projects pose some similarities on the planning process and that is the reason that specific partsincluded in the current report are referenced to the previous one. Similarly to the current project, pro-vided GIS data corresponding to houses and the road network in Lolland municipality has been providedby the Center for Network Planning (CNP) of Aalborg University. The target has been set to deploy agreen-field FTTH network aiming at 100% coverage of premises in the area. Passive optical network(PON), Point-To-Point (PtP) and Active Optical Network (AON) architectures have been compared andthe first two have been implemented. CAPEX of the two deployed architectures has been calculated andthe best cost-wise solution has been chosen as the preferable technology for deployment in the area. Thesame tools have been used to achieve the goal set. Minimal Steiner Tree (SMT) algorithm has been im-plemented by the group members during this time. Also, k-means clustering algorithm took its currentform at this period of time.

Looking back at this project, 100% of premises were connected to the access network using PtP topology,while 99.98% of them were connected using PON topology. SMT and A algorithms have been used tocalculate the total trenching and fiber length for connecting the end users to the access network in botharchitectures. The PON architecture in the area and trenching as well as deploying the fiber cables fromthe Central office (CO) until the users premises using SMT algorithm, returned the least expensive solu-tion. The results are summarized in figure 3.1 on the next page.

We indicatively mention that the overall expenditure (CAPEX) calculated in the PON case using SMTalgorithm, amounted to 425 Million crones with 722 thousand crones less than using A approach bothfor trenching and fiber deployment in the area.

17

CHAPTER 3. PREVIOUS RELATED WORK

Figure 3.1: PON vs. PtP CAPEX comparison in Lolland[11]

It should be stated here that not everything was reused in the current project the way it was developedthen. In this project, PtP architecture has been chosen for the FTTH network deployment for reasonsthat will be later on justified. A big improvement has been achieved in the planning method of the ar-chitecture, that brings it closer to real-life implementation. In the 9th semester project, PtP has beendeployed as a single dedicated link connecting the CO with the corresponding household. In other words,for two houses that are a few meters away from each other, one fiber cable will start from the CO untilthe first house and a second one will start from the same CO up until the second premise. However, thisis not applicable in real case scenarios, especially when PtP topology is used to connect a high numberof Network Termination point (NT)s with a CO. The way the topology is designed in the current project,which adjusts to real life implementation, is by bundling a certain number of fiber cables that start fromthe CO up until a Primary Concentration Point (PCP), and are spliced from that point on to connect theend users premises. In that way, more accurate calculation of the total fiber cost needed to add end usersto the access network is achieved, as the price of the fiber bundle differs from the price of a single fibercable pair (Uplink & Downlink) corresponding to an individual customer.

The proposed final hybrid network design now and in the upcoming years is regarded to be an improve-ment compared to a green-field 100% FTTH deployment in an area. Currently, the cost needed for a purefiber access network deployment is very high for a telco. If the FTTH is deployed by a municipality ora government, it is most probably funded by the Europian Union (EU), turning it into a more feasibledeployment case. It also makes sense that no telco intends to build a FTTH network targeting at con-necting 100% of the residents in a big city, for the reason that customers penetration into the new builtnetwork will never reach that percentage. In reality, such a network is built stepwise, prioritizing densecity centres (cost-related decision) as well as certain end-users (industrial zones, big enterprises, schoolbuildings, univercity campuses etc.). Areas where broadband infrastructure is absent are also acceptablecandidate places for deployment. After the network is launched, it is expected to grow steadily to covermore regions depending on the customers needs, a fact that is taken into consideration in the currentproject.

18

Chapter 4Technologies

4.1 Fiber Optics Technology

What is fiber optics1

Fiber optics or optical fiber is a light, flexible, transparent fiber usually made of glass, quartz orplastic, which act as a wave carrier for the light signal [12]. For a special application the fiber canbe made of sapphire, fluoride or calcogenide. Due to their flexibility they can be produced in anypossible length. In order to achieve good light transmission some requirements should be fulfilled:

Pure glass materials for the core should be used

High transparency for the spectrum of interest

Minimum optical dispersion is also required - meaning that when the light is reflected itshould keep its phase velocity (or the rate at which the phase of the wave propagates in space).Basically this parameter shows how light can be deformed while it is propagated trough thefiber tube and it is the most important parameter that limits the bandwidth.

How does it functionOptical fiber is usually made of Silicia [13]. The main parts of a fiber can be seen on figure 4.1on the next page. The transmission in fiber optics is based on a light emitting device such as laserdiode or Light emitting diode (LED). The idea is that the diode will emit a light and this lightshould fill up the fiber tube. From technological point of view this is very hard to achieve becauseif we use a standard light bulb the light cannot be concentrated into the small fiber tube, which willlead to a light dispersal. That is why a lot of companies use the so called pig tail, which is detachedto the diode, as can be seen in figure 4.2 on the following page. The purpose of it is to assemblethe light from the source in order to optimize the light coupling and reduce the dispersal.

1The up-stated section 4.1 was obtained from report [11], which was written by the same group members that participated inwriting the present MSc thesis

19

CHAPTER 4. TECHNOLOGIES

Figure 4.1: Fiber optic cable [13] Figure 4.2: Pig tail [13]

When the transmission is initialized the light signal will start travelling through the already estab-lished glass tunnel. When the light reaches the cladding it will interact with it and at some pointit will reach the core material boundary and it will reflect back to the core. The core will use thelight to transmit and the cladding ensures that the light will be kept in the inner cylinder (or thecore). The core and the cladding are very sensitive and fragile so they should be protected by morelayers of coating, which can be produced by different materials depending on the application andthe environment where the fiber will be used. The thinnest part of the fiber is obviously the core.It reaches sizes around several m. In comparison with the core the cladding is few times bigger.The size of both is used as a classification of different type of fibers. As it was already mentioned,fiber has a big flexibility so it can be designed in a way that the light can band around curves whichwill allow it to travel over longer distance without the need of being amplified. The light signalis constructed of binary code that emits on and off from which the content information of a givensignal can be obtained.

Different optical fibers and cablesThe basic optical fiber cable can be seen on figure 4.3. The optical fiber is protected with a bufferenclosed in a buffer tube which allows flexibility and bending. Around this tube a Kevlar yarncould be used to reduce the stress and the pressure of the fiber. The outer layer or the so calledoutlet jacket is used to protect the cable from any moisture. The basic difference among all fibersis the size of the core (or the so called caring area).

Figure 4.3: Single mode fiber structure [14]

20


Single-mode fiber - The cable carries only one wavelength and it has smaller core comparedto the multi-mode fiber. Also, it has higher bandwidth and less losses. The standard single-mode fiber has size of usually 8-10 m. Because of its higher bandwidth, the single-modefiber is typically used when we want to transmit in a long distance, while the multi-mode fiberis typically used for distances less than 2 km.

Multi-mode fiber - When using multi-mode fiber we are capable of carrying multiple wave-lengths independent of the ones that are carried by the other multi-mode fibers in the samebundle. These large size bundles pose greater bandwidth. They allow hundreds of rays totravel simultaneously.

What are the advantages of using fiber opticsIn order to qualify the quality of the connection we should investigate how well the informationtravels from one point to another. Some of the main advantages and disadvantages based on thelight that can be used as a carrier are [15]:

Huge bandwidth for data transmission - Fiber optic operates at speeds in range of Gbpsto Tbps (depending on the network layer, for example if we are on the access layer or on thebackbone layer).

Low attenuation when the light travels through the optical cable - The attenuation indi-cates how much power of the pulse has been lost (dB/km). This loss in the fiber optics cablecan vary between 0.2 to 3.0 dB/km, depending on how the fiber is constructed, if there aremany bending or splicing places, if it is a single or multi mode fiber, etc.

Range - The fiber range transmission can be exceeded by the use of optical amplifiers.Theirplacement varies between 300 meters and 40 kilometres, depending on the cable type that isused, the network and the wavelength.

Material - Since fiber is made of glass there is no electromagnetic interference that can de-grade the propagation of the light signal. Fiber can be buried directly in most kinds of soiland will not be affected by any chemicals due to its glass structure

What are the disadvantages of using fiber opticsWhile the light is propagating through the fiber it will experience some losses:

There is always loss due to reflection when the light enters and exits surface of the fiber. The core of the cable is made of ultra-pure low-loss glass. So when the light has to travel few

thousand meters, the purity of the glass should be very high in order not to get losses or tominimize them as much as possible.

Another loss may emerge when the fiber is bent. This may lead the light to exit the core area.The smaller the bend radios is, the higher losses we experience.

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4.2 Long Term Evolution(LTE)

4.2.1 Evolution of Cellular Wireless Technologies

The mobile networks of most operators are witnessing an unprecedented rise in data traffic, due to anincreasing consumer demand to access bandwidth intensive content on-the-go and the proliferation of alarge number of mobile devices such as smart-phones and tablets. This trend is exerting extremely highpressure on the capacity constrained operators networks. Faced with this challenge, wireless providersneed to upgrade their network infrastructure in order to keep up with data traffic volumes and deliver bitsmore cost-effectively. This pressure leads to the change of different cellular mobile technologies in thepast few years.

The increasing proliferation of a range of Internet enabled mobile devices, added to the rising consumersneeds to access rich content, has resulted in the explosion of data traffic exerting an unprecedented de-mand on the network of wireless operators. Bandwidth intensive applications, especially those basedon video, expose the capacity bottlenecks and the gap which customers are increasingly facing betweenpeak rates in perfect conditions and real everyday experience. It is, therefore, imperative for operators toensure that the average users experience is not compromised, especially in high traffic areas.

In order to enhance subscriber experience, prepare networks capacity for bandwidth hungry applicationsand reduce operational expenditure, operators are upgrading their networks. Multiple technology optionscan serve towards this direction, such as Wideband Code Division Multiple Access (WCDMA), HighSpeed Packet Access (HSPA), HSPA+, Code Division Multiple Access (CDMA)2000, Evolution DataOptimized (EV-DO), WiMAX and LTE to choose from. The migration strategy of each operator is likelyto be different and will be based on several factors such as the existing state of their networks, currentand projected data demand, costs considerations and spectrum availability. However, given the variousmigration options, LTE seems to offer the most efficient, cost effective and future proof solution foroperators. LTE has led service providers to re-think their current deployment strategies in order to providethe highest data speed throughout their networks. When compared to some of the major technologiescurrently in deployment, LTE is overwhelmingly the preferred ones due to the data-rate speeds achievedas shown in fig 4.4.

Figure 4.4: Cellular Network Technology Speed Comparison[16]

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The main objective of this project is to design a fixed broadband network infrastructure in cost effectiveway. Currently, the preferred technology in fixed networks is FTTH, which is a future proof technol-ogy. Fixed cellular broadband technology is also becoming a popular connectivity option by networkproviders, where wired networks are not reachable or too expensive to deploy. Out of the two technolo-gies that are the core of this project, LTE is chosen as a fixed cellular broadband technology for thereasons discussed in section 4.2.2 on the next page. Before going directly to the design of the network,it is good to briefly discuss the evolution of cellular network technologies and detailed discussion of thetechnologies used here. Cellular broadband evolution[17] has taken the path shown in table 4.1.

2.5G 3G 3.5G 4G

EDGE cdma2000 UMTS1 EV DO2 HSDPA EV-DV LTE

Channel bandwidth (MHz) 0.2 1.25 5 1.25 5,10 1 .25, 3.75 5,10,15,20

Duplexing FDD FDD FDD FDD FDD FDD FDD/TDD

Multiplexing TDMA TDMA WCDMA TD-CDMA WCDMA TD-CDMA OFDM/SCFDMA

Modulation GMSK/8PSK

GMSK/8PSK

QPSK QPSK/8PSK/16QAM

QPSK/16QAM

QPSK/8PSK/16QAM

QPSK/16QAM/64QAM

Coding C CTC CTC CTC CTC CTC CTC

Maximum data rate (UL)0.04 (UL)0.05 (UL)0.14 (UL)1.8 (UL)2 (UL)1 (UL)50

(Mbps) (DL)0.18 (DL)0.38 (DL)0.38 (DL)3.1 (DL)7.2 (DL)3-5 (DL)1003

Table 4.1: Characteristics of Different Cellular Networks[18]

Where,

1 - Universal Mobile Telecommunications Systems R99 2 - Evolution data optimized (EV-DO) REV A 3 - No MIMO GMSK - Gaussian minimum shift keying QPSK - Quadrature phase shift keying QAM - Quadrature amplitude modulation TD-CDMA - Time division-synchronous CDMA OFDMA - Orthogonal frequency division multiple acces SC-FDMA: Single carrier frequency di-

vision multiple access

CTC - Convolutional/Turbo coding

23


4.2.2 Long Term Evolution

LTE is a pure packet switched evolution of UMTS 3G technology that builds on GSM/Enhanced Data forGlobal Evolution (EDGE) and WCDMA/HSPA technologies to make higher data rates for cellular broad-band services economically viable. The LTE approach is also suitable for replacing existing CDMA2000networks. This evolved technology offers significant advantages such as higher spectral efficiency, lowercost of transmission per bit, higher throughput, and lower latency when compared to existing wirelessnetwork technologies. It is also backward compatible with the CDMA family of technologies. Further-more, by deploying LTE, ISPs can significantly improve operational efficiency and reduce OperationalExpenditure (OPEX).

LTE delivers a performance superior to that of existing 3GPP networks based on HSPA technology.Specially with the evolution and standardization its going through, clearly it has a hugh potential for thefuture ever increasing data traffic in mobile networks. The standardization has been going on for a whileby 3GPP, with the first standard frozen out in 2008,in 3GPP release 8. The standardization and evolutionhas progressed with new releases in LTE-Advanced and now with LTE-Beyond as shown in figure 4.5.

Figure 4.5: The evolution of LTE beyond LTE-A[19]

The main characteristic summary of the different LTE releases are[20]:

3GPP Release 8 Freeze Date 2008 Release 8 introduced LTE for the first time, with a completelynew radio interface and core network, enabling substantially improved data performance comparedwith previous systems. Highlights included:

up to 300Mbit/s downlink and 75Mbit/s uplink latency down to 10ms implementation in bandwidths of 1.4, 3 ,5 , 10, 15 or 20MHz, to allow for different deploy-

ment scenarios Orthogonal Frequency Division Multiple Access (OFDMA) downlink, Single-Carrier Fre-

quency Division Multiple Access (SC-FDMA) uplink and Multiple Input Multiple Output(MIMO) antennas.

flat radio network architecture, with no equivalent to the GSM BSC or UMTS RNC, andfunctionality distributed among the base stations (eNodeBs).

all IP core network, the System Architecture Evolution (SAE).

3GPP Release 9 Freeze Date 2009 Release 9 brought a number of refinements to features in-troduced in Release 8, along with new developments to the network architecture and new servicefeatures. These included:

24


introduction of LTE femtocells in the form of the Home eNodeB (HeNB) self organising network (SON) features, such as optimisation of the random access channel evolved multimedia broadcast and multicast service (eMBMS) for the efficient delivery of the

same multimedia content to multiple destinations

location services (LCS) to pinpoint the location of a mobile device.

3GPP Release 10 Freeze Date 2011 Release 10 provided a substantial uplift to the capacity andthroughput of the LTE system and also took steps to improve the system performance for mobiledevices located at some distance from a base station. Notable features included:

up to 3Gbit/s downlink and 1.5Gbit/s uplink carrier aggregation (CA), allowing the combination of up to five separate carriers to enable

bandwidths up to 100MHz

higher order MIMO antenna configurations up to 8x8 downlink and 4x4 uplink relay nodesto support Heterogeneous Networks (HetNets) containing a wide variety of cell sizes

enhanced inter-cell interference coordination (eICIC) to improve performance towards theedge of cells.

3GPP Release 11 Freeze Date 2013 Release 11 will build on the platform of Release 10 with anumber of refinements to existing capabilities, including:

enhancements to Carrier Aggregation, MIMO, relay nodes and eICIC introduction of new frequency bands coordinated multipoint transmission and reception to enable simultaneous communication

with multiple cells

advanced receivers.

3GPP Release 12 Freeze Date 2014 Potential features for Release 12 were discussed at a 3GPPworkshop in Slovenia in June 2012. A strong requirement was the need to support the rapid increasein mobile data usage, but other items included the efficient support of diverse applications whileensuring a high quality user experience. Some of the candidates for Release 12 included:

enhanced small cells for LTE, introducing a number of features to improve the support ofHetNets

inter-site carrier aggregation, to mix and match the capabilities and backhaul of adjacent cells new antenna techniques and advanced receivers to maximise the potential of large cells inter-

working between LTE and WiFi or HSPDA

further developments of previous technologies.

Current commercial LTE deployments are based on 3GPP Release 8 and Release 9 that is, the firstreleases of the LTE technical specifications[19]. As a result the analysis and LTE parameters used in thisproject are taken from lte relese 8. The performance advantages of LTE Release 8 in 3GPP are definedrelative to HSPA Release 6. The main performance advantages are[21][22]:

Spectral Efficiency :LTEs spectral efficiency is two to four times more than HSPA Release 6. LTEs greater spectralefficiency allows operators to support increased numbers of customers within their existing and

25


future spectrum allocations, with a reduced cost of delivery per bit (Spectral Efficiency is discussedin detail on section 4.2.2.2 on page 30). Figure 4.6 shows the comparison of LTE with HSPA andWiMAX for different antenna configuration scenarios. As clearly seen from the results, LTE has abig advantage over the two currently competing technologies.

Figure 4.6: Comparison of current cellular technologies average spectral efficiency[22]

Peak rate exceeds 100 Mbps in the downlink and 50 Mbps in the uplink:Enhanced air interface allows increased data rates, with physical layer downlink peak data rates areextended up to a theoretical maximum of 300 Mbit/s per 20 MHz of spectrum.

Figure 4.7: Comparision of LTEs peak theoretical throughput[22]

26


Similarly, LTE theoretical uplink rates can reach 75 Mbit/s per 20 MHz of spectrum, with theo-retical support for at least 200 active users per cell in 5 MHz[23]. The comparison of theoreticalpeak downlink and uplink values for LTE with different antennas and bandwidth configuration areshown in figure 4.7 on the facing page.

Enables a Round Trip Time (RTT) of


working environment to their passengers. These requirements mean that handover between cellshas to be possible without interruption in other words, with imperceptible delay and packet lossfor voice calls, and with reliable and secure transmission for data services.

Optimized terminal power efficiency:A key consideration for competitive deployment of LTE is the availability of low-cost terminalswith long battery life, both in stand-by and during activity. Therefore, low terminal complexity hasbeen taken into account, as well as designing the system wherever possible to support low terminalpower consumption.

Frequency flexibility with allocations from below 1.5 MHz up to 20 MHz:The possible channel bandwidths used by LTE are 1.5, 3, 5, 10, 15 and 20 MHz. This flexible band-width is desirable to take advantage of the diverse spectrum assets: refarming typically requires anarrow-band option below 5 MHz while the new spectrum allocations could take advantage of awide band option of data rates by using upto 20 MHz.

4.2.2.1 Factors Contributing to LTE System Capacity[21]

LTEs system capacity is much higher than the currently existing 3GPP technologies. This increase incapacity is achieved by some technological factors included which didnt exist in other 3GPP technolo-gies or improved. The main difference in both downlink and uplink between LTE and UMTS Release 6(HSPA) is that the LTE system provides orthogonal resource allocation in the frequency domain, whichenables frequency-domain multi-user diversity gain to be exploited. In addition, the LTE downlink sup-ports transmission with up to two or four spatial layers via multiple antennas, which enhances the peakdata rate, the cell average and cell edge spectral efficiencies. The key features are discussed in more detailbelow:

Multiple Access Techniques:

Downlink: LTE downlink is based on OFDMA which enables flexible channel-dependentmulti-user resource allocation in both the frequency and time domains. This leads to improvedmulti-user diversity gain.There are two truly remarkable aspects of using OFDMA. First, each symbol is preceded bya cyclic prefix (CP), which is used to effectively eliminate Inter Spacial Interference(ISI).Second, the sub-carriers are very tightly spaced to make efficient use of available bandwidth,yet there is virtually no interference among adjacent sub-carriers (Inter Carrier Interference,or ICI).

Uplink: LTE uplink is based on the SC-FDMA scheme which enables to achieve frequency-domain intra-cell orthogonality among User Equipment (UE) while also maintaining a lowPeak-to-Average Power Ratio which is important for maximizing data rates at the cell edge.In addition, LTE uplink facilitates multi-user scheduling and rate adaptation strategies to en-hance spectral efficiency.

Frequency Reuse and Interference Management:LTE is designed to operate with a frequency reuse factor to maximize the spectral efficiency. Insuch a system, however, data and control channels can experience a significant level of interferencefrom neighbour cells, which reduces the achievable spectral efficiency, especially at the cell edge.LTE therefore supports various techniques to manage and mitigate inter-cell interference.

28


Multiple Antenna Technology:The LTE Physical layer can optionally exploit multiple transceivers at both the base-station andUE in order to enhance link robustness and increase data rates for the LTE downlink. This schemeis called a MIMO configuration. The use of multiple antenna technology allows the exploitationof the spatial-domain as another new dimension. This becomes essential in the quest for higherspectral efficiencies. Multiple antennas can be used in a variety of ways, mainly based on threefundamental principles:

Diversity gain: Use of the spatial diversity provided by the multiple antennas to improve therobustness of the transmission against multi-path fading. Normal two-branch diversity recep-tion or transmission has the benefit of producing two copies of the same signal for reception,which with a suitable signal combining technique reduces fading variation. For example, a2Tx * 2Rx antenna transmission results in reception of four signal replicas, with the corre-sponding additional reduction in fading.

Array gain: Concentration of energy in one or more given directions via pre-coding or beam-forming. This also allows multiple users located in different directions to be served simulta-neously. This requires closely spaced antennas, unlike the diversity schemes which require atleast a few wavelength antenna spacing.

Spatial multiplexing gain: Transmission of multiple signal streams to a single user on mul-tiple spatial layers created by combinations of the available antennas. For example, with 2Tx* 2Rx spatial multiplexing the idea is to transmit two parallel information streams over thesame bandwidth, hence theoretically doubling the data rate and spectral efficiency. In uplink,spatial multiplexing is not supported for a single UE, but two different UEs are allowed totransmit at the same time; this is called multi-user-MIMO.

Semi-Persistent Scheduling:The scheduler in the BS distributes the available radio resources in one cell among the UEs, andamong the radio bearers of each UE. The details of the scheduling algorithm are left to the BSimplementation, but the signalling to support the scheduling is standardized. The usual mode ofscheduling is dynamic scheduling, by means of downlink assignment messages for the allocationof downlink transmission resources and uplink grant messages for the allocation of uplink trans-mission resources; these are valid for specific single subframes.

LTE uses Semi-Persistent Scheduling (SPS) which alleviate pressure from the limited downlinkcontrol channel capacity by replacing dynamic scheduling signalling with semi-static signalling.This allows a larger number of UEs to be scheduled, which is especially beneficial for servicessuch as Voice over IP (VoIP) for which the data packets are small, periodic and semi-static in size.

Short Subframe Duration and Low Round Trip Time:LTE has a subframe duration of 1 ms for both uplink and downlink shorter than the 2 ms subframeduration of UMTS. This leads to reduced latency (with a shorter Round Trip Time (RTT)) and moreflexible multi-user scheduling in the time domain.

Advanced Receivers:Advanced receivers provide an implementation method to enhance further the capacity of LTE sys-tem. Suitable for both uplink and downlink, such receivers compute the signal combining weightsby exploiting statistical knowledge, such as the covariance matrix, of the inter-cell interference.This ability of the receivers to suppress interference using the statistics improves performance.

29


Layer 1 and Layer 2 Overhead:Any part of the time-frequency transmission resources that are not used directly for data transmis-sion constitutes an overhead when considering the overall spectral efficiency. One design criterionfor LTE was to minimize these overheads while achieving high system performance and flexibility.

4.2.2.2 Spectral Efficiency[24][21]

LTE technology is spectrally efficient, hence the number of bits per second over a fixed bandwidth ishigher than former technologies and as a result, if a reasonable error rate coding is taken into account , apeak data rate can be reached that is more realistic for commercial deployment. These capacity improve-ments over other 3GPP technologies is the key for achieving the efficiencies necessary to reach the massmarket and reducing the cost per bit for the operator.

Comparing the downlink Cell edge spectral efficiency and average spectral efficiency of LTE with HSPAfor different scenarios, LTE has a clear advantage over other technologies. This substantial gain is mainlyattributable to frequency domain multi-user scheduling and MIMO transmission. Figure 4.9 shows thedownlink average and cell-edge spectral efficiencies for Release 8 LTE FDD 4x2 downlink SU-MIMOtransmission in the ITU-R deployment scenarios.Vertical antenna tilting is assumed at the eNodeB, withtilt angles of 12, 12 and 6 degrees in the urban microcell, urban macrocell, and rural macrocell scenariosrespectively. The antenna separation is assumed to be four wavelengths at the eNodeB and half a wave-length at the UE. The higher performance in the indoor hotspot scenario compared with the others can beattributed to the isolated cell environment with low inter-cell interference; this is especially advantageousfor high-order MIMO spatial multiplexing.

Figure 4.9: Downlink spectral efficiency of a Release 8 LTE FDD system with 4x2 SU-MIMO in theITU-R deployment scenarios.

[21]

30


4.2.2.3 Spectral Efficiency as a Function of LTE Bandwidth[24]

Most LTE system simulations assume 10MHz bandwidth. The system bandwidth has some impact on theefficiency mainly due to the following factors:

The frequency domain scheduling gain is higher with larger bandwidth since there is more free-dom for the scheduler to optimize the transmission. For 1.4MHz bandwidth the frequency domainscheduling gain is very low since the whole channel bandwidth likely has flat fading.

The relative overhead from common channels and control channel is lower with larger bandwidths. The relative guard band is higher with a 1.4MHz bandwidth: six resource blocks at 180 kHz equal

to 1.08MHz corresponding to 77% utilization compared to the channel spacing of 1.4 MHz. Theutilization is 90% for other bandwidths.

The relative efficiency is quite similar for the bandwidths of 5 to 20MHz while there is a 15% differencefor 3 MHz. The efficiency with 1.4MHz bandwidth is approximately 35-40% lower than for 10 MHz.The typical downlink cell throughput for 20MHz is 1.74 bps/Hz/cell * 20MHz = 35 Mbps, while for1.4MHz the cell throughput is 1.74 bps/Hz/cell * 60% * 1.4MHz = 1.5Mbps. The results for relativespectral efficiency of bandwidths compared to 10MHz bandwidth in macro cells is shown in Figure 4.10.

Figure 4.10: Relative spectral efficiency compared to 10MHz bandwidth in macro cells[24]

The conclusion is that LTE should be deployed using as large bandwidth as possible. Main motivationsare to maximize the LTE data rates as well as optimize the spectral efficiency. The narrowband optionsare still useful for refarming purposes in case initial allocation of larger bandwidth is not possible.

The shift towards LTE is facilitated by all the advantages it has over other cellular technologies. As aresult, it is currently being deployed and built-out in all regions and continues to lead the way in thefuture.

31

Chapter 5Network Planning

5.1 Fiber Access Network Planning

At the current project fiber will be deployed in the access part of the network, or else, in the local loop.We assume that the Local Area Network (LAN) extends from the COs until the users premises. COswill not be interconnected with each other with a specific topology, such as ring or double ring. Hence,the network of COs does not belong to the backhaul network. In this chapter, three popular accessarchitectures will be presented and a comparison between them will follow. Also, a flowchart will begiven that determines the basic parameters that must be taken into account and actions that must be carriedout for a successful network design. Finally, some economic elements regarding the cost expenditure offiber will close up the chapter 1.

5.1.1 Optical access network architectures

The most commonly used architectures in the access network are PON, PtP and AON. None of them ispreferable over the other as basic differences concerning the topological formation exist. The choice ofthe most suitable one is related to the geographical area, scenario, problem scale and final target set.

5.1.1.1 Passive Optical Network

PON topology describes a single fiber separated into multiple strands. PON gets its name from thefact that no active electronics like power supply or any other power equipment is used within the accessnetwork (without taking into account equipment placed inside the CO and Customer Premises Equipment(CPE)). Instead, passive optical splitters are used to divide the bandwidth between the end users [25].Figure 5.1 on the next page shows the PON architecture and that the maximum coverage distance betweenthe CO and the end user should be in range between 10 and 20 kilometres, which also depends on thenumber of splits (for example this range could be exceeded with the use of optical amplifiers).

1The down-stated section 5.1.1 was obtained from report [11], which was written by the same group members that participatedin writing the following MSc thesis

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CHAPTER 5. NETWORK PLANNING

The main components in the PON architecture are:

Figure 5.1: PON architecture [25]

CO - It is a physical building located in an area and contains the inside plant equipment needed toestablish a fiber optical network.

Optical line terminator (OLT) - The OLT is placed inside the CO. Its two main functions are:

To convert the electrical signals used by the ISP equipment to send information over thenetwork, into a light used by the fiber optic infrastructure and in this case the PON.

To synchronize the multiplexing between the devices on the other side of the fiber optic cablewhich are called Optical network terminal (ONT)s.

Splitter - A passive component, which connects the CO with the NTs. The functionality of thisdevice is to split equally the bandwidth between the NTs connected to it.

ONT - A device that connects carriers network with the subscribers premises wiring. Both ofthese devices, OLT and ONT, require a power source.

5.1.1.2 Point-to-Point Optical Network

In PtP topology a direct and dedicated link between two end-point devices exist (the CO and the end user).This architecture is highly scalable, upgradeable and service transparent (meaning that it can provideservice regardless of the other users in the network) due to its flexibility. The PtP architecture providesmore bandwidth per end subscriber in comparison with the other shared networks and also dedicatedbroadband speed up to 1Gbps per subscriber.

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Figure 5.2: Point-To-Point architecture [26]

In a PtP network deployment, N number of fibers (this number depends on how many subscribers we willhave in the network) and 2xN number of transceivers are needed to provide certain service to N numberof end-users, as it can be seen on figure 5.2. Each new subscriber can be added without affecting therest connected to the network. This type of connection is also known as pay as you grow. One of thedrawbacks in this technology is that the increasing number of users will result into a higher number offibers into the CO, which will lead to an increase in the equipment needed to support the needs of eachsubscriber.

The PtP architecture is way more suitable in comparison with the already mentioned PON architecturein the sense that each individual user can be migrated to more powerful service without affecting therest of the users already connected to the CO. This fact applies for either home residence or businessusers, which makes this architecture very flexible for future proof solutions as it also provides virtuallyunlimited bandwidth per subscriber. Based on the statistical data from [27], the civil work costs the mostin the FTTH deployment of the network and this is common for the PtP and PON architecture. Figure 5.3shows the cost breakdown for PtP architecture. PtP architecture also supports the so called future-poofhybrid deployment, which is a mixture between the FTTH and FTTC with a copper (UTP) connection toeach subscriber.

Figure 5.3: Cost breakdown for Point-to-Point[11]

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5.1.1.3 Active Optical Network

AON got its name from the active elements included in the architecture. As it can be seen in figure 5.4,the active network looks quite similar and basically follows the same functionality pattern like the PONwith a few main differences:

Figure 5.4: Active Architecture [25]

The non-controlled passive optical splitter is substituted with a powered ethernet switch Instead of separating the bandwidth between the users in the network, full bi-directional bandwidth

spectrum to everyone will be provided.

The maximum distance separating the CO from the end users is increased to 80 kilometres anddoes not depend on the total number of subscribers that will be connected to the network. As it canbe seen on figure 5.4, the Ethernet switch may be located 70km away from the CO and the distancebetween the switch and the end-users can reach a distance up to 10 km. The limitation factor in thiscase comes from the number of subscribers connected to the switch (with respect to the capacity ofthe switch) and not with the infrastructure, like in the PON architecture.

The most common speed that the AON can provide is 100Mbps in downstream and upstream directionfor a home residence and up to 1Gbps for the business sector.

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5.1.1.4 Analysis on the three architectures

Selecting one out of the three topologies to implement is quite tricky issue, as trade-offs exist that turnan advantage in one to a drawback in another. The primary objective must be clearly set by the net-work designer, in most cases cost minimization, for the topological choice to suit best to the needs andgeographical scenario.

The following table 5.1 shows the main advantages and disadvantages of the discussed three architectures.The scale that it was used is from 1 to 3, where 1 is low and 3 is high.

Qualificationcharacteristics

PONActive

NetworkPoint-to-Point

NetworkSecurity 1 2 3

Cost 1 2 3Redundancy 1 2 3Scalability 1 1 3

Detect and fix time 1 2 3Energy efficiency 1 2 3

Table 5.1: Advantages and disadvantages of the different technologies[11]

As it can be seen from the table 5.1, PtP will provide us with the best security, redundancy, scalability,detect and fix time and energy efficiency among the rest, but the cost of the architecture, in most cases, ishigher than the PON and the active network.

PON architecture appears to be the cheapest one as the equipment needed to install for providing servicesto the end-users is passive compared to the AON which is active and consequently, more expensive. Espe-cially in rural and suburban areas, the CAPEX tends to be lower for the PON architecture while in densepopulated areas, the cost difference converges more to the PtP. Also, the total fiber length deployed inthe trenches in the PON and AON networks is smaller than the PtP network, especially in the case wherethe optical splitters are optimally located in a block of households with regards to minimum connectiondistance and their capacity is fully utilized. Another important issue is scalability. Imagine the case inwhich for a certain block of houses, a PON or AON architecture is deployed to provide service to theend-users. If an 1x32 optical splitter is used and all splitters ports are connected to 32 households in thisblock, then a construction of a new building very close to the cabinet that requires connectivity will raisedifficulties in doing so, as the capacity of the installed splitter is fully utilized. In that case, a strand offiber should be pulled all the way up to the streaming splitter or the network should require redesign inorder to be able to service a higher number of end-users in the new building. Additional trenching mayalso be required. An easy solution to this would be to replace the existing 1x32 splitter with a biggercapacity one, for example 1x64 splitter. That will lead to a certain down period and bandwidth reductionfor the already 32 connected end-users.

Scalability also refers to the easiness of upgrading the services delivered to one or more individual end-users, while keeping the previous service for the rest. In the PtP architecture this can be seamlessly doneby upgrading the capacity of the fiber links that connect the CO with the respective end-users, while inthe other two architectures will require re-trenching and replacement of the link that connects the CO tothe optical splitter to increase the bandwidth.

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Its obvious that PtP is the most redundant architecture compared to the other two. If for some reason afailure occurs to the fiber that connects the CO to the optical splitter, then a down period will last for theend-users connected to this splitter until connectivity is restored. On the other hand, if this failure occursto one or more of the fibers connecting directly the CO with one or two households, it will affect onlythese end-users.

Security is better achieved in PtP and AON architectures due to the active nature of the equipment usedto connect the end-users. In the PtP case, due to the fact that each end-user is served by a dedicated line itis easier to detect a security breach. This active nature affects up to a point the time it takes to detect andrestore a failure. Especially, in case the problem is related to software configuration issues, the restorationprocess can be completed from distance without the physical presence of a technician.

From energy point of view, PtP after 300Mbps is the least energy consuming architecture. Figure 5.5shows the energy consumption in fiber access networks with respect to the average access rates (Mbps)and energy per bit. As the average access rate increases, the amount of energy per bit decreases. Thatsthe reason why nowadays PON architecture is, in many times, preferable over PtP topology.

Figure 5.5: Energy consumption in Access network [28]

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5.1.2 Planning process

The methodology a network engineer uses to implement the LAN fiber planning is a very important factorin the network modelling process. A rational structuring of the modelling process into successive imple-mentation phases should be done that will help the designer carry out the technical task efficiently, withregards to low computational time and proper output. A general fiber planning scheme consists of threebasic phases, as can be seen in figure 5.7 on the next page:

Figure 5.6: General wired planning method structure including Data preparation and planningalgorithms[11]

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Figure 5.7: General wired planning method structure including documentation presentation[11]

5.1.2.1 Data Preparation

Data preparation is the initial phase of the planning method. It includes gathering of GIS data for tracesand node locations placed on the specific geographical area, storing all these data in a database so as toenable easier manipulation of them and reducing data dimensionality by normalizing them.

Available GIS data is essential for an easier, faster and more accurate planning of a fiber network in anygeographical area by digitizing the whole planning procedure. This geographical information is obtainedand handled through computer based GIS applications. For wired network planning purposes, 2D GISdata is adequate for the graphical representation of important elements that describe an area, such asroads, railway trails or agriculture fields. 3D GIS is preferable in case wireless infrastructure exists inthe area and there is a need to provide the highest population coverage using the minimum number ofBSs.2. Usually, municipalities retain GIS mapping information of their region. In that way, it is rathereasy and in most cases quite cheap to seek such information. Also, private companies exist that maintainGIS data important for the planning process, however they are usually offering it at a high price. Themost interesting information someone could extract from this data is the road network. Especially whenit comes to design a network in a big city with dense building infrastructure, roads are the main path forthe fibers to pass by and interconnect all the desired communication nodes. In rural areas, GIS data is stillimportant although the whole process becomes less complex as the digging traces for the fiber to pass canbe picked more loosely and closer to the designer needs for better optimization of the final result. Thisfact arises from the reduced cost of digging traces in rural areas compared to urban ones, as optimizationcan be succeeded more efficiently through agriculture fields, for example, rather than through industrialareas. A digital road map can be viewed as an approximation to the trace level for a potential optical fiberICT infrastructure development [29]. A digital road map is represented through tables which containmost of the road map information in digital form, such as road names and unique identities related toindividual road segments.

Figure 5.8 on the following page presents the digital road network of Aalborg commune, which is thesubject of the current project research. Using GIS tools, such as Mapinfo, roads can be segmentedto smaller parts, points that form the start and ending of every segment (Segment Point (SP)s) can becreated, more ids can be added.

2The 3D GIS data was not used in the present project due the fact that Aalborg commune has almost flat relief

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Figure 5.8: Aalborg commune drew in MapInfo

Availability of households and buildings location is significant for the whole planning process. Data re-garding NTs, such as real coordinates, address and post district, are also available in every municipality.

Databases are important for handling huge amount of spatial data in tables. This data enables the networkdesigners to view the mapping of the road network and the end-users buildings distribution and exactlocation at the region where an optical fiber network is under construction. It is important that every tablestored in the database is well structured. In that way, the task of reducing the total amount of this data,also known as normalization, as well as seeking desired data through a high quantity of tables entriesbecomes much more efficient in terms of time consumption. Consistent data preservation in databasesfacilitates the network planning process in its total.

Normalization of the road network refers to the minimization of the initial networks dimensionality be-fore applying graph algorithms to achieve the desired network topological structure. It is a very importantprocess as it leads to a huge drop in computational time needed from the algorithms applied in the Plan-ning Algorithms phase 2. The data points that should be normalized include SP nodes of degree 1 or2 that do not serve any NT. After finding out the data points that satisfy this condition, they should bedeleted from the respective tables stored in the database. Figure 5.9 on the next page shows an exampleof a small part of an optical fiber network. Several SPs of different degree value are connected with each

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other and houses. The three dots sign in the figure depict the expansion of the network beyond this region.In figure 5.10, SPs B, D, E, G and I as well as all consecutive segments linking them are marked. All thesesegments and SPs should be deleted. Figure 5.11 presents the optical network after the completion of thenormalization process. Segment AC replaced segments AB and BC and a new lengthAC = 14m wasassigned to it, derived from the summation of lengthAB = 8m and lengthBC = 8m = 6m. Followingthe same principle, segment CF of lengthCF = 20m and FJ of lengthFJ = 15m were created. SegmentFG is just deleted, as SP G is not a connection point between NTs andCO.

Figure 5.9: Part of an optical fiber network[11]

Figure 5.10: Deleting SPs of degree 2 and all the segments interconnecting them[11]

Figure 5.11: Normalized network[11]

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5.1.2.2 Planning Algorithms

The second phase includes the selection of preferable planning tools and platforms, application of differ-ent graph algorithms, performance measurement of the designed network and optimization of the finalnetwork structure to achieve lower total planning cost and at the same time fulfil the predefined require-ments.Modification of SPs or segments location is sometimes crucial for the successful run of the graph algo-rithms applied. In many cases the road network is cut because a small island close to the shore exists or ariver runs through a city, for instance. The planning algorithms that are applied next are pure graph algo-rithms. In most cases, they belong to the family of shortest path algorithms and spanning tree algorithms,as the target set is minimization of the total trenching and fiber cost at the area. In some cases, due tothe complexity of the problems a network engineer is dealing with, genetic algorithms are preferred togenerate a near optimal planning solution in a short time interval. Such solutions are to run multiple timesand are continuously compared with previous outcomes held in the plan repository, until the optimal oneis found. We will not dig into specific algorithms and methods in this section, as the ones used to in thisproject will be presented in more detail in chapter 7.1 on page 62.

5.1.2.3 Documentation presentation

The last phase of the planning method is limited in documenting the network planning terminology. Oneof the objectives of the project was to develop and document the multiphase planning methodology suchas used architecture, graph algorithms, the economic model and the corresponding network planningparameters. Mapping representation of the final form of the proposed network and the achieved resultswas accomplished by using MapInfo software for digitally visualizing the final outcome of the designprocess.

5.1.3 Economic aspect

Main part of the planning process is the accurate calculation of the networks cost expenditure, CAPEXand OPEX. A typical network life cycle consists of the following five stages [30]:

Planning - up-front planning including technology choice, topology design, area scenario, etc.This initial planning phase deals with important decisions on many cost-driving factors for the de-ployment phase. For example, is it most suitable in the area under consideration (urban, rural orsuburban) to use PON or PtP architecture? If PON topology is chosen, would it be Gigabit Pas-sive optical network (GPON), Ethernet Passive optical network (EPON) or Wavelength division-multiplexing (WDM) PON?

Deployment - actual network deployment, outside as well as inside plant. CAPEX comprisingtotal trenching and total fiber as well as all needed equipment inside and outside the CO main nodeis calculated. In general, this cost accounts for 60% - 70% [31] of the total network cost and thatraises the need of a detailed business model during this phase.

Penetration and service provisioning - the actual connection of the customers to the new serviceonce the infrastructure is in place.

Up and running - operating the network during its normal state; includes monitoring, mainte-nance, repairing costs, etc. .However, repairing costs cannot be calculated prior to network opera-tion. Thus, statistics for average repairing cost per year should be added to the OPEX.

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The overall cost breakdown for a fiber cost deployment distinguishes between deployment - CAPEX -and customer migration and running costs - OPEX - of a FTTH network. Figure 5.12 shows the CAPEXbreakdown in fiber access networks. Around 70% accounts for the network deployment cost, almost 10%includes maintenance, pricing, billing, energy consumption as well as an estimation on possible repaircosts, in case of a cut fiber for example, and the rest refers to connecting up front the total amount ofsubscribers in an area with the LAN.

Figure 5.12: FTTH price breakdown[30]

Concerning the networks running operational costs, figure 5.13 presents a typical OPEX breakdown. Itmust be stated here that the percentages for every different cost type should not be taken as the rule tofollow but as an indicative scaling of the main diverse operational costs of the network. In every LANdeployment case, the designer is responsible for estimating the proportion and the nature of the networksrunning costs.

Figure 5.13: OPEX cost breakdown for keeping the network up and running[30]

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5.2 LTE Cellular Network Planning

The core task of cellular network planning is to set up the best possible radio network which provides agood feasible coverage of the investigated planning region. Due to the radical changes in technology andusage of cellular radio systems the design criteria of cellular networks have altered substantially. Besidethe primary objective of providing a reliable radio link at every location within the planning region, astate of the art network design has to ensure a high quality of service as well, considering the aspects ofreducing the cost of deployment a cellular radio system. The radio network planning process is dividedinto five main steps as shown in figure 5.14, from which the initial four are before the actual launch of thenetwork. After detailed planning, the network is ready for commercial usage, but the post-planning phasecontinues the process and targets the most optimal network configuration. The network planning processis a never ending cycle due to changes in the design parameters. Hence, this makes cellular networkPlanning a hard combinatorial problem that is multi-objective in nature.

Figure 5.14: Network planning process steps[32]

In cellular network planning, a set of parameters or metrics join as an objective function, are used toquantify and evaluate the designed network in relation to meeting the targets and objectives. Thesemetrics are called Key performance indicators (KPI) and they are used to set measurable objectives,evaluate progress, monitor trends, make improvements and support decision making[32]. The typicalKPIs used in the planning of fixed LTE network in this project are:

Coverage (Section 5.2.1 on the next page) Capacity (Section 5.2.2 on page 46) and Economic aspects (Section 5.2.3 on page 52)

Given an area to serve and keeping KPIs in mind, a network designer have to decide the following[33]:

Number of BSs to be located in the service area. Optimal placement of BSs; necessary to maximize the coverage in the region (particularly in rural

areas where the users are located sparsely, the number of BSs are expected to be less with widerranges and thus their locations are more critical).

Channel capacity of each BS subject to the total channel capacity. This would mainly depend onthe traffic capacity demand at each BS.

Maximal BS transmitting power. Antenna height.

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5.2.1 Coverage Planning

The target for the coverage planning phase is to find the optimal locations for BSs and design continuouscoverage according to the planning requirements. Coverage planning is performed with the help of aplanning tool, including a digital topographical map (GIS data) and a tuned model for propagation (likeOkumura-Hata, Winner II, ITU-529 and COST-231). To achieve the objectives set by cellular networkplanning of any radio access network, the first task is the calculation of radio link budget.

5.2.1.1 Link Budgets

The radio link budget aims to calculate the cell coverage area. The link budget calculations estimatethe maximum allowed signal attenuation, called Path loss (PL), between the mobile and the base stationantenna. The maximum path loss allows the maximum cell range to be estimated with a suitable prop-agation model and the cell range can be used to compute the number of BS sites required to cover thetarget geographical area. The link budget calculation can be also used to compare the relative coverageof the different systems when compared to LTE technology.

Propagation models have been developed to estimate the radio wave propagation as accurately as possi-ble. Models have

Hybrid PtP/LTE Infrastructure planning focusing on CAPEX-based migration

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