Design, Deployment and Performance of 4G LTE Networks

  

DESIGN, DEPLOYMENT

AND PERFORMANCE

OF 4G-LTE NETWORKS

  

DESIGN, DEPLOYMENT

AND PERFORMANCE

OF 4G-LTE NETWORKS

  A PRACTICAL APPROACH Ayman Elnashar Emirates Integrated Telecomms Co., UAE Mohamed A. El-saidny QUALCOMM Technologies, Inc., USA Mahmoud R. Sherif Emirates Integrated Telecomms Co., UAE This edition first published 2014 © 2014 John Wiley & Sons, Ltd Registered office John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United Kingdom For details of our global editorial offices, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at

  

The right of the author to be identified as the author of this work has been asserted in accordance with the Copyright,

Designs and Patents Act 1988.

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any

form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK

Copyright, Designs and Patents Act 1988, without the prior permission of the publisher. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books.

Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and

product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The publisher is not associated with any product or vendor mentioned in this book.

Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing

this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of

this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. It is

sold on the understanding that the publisher is not engaged in rendering professional services and neither the publisher nor the author shall be liable for damages arising herefrom. If professional advice or other expert assistance is required, the services of a competent professional should be sought.

  Library of Congress Cataloging-in-Publication Data Elnashar, Ayman.

  Design, deployment and performance of 4G-LTE networks : A Practical Approach / Dr Ayman Elnashar, Mr Mohamed A. El-saidny,  Dr Mahmoud Sherif. pages cm Includes bibliographical references and index.

  ISBN 978-1-118-68321-7 (hardback) 1. Wireless communication systems. 2. Mobile communication systems. I. Title.

  TK5103.2.E48 2014 _′ 621.3845 6–dc23 2013037384 A catalogue record for this book is available from the British Library.

  ISBN: 978-1-118-68321-7 Typeset in 10/12pt TimesLTStd by Laserwords Private Limited, Chennai, India

  To my beloved kids Noursin, Amira, and Yousef. You’re the inspiration!

This book is dedicated to the memory of my father (God bless his soul) and also

my mother, who’s been a rock of stability throughout my life. This book is also

dedicated to my beloved wife whose consistent support and patience sustain me

still.

My sincerest appreciations for a lifetime career that has surpassed anything my

imagination could have conceived.

  Ayman Elnashar

To my Family for all their continuous support. To my elder brother for his guidance

and motivation throughout the years. To my inspirational, intelligent, and beautiful

daughter, Hana.

  Your work is going to fill a large part of your life, and the only way to be truly satisfied is to do what you believe is great work. And the only way to do great work is to love what you do. If you haven’t found it yet, keep looking. Don’t settle. As with all matters of the heart, you’ll know when you find it. – Steve Jobs

  Mohamed A. El-saidny

This work would not have been possible without the consistent and full support of

my beloved family. To my beloved wife, Meram, to my intelligent, motivating, and

beautiful kids, Moustafa, Tasneem, and Omar. You are my inspiration.

To my Dad, my Mom (God bless her soul), my brother, and my entire family. Thank

you for all your support and encouragement.

  There is no elevator to success. You have to take the stairs. – Unknown Author Those who think they have found this elevator will end up falling down the elevator shaft

  Mahmoud R. Sherif

  Contents

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

   Ayman Elnashar and Mohamed A. El-saidny

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

   Mohamed A. El-saidny

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  Mohamed A. El-saidny

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

3 Analysis and Optimization of LTE System Performance 103

  

4 Performance Analysis and Optimization of LTE Key Features: C-DRX,

  

  

  

  

  

  

  

  

  

  

  

  

  Ayman Elnashar

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  3.7.2 Inter-RAT and Inter-Frequency Handover Optimization

  

  

  

  Mohamed A. El-saidny and Ayman Elnashar

  

5 Deployment Strategy of LTE Network 273

  

  

  

  

  

  

  

  

  

  

  

  Ayman Elnashar

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

6 Coverage and Capacity Planning of 4G Networks 349

  

  

  

  

  

  

  

  

  

  

7 Voice Evolution in 4G Networks 445

  

   Ayman Elnashar and Mohamed A. El-saidny

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  Mahmoud R. Sherif

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  Authors’ Biographies

Ayman Elnashar was born in Egypt in 1972. He received the B.S. degree in electrical

engineering from Alexandria University, Alexandria, Egypt, in 1995 and the M.Sc. and Ph.D.

  degrees in electrical communications engineering from Mansoura University, Mansoura, Egypt, in 1999 and 2005, respectively. He obtained his M.Sc. and Ph.D. degrees while work- ing fulltime. He has more than 17 years of experience in telecoms industry including GSM, GPRS/EDGE, UMTS/HSPA +/LTE, WiMax, WiFi, and transport/backhauling technologies. He was part of three major start-up telecom operators in MENA region (Mobinil/Egypt, Mobily/KSA, and du/UAE) and held key leadership positions. Currently, he is Sr. Director of Wireless Broadband, Terminals, and Performance with the Emirates Integrated Telecommuni- cations Co. “du”, UAE. He is in charge of mobile and fixed wireless broadband networks. He is responsible for strategy and innovation, design and planning, performance and optimization, and rollout/implementation of mobile and wireless broadband networks. He is the founder of the Terminals department and also the terminals lab for end-to-end testing, validation, and benchmarking of mobile terminals. He managed and directed the evolution, evaluation, and introduction of du mobile broadband HSPA +/LTE networks. Prior to this, he was with Mobily, Saudi Arabia, from June 2005 to Jan 2008 and with Mobinil (orange), Egypt, from March 2000 to June 2005. He played key role in contributing to the success of the mobile broadband network of Mobily/KSA.

  He managed several large-scale networks, and mega projects with more than 1.5 billion USD budgets including start-ups (LTE 1800 MHz, UMTS, HSPA +, and WiMAX16e), networks expansions (GSM, UMTS/HSPA +, WiFi, and transport/backhauling) and swap projects (GSM, UMTS, MW, and transport network) from major infrastructure vendors. He obtained his PhD degree in multiuser interference cancellation and smart antennas for cellular systems. He published 20 + papers in wireless communications arena in highly ranked journals such as

  

IEEE Transactions on Antenna and Propagation, IEEE Transactions Vehicular technology,

and IEEE Transactions Circuits and Systems I, IEEE Vehicular technology Magazine, IET

Signal Processing, and international conferences. His research interests include practical

  performance analysis of cellular systems (CDMA-based & OFDM-based), 3G/4G mobile networks planning, design, and Optimization, digital signal processing for wireless com- munications, multiuser detection, smart antennas, MIMO, and robust adaptive detection and beamforming. He is currently working on LTE-Advanced and beyond including eICIC, HetNet, UL/DL CoMP, 3D Beamforming, Combined LTE/HSPA +, Combined LTE/WiFi: simultaneous reception, etc …

  

Mohamed A. El-saidny is a technical expert with 10 + years of international technical and degree in Electrical Engineering from the University of Alabama in Huntsville, USA in 2002 and 2004, respectively. From 2004 to 2008, he worked in Qualcomm CDMA Technology, Inc. (QCT), San Diego, California, USA. He was responsible for performance evaluation and analysis of the Qualcomm UMTS system and software solutions used in user equipment. As part of his assignments, he developed and implemented system studies to optimize the perfor- mance of various UMTS algorithms. The enhancements utilize Cell re-selection, Handover, Cell Search and Paging. He worked on several IOT and field trials to evaluate and improve the performance of 3G systems. Since 2008, he has been working in Qualcomm Corporate Engineering Services division in Dubai, UAE. He has been working on expanding the 3G/4G technologies footprints with operators, with an additional focus on user equipment and net- work performance as well as technical roadmaps related to the industry. Mohamed is currently supporting operators in Middle East and North Africa in addition to worldwide network oper- ators and groups in LTE commercial efforts. His responsibilities are to ensure the device and network performance are within expectations. He led a key role in different first time features evaluations such as CSFB, C-DRX, IRAT, and load balance techniques in LTE. As part of this role, he is focused on aligning network operators to the device and chipset roadmaps and products in both 3G and 4G. Mohamed is the author of several international IEEE journal papers and contributions to 3GPP, and an inventor of numerous patents.

  

Mahmoud R. Sherif is a leading technical expert with more than 18 years of international

  experience in the design, development and implementation of fourth generation mobile broad- band technologies and networks. He received his Ph.D. degree in Electrical Engineering from the City University of New York, USA in February 2000. His Ph.D. degree was preceded by the B.Sc. degree in Computer Engineering and the M.Sc. degree in Electrical Engineer- ing from the University of Ain Shams in Cairo, Egypt in 1992, and 1996, respectively. From 1997 to 2008, he was working in the Wireless Business Unit at Lucent Technologies (which became Alcatel-Lucent in 2007), in Whippany, New Jersey, USA. He led the Voice and Data Quality and Performance Analysis team responsible for the end-to-end performance anal- ysis of the different wireless/mobile technologies. In November 2008, he moved to Dubai in the United Arab Emirates to join the Emirates Integrated Telecommunications Co. “du” where he is now the Head of the Mobile Access Planning within du (Senior Director Mobile Access Planning) managing the Radio Planning, Site Acquisition and Capacity and Feature Management Departments. He is responsible for managing the planning of the mobile access network nationwide, Mobile Sites’ Acquisition, Strategic Planning on Mobile Access Net- work Capacity Management, all Feature testing and rollout across 2G, 3G and LTE, defining and managing the financial resources efficiently and with alignment with company’s financial targets (CAPEX & OPEX). He is also responsible for the mobile access network technology strategy in coordination with the commercial and marketing teams. He is considered a com- pany expert resource in the various mobile broadband technologies, including HSPA +, LTE, VoLTE and LTE-A. He has published several related papers in various technical journals as well as multiple international conferences. He has multiple contributions to the 3GPP and other telecommunications standards. He also has multiple granted patents in the USA.

  Preface

  Cellular mobile networks have been evolving for many years. Several cellular systems and networks have been developed and deployed worldwide to provide the end user with quality and reliable communication over the air. Mobile technologies from the first to third generation have been quickly evolving to meet the need of services for voice, video, and data.

  Today, the transition to smartphones has steered the user’s interest toward a more mobile-based range of applications and services, increasing the demand for more network capacity and bandwidth. Meanwhile, this transition presents a significant revenue opportunity for network operators and service providers, as there is substantially higher average revenue per user (ARPU) from smartphone sales and relevant services. While the rollout of more advanced radio networks is proceeding rapidly, smartphone penetration is also increasing exponentially. Therefore, network operators need to ensure that the subscribers’ experience stays the same as, or is even better than, with the older existing systems.

  With the growing demand for data services, it is becoming increasingly challenging to meet the required data capacity and cell-edge spectrum efficiency. This adds more demand on the network operators, vendors and device providers to apply methods and features that stabilize the system’s capacity and consequently improves the end-user experience. 4G systems and relevant advanced features have the capabilities to keep up with today’s widespread use of mobile-communication devices, providing a range of mobile services and quality communications.

  This book describes the long term evolution (LTE) technology for mobile systems; a transi- tion from third to fourth generation. LTE has been developed in the 3GPP (Third Generation Partnership Project), starting from the first version in Release 8 and through to the contin- uing evolution to Release 10, the latest version of LTE, also known as LTE-Advanced. The analysis in this book is based on the LTE of 3GPP Release 8 together with Release 9 and Release 10 roadmaps, with a focus on the LTE-FDD (frequency division duplex) mode . Unlike other books, the authors have bridged the gap between theory and practice, thanks to hands on experience in the design, deployment, and performance of commercial 4G-LTE networks and terminals.

  The book is a practical guide for 4G networks designers, planners, and optimizers, as well as other readers with different levels of expertise. The book brings extensive and broad prac- tical hands-on experience to the readers. Practical scenarios and case studies are provided, including performance aspects, link budgets, end-to-end architecture, end-to-end QoS (quality of service) topology, dimensioning exercises, field measurement results, applicable business case studies, and roadmaps. Chapters 1 and 2 describe the LTE system architecture, interfaces, and protocols. They also introduce the LTE air interface and layers, in addition to downlink and uplink channels and procedures.

  Chapters 3 to 8 constitute the main part of the book. They provide a deeper insight into the LTE system features, performance, design aspects, deployment scenarios, planning exercises, VoLTE (voice over long term evolution) implementation, and the evolution and roadmap to LTE-Advanced. Further material supporting this book can be found in

  Acknowledgments

  We would like to express our deep gratitude to our colleagues in Qualcomm and du for assist- ing in reviewing and providing excellent feedback on this work. We are indebted to Huawei team in the UAE for their great support and review of Chapters 5 and 6, and also for providing the necessary supporting materials. Special thanks go to the wireless broadband and termi- nals team at du for their valuable support. We acknowledge the support of Harri Holma from NSN, for reviewing and providing valuable comments on Chapters 5 and 6. We wish to express our appreciation to every reviewer who reviewed the book proposal and provided very posi- tive feedback and insightful comments. Thanks for their valuable comments and suggestions. Our thanks go to our families for their patience, understanding, and constant encouragement, which provided the necessary enthusiasm to accomplish this book. Also, our deep and sincere appreciations go to our professors who supervised and guided us through our academic career. Finally, we would like to thank the publishing team at John Wiley & Sons for their competence, extensive support and encouragement throughout the project to bring this work to completion.

  

Abbreviations and Acronyms

  16-QAM 16-Quadrature amplitude modulation 64-QAM 64-Quadrature amplitude modulation

  1G, 2G, 3G or 4G 1st, 2nd, 3rd, 4th generation

  3GPP Third generation partnership project

  3GPP2 Third generation partnership project 2 AAA Authentication, authorization and accounting ACK Acknowledgment AES Advanced encryption standard AF Application Function AIPN All-IP network AMBR Aggregate maximum bit rate AMC Adaptive modulation and coding AMD Acknowledged mode data AN Access network APN Access point name ARP Allocation and retention priority ARQ Automatic repeat request AS Access stratum BC Business Case BCCH Broadcast control channel BCH Broadcast channel BI Backoff indicator BLER Block error rate BP Bandwidth part BSR Buffer status report BW Bandwidth CAPEX Capital Expenditure CCCH Common control channel CCE Control channel elements CDD Cyclic delay diversity CDM Code Division Multiplexed CDS Channel dependent scheduling CFI Control format indicator CN Core network COGS Cost of Goods Sold CP Control plane

  Cyclic prefix CQI Channel quality indicator CRC Cyclic redundancy check CRF Charging Rules Function C-RNTI Cell radio network temporary identifier CS Circuit switched CSG Closed subscriber group CSI Channel signal information CW Code word DAS Distributed Antenna System DCCH Dedicated control channel DCI Downlink control information DFT Discrete Fourier transform DFTS-OFDM Discrete Fourier transform spread orthogonal frequency division multi- plexing DL Downlink DL-SCH Downlink shared channel DM Demodulation DM-RS Demodulation reference signal DNS Domain Name System DRX Discontinuous transmission DS Data services DTCH Dedicated traffic channel E-AGCH Enhanced absolute granting channel EBITDA Earnings Before Interest, Taxes, Depreciation, and Amortization E-DCH Enhanced dedicated channel E-DPCCH Enhanced dedicated physical control channel E-DPDCH Enhanced dedicated physical data channel E-HICH Enhanced hybrid indicator channel EEA EPS encryption algorithm EIA EPS integrity algorithm EIR Equipment Identity register EMM EPS mobility management eNB Evolved node B EPC Evolved packet core EPLMN Equivalent PLMN EPRE Energy per resource element EPS Evolved packet system E-RGCH Enhanced relative granting channel ETWS Earthquake and tsunami warning system E-UTRA Evolved UMTS terrestrial radio access; PHY aspects E-UTRAN Evolved UMTS terrestrial radio access network; MAC/L2/L3 aspects FD Full-duplex FDD Frequency division duplex FDM Frequency division multiplexing FDMA Frequency division multiple access FFT Fast Fourier transform FH Frequency hopping FI Framing information FL Forward link FMS First missing sequence FS Frame structure FSTD Frequency shift time diversity GBR Guaranteed bit rate GERAN GSM/EDGE radio access network GGSN GPRS gateway support node GPRS General packet radio service GSM Global system for mobiles (European standard) GTP-U GPRS tunneling protocol – user GUMMEI Globally unique MME identity GUTI Globally unique temporary identifier GW Gateway HA Home agent HAP ID HARQ process ID HARQ Hybrid ARQ HD Half-duplex HFN Hyper frame number HI Hybrid ARQ indicator HLD High Level Design HLR Home location register HNBID Home evolved node B identifier HO Handover HPLMN Home public land mobile network HRPD High rate packet data HS High speed HSDPA High speed downlink packet access HS-DPCCH High speed dedicated control channel HSPA High speed packet access HSPA + High speed packet access evolved or enhanced HSS Home subscriber service HSUPA High speed uplink packet access

  IDFT Inverse discrete Fourier transform

  IETF Internet Engineering Task Force IMSI International Mobile Subscriber Identity

  IP Internet protocol

  IP-CAN

  IP connectivity access network

  ISI Inter-symbol interference

  ISR Idle signaling load reduction

  IRR Internal Rate of Return L1, L2, L3 Layer 1, 2, 3 LA Location area LAC Location area code LAI Location area identifier LAU Location area updating LCG Logical channel group LDAP Lightweight Directory Access LFDM Localized frequency division multiplexing LI Lawful Interception LI Length indicators LTE Long term evolution LTI Linear time invariant MAC Medium access control MAC-I Message authentication code for integrity MBMS Multimedia broadcast multicast service MBR Maximum bit rate MBSFN Multimedia broadcast over a single frequency network MCCH Multicast control channel MCH Multicast channel MCS Modulation and coding schemes MCW Multiple code word ME Mobile equipment MIB Master information block MIMO Multiple-input–multiple-output MME Mobility management entity MMEC MME code MMEGI MME group ID MSISDN Mobile Subscriber Integrated Services Digital Network-Number MOS Mean Opinion Score MTCH Multicast traffic channel MU-MIMO Multi-user multiple-input–multiple-output NAK Negative acknowledgment NAS Non-access stratum NDI New data indicator NID Network ID NPV Net Present Value OCS Online Charging System OFCS Offline Charging System

  Abbreviations and Acronyms OS Operating system PAPR Peak-to-average power ratio PAR Peak to average ratio PBCH Physical broadcast channel PCC Policy charging and control PCCH Paging control channel PCFICH Physical control format indicator channel PCH Paging channel PCRF Policy and charging rules function PDCCH Physical downlink control channel PDCP Packet data convergence protocol PDG Packet data gateway PDN Packet data network PDSCH Physical downlink shared channel PDSN Packet data serving node PDU Protocol data unit PELR Packet error loss rate P-GW Packet data network gateway PHICH Physical hybrid automatic repeat request indicator channel PHR Power headroom report PHY Physical layer PIM Passive Intermodulation PLMN Public land mobile network PMCH Physical multicast channel PMI Precoding matrix indicator PMIP Proxy mobile IP PoC Push-to-talk over cellular PRACH Physical random access channel PRB Physical resource block PS Packet switched PSC Primary synchronization code P-SCH Primary synchronization channel PSS Primary synchronization signal PSTN Packet switched telephone network PSVT Packet switched video telephony PTT Push-to-talk PUCCH Physical uplink control channel PUSCH Physical uplink shared channel QAM Quadrature amplitude modulation QCI QoS class identifier QoS Quality of service QPSK Quadrature phase shift keying RA Routing area RAC Routing area code RAPID Random access preamble identifier RAR Random access response RAU Routing area updating RB Resource block RBG Resource block group RDS RMS delay spread RE Resource element REG Resource element group RI Rank indicator RIV Resource indication value RL Reverse link RLC Radio link control RLF Radio link failure RMS Root-mean-square RN Relay Node RNC Radio network controller RNL Radio network layer RNTI Radio network temporary identifier ROHC Robust header compression ROI Return On Investment RPLMN Registered PLMN RRC Radio resource control RRM Radio resource management RS Reference signal RV Redundancy version SAE System architecture evolution SAW Stop-and-wait SC-FDM Single-carrier frequency division multiplexing SC-FDMA Single-carrier frequency division multiple access SCH Supplemental channel (CDMA2000)

  Synchronization channel (WCDMA) SCTP Stream control transmission protocol SCW Single code word SDF Service data low SDM Spatial division multiplexing SDMA Spatial division multiple access SDU Service data unit SFBC Space frequency block code SFN System frame number SGSN Serving GPRS support node S-GW Serving gateway SI System information message SIB System information block SINR Signal to interference noise ratio Abbreviations and Acronyms SNR Signal to noise ratio SOAP Simple Object Access Protocol SPOF Single Point of Failure SPS Semi-persistent scheduling SR Scheduling request SRS Sounding reference signals SSC Secondary synchronization code S-SCH Secondary synchronization channel SSS Secondary synchronization signal SU-MIMO Single-user multiple-input–multiple-output TA Tracking area

  Timing advance/alignment TAC Tracking area code TAI (_List) Tracking area identifier (_List) TAU Tracking area update TDD Time division duplex TDM Time division multiplexing TDMA Time division multiple access TFT Traffic flow template TPC Transmit power control TTI Transmission time interval Tx Transmit UCI Uplink control information UE User equipment UL Uplink UL-SCH Uplink shared channel UMTS Universal mobile telecommunications system UP User plane UTRA UMTS terrestrial radio access UTRAN UMTS terrestrial radio access network

  VAF Voice Activity Factor VoIP Voice over Internet protocol VoLTE Voice over LTE

  VRB Virtual resource block

  VT Video telephony WACC Weighted Average Cost of Capital WCDMA Wideband code division multiple access WiMAX Worldwide interoperability for microwave access

  X2 The interface between eNodeBs ZC Zadoff–Chu

1 LTE Network Architecture and

  Protocols Ayman Elnashar and Mohamed A. El-saidny

  Cellular mobile networks have been evolving for many years. The initial networks are referred to as First Generation, or 1G systems. The 1G mobile system was designed to utilize analog. It included the AMPS (advanced mobile phone system). The Second Generation,

  2G mobile systems, were introduced utilizing digital multiple access technology; TDMA (time division multiple access) and CDMA (code division multiple access). The main 2G networks were GSM (global system for mobile communications) and CDMA, also known as cdmaOne or IS-95 (Interim Standard 95). The GSM system still has worldwide support and is available for deployment on several frequency bands, such as 900, 1800, 850, and 1900 MHz. CDMA systems in 2G networks use a spread spectrum technique and utilize a mixture of codes and timing to identify cells and channels. In addition to being digital, as well as improving capacity and security, the 2G systems also offer enhanced services, such as SMS (short message service) and circuit switched (CS) data. Different variations of the

  2G technology evolved later to extend the support of efficient packet data services, and to increase the data rates. GPRS (general packet radio system) and EDGE (enhanced data rates for global evolution) systems have been the evolution path of GSM. The theoretical data rate of 473.6 kbps enabled the operators to offer multimedia services efficiently. Since it does not comply with all the features of a 3G system, EDGE is usually categorized as 2.75G.

  3G (Third Generation) systems are defined by IMT2000 (International Mobile Telecom- munications). IMT2000 defines that a 3G system should provide higher transmission rates in the range of 2 Mbps for stationary use and 348 kbps in mobile conditions. The main 3G technologies are:

• WCDMA (wideband code division multiple access) – This was developed by the 3GPP

  (Third Generation Partnership Project). WCDMA is the air interface of the 3G UMTS (uni- versal mobile telecommunications system). The UMTS system has been deployed based on

  Design, Deployment and Performance of 4G-LTE Networks: A Practical Approach the existing GSM communication core network (CN) but with a totally new radio access technology (RAT) in the form of WCDMA. Its radio access is based on FDD (frequency division duplex). Current deployments are mainly at 2.1 GHz bands. Deployments at lower frequencies are also possible, such as UMTS900. UMTS supports voice and multimedia services.

• TD-CDMA (time division multiple access) – This is typically referred to as UMTS TDD

  (time division duplex) and is part of the UMTS specifications. The system utilizes a com- bination of CDMA and TDMA to enable efficient allocation of resources.

• TD-SCDMA (time division synchronous code division multiple access) – This has links to the UMTS specifications and is often identified as UMTS-TDD low chip rate. Like TD-CDMA, it is also best suited to low mobility scenarios in microcells or picocells.
• CDMA2000 – This is a multi-carrier technology standard which uses CDMA. It is part of the 3GPP2 standardization body. CDMA2000 is a set of standards including CDMA2000 EV-DO (evolution-data optimized) which has various revisions. It is backward compatible with cdmaOne.
• WiMAX (worldwide interoperability for microwave access) – This is another wireless technology which satisfies IMT2000 3G requirements. The air interface is part of the IEEE (Institute of Electrical and Electronics Engineers) 802.16 standard which originally defined PTP (point-to-point) and PTM (point-to-multipoint) systems. This was later enhanced to provide greater mobility. WiMAX Forum is the organization formed to promote interoper- ability between vendors.

  4G (Fourth Generation) cellular wireless systems have been introduced as the latest version of mobile technologies. 4G is defined to meet the requirements set by the ITU (International Telecommunication Union) as part of IMT Advanced.

  The main drivers for the network architecture evolution in 4G systems are: all-IP (Internet protocol) -based, reduced network cost, reduced data latencies and signaling load, interwork- ing mobility among other access networks in 3GPP and non-3GPP, always-on user experience with flexible quality of service (QoS) support, and worldwide roaming capability. 4G systems include different access technologies:

• LTE and LTE-Advanced (long term evolution) – This is part of 3GPP. LTE as it stands now does not meet all IMT Advanced features. However, LTE-Advanced is part of a later 3GPP release and has been designed specifically to meet 4G requirements.
• WiMAX 802.16m – The IEEE and the WiMAX Forum have identified 802.16m as their offering for a 4G system.
• UMB (ultra mobile broadband) – This is identified as EV-DO Rev C. It is part of 3GPP2.

  Most vendors and network operators have decided to promote LTE instead.

1.1 Evolution of 3GPP Standards

  The specifications of GSM, GPRS, EDGE, UMTS, and LTE have been developed in stages, known as 3GPP releases. Operators, network, and device vendors use these releases as part of their development roadmap. All 3GPP releases are backward compatible. This means that a

  LTE Network Architecture and Protocols The availability of devices on a more advanced 3GPP release makes a great contribution to the choice of evolution by the operator. Collaboration between network operators, network vendors, and chipset providers is an important step in defining the roadmap and evolution of 3GPP features and releases. This has been the case in many markets.

  1.1.1

  3GPP Release 99

  3GPP Release 99 has introduced UMTS, as well as the EDGE enhancement to GPRS. UMTS contains all features needed to meet the IMT-2000 requirements as defined by the ITU. It is able to support CS voice and video services, as well as PS (packet switched) data services over common and dedicated channels. The theoretical data rate of UMTS in this release is 2 Mbps. The practical uplink and downlink data rates for UMTS in deployed networks have been 64, 128, and 384 kbps.

  1.1.2

  3GPP Release 4

  Release 4 includes enhancements to the CN. The concept of all-IP networks has been intro- duced in this release. There has not been any significant change added to the user equipment (UE) or air interface in this release.

  1.1.3

  3GPP Release 5

  Release 5 is the first major addition to the UMTS air interface. It adds HSDPA (high speed downlink packet access) to improve capacity and spectral efficiency. The goal of HSDPA in the 3GPP roadmap was to improve the end-user experience and to keep up with the evolution taking place in non-3GPP technologies. During the time when HSDPA was being developed, the increasing interest in mobile-based services demanded a significant improvement in the air interface of the UMTS system.

  HSDPA improves the downlink speeds from 384 kbps to a maximum theoretical 14.4 Mbps. The typical rates in the Release 5 networks and devices are 3.6 and 7.2 Mbps. The uplink in Release 5 has preserved the capabilities of Release 99.

  HSDPA provides the following main features which hold as the fundamentals of all subse- quent 3GPP evolutions:

• Adaptive modulation – In addition to the original UMTS modulation scheme, QPSK

  (quadrature phase shift keying), Release 5 also includes support for 16-QAM (quadrature amplitude modulation).

• Flexible coding – Based on fast feedback from the mobile in the form of a CQI (chan- nel quality indicator), the UMTS base station (known as NodeB) is able to modify the effective coding rate and thus increase system efficiency. In Release 99, such adaptive data rate scheduling took place at the RNC (radio network controller) which impacted the cell capacity and edge of cell data rates.
• Fast scheduling – HSDPA includes a shorter TTI (time transmission interval) of 2 ms, which enables the NodeB scheduler to quickly and efficiently allocate resources to mobiles.

• HARQ (hybrid automatic repeat request) – If a packet does not get through to the UE successfully, the system employs HARQ. This improves the retransmission timing, thus requiring less reliance on the RNC. In Release 99, the packet re-transmission was mainly controlled by the physical (PHY) layer as well as the RNC’s ARQ (automatic repeat request) algorithm, which was slower in adapting to the radio conditions.

  1.1.4

  3GPP Release 6

  Release 6 adds various features, with HSUPA (high speed uplink packet data) being the key one. HSUPA also goes under the term “enhanced uplink, EUL”. The term HSPA (high speed packet access) is normally used to describe a Release 6 network since an HSUPA call requires HSDPA on the downlink.

  The downlink of Release 6 remained the same as in HSDPA of Release 5. The uplink data rate of the HSUPA system can go up to 5.76 Mbps with 2 ms TTI used in the network and devices. The practical uplink data rates deployed are 1.4 and 2 Mbps. It is worth noting that there is a dependence between the downlink and uplink data rates. Even if the user is only downloading data at a high speed, the uplink needs to cope with the packet acknowledgments at the same high speed. Therefore any data rate evolution in the downlink needs to have an evolved uplink as well.

  HSUPA, like HSDPA, adds functionalities to improve packet data which include:

• Flexible coding – HSUPA has the ability to dynamically change the coding and therefore improves the efficiency of the system.
• Fast power scheduling – A key fact of HSUPA is that it provides a method to schedule the power to different mobiles. This scheduling can use either a 2 or 10 ms TTI. 2 ms usually reveals a challenge on the uplink interference and coverage when compared to 10 ms TTI operation. Hence, a switch between the two TTI is possible within the same EUL data call.
• HARQ – Like HSDPA, HSUPA also utilizes HARQ concepts in lower layers. The main difference is the timing relationship for the retransmission and the synchronized HARQ processes.

  1.1.5

  3GPP Release 7

  The main addition to this release is HSPA+, also known as evolved HSPA. During the commer- cialization of HSPA, LTE system development has been started, promising a more enhanced bandwidth and system capacity. Evolution of the HSPA system was important to keep up with any competitor technologies and prolong the lifetime of UMTS systems.

  HSPA+ provides various enhancements to improve PS data delivery. The features in HSPA+ have been introduced as add-ons. The operators typically evaluate the best options of HSPA+ features for deployment interests, based on the traffic increase requirements, flexibility, and the cost associated for the return of investment. HSPA+ in Release 7 includes:

• 64 QAM – This is added to the downlink and enables HSPA+ to operate at a theoretical rate of 21.6 Mbps.

  LTE Network Architecture and Protocols

• MIMO (multiple input multiple output) operation – This offers various capacity benefits including the ability to reach a theoretical 28.8 Mbps data rate in the downlink.
• Power and battery enhancements – Various enhancements such as CPC (continuous packet connectivity) have been included. CPC enables DTX (discontinuous transmission) and DRX (discontinuous reception) functions in connected mode.
• Less data packet overhead – The downlink includes an enhancement to the lower layers in the protocol stack. This effectively means that fewer headers are required, and in turn, improves the system efficiency.

  1.1.6

  3GPP Release 8

  On the HSPA+ side, Release 8 has continued to improve the system efficiency and data rates by providing:

• MIMO with 64 QAM modulation – It enables the combination of 64 QAM and MIMO, thus reaching a theoretical rate of 42 Mbps, that is, 2 × 21.6 Mbps.
• Dual cell operation – DC-HSDPA (dual cell high speed downlink packet access) is a fea- ture which is further enhanced in Releases 9 and 10. It enables a mobile to effectively utilize two 5 MHz UMTS carriers. Assuming both are using 64 QAM (21.6 Mbps), the theoreti- cal data rate is 42 Mbps. DC-HSDPA has gained the primary interest over other Release 8 features, and most networks are currently either supporting it or in the deployment stage.
• Further power and battery enhancements – deploys a feature known as enhanced fast dormancy as well as enhanced RRC state transitions.

  The 3GPP Release 8 defines the first standardization of the LTE specifications. The evolved packet system (EPS) is defined, mandating the key features and components of both the radio access network (E-UTRAN, evolved universal terrestrial radio access network) and the CN (evolved packet core, EPC). Orthogonal frequency division multiplexing is defined as the air interface with the ability to support multi-layer data streams using MIMO antenna systems to increase spectral efficiency.

  LTE is defined as an all-IP network topology differentiated over the legacy CS domain. However, the Release 8 specification makes use of the CS domain to maintain compatibility with the 2G and 3G systems utilizing the voice calls circuit switch Fallback (CSFB) technique for any of those systems.

  LTE in Release 8 has a theoretical data rate of 300 Mbps. The most common deployment is 100 to 150 Mbps with a full usage of the bandwidth, 20 MHz. Several other variants are also deployed in less bandwidth and hence with lower data rates. The bandwidth allocation is tied to the amount of spectrum acquired by the LTE network operators in every country.

  The motivations and different options discussed in 3GPP for the EPS network architecture have been detailed in several standardized technical reports in [1–4].

  1.1.7

  3GPP Release 9 and Beyond

  Even though LTE is a Release 8 system, it is further enhanced in Release 9. There are a number