Cover Page

AN INTRODUCTION TO LTE

LTE, LTE-ADVANCED, SAE, VoLTE AND 4G MOBILE COMMUNICATIONS

Second Edition

 

Christopher Cox

 

Director, Chris Cox Communications Ltd, UK

 

 

 

 

Title Page

To my nieces, Louise and Zoe

Preface

This book is about the world's dominant 4G mobile telecommunication system, LTE.

In writing the book, my aim has been to give the reader a concise, system level introduction to the technology that LTE uses. The book covers the whole of the system, both the techniques used for radio communication between the base station and the mobile phone, and the techniques used to transfer data and signalling messages across the network. I have avoided going into excessive detail, which is more appropriate for specialized treatments of individual topics and for the LTE specifications themselves. Instead, I hope that the reader will come away from this book with a sound understanding of the system and of the way in which its different components interact. The reader will then be able to tackle the more advanced books and the specifications with confidence.

The target audience is twofold. Firstly, I hope that the book will be valuable for engineers who are working on LTE, notably those who are transferring from other technologies such as GSM, UMTS and cdma2000, those who are experts in one part of LTE but who want to understand the system as a whole and those who are new to mobile telecommunications altogether. Secondly, the book should give a valuable overview to those who are working in non technical roles, such as project managers, marketing executives and intellectual property consultants.

Structurally, the book has four parts. The first part lays out the foundations that the reader will need in the remainder of the book. Chapter 1 is an introduction, which relates LTE to earlier mobile telecommunication systems and lays out its requirements and key technical features. Chapter 2 covers the architecture of the system, notably the hardware components and communication protocols that it contains and its use of radio spectrum. Chapter 3 reviews the radio transmission techniques that LTE has inherited from earlier mobile telecommunication systems, while Chapters 4 and 5 describe the more recent techniques of orthogonal frequency division multiple access and multiple input multiple output antennas.

The second part of the book covers the air interface of LTE. Chapter 6 is a high level description of the air interface, while Chapter 7 relates the low level procedures that a mobile phone uses when it switches on, to discover the LTE base stations that are nearby. Chapter 8 covers the low level procedures that the base station and mobile phone use to transmit and receive information, while Chapter 9 covers a specific procedure, random access, by which the mobile phone can contact a base station without prior scheduling. Chapter 10 covers the higher level parts of the air interface, namely the medium access control, radio link control and packet data convergence protocols.

The third part covers the signalling procedures that govern how a mobile phone behaves. In Chapter 11, we describe the high level procedures that a mobile phone uses when it switches on, to register itself with the network and establish communications with the outside world. Chapter 12 covers the security procedures used by LTE, while Chapter 13 covers the procedures that manage the quality of service and charging characteristics of a data stream. Chapter 14 describes the mobility management procedures that the network uses to keep track of the mobile's location. Chapter 15 describes how LTE inter-operates with the earlier technologies of GSM and UMTS, while Chapter 16 discusses inter-operation with other technologies such as wireless local area networks and cdma2000. Chapter 17 covers the self-configuration and self-optimization capabilities of LTE.

The final part covers more specialized topics. Chapters 18, 19 and 20 describe the enhancements that have been made to LTE in later releases of the specifications, notably an enhanced version of the technology that is known as LTE-Advanced. Chapters 21 and 22 cover the two most important solutions for the delivery of voice calls to LTE devices, namely circuit switched fallback and the IP multimedia subsystem. Finally, Chapter 23 reviews the performance of LTE and discusses the techniques that are used to estimate the coverage and capacity of an LTE network.

LTE has a large number of acronyms, and it is hard to talk about the subject without using them. However, they can make the material appear unnecessarily impenetrable to a newcomer, so I have aimed to keep the use of acronyms to a reasonable minimum, often preferring the full name or a colloquial one. There is a full list of abbreviations in the introductory material and new terms are highlighted using italics throughout the text.

I have also endeavoured to keep the book's mathematical content to the minimum needed to understand the system. The LTE air interface makes extensive use of complex numbers, Fourier transforms and matrix algebra, but the reader will not require any prior knowledge of these in order to understand the book. We do make limited use of complex numbers in Chapters 3 and 4 to illustrate our discussion of modulation, and introduce Fourier transforms and matrices in subsections of Chapters 4 and 5 to cover the more advanced aspects of orthogonal frequency division multiple access and multiple antennas. Readers can, however, skip this material without detracting from their overall appreciation of the subject.

Acknowledgements

Many people have given me assistance, support and advice during the creation of this book. I am especially grateful to Liz Wingett, Susan Barclay, Sophia Travis, Sandra Grayson, Mark Hammond and the rest of the publishing team at John Wiley & Sons, Ltd for the expert knowledge and gentle encouragement that they have supplied throughout the production process.

I am indebted to Michael Salmon and Geoff Varrall for encouraging me to write the first edition of this book and to the publishing team at Wiley for requesting a second. The advice and feedback I have received while preparing the manuscript have been invaluable and have given me many opportunities to correct errors and improve the material. In this respect, I would particularly like to thank Jeff Cartwright, Joseph Hoy, Julian Nolan, Michael Salmon, Mohammad Anas, Obi Chiemeka, Pete Doherty, Les Granfield, Karl van Heeswijk, Kit Kilgour and Paul Mason. I am especially indebted to Nicola Rivers, for her support and encouragement throughout the preparation of the second edition. Naturally, the responsibility for any remaining errors or omissions in the text, and for any lack of clarity in the explanations, is entirely my own.

Much of my knowledge of the more detailed aspects of LTE, notably of circuit switched fallback and the IP multimedia subsystem, has been gathered while delivering courses on behalf of various training providers. I am indebted to the directors and staff of Imagicom, Informa Telecoms Academy, Wray Castle and Mpirical, for the support and learning opportunities that they have provided to me. I would also like to extend my thanks to the delegates who have attended my training courses on LTE. Their questions and corrections have extended my knowledge of the subject, while their feedback has regularly suggested ways to explain topics more effectively.

Several diagrams in this book have been reproduced from the technical specifications for LTE, with permission from the European Telecommunications Standards Institute (ETSI), © 2013, 2012, 2011, 2010, 2006. 3GPP™ TSs and TRs are the property of ARIB, ATIS, CCSA, ETSI, TTA and TTC who jointly own the copyright for them. They are subject to further modifications and are therefore provided to you ‘as is’ for information purposes only. Further use is strictly prohibited.

Analysys Mason Limited kindly supplied the market research data underlying the illustrations of network traffic and operator revenue in Figures 1.6 and 21.1. I would like to extend my appreciation to Hilary Bailey, Morgan Mullooly, Terry Norman and James Allen for providing this information. The measurements of network traffic in Figure 1.5 and the subscription data underlying Figures 1.9 and 1.10 are by Ericsson, and I am grateful to Elin Pettersson and Svante Bergqvist for making these available.

List of Abbreviations

16-QAM16 quadrature amplitude modulation
1GFirst generation
1xRTT1x radio transmission technology
2GSecond generation
3GThird generation
3GPPThird Generation Partnership Project
3GPP2Third Generation Partnership Project 2
4GFourth generation
64-QAM64 quadrature amplitude modulation
AAAAuthentication, authorization and accounting
ABMFAccount balance management function
ABSAlmost blank subframe
ACKPositive acknowledgement
ACMAddress complete message
ADCAnalogue to digital converter
AESAdvanced Encryption Standard
AFApplication function/Assured forwarding
AKAAuthentication and key agreement
AMAcknowledged mode
AMBRAggregate maximum bit rate
AMRAdaptive multi rate
AMR-WBWideband adaptive multi rate
ANDSFAccess network discovery and selection function
ANMAnswer message
APIApplication programming interface
APNAccess point name
APN-AMBRPer APN aggregate maximum bit rate
ARIBAssociation of Radio Industries and Businesses
ARPAllocation and retention priority
ARQAutomatic repeat request
ASAccess stratum/Application server
ASMEAccess security management entity
ATCFAccess transfer control function
ATGWAccess transfer gateway
ATISAlliance for Telecommunications Industry Solutions
AuCAuthentication centre
AVPAttribute value pair/Audio visual profile
AWSAdvanced Wireless Services
B2BUABack to back user agent
BBERFBearer binding and event reporting function
BBFBearer binding function
BCCHBroadcast control channel
BCHBroadcast channel
BDBilling domain
BEBest effort
BGCFBreakout gateway control function
BICCBearer independent call control
BM-SCBroadcast/multicast service centre
BPSKBinary phase shift keying
BSCBase station controller
BSRBuffer status report
BSSAP+Base station subsystem application part plus
BSSGPBase station system GPRS protocol
BTSBase transceiver station
CACarrier aggregation
CAMELCustomized applications for mobile network enhanced logic
CBCCell broadcast centre
CBSCell broadcast service
CCCall control/Component carrier
CCCHCommon control channel
CCEControl channel element
CCOCell change order
CCSAChina Communications Standards Association
CDFCharging data function
CDMACode division multiple access
CDRCharging data record
CFIControl format indicator
CGFCharging gateway function
CIFCarrier indicator field
CLICalling line identification
CMConnection management
CMASCommercial mobile alert system
C-MSISDNCorrelation mobile subscriber ISDN number
CoMPCoordinated multi-point transmission and reception
COSTEuropean Cooperation in Science and Technology
CPCyclic prefix
CQIChannel quality indicator
CRCCyclic redundancy check
C-RNTICell radio network temporary identifier
CSCircuit switched
CS/CBCoordinated scheduling and beamforming
CSCFCall session control function
CSFBCircuit switched fallback
CSGClosed subscriber group
CSIChannel state information
CS-MGWCircuit switched media gateway
CTFCharging trigger function
D2DDevice to device
DACDigital-to-analogue converter
dBDecibel
dBiDecibels relative to an isotropic antenna
dBmDecibels relative to one milliwatt
DCCHDedicated control channel
DCIDownlink control information
DeNBDonor evolved Node B
DFTDiscrete Fourier transform
DFT-S-OFDMADiscrete Fourier transform spread OFDMA
DHCPDynamic host configuration protocol
DiffServDifferentiated services
DLDownlink
DL-SCHDownlink shared channel
DNSDomain name server
DPSDynamic point selection
DRSDemodulation reference signal
DRVCCDual radio voice call continuity
DRXDiscontinuous reception
DSCPDifferentiated services code point
DSLDigital subscriber line
DSMIPDual-stack mobile IP
DTCHDedicated traffic channel
DTMDual transfer mode
DTMFDual tone multi-frequency
EAGExplicit array gain
eANEvolved access network
EAPExtensible authentication protocol
EATFEmergency access transfer function
ECGIE-UTRAN cell global identifier
ECIE-UTRAN cell identity
ECMEPS connection management
ECNExplicit congestion notification
E-CSCFEmergency call session control function
EDGEEnhanced Data Rates for GSM Evolution
EEAEPS encryption algorithm
EFExpedited forwarding
eHRPDEvolved high rate packet data
EIAEPS integrity algorithm
EICICEnhanced inter cell interference coordination
EIREquipment identity register
EIRPEquivalent isotropic radiated power
eMBMSEvolved MBMS
EMMEPS mobility management
eNBEvolved Node B
EPCEvolved packet core
ePCFEvolved packet control function
EPDCCHEnhanced physical downlink control channel
ePDGEvolved packet data gateway
EPREEnergy per resource element
EPSEvolved packet system
E-RABEvolved radio access bearer
ERFEvent reporting function
ESMEPS session management
E-SMLCEvolved serving mobile location centre
ESPEncapsulating security payload
ETSIEuropean Telecommunications Standards Institute
ETWSEarthquake and tsunami warning system
E-UTRANEvolved UMTS terrestrial radio access network
EV-DOEvolution data optimized
FCCFederal Communications Commission
FDDFrequency division duplex
FDMAFrequency division multiple access
FD-MIMOFull-dimension MIMO
FFTFast Fourier transform
FTPFile transfer protocol
GBRGuaranteed bit rate
GCPGateway control protocol
GERANGSM EDGE radio access network
GGSNGateway GPRS support node
GMLCGateway mobile location centre
GMMGPRS mobility management
GNSSGlobal navigation satellite system
GPGuard period
GPRSGeneral Packet Radio Service
GPSGlobal Positioning System
GREGeneric routing encapsulation
GRXGPRS roaming exchange
GSMGlobal System for Mobile Communications
GSMAGSM Association
GTPGPRS tunnelling protocol
GTP-CGPRS tunnelling protocol control part
GTP-UGPRS tunnelling protocol user part
GUMMEIGlobally unique MME identifier
GUTIGlobally unique temporary identity
HARQHybrid ARQ
HeNBHome evolved Node B
HIHybrid ARQ indicator
HLRHome location register
H-PCRFHome policy and charging rules function
HRPDHigh rate packet data
HSDPAHigh speed downlink packet access
HSGWHRPD serving gateway
HSPAHigh speed packet access
HSSHome subscriber server
HSUPAHigh-speed uplink packet access
HTTPHypertext transfer protocol
IIn phase
IAMInitial address message
IARIIMS application reference identifier
IBCFInterconnection border control function
ICICInter-cell interference coordination
ICSIMS centralized services
I-CSCFInterrogating call session control function
ICSIIMS communication service identifier
IDCIn device coexistence
IEEEInstitute of Electrical and Electronics Engineers
IETFInternet Engineering Task Force
iFCInitial filter criteria
IFOMIP flow mobility
II-NNIInter IMS network to network interface
IKEInternet key exchange
IMEIInternational mobile equipment identity
IM-MGWIMS media gateway
IMPIIP multimedia private identity
IMPUIP multimedia public identity
IMSIP multimedia subsystem
IMS-ALGIMS application level gateway
IMSIInternational mobile subscriber identity
IM-SSFIP multimedia service switching function
IMTInternational Mobile Telecommunications
IPInternet protocol
IP-CANIP connectivity access network
IPSecIP security
IP-SM-GWIP short message gateway
IPv4Internet protocol version 4
IPv6Internet protocol version 6
IPXIP packet exchange
IRLIsotropic receive level
ISDNIntegrated services digital network
ISIInter symbol interference
ISIMIP multimedia services identity module
ISRIdle mode signalling reduction
ISRPIntersystem routing policy
ISUPISDN user part
ITUInternational Telecommunication Union
IWFInterworking function
JPJoint processing
JRJoint reception
JTJoint transmission
LALocation area
LBSLocation-based services
LCSLocation services
LCS-APLCS application protocol
LDAPLightweight directory access protocol
LGWLocal gateway
LIPALocal IP access
LIRLocation info request
LPPLTE positioning protocol
LRFLocation retrieval function
LTELong term evolution
LTE-ALTE-Advanced
M2MMachine to machine
MACMedium access control
MAPMobile application part
MAPCONMulti access PDN connectivity
MARMultimedia authentication request
MBMSMultimedia broadcast/multicast service
MBMS-GWMBMS gateway
MBRMaximum bit rate
MBSFNMulticast/broadcast over a single frequency network
MCCMobile country code
MCCHMulticast control channel
MCEMulticell/multicast coordination entity
MCHMulticast channel
MDTMinimization of drive tests
MEMobile equipment
MEGACOMedia gateway control
MeNBMaster evolved Node B
MGCFMedia gateway control function
MGLMeasurement gap length
MGRPMeasurement gap repetition period
MGWMedia gateway
MIBMaster information block
MIMOMultiple input multiple output
MIPMobile IP
MMMobility management
MMEMobility management entity
MMECMME code
MMEGIMME group identity
MMEIMME identifier
MMSEMinimum mean square error
MMTelMultimedia telephony service
MNCMobile network code
MOManagement object
MOSMean opinion score
MPLSMultiprotocol label switching
MRBMedia resource broker
MRFMultimedia resource function
MRFCMultimedia resource function controller
MRFPMultimedia resource function processor
M-RNTIMBMS radio network temporary identifier
MSCMobile switching centre
MSISDNMobile subscriber ISDN number
MSKMaster session key
MSRPMessage session relay protocol
MTMobile termination
MTCMachine-type communications
MTC-IWFMachine-type communications interworking function
MTCHMulticast traffic channel
M-TMSIM temporary mobile subscriber identity
MTSIMultimedia telephony service for IMS
MU-MIMOMultiple user MIMO
NACCNetwork-assisted cell change
NACKNegative acknowledgement
NAINetwork access identifier
NAP-IDNetwork access provider identity
NASNon-access stratum
NATNetwork address translation
NHNext hop
NMONetwork mode of operation
OCFOnline charging function
OCSOnline charging system
OMAOpen Mobile Alliance
OFCSOffline charging system
OFDMOrthogonal frequency division multiplexing
OFDMAOrthogonal frequency division multiple access
OSAOpen service access
OSIOpen systems interconnection
OTDOAObserved time difference of arrival
OUIOrganizational unique identifier
PAPRPeak-to-average power ratio
PBCHPhysical broadcast channel
PBRPrioritized bit rate
PCCPolicy and charging control
PCCHPaging control channel
PCEFPolicy and charging enforcement function
PCellPrimary cell
PCFICHPhysical control format indicator channel
PCHPaging channel
PCRFPolicy and charging rules function
PCSPersonal Communications Service
P-CSCFProxy call session control function
PDCCHPhysical downlink control channel
PDCPPacket data convergence protocol
PDNPacket data network
PDPPacket data protocol
PDSCHPhysical downlink shared channel
PDUProtocol data unit
PESQPerceptual evaluation of speech quality
P-GWPacket data network gateway
PHBPer hop behaviour
PHICHPhysical hybrid ARQ indicator channel
PLPath loss/Propagation loss
PLMNPublic land mobile network
PLMN-IDPublic land mobile network identity
PMCHPhysical multicast channel
PMDPseudonym mediation device
PMIPrecoding matrix indicator
PMIPProxy mobile IP
PoCPush to talk over cellular
POLQAPerceptual objective listening quality assessment
PPRPrivacy profile register
PRACHPhysical random access channel
PRACKProvisional response acknowledgement
PRBPhysical resource block
P-RNTIPaging radio network temporary identifier
ProSeProximity services
PSPacket switched
PSAPPublic safety answering point
PSSPrimary synchronization signal
PSTNPublic switched telephone network
P-TMSIPacket temporary mobile subscriber identity
PUCCHPhysical uplink control channel
PUSCHPhysical uplink shared channel
PWSPublic warning system
QQuadrature
QAMQuadrature amplitude modulation
QCIQoS class identifier
QoSQuality of service
QPSKQuadrature phase shift keying
RARouting area
RACHRandom access channel
RADIUSRemote authentication dial in user service
RANAPRadio access network application part
RA-RNTIRandom access radio network temporary identifier
RBResource block
RBGResource block group
RCSRich communication services
REResource element
REGResource element group
RFRadio frequency/Rating function
RFCRequest for comments
RIRank indication
RIMRadio access network information management
RLCRadio link control
RLFRadio link failure
RNRelay node
RNCRadio network controller
RNTIRadio network temporary identifier
ROHCRobust header compression
R-PDCCHRelay physical downlink control channel
RRCRadio resource control
RRHRemote radio head
RSReference signal
RSCPReceived signal code power
RSRPReference signal received power
RSRQReference signal received quality
RSSIReceived signal strength indicator
RTCPRTP control protocol
RTPReal time transport protocol
S1-APS1 application protocol
SAESystem architecture evolution
SaMOGS2a mobility based on GTP
SARServer assignment request
SCService centre
SCC-ASService centralization and continuity application server
SCellSecondary cell
SC-FDMASingle-carrier frequency division multiple access
SCSService capability server
S-CSCFServing call session control function
SCTPStream control transmission protocol
SDFService data flow
SDPSession description protocol
SDUService data unit
SEGSecure gateway
SeNBSlave evolved Node B
SFNSystem frame number
SGsAPSGs application protocol
SGSNServing GPRS support node
S-GWServing gateway
SIBSystem information block
SIDSilence information descriptor
SIMSubscriber identity module
SINRSignal-to-interference plus noise ratio
SIPSession initiation protocol
SIPTOSelective IP traffic offload
SI-RNTISystem information radio network temporary identifier
SLFSubscription locator function
SMSession management
SMSShort message service
SMS-GMSCSMS gateway MSC
SMS-IWMSCSMS interworking MSC
SMTPSimple mail transfer protocol
SNRSubscribe notifications request
SOAPSimple object access protocol
SONSelf-optimizing network/Self organizing network
SPRSubscription profile repository
SPSSemi persistent scheduling
SPTService point trigger
SRScheduling request
SRBSignalling radio bearer
SRSSounding reference signal
SRVCCSingle radio voice call continuity
SSSupplementary service
SS7Signalling system 7
SSIDService set identifier
SSSSecondary synchronization signal
S-TMSIS temporary mobile subscriber identity
STN-SRSession transfer number single radio
SU-MIMOSingle-user MIMO
SVDSingular value decomposition
TATiming advance/Tracking area
TACTracking area code
TAITracking area identity
TCPTransmission control protocol
TDDTime division duplex
TDMATime division multiple access
TD-SCDMATime division synchronous code division multiple access
TETerminal equipment
TEIDTunnel endpoint identifier
TETRATerrestrial Trunked Radio
TFTTraffic flow template
THIGTopology hiding inter network gateway
TMTransparent mode
TMSITemporary mobile subscriber identity
TPCTransmit power control
TRTechnical report
TrGWTransition gateway
TSTechnical specification
TTATelecommunications Technology Association
TTCTelecommunication Technology Committee
TTITransmission time interval
UAUser agent
UARUser authorization request
UCIUplink control information
UDPUser datagram protocol
UDRUser data repository/User data request
UEUser equipment
UE-AMBRPer UE aggregate maximum bit rate
UICCUniversal integrated circuit card
ULUplink
UL-SCHUplink shared channel
UMUnacknowledged mode
UMBUltra Mobile Broadband
UMTSUniversal Mobile Telecommunication System
URIUniform resource identifier
USIMUniversal subscriber identity module
USSDUnstructured supplementary service data
UTDOAUplink time difference of arrival
UTRANUMTS terrestrial radio access network
VANCVoLGA access network controller
VLRVisitor location register
VoIPVoice over IP
VoLGAVoice over LTE via generic access
VoLTEVoice over LTE
V-PCRFVisited policy and charging rules function
VRBVirtual resource block
vSRVCCSingle radio video call continuity
WCDMAWideband code division multiple access
WCSWireless Communications Service
WiMAXWorldwide Interoperability for Microwave Access
WINNERWireless World Initiative New Radio
X2-APX2 application protocol
XCAPXML configuration access protocol
XMLExtensible markup language
ZUCZu Chongzhi