`
`
`
`r‘ TE
`. \The UMTS Long Term Evolution
`I; FROM THEORY ETO PRACTICE
`a.
`w
`Edited by: Stefania Sesia - Issam Touffik - Matthew Baker
`
`@WILEY
`
`Sainsung Ex. 1017
`
`Samsung Ex. 1017
`
`
`
`LTE - The UMTS
`Long Term Evolution
`
`From Theory to Practice
`
`Stefania Sesia
`
`ST-NXP Wireless/ETSI, France
`
`Issam Toufik
`
`ST-NXP Wireless, France
`
`Matthew Baker
`Philips Research, UK
`
`@2)WILEY
`
`A John Wiley and Sons, Ltd, Publication
`
`Samsung Ex. 1017
`
`
`
`Thiscdilion firsl published 2009
`© 2009 John Wiley & Sons Ltd.
`
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`
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`lhc Copyrighl. De.~igns and Palcnl~ Acl 1988.
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`All rights reserved. No part of this publication may be reproduced. 5lored in a retrieval system. or
`transmiucd. in an) form or by any mean~. electronic. m~hanical. photocopying. recording or
`mhcrwisc, except as permiued by Lhe UK Copyright, Designs and PillcnLs Act 1988, without ihc prior
`pertnission or lhe puhlishcr.
`Figure on cover: Reproduced by permission of O 3GPP1 \1 _
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`
`l ihra1y of Co11gress Caralogi11g•u1·1'ublicatio11 Dula
`
`Scsia. Stefunia.
`I :J'E-thc lJMTS long renn evolution : from theory to prnctice / Stefania ScsiM, Matlhew Baker. and
`lssilm Toufik.
`p. cm.
`Jncludcs hibliogruphic:il reference~ and index.
`ISBN 978-0-47/).6':1716-0 (cloth)
`I. Universal Mobile Tck~-ommunications System. I. Raker, Matthew (Maubew P . .I .) II. Tourik. ~sam
`HI . Tille.
`T K5103.488:tS47 2009
`62 l.1R45" 6-dc22
`
`20080-+1823
`
`A calaloguc record for this book is .i,ailable from lhe British Library.
`
`ISBN 9780-1-70697160 (11/B)
`
`FSC
`
`Samsung Ex. 1017
`
`
`
`List of Acronyms
`
`3GPP 3rd Generatioo Partnership Project
`JGPP2 3rd Generation Partnership Project 2
`AC Access Class
`ACI Adjacent Channel Interfe1-ence
`ACIR Adjacent Channel Interference Ratio
`ACK Acknowledgement
`ACLR Adjacent Channel Leakage Ratio
`ACS Adjacent Channel Selectivity
`ADC Analogue to Digital Converter
`ADSL Asymmetric Digital Subscriber Line
`AGI Antenna Gain Imbalance
`AM Acknowledged Mode
`AMC Adaptive Modulation and Coding
`AMPS Analogue Mobile Phone System
`AMR Adaptive MultiRate
`ANR Automatic Neighbour Relation
`ANRF Automatic Neighbour Relation Function
`AoA Angle-of-Arrival
`AoD Angle-of-Departure
`APN Access Point Name
`APP A-Posteriori Probability
`ARFCN Absolute Radio Frequency Channel
`Number
`ARIB Associalion of Radio Indusiries and
`Businesses
`ARP Almost Regular Permutation*
`ARP Allocation and Retention Priority*
`ARQ Automatic Repeat reQuest
`AS Access Stratum*
`
`AS Angular Spread*
`A-SEM Additional SEM
`ATDMA Advanced TOMA
`ATIS Alliance for Telecommunications Industry
`Solutions
`AuC Authentication Centre
`AWGN Additive White Gaussian Noise
`BCC Base station Colour Code
`BCH Broadcast CHannel
`BCCH Broadcast Control CHannel
`BCJR Algorithm named after its inventors,
`Bahl, Cocke, Jelinek and Raviv
`BER Bit Error Rate
`BLER BLock Error Rate
`BM-SC Broadcast-Multicast Service Centre
`BP Belief Propagation
`BPRE Bits Per Resource Element
`bps bits per second
`BPSK Binary Phase Shift Keying
`BSIC Base Station Identification Code
`BSR Buffer Status Repo1ts
`CAZAC Constant Amplitude Zero
`AutoCorrelation
`CB Circular Buffer
`CCCH Common Control CHannel
`CCE Control Channel Element
`CCI Co-Channel Interference
`CCO Cell Change Order
`CCSA China Communications Standards
`,\ssociation
`
`Samsung Ex. 1017
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`xxx
`COD Cyclic Delay Diversity
`CDF Cumulative Distribution Function
`CDL Clustered Delay Line
`CDM Code Division Multiplex(ed/ing)
`CDMA Code Division Multiple Access
`C/I Can·ier-to-lntcrference ratio
`CF Contenlion-free
`CFl Control Format Indicator
`CFO Carrier Frequency Offset
`CINR Carrier-to-Interference-and-Noise Ratio
`
`CIR Channel Impulse Response
`CM Cubic Metiic
`CMHH Constant Modulus HouseHolder
`CN Core Network
`CODIT UMTS Code Dlvision Testbed
`
`COFDM coded OFDM
`CP Cyclic Prefix
`CPlCH Common PIiot CHannel
`CPR Common Phase Rotation
`CPT Control PDU Type
`CQl Channel Quality Indicator
`CRC Cydic Redundancy Check
`C-RNTI Cell Radio Network Temporary
`Identifier
`CS Cit·cuit-Swllcned
`CSG Closed Subscriber Group
`CSI Channel State lnforiootion
`CSJT Channel Stnte I nformation at the
`Transmitter
`CTF Channel Transfer Function
`CVA Circular Viterbi Algorithm
`CVQ Channel Vector Quantization
`
`CW Continuous-Wave
`DAB Digital Audio Broadcasting
`DAC Digilal to Analogue Converter
`
`dB deci-Bel
`d.c. dlrecl current
`DCCH Dedicated Control CHannel
`
`LIST OF ACRONYMS
`
`DCFB Direct Channel FeedBack
`DCI Downlink Control lnformotion
`Dl<'T Discrete Fourier Transform
`DFf-S-OFDM OFT-Spread OFDM
`Diff'serv Differentiated Services
`DL DownUnk
`DL-SCH DownLink Shared CHannel
`Dl.\-ffi Digital Mobile Broadcasting
`OM RS DeModulation RS
`DOA Direction Of Arrival
`DPC Dirty-Paper Coding
`ORB Data Radio Bearer
`DRX Discontinuous Reception
`DS-CDMA Direct-Sequence Code Division
`Multiple Access
`DSP Digitnl Signal Processor
`DTCH Dedicated Traffic CHannel
`DTX Discontinuous Transmission
`DVB-H Digital Video Broadcasting - Handheld
`DVU-T Digital Video Broadcasting -Terrestrial
`DwPTS Downlink Pilot TimeSlot
`ECM EPS Connection Managemenl
`EDGE Enhanced Data rates for GSM Evolution
`EESM Exponential Effective SINR Mapping
`El\-1M EPS Mobj\jty Management
`eNodeB evolved NodeB
`EPA E,:,r.tended Pedestrian A
`EPC Evolved Packet Core
`EPS Evolved Packet System
`ESP Encapsulating Security Payload
`ETSI European Telecommunications Standards
`Institute
`ETU Ex.ten<led Typical Urban
`E-UTRA Evolvcd-UTRA
`E -UTRAN Evo!ved-UTRAN
`EVA Extended Vehicular A
`EVM Error Vector Mognitude
`FACH Forward Access CHanne!
`FB Fre(luen<.--y Burst
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`Samsung Ex. 1017
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`
`LIST OF ACRONYMS
`
`FCCH Frequency Control CHannel
`FDD Frequency Division Duplex
`FDE Frequency Domain Equalizer
`FDM Frequency Division Multiplexing
`FDMA Frequency Division Multiple Access
`FDSS Frequency Domain Spectral Shaping
`FIT Fast Fourier Transform
`FI Framing Info
`FIR Finite Impulse Response
`FMS First Missing SDU
`FSTD Frequency Switched Transmit Diversity
`FrP File Transfer Protocol
`FTTH Fibre-To-The-Home
`GBR Guaranteed Bit Rate
`GCL Generalized Chirp-Like
`GERAN GSM EDGE Radio Access Network
`GGSN Gateway GPRS Support Node
`GMSK Gaussian Minimum-Shift Keying
`GPRS General Packet Radio Service
`GPS Global Positioning System
`GSM Global System for Mobile
`communications
`GT Guard Time
`GTP GPRS Tunnelling Pmtocol
`GTP-U OTP-User plane
`HARQ Hybrid Automatic Repeal reQuest
`HD-FDD Half-Duplex FDD
`HFN Hyper Frame Number
`HII High Interference Indicator
`HLR Home Location Register
`HRPD High Rate Packet Data
`HSDPA High Speed Downlink Packet Access
`HSPA High Speed Packet Access
`HSPA+ High Spee.cl Packet Access Evolution
`HSS Home Subsctiber Server
`HSUPA High Spi..-ed Uplink Packet Access
`HTTP HyperText Transfer Protocol
`ICI lnterCarrier Interference
`
`xxxi
`
`ICIC InterCell Interference Coordination
`IDFT Inverse Discrete Fourier Transform
`IETF Internet Engineering Task Fort:e
`IFDMA Interleaved Frequency Division
`Multiple Access
`IFFT Inverse Fast Fourier Transform
`i.i.d. Independently identically distributed
`IM Implementation Margin
`IMD lnterModulation Distortion
`IMS IP Multimedia Subsystem
`IMSI International Mobile Subscriber Identity
`IMT International Mobile Telecommunications
`IP Internet Protocol
`IR Incremental Redundancy
`IRC Interference Rejection Combining
`ISD InterSite Distance
`ISi lnterSymbol Interference
`IST-WINNER Information Society
`Technologies-Wireless world INitiative
`NEwRadio
`ITU International Telecommunication Union
`ITU-R ITU Radiocommunication sector
`J-TACS Japanese Total Access Communication
`System
`LA Local Area
`LB Long Block
`LBP Layered Belief Propagation
`LBRM Limited Buffer Rate Matching
`LCID Logical Channel ID
`LDPC Low-Density Parity Check
`LI Length Indicator
`LLR Log-Likelihood Ratio
`LM:MSE Linear MMSE
`LNA Low Noise Amplifier
`LO Local Oscillator
`LOS Line-Of-Sight
`LS Least Squares
`LSF Last Segment Flag
`LTE Long-Term Evolution
`
`Samsung Ex. 1017
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`x.x.xii
`M...\ Metropolitan Are11
`MAC Medium Access Control
`MAC-I Message Authentication Code for
`Integrity
`MAN Metropolitan Area Network
`MAP Maximum A posteriori Probability
`MDMS Multimedia Broadcast/Multicast Service
`
`MUMS GW MBMS ~teWay
`MBR Maitimum Bit Rate
`MBSFN Mullimedia Broodcast Single
`Frequency Network
`MCCH Mullic!lSt Control CHannel
`MCE MulticeIUMulticast Coordination Entity
`
`MCH Multicast CHannel
`MCL Minimum Coupling Loss
`MCS Modulation and Coding Scheme
`Mcps Megachips per second
`MDS Minimum Discernible Signal
`MediaFLO Media Forward Link Only
`MIB Master lnformation Block
`MIMO Multiple-Input Multiple-Output
`1\flP Mobile Internet Protocol
`MlSO Mulliple-Jnpul Single-Output
`ML Maximum Like\ihood
`MLD Maximum Likelihood Detector
`MME Mobility Management Entity
`"MMSE Minimum MSE
`MO Mobile Originated
`M-PSK M-ary Phase-ShifL Keying
`MQE Minimum Quantization Error
`MRC Maximum Ratio Combining
`MSAP MCH Subframe Allocation Pauern
`MSB Most Significant Bil
`MSE Minimum Squared Error
`MSR Mmdmum Sensitivity Reduction
`MTCH Multicast Trame C Hannel
`MU-MIMO Multi-User MIMO
`NACC Network Assisted Cell Change
`
`LIST OF ACRONYMS
`
`NACK Negative ACKoowledgemenl
`NACS NonAdjacent Channel Selectivity
`NAS Non Access Stratum
`NCC Network Colour Code
`NCL Neighbour Cell List
`NDl New Data indicator
`NF Noise Figure
`NGMN Next Generation Mobile Networks
`NLMS Normalized Least-Me3n-Square
`NLOS Non-Line-Of-Sighl
`NMT Nordic Mobile Tele-phone
`NNSF NAS Node Selection Function
`Node"B The base station in WCDMA systems
`o&M Operation and Maintenance
`OBPD Occupied Bandwidth Power De-raLing
`OBW Occupied BandWidth
`OFDM Orthogonal frequency Divtsion
`Multiplexing
`OFDMA Orthogonal Frequency Division
`Multiple Access
`01 Overload Indicator
`OOB Out-Of-Band
`PIS Parallel-to-Serial
`PA Power Amplifier
`PAN Personal Area Network
`PAPR Peak-to-Average Power Ratio
`PilCH Physical Broadcast CHannel
`PBR Prioriti7..ed Bit Rate
`PCC Policy Control and Charging
`PCCH Paging Control CHannel
`P-CCPCH Primary Common Control Physical
`CHannel
`PCEF Policy Control Enforcement Function
`PCFICH Physical Control Format indicator
`CHanne!
`PCG Project Coordination Group
`PCH Paging CHannel
`PCl Physical Cell Identity
`P-CPICB Primary Common Pllot CHannel
`
`Samsung Ex. 1017
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`
`LIST OF ACRO!'I-YMS
`
`PCRF Policy Control and charging Rul<.-s
`Function
`PDCCH Physical Downlink Control CHannel
`PDCP Packet Data Convergence Protocol
`PDN Packet Data Network
`PDP Power Delay Profile
`PDSCH Physical Downlink Shared CHannel
`PDU Protocol Daia Unit
`PF Paging Frame
`PFS Proportional Fair Scheduling
`P-GW PDN Gate Way
`PHICH Physical Hybrid ARQ Indicator
`CHannel
`PLL Phase-Locked Loop
`PLMN Public Land Mobile Network
`P-MCCH Primary MCCH
`PMCH Physical Multicast CHannel
`P~II Precoding Matrix Indicators
`PMIP Proxy M!P
`PN Pseudo-Noise
`PO Paging Occasion
`PRACH Physical Random Access CHnnnel
`PUB Physical Resource Block
`P-R!'.'Tl Paging RNTI
`PS Packet-Switched
`P·SCH Primary Synchronization CHannel
`PSD Power Spectral Density
`PSS Primary Synchronizatioo Signal
`PUCCH Physical Uplink Control CHanncJ
`PUSCH Physical Uplink Shared CHannel
`PVI Precoding Vector [ndicator
`QAM Quadrature Amplitude Modulatioo
`QCI QoS CUlss Jdenti!!er
`QoS Qualily-of-Service
`QPP Quadratic Permutation Polynomial
`QPSK Quadrature Phase Shift Keying
`RA Random Access
`RACH Random Access CHannel
`
`xxxiii
`
`RAN Radio Access Network
`RAR Random Access Response
`RA-IL"'lTI Random Access Radio Network
`Temporary Identifier
`RAT Radio Access Technology
`RB Resoorce Block
`RE Resource Element
`REG Resource Element Group
`RF Radio Frequency
`RFC Request For Comments
`RI Rank Indicator
`RLC Radio Link Control
`RLS Recursive Least Squares
`RM Rate Matching
`RNC Radio Network Controller
`RNTI Radio Network Temporal)' ldentifie1·
`RNTP Relative Nanowband Transmit Power
`ROHC RObust Hender Compression
`RoT Rise over Thermal
`RPF RePetition Factor
`R-PLMN Registered PLMN
`RRC Radio Resource Control"'
`RRC Root-Raised-Cosine*
`RRM Radio Resource Management
`RS Reference Signal
`RSCP Received Signal Code Power
`RSRP Reference Signal Received Power
`RSRQ Reference Signal Received Quality
`RSSI Received Signal Strength lndicator
`RTCP Real-time Transport Control Protocol
`RTD Round-Trip Delay
`RTP Real-time Transport Protocol
`RTT Round-Trip Time
`RV Redundancy Version
`SIP Serial-to-Parallel
`SlAP SI Application Protocol
`SAE System Architecture Evolution
`SAP Service Access Point
`SAW Stop-And-Wait
`
`Samsung Ex. 1017
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`
`
`xxxiv
`
`LIST OF ACRONYMS
`
`SB Short Block*
`SB Synchronization Burst*
`SBP Systematic Bit Punctuiing
`SC-FDMA Single-Carrie. Frequenc;· Division
`Multiple Access
`SCH Synchronization CHannel
`SCM Spatial Channel Model
`SCME Spatial Channel Model Extension
`SCTP Stream Control Transmission Protocol
`SDMA Spatial Division Multiple Access
`SDO Standards Developmenl Organization
`SDU Service Data Unit
`SEM Spectrum Emission Mask
`SFBC Space-Frequency Block Code
`SFDR Spurious-Pree Dynamic Range
`SFN System Frame Number
`SGSN Serving GPRS Support Node
`S-GW Serving GateWay
`SJ System Information
`SID System Information Block
`SIC Successive Interference Cancellation
`SIMO Single-Input Multiple-Output
`SINR Signal-to-Interference plus Noise Ratio
`SIP Session Initiation Protocol
`SIR Signal-to-Interference Ratio
`SI-R.t."'i!TI System lnfonnation Radio Network
`Temporary Identifier
`SISO Single-Input Single-Output*
`SISO Soft-Input Soft-Output"'
`S-MCCH Secondary MCCH
`SMS Short Message Service
`SN Sequence Number
`SNR Signal-to-Noise Ratio
`SO Segmentation Offset
`SON Self-Optimizing Networks
`SPA Sum-Product Algorithm
`SPS Semi-Persistent Scheduling
`SPS-CRNTI Semi-Persistent Scheduling
`C-RNTI
`
`SR Scheduling Request
`SRB Signalling Radio Bearer
`SRNS Serving Radio Network Subsystem
`SRS Sounding Reference Signal
`S-SCH Secondary Syncronization CHannel
`SSS Secondary Synchronization Signal
`STBC Space-Time Block Code
`S-TMSI SAE-Temporary Mobile Subscriber
`Identity
`STTD Space-Time Transmit Diversity
`SU-MIMO Single-User MIMO
`SVD Singular-Value Decomposition
`TA Tracking Area
`TACS Total Access Communication System
`TB Transport Block
`TCP Transmission Control Protocol
`TDD Time Division Duplex
`TDL Tapped Delay Line
`TDMA Time Division Multiple Access
`TD•SCDl.\.iA Time Division Synchronous Code
`Division Multiple Access
`TEID Tunnelling End lD
`TF Transport Format
`TFT Traffic Flow Template
`Tlvl Transparent Mode
`TMD Transparent Mode Dala
`TNL Transport Network. Layer
`TNMSE Truncated Normalized Mean-Squared
`Error
`TPC Transmitter Power Control
`TPD Total Power De-rating
`TR Tone Reservation
`TSC Training Sequence Code
`TSG Technical Specification Group
`TIA Tulecommunications Tuclmology
`Association
`TIC Telecommunications Technology
`Committee
`TTI Transmission Time Interval
`
`Samsung Ex. 1017
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`
`
`LIST OF ACRONYMS
`
`TU Typical Urban
`UDP User Dacagram Prolocol
`UE User Equipment
`UL UpLink
`UL-SCH UpLink Shared CHannel
`UM Unacknowledged Mode
`UMB Ultra-Mobile Broadband
`UMTS Universal Mobile Telecommunications
`System
`UP Unitary Preceding
`UpPTS Uplink Pilot TimeSlot
`US Uncorrelate<l-Scauered
`USlM Universal Subscriber Identity Module
`UTRA Universal Tcrres1ri11I Radio Access
`UTRAN Universal Terrestrial Radio Access
`Network
`VA Viterbi Algorithm
`vcn Virttllll Circular Buffer
`VCO Voltage-Controlled Oscillator
`VoIP Voice-over-IP
`
`XXXV
`
`VRB Vinual Resource Block
`WA WideArca
`WAN Wide Area Network
`WCDMA Wideband Code Division Multipk
`Access
`WFT Winograd Fourier Transform
`WG Wrnidng Group
`
`WiMAX Worldwide interoperability for
`Microwave Access
`WINNER Wireless world INiLiative NEw Radio
`WLAN Wireless Local Area Network
`WPD Waveform Power De-rating
`WRC World Rodiocommunication Conference
`WSS Wide-Sense Stationary
`WSSUS Wide-Sense Stationary Uncorrelated
`Scallering
`ZC Zadoff-Chu
`ZCZ Zero Correlation Zone
`ZF Zero-Forcing
`ZFEP Zero-Forcing Equal Power
`
`*This acrnnym can have different meanings depending on the comexL The meaning is clearly
`indicated in the chapter when used.
`
`Samsung Ex. 1017
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`
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`2
`
`Network Architecture
`
`Sudeep Palat and Philippe Godin
`
`2.1
`
`Introduction
`
`As mentioned in the preceding chapter, LTE has been designed to support only packel(cid:173)
`switched services, in contrast to the circuit-switched model of previous cellular systems. lt
`aims to provide seamless lnternet Protocol (IP) connectivity between User Equipment (UE)
`and the Packet Data Network (PDN), without any disruption to the end users' applications
`during mobility. While the term 'LTE' encompasses the evolution of the radio access through
`the Evolved-UTRAN (E-UTRAN), it is accompanied by an evolution of the non-radio aspects
`under the term 'System Architecture Evolution' (SAE) which includes the Evolved Packet
`Core (EPC) network. Together LTE and SAE comprise the Evolved Packet System (EPS).
`EPS uses the concept of EPS bearers to route IP traffic from a gateway in the PDN to
`the UE. A bearer is an IP packet flow with a defined Quality of Service (QoS) between the
`gateway and the UE. The E-UTRAN and EPC together set up and release bearers as required
`by applications.
`In this chapter, we present the overall EPS network architecture, giving an overview of the
`functions provided by the Core Network (CN) and E-UTRAN. The protocol stack across the
`different interfaces is then explained, along with an overview of the functions provided by
`the different protocol layers. Section 2.4 outlines the end-to-end bearer path including QoS
`aspects and provides details of a typical procedure for establishing a bearer. The remainder of
`the chapter presents the network interfaces in detail, with particular focus on the E-UTRAN
`interfaces and the procedures used across these interfaces, including those for the support of
`user mobility. The network elements and interfaces used solely to support broadcast services
`are covered in Chapter 14.
`
`LTE- The UMTS Long Term Evolmion: from 11ieory to Practice Stefania Sesia, lssam Toufik and Manhew Baker
`© 2009 John Wiley & Sons, Ltd
`
`Samsung Ex. 1017
`
`
`
`24
`
`LTE - THE UMTS LONG TERM EVOLUTION
`
`I : ,---~~----G
`
`SI-MME
`
`I ~
`r---r -~ - --:
`
`,---~-- ---,
`Gx' ~ - Rx1
`I
`I
`I
`
`1$1 1
`I
`I
`I
`
`UE
`
`N d B ,__~~--< Serving i--~----< PDN
`L TE-Uu c o e
`SI -U
`Gateway S5/S8
`Galeway
`
`SGi
`
`Operator's
`IJ- services
`(e.g.'!MS, .PSS etc.)
`
`"'-.
`)
`
`Figure 2.1 The EPS network elements.
`
`2.2 Overall Architectural Overview
`
`EPS provides the user with IP connectivity to a PDN for accessing the Internet, as well as for
`running services such as Voice over IP (VoIP). An EPS bearer is lypically associated with a
`QoS. Multiple bearers can be established for a user in order to provide different QoS streams
`or connectivity to different PDNs. For example, a user might be engaged in a voice (VoIP) call
`while at the same time p_erforming web browsing or File Transfer Protocol (FTP) download.
`A VoIP bearer would provide the ne,cessary QoS for the voice call, while a best-effort bearer
`would be suitable for the web browsing or FTP session.
`The network must also provide sufficient security and privacy for the user and protection
`for the network against frau~ulent use.
`This is achieved by means of several BPS network elements which have different roles.
`Figure 2.1 shows the overall network architecture including the network elements and
`the standardized interfaces. At a high level, the network is comprised of the CN (EPC)
`and the access network (E-UTRAN). While the CN consists of many logical nodes, the
`access network is made up of essentially just one node, the evolved NodeB (eNodeB),
`which connects to the UEs. Each of these network elements is inter-connected by means of
`interfaces which are standardized in order to allow multiveodor interoperability. This g ives
`network operators the possibility to sourcedifferentnetwork elements from different vendors.
`In fact, network operators may choose in their physical implementations to split or merge
`these logical network elements depending on commercial considerations. The functional split
`between the EPC and E-UTRAN is shown in Figure 2.2, The EPC and E-UTRAN network
`elements are described in more detail below.
`
`2.2.1 The Core Network
`The CN (called EPC in SAE) is responsible for the overall control o f the UE and
`establishment of the bearers. The main logical nodes of the EPC are:
`
`• PDN Gateway (P-GW);
`
`• Serving Gateway (S-GW);
`
`• Mobility Management Entity (MME).
`
`Samsung Ex. 1017
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`NETWORK A R CHITECTURE
`
`25
`
`eNs··
`
`'~- __ lnl_er_c_e_ll R_R_M_~
`
`RB Control
`
`· 1 Connection Mobility Cont.
`
`. : r. R~dio Adrr:~~~ ~~•nt~oJ
`eNS Measul'ement
`Configuration & Provision
`
`M~~/'._ .," .f:.•.·c [': ·,\.•
`
`NAS Security
`
`idle State Mobil~y
`Handling
`
`1 ·
`
`•
`
`S I
`
`E-UTRAN
`
`EPC
`
`Figure 2.2 Functional split between E-UTRAN and EPC. Reproduced by permission of
`©3GPP.
`
`In addition to these nodes, EPC also .includes other logical nodes and functions such as
`the Home Subscriber Server (HSS) and Lhe Policy Control and Charging Rules Function
`(PCRF). Since the EPS only provides a bearer path of a certain QoS, control of multimedia
`applications such as VoIP .is provided by the JP M ultimedia Subsystem (IMS) which is
`considered to be outside the EPS itself
`The logical CN nodes (specified in [ I]) are shown in Figure 2.1 and discussed in more
`detail in the following.
`
`• PCRF. It is responsible for policy control decision-making, as well as for controlling
`the flow-based charging functionalities in the Policy Control Enforcement Function
`(PCEF) which resides in the P-GW. The PCRF provides the QoS autho1faation (QoS
`class identifier and bitrates) that decides how a certain data tlow will be treated in the
`PCEF and ensures that this is in accordance with the user's subscription profile.
`
`• Home Location Register (HLR). The HLR contains use rs' SAE subscription data
`such a~ the BPS-subscribed QoS profile and any access restrictions for roaming (see
`Section 2.2.3). It also holds information about the PDNs to which the user can connect.
`This could be in the form of an Access Point Name (APN) (which is a label according
`to DNS 1 naming conventions describing the access point to the PDN), or a PON
`Address (indicating subscribed IP address(es)). In addition the HLR holds dynamic
`information such as the identity of the MME to which the user is currently attached
`
`1 Domain Name Sys1em.
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`26
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`LTB - THE UMTS LONG TERM EVOLUTION
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`or registered. The HLR may also integrate the Authentication Centre (AuC) which
`generates the vectors for authentication and security keys.
`
`• P-GW. T he P-GW is responsible for IP address allocation for the UE, as well as QoS
`enforcement and flow -based charging according to rules from the PCRF. The P-GW is
`responsible for the filtering of downlink user IP packets into the different QoS based
`bearers. This is performed based on Traffic Flow Templates (TFTs) (see Section 2.4).
`The P-GW performs QoS enforcement for Guaranteed Bit Rate (GBR) bearers. It also
`serves as the mobility anchor for inter-working with non-3GPP tech1plbgies such
`as CDMA2000 and WiMAX networks (see Section 2.2.4 and Chapter 13 for more
`information about mobility).
`
`• S -G\.V. All user IP packets are transferred through the S-GW, which serves as the local
`mobility anchor for the data bearers when the UE moves between eNodeBs. It also
`retains the information about the bearers when the UE is in idle state (known as ECM(cid:173)
`IDLE, see Section 2.2. 1.1) and temporarily buffers downlink data while the MME
`initiates paging of the UE to re-establish the bearers. Jn addition, the S-GW performs
`some administrative functions in rhe visited network such as collecting information
`for charging (e.g. the volume of data sent to or received from the user), and legal
`interception. It also serves as the mobility anchor for inter-working with other 3GPP
`technologies such as GPRS and UMTS (see Section 2.2.4 and Chapter 13 for more
`information about mobility).
`
`• MME. The MME is the control node which processes the signalling between the UE
`and the CN. The protocols running between the UE and the CN are known as the
`Non-Access Stratum (NAS) protocols.
`The main functions supported by the MME are classified as:
`F unctio ns -related to bearer management. This includes the establishment, mainte(cid:173)
`nance and release of the bearers, and is handled by the session management layer in
`the NAS protocol.
`Functions related to connection management. This includes the establishment of the
`connection and security between the network and UE, and is handled by the connection
`or mobility management layer in the NAS protocol layer.
`NAS control procedures are specified in [1] and are discussed in more detail in the
`following section.
`
`2.2.1.1 Non-Access Stratum (NAS) Procedures
`
`The NAS procedures, especially the connection management procedures, are fundamentally
`similar to UMTS. The main change from UMTS is that EPS allows concatenation of some
`procedures to allow faster establishment of the connection and the bearers.
`The MME creates a UE con.text when a UE is turned on and attaches to the network. It
`assigns a unique short temporary identity termed the SAE-Temporary Mobile Subscriber
`Identity (S-TMSI) to the UE which identifies the UE context in the MME. This UE
`context holds user subscription information downloaded from the HSS. The local storage
`of subscription data in the MME allows faster execution of procedures such as bearer
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`NETWORK ARCHITECTURE
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`27
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`establishment since it removes the need to consult the HSS every time. In addition, the UE
`context also holds dynamic information such as the list of bearers that are established and the
`terminal capabilities.
`To reduce the overhead in the E-UTRAN and processing in the UE, all DE-related
`information in the access network can be released during long periods of data inactivity.
`This state is called EPS Connection Management IDLE (ECM-IDLE). The MME retains the
`UE context and the information about the established bearers during these idle periods.
`To allow the network to contact an ECM-IDLE UE, the UE updates the network as to
`its new location whenever it moves out of its current Tracking Area (TA); this procedure
`is called a 'Tracking Area Update'. The MME is responsible for keeping track of the user
`location while the UE is in ECM-IDLE.
`When there is a need to deliver downlink data to an ECM-IDLE UE, the MME sends a
`paging message to all the eNodeBs in its current TA, and the eNodeBs page the UE over the
`radio interface. On receipt of a paging message, the UE performs a service request procedure
`which results in moving the UE to ECM-CONNECTED state. DE-related information is
`thereby created in the E-UTRAN, and the bearers are re-established. The MME is responsible
`for the re-establishment of the radio bearers and updating the UE context in the eNodeB. This
`transition between the UE states is called an idle-to-active transition. To speed up the idle-to(cid:173)
`active transition and bearer establishment, BPS supports concatenation of the NAS and AS
`procedures for bearer activation (see also Section 2.4.1). Some inter-relationship between
`the NAS and AS protocols is intentionally used to allow procedures to run simultaneously
`rather than sequentially, as in UMTS. For example, the bearer establishment procedure can
`be executed by the network without waiting for the completion of the security procedure.
`Security functions are the responsibility of the MME for both signalling and user data.
`When a UE attaches with the network, a mutual authentication of the UE and the network is
`performed between the UE and the MME/HSS. This authentication function also establishes
`the security keys which are used for encryption of the bearers, as explained in Section 3.2.3. l.
`The security architecture for SAE is specified in [2].
`
`2.2.2 The Access Network
`
`The Access Network of LTE, E-UTRAN, simply consists of a network of eNodeBs, as
`illustrated in Figure 2.3. For normal user traffic (as opposed to broadcast), there is no
`centralized controller in E-UTRAN; hence the E-UTRAN architecture is said to be flat.
`The eNodeBs are normally inter-connected with each other by means of an interface
`known as X2, and to the EPC by means of the SJ interface - more specifically, to the MME
`by means of the SI-MME interface and to the S-GW by means of the SI-U interface.
`The protocols which run between the eNodeBs and the UE are known as the Access
`Stratum (AS) protocols.
`The E-UTRAN is responsible for all radio-related functions, which can be summarized
`briefly as:
`
`• Radio Resource Management. This covers all functions related to the radio bearers,
`such as radio bearer control, radio admission control, radio mobility control, schedul(cid:173)
`ing and dynamic allocation of resources to UEs in both uplink and downlink (see
`Chapter 13).
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`28
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`LTE - THE UMTS LONG TERM EVOLUTION
`
`E-UTRAN
`
`MME / S-GW
`I
`I I
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`f
`i
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`l
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`eNB#2
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`Figure 2.3 Overall E-UTRAN architecture. Reproduced by permission of© 3GPP.
`
`• Header Compres,sion. T his helps to ensure efficient use of the radio interface by
`compressing the IP packet headers which could otherwise represent a significant
`overhead, especially for small packets such as VoIP (see Section 4.2.2).
`
`• Security. All data sent over the radio interface is encrypted (see Sections 3.2.3. 1 and
`4.2.3).
`
`• Connectivity to the EPC. This consists of the signalling towards the MME and the
`bearer path towa!·ds the S-GW.
`
`On the network side, all of these functions reside in the eNodeBs, each of which can
`be responsible for managing multiple cells. Unlike some of the previous second- and third(cid:173)
`generation technologies, LTE integrates the radio controller function into the eNodeB. This
`allows Light interaction between the different protocol layers of the radio access network, thus
`reducing latency and improving efnciency. Such distributed control eliminates the need for
`a high-availability, processing-intensive controller, which in turn has the potential to reduce
`costs and avoid 'single points of failure'. Furthermore, as LTE does not support soft handover
`there is no need for a centralized data-combining function in the network.
`O ne consequence of the lack of a centralized controller node is that, as the UE moves, the
`network must transfer all information related to a UE, i.e. the UE context, together with any
`buffered data, from one eNodeB to another. As discussed in Section 2.3.1. l, mechanisms are
`therefore needed to avoid data loss during handover. T he operation of the X2 interface for
`this purpose is explained in more detail in Section 2.6.
`An important feature of the Sl interface linking the Access Network to the CN is known
`as SJ-flex. This is a concept whereby multiple CN nodes (MME/S-GWs) can serve a common
`geographical area, being connected by a mesh network to the set of eNodeBs in that area (see
`Section 2.5). An eNodeB may thus be served by mu ltiple MME/S-GWs, as is the case for
`
`Samsung Ex. 1017
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`NETWORK ARCH