IMT-2000 And UMTS
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeIMT-2000 and UMTSIMT-2000 (International Mobile Telecommunications) was started as activity by ITU todefine a world-wide standardized 3G communication system. Lots of proposals weredeveloped: UWC-136, cdma2000, WP-CDMA, and UMTS (Universal Mobile Telecommunications System, ETSI)UMTS bases on the so-called UTRA: Universal Terrestrial Radio Access Integration of different mobile, cordless and pager systems into only one radioaccess network supporting world-wide roaming Integration von voice, data, and multimedia data services Enhancement of GSM: higher data rates, enhanced service concept, global roaming Data rates: 144 kBit/s up to 2 MBit/s– min. 144 kBit/s rural (target: 384 kBit/s)– min. 384 kBit/s suburban (target: 512 kBit/s)– up to 2 MBit/s urban Compatibility to GSM, ISDN, ATM, and IPChapter 3.4: Mobile Telecommunication Networks43
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeFrequencies for IMT-200018501900IMT-2000ITU allocationEuropeChina1950GSM DE1800 CTGSM1800JapanTDDNorthAmerica1900TDDMSS 2000MSS: Mobile satellite servicesDECT: Digital Enhanced Cordless TelecommunicationsPHS: Personal Handyphone SystemPCS: Personal Communications Service (GSM1900)Chapter 3.4: Mobile Telecommunication Networks2200MHzMSS UTRA MSSFDD IMT-2000MSS cdma2000 MSSW-CDMA MSS 19502100 2150IMT-2000cdma2000 MSSW-CDMA PCS18502050MSS UTRA MSSFDD IMT-2000PHS2000rsv.20502100 2150MSS 2200MHz44
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeIMT-2000 FamilyIMT-2000 UMTS IMT-2000 It was not possible to definea world-wide acceptedstandard; thus a family ofspecifications was acceptedIMT-2000core networkITU-TGSMInitial UMTS(Release99 with FDD)IMT-2000radio accessITU-RInterface for networkingANSI-41(IS-634)IP networkFlexible assignment of core networkand radio accessIMT-DSIMT-TCIMT-MCIMT-SCIMT-FT(Direct Spread)(Time Code)(Multi Carrier)(Single Carrier)(Freq. Time)UTRA FDD(W-CDMA)UTRA ter 3.4: Mobile Telecommunication Networks45
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeLicensing of UMTS in Germany, 18.8.2000 UTRA-FDD:Uplink 1920-1980 MHzDownlink 2110-2170 MHzDuplex spacing 190 MHz12 channels, 5 MHz each UTRA-TDD:1900-1920 MHz2010-2025 MHz5 MHz channels Planned coverage: 25% ofthe population till 12/2003,50% till 12/2005Sum: 50,81 billion Chapter 3.4: Mobile Telecommunication Networks46
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeUMTS – End of 2007 (www.gsmworld.com)ePlusO2VodafoneChapter 3.4: Mobile Telecommunication Networks47
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeUMTS Architectur (Release 99) UTRAN (UTRA Network) Cell level mobility Comprises several Radio Network Subsystems (RNS) Encapsulation of all radio specific tasks UE (User Equipment) CN (Core Network) Handover between systems Gateways to other systems Location management, if there is no dedicated connection between UE andUTRAN Usage of existing GSM/GPRS infrastructure, change to an IP-based corenetwork with release 5UuUEIuUTRANChapter 3.4: Mobile Telecommunication NetworksCN48
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeUMTS Domains and omainYuTransitNetworkDomainCore Network DomainUser Equipment DomainInfrastructure Domain User Equipment Domain Assigned to a single user in order to access UMTS services Infrastructure Domain Shared among all users Offers UMTS services to all accepted usersChapter 3.4: Mobile Telecommunication Networks49
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeUMTS Domains and Interfaces Universal Subscriber Identity Module (USIM) Functions for encryption and authentication of users Located on the SIM Mobile Equipment Domain Functions for radio transmission User interface for establishing/maintaining end-to-end connections Access Network Domain Access network dependent functions Core Network Domain Access network independent functions Serving Network Domain Network currently responsible for communication Home Network Domain Location and access network independent functionsChapter 3.4: Mobile Telecommunication Networks50
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeUTRAN ArchitectureRNSUE1Node BIubRNC: Radio Network ControllerRNS: Radio Network SubsystemIuRNCCNUE2Node BUE3IurNode BIubNode BRNC UTRAN comprises severalRNSs Node B can support both, FDDor TDD RNC is responsible forhandover decisions requiringsignaling to the UE Cell offers FDD or TDDNode BRNSChapter 3.4: Mobile Telecommunication Networks51
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeUTRAN Functions Admission ControlCongestion ControlSystem Information BroadcastingRadio Channel EncryptionHandoverRadio Network ConfigurationChannel Quality MeasurementsMacro DiversityRadio Carrier ControlRadio Resource ControlData Transmission over the Radio InterfacePower ControlChannel CodingAccess ControlChapter 3.4: Mobile Telecommunication Networks52
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeCore Network: DN (X.25),Internet (IP)HLRRNSLayer 3: IPLayer 2: ATMLayer 1: PDH,SDH, SONETUTRANSGSNGPRS Backbone (IP)SS 7CNRNS can be UMTS RNS or GSM BSSChapter 3.4: Mobile Telecommunication Networks53
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeCore NetworkThe Core Network and thus also the interface Iu are separated into two logicaldomains: Circuit Switched Domain (CSD) Circuit switched service inclusive signaling Resource reservation at connection setup GSM components (MSC, GMSC, VLR) Packet Switched Domain (PSD) GPRS components (SGSN, GGSN)Release 99 uses the GSM/GPRS network and just adds a new radio access Lower costs, faster deployment Not as flexible as newer releases since 5 (change to IP based functions, )Chapter 3.4: Mobile Telecommunication Networks54
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeSupport of Mobility: Macro Diversity A device can receive signals over 3antennas in parallel Multicast of data via several physicalchannels Enables soft handover only in FDD modeUENode BNode BRNCCN Uplink Simultaneous reception of UEdata at several Node Bs Reconstruction of data at NodeB, SRNC or DRNC Downlink Simultaneous transmission ofdata via different cells Different spreading codes indifferent cellsChapter 3.4: Mobile Telecommunication Networks55
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeSupport of Mobility: Handover From and to other systems (e.g. UMTS to GSM) A must for the beginning when UMTS coverage is poor RNS controlling the connection is called SRNS (Serving RNS) RNS offering additional resources (e.g. for soft handover) is called DRNS (DriftRNS) End-to-end connections between UE and CN only via Iu at the SRNS Change of SRNS requires change of Iu Initiated by SRNS Controlled by the RNC and CNNode BIubUECNSRNCNode BIurIuDRNCIubChapter 3.4: Mobile Telecommunication Networks56
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeExample Handover Types in in UMTS/GSMUE1Node B1UE2UE3UE4RNC13G MSC1IuNode B2IurIubNode B3RNC23G MSC2BTSBSC2G MSC3AbisChapter 3.4: Mobile Telecommunication NetworksA57
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeSpreading and Scrambling of User Data Constant chipping rate of 3.84 million chip/s in UMTS cells Modulation is done using QPSK Different user data rates supported via different spreading factors Higher data rate: less chips per bit and vice versa Separation of different transmissions is done with a combination of orthogonalspreading codes and quasi-orthogonal scrambling codes Base station manages codes and provides sender1Chapter 3.4: Mobile Telecommunication Networksscramblingcode2sender258
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeSpreading: OSVF CodingOSVF: Orthogonal Variable Spreading Factors Simple generation of orthogonal chip sequences Thus: simple code management Code length can be adapted tonumber of data ,1,-1,1SF nSF 1,1,-1SF: spreading factorChapter 3.4: Mobile Telecommunication NetworksSF 1 SF 2SF 4SF 859
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeScrambling: Gold CodesAs addition to spreading, scrambling is used: With linear feedback shift registers, pseudo-random numbers can be generated With “good” pseudo-random numbers, the numbers are quasi-orthogonal Quasi-orthogonal: only low influence between the codes As for Barker codes in WLAN: use codes which also stay quasi-orthogonal ifsynchronization is not perfect Used here: so-called Gold codesWhy to use spreading and scrambling, not only one method? Data streams in one station, several mobile stations, base stations in different(overlapping) cells Too much synchronization to coordinate everything, especially all base stationsin one region!Chapter 3.4: Mobile Telecommunication Networks60
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeUsage of Spreading and ScramblingOn the uplink Use OVSF to generate spreading codes for several transmissions of a mobilestation Each mobile station generates spreading codes only by itself, depending on thenumber of own data streams (4 – 256 chips) Scrambling codes are assigned by the base station to each mobile station toseparate the transmissions of all mobile stations (38400 chips / 256 chips) Use of scrambling to separate stations needs less synchronization thanspreadingOn the downlink Use of OVSF by the base station to generate orthogonal codes for the mobilestations – synchronization here is no problem because the base station isoverlaying all transmissions before sending (4 – 512 chips) Use scrambling codes to scramble spread data streams for separating cells Each base station uses on scrambling code, otherwise also cells would have tobe synchronizedChapter 3.4: Mobile Telecommunication Networks61
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeUMTS FDD Frame StructureLike in GSM, lots of channels are necessary for data and control purposes, e.g.:Radio frame10 ms012.121314Time slot666,7 µsPilotTFCIFBITPCUplink DPCCH2560 Chips, 10 Bits666,7 µsUplink DPDCHData2560 Chips, 10*2k Bits (k 0.6)666,7 µsData1 TPC TFCI Data2PilotDownlink DPCHDPDCH DPCCH DPDCH DPCCH2560 Chips,10*2kW (Wideband)-CDMA 1920-1980 MHz Uplink 2110-2170 MHz Downlink Chipping rate: 3,840 MChip/s Soft handover Complex power control (1500power control cycles/s) Spreading factor:UL: 4-256; DL: 4-512Bits (k 0.7)Slot structure not for user separationbut synchronization!Chapter 3.4: Mobile Telecommunication NetworksFBI: Feedback Information (e.g. for handover)TPC: Transmit Power ControlTFCI: Transport Format Combination IndicatorDPCCH: Dedicated Physical Control ChannelDPDCH: Dedicated Physical Data ChannelDPCH: Dedicated Physical Channel62
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeUMTS TDD Frame StructureRadio Frame10 ms666,7 µs012Time slotDataMidample1104 Chips 256 Chips.12DataGP1104 Chips2560 Chips1314Traffic burstGP: guard period96 ChipsTD-CDMA 2560 Chips per slot Spreading factor: 1-16 Symmetric or asymmetricslot assignment to UL/DL(min. 1 per direction) Tight synchronizationneeded Simpler power control(100-800 power controlcycles/s)Shown on both slides are only dedicated channels (control / data) for one station –but there are also available all the channels as in GSM, e.g. for random access ofnew mobile stations.Chapter 3.4: Mobile Telecommunication Networks63
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeCell BreathingGSM Device gets adapted power from the base station to send in one slot exclusively Number of connected devices has no influence on the cell sizeUMTS Cell size and number of devices are tightly correlated Transmission quality is determined by the Signal-to-Noise-Ratio Noise is increased by interference with other cells with other participants If noise is too high, transmit power needs to be increased Devices at the cell border are the first which can not furthermore increase thesignal strength (power limitation) for too high noise no communication is possible Restriction of simultaneous number of users necessary Cell breathing makes cell planning complicatedChapter 3.4: Mobile Telecommunication Networks64
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeCell Breathing: ExampleChapter 3.4: Mobile Telecommunication Networks65
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeUMTS EvolutionUMTS is only one way how to implement IMT-2000. Initial release (Release99): Make it cheap: re-use GSM/GPRS in the core network (with small enhancements) Define only new CMDA-based radio network (as shown before)In 2000: definition of release 4 and 5 with some enhancements: Almost IP-all based core network for better integration with the Internet Integration of IMS (IP Multimedia Subsystem) which should give guarantees in anIP-based network necessary for voice transmission Adaptive rate codec for better quality of the transmitted speech Integration of “Customized Applications for Mobile Enhanced Logic” (CAMEL)which allows an operator to define services over and above standard GSM services First mentioning of beamforming High-speed transmission on the radio interface (HSDPA, up to 10 MBit/s downlink)Chapter 3.4: Mobile Telecommunication Networks66
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeHSDPAA higher speed is achieved by improving several details in the data transmission: Hybrid ARQ: use of a stop-and-wait flow control with ACKs and NACKs. If areceived packet is erroneous, a negative ACK is passed back, but the received(damaged) packet is stored. The packet is retransmitted and combined with thedamaged version (chase combining) to increase the chance to get a correctpacket even if the retransmission also is damaged. The radio frame is shortened from 10 to 2 ms (equals only 3 slots) to reduce theround trip time Fast packet scheduling: user devices periodically transmits an indication of thedownlink signal quality (500 times per second). Based on this information, thebase station decides which users will be sent data in the next 2 ms frame andhow much data should be sent for each user (channelization codes). Adaptive modulation and coding: QPSK and 16QAM are allowedResult: down-link speeds of 1.8, 3.6, 7.2 and 14.4 Mbit/s.Chapter 3.4: Mobile Telecommunication Networks67
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeMore recent releasesRelease 6 High-speed uplink (HSUPA) in analogy to HSDPA UMTS/WLAN interworking Fast cell selection, security enhancements, first mentioning of OFDM, Release 7 HSDPA improvement by MIMO Advanced coding with 64QAM (downlink), 16QAM (uplink) QoS on UMTS/WLAN New frequency ranges, Release 8 Long Term Evolution (LTE) as HSPA enhancement with 100 MBit/s (downlink)and 50 MBit/s (uplink) How? By making use of MIMO/64QAM – and using OFDMA Chapter 3.4: Mobile Telecommunication Networks68
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeWhat is Next?Cellular phonesanalogSatellitesWirelessLANs1980:CT01981:NMT 4501982:Inmarsat-A1983:AMPSdigital1984:CT11986:NMT 9001987:CT1 :D-AMPS1993:PDC1994:DCS 18001989:CT 0:GPRSChapter 3.4: Mobile Telecommunication Networks1997:IEEE 802.111999:802.11b, Bluetooth2004:IEEE 802.162000:IMT-20004G – Fourth Generation; integration ofdata and voice technologies (like in LTE)by focusing on network integrationand handover199x:proprietary200?:Fourth Generation(Internet-based)69
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeOverlay Networks – the global GoalIntegration of heterogeneous fixed andmobile networks with differenttransmission characteristicsregionverticalhandoverurban areacompanycar,house,personal rangeChapter 3.4: Mobile Telecommunication Networkshorizontalhandover70
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemeExemplarily IP-based 4G/Next G/ NetworkSS7-SignalingServer-Farm,Gateways, ProxiesRadio/TV broadcastPSTN, CS-CoreGatewaysMSCIP-basedcore networkSGSNBSCGSMFirewall, NCprivateWLANUMTSpublicWLAN or WMANChapter 3.4: Mobile Telecommunication Networks71
Lehrstuhl für Informatik 4Kommunikation und verteilte SystemePossible Problems Quality of Service The Internet provides best effort data transfer Integrated Services has bad scalability, Differentiated Services have still to beproofed Simplicity of the Internets? DoS attacks auf QoS? Internet Protocols are well-known also for attackers, hackers, Reliability, maintenance Still an open question if Internet technology is cheaper, when a high reliability isneeded (99.9999%) and all demanded services are integrated Missing accounting technology Accounting based of technical parameters (data volume, time) makes no sense A content- or application-based accounting is much better Killer Application! There is no single killer application: The selection of provided services and the seamless access to the servicesusing different access technologies is importantChapter 3.4: Mobile Telecommunication Networks72
Chapter 3.4: Mobile Telecommunication Networks 56 Support of Mobility: Handover † From and to other systems (e.g. UMTS to GSM) A must for the beginning when UMTS coverage is poor † RNS controlling the connection is called SRNS (Serving RNS) † RNS offering additional resou
– FDD mode of UMTS: W-CDMA – TDD mode of UMTS: TD-CDMA and Chinese TD-SCDMA – cdma2000 (IS95 evolution) – UWC136: this is an evolution of IS136 that relies on EDGE and GPRS, but that was finally abandoned – DECT IMT-2000 standards are evolutions of 2G standards – UMTS
UMTS FDD (W-CDMA) UMTS Release 4 (2001) Separation of user data flows and control mechanisms, UMTS TDD Time Division CDMA (TD-CDMA), zHigh data rate with UMTS TDD 3 84 Mchips /s z High data rate with UMTS TDD 3. 84, z Narrowband TDD with 1.28 Mchips/s, Position location functionality. Mobile Communication Wireles
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Carrier IMT-SC UWC-136 Multi Carrier IMT-FT DECT Frequency Time UMTS Evolved GSM Evolved ANSI-41 IP-based Networks Core Networks IMT-TC Time-Code WLAN Bluetooth FDD:Paired . GSM/GPRS/EDGEGSM/GPRS/EDGE Common PartsCommon Parts WCDMAWCDMA " GSM/EDGE radio " 800/900/1800/1900 MHz spectrum " Nationwide " WCDMA radio
GSM and handoffs in WLAN. But first UMTS is introduced and the different levels and parts of the system are described. 3. Introduction to UMTS The third generation mobile communication system UMTS (Universal Mobile Telecommunications System) is successor of GSM (Global System for Mobile Communications). UMTS networks can be divided in two parts.
Chapter 1 : UMTS Overview 1.1 Introduction Universal Mobile Telecommunications System (UMTS) is a 3G cellular telecommunication system. It will be the successor of GSM. UMTS is designed to cope with the growing demand of mobile and internet applications with required quality of service parameters. WCDMA is used for the radio interface of UMTS. It
UMTS FDD (W-CDMA) UMTS Release 4 (2001) Separation of user data flows and control mechanisms, UMTS TDD Time Division CDMA (TD-CDMA), zHigh data rate with UMTS TDD 3 84 Mchips /s z High data rate with UMTS TDD 3. 84, z Narrowband TDD with 1.28 Mchips/s, Position location functionality. Mobile Communication Wireless Telecommunication 90
The (IMT-2000), consists of 3 operating modes based on Code Division Multiple Access (CDMA) technology. 3G CDMA modes are most commonly known as: -CDMA2000, -WCDMA (called UMTS) and -TD-SCDMA (Time Division-Synchronous Code Division Multiple Access)
