3G.pptx

UMTS Universal Mobile Telecom System The 3G Technology The Multiple Access Problem The Multiple Access Problem • The base stations need to serve many mobile terminals at the same time (both downlink and uplink) • All mobiles in the cell need to transmit to the base station • Interference among...

UMTS Universal Mobile Telecom System The 3G Technology The Multiple Access Problem The Multiple Access Problem • The base stations need to serve many mobile terminals at the same time (both downlink and uplink) • All mobiles in the cell need to transmit to the base station • Interference among different senders and receivers • So we need multiple access scheme 1G, 2G, 3G Multi-Access Technologies Courtesy of Petri Possi, UMTS World Multiple Access Schemes 3 orthogonal Schemes: • Frequency Division Multiple Access (FDMA) • Time Division Multiple Access (TDMA) • Code Division Multiple Access (CDMA) Frequency Division Multiple Access frequency • Each mobile is assigned a separate frequency channel for the duration of the call • Sufficient guard band is required to prevent adjacent channel interference • Usually, mobile terminals will have one downlink frequency band and one uplink frequency band • Different cellular network protocols use different frequencies • Frequency is a precious and scare resource. We are running out of it • Cognitive radio 1G – Separate Frequencies FDMA - Frequency Division Multiple Access 30 KHz Frequency 30 KHz 30 KHz 30 KHz 30 KHz 30 KHz 30 KHz 30 KHz 2G – Time Division Multiple Access One timeslot = 0.577 ms One TDMA frame = 8 timeslots Frequency 200 KHz 200 KHz 200 KHz 200 KHz Time Time Division Multiple Access Guard time – signal transmitted by mobile terminals at different locations do no arrive at the base station at the same time • Time is divided into slots and only one mobile terminal transmits during each slot • Each user is given a specific slot. No competition in cellular network 2G & 3G – Code Division Multiple Access • Spread spectrum modulation • originally developed for the military • resists jamming and many kinds of interference • coded modulation hidden from those w/o the code • All users share same (large) block of spectrum • one for one frequency reuse • soft handoffs possible • All 3G radio standards based on CDMA • CDMA2000, W-CDMA and TD-SCDMA Courtesy of Suresh Goyal & Rich Howard TD-SCDMA (Time division synchronous CDMA) • Chinese development • IPR bargaining tool with West? Late to market, but big deployment plans • Single spectral band • unpaired spectrum; as little as 1.6 MHz; time division duplex (TDD) with high spectral efficiency; good match for asymmetrical traffic! • Power amplifiers must be very linear • relatively hard to meet specifications Code Division Multiple Access • Use of orthogonal codes to separate different transmissions • Each symbol of bit is transmitted as a larger number of bits using the user specific code – Spreading • But all users use the same frequency band together Orthogonal among users CDMA t Freq: Chips X user 1 user 2 usern Separated by PN codes t III All persons are created equal Message Channelization code: Separate xmissions from a single source from each other Scrambling code: separate different sources from each other t Spreading Code = Channelization code x Scrambling code Resulting Signal The Road Towards 3G Cellular Network Generations • It is useful to think of cellular Network/telephony in terms of generations: 0G: Briefcase-size mobile radio telephones 1G: Analog cellular telephony 2G: Digital cellular telephony 3G: High-speed digital cellular telephony (including video telephony) • 4G: IP-based “anytime, anywhere” voice, data, and multimedia telephony at faster data rates than 3G (to be deployed in 2012–2015) • • • • Typical 2G Mobile Architecture PSDN BSC BTS BSC HLR SMS-SC PLMN MSC/VLR BSC MSC/VLR BSC BTS Base Transceiver Station BSC Base Station Controller GMSC Tandem CO PSTN Tandem CO CO MSC Mobile Switching Center VLR Visitor Location Register HLR Home Location Register Separation of Signaling & Transport  Like PSTN, 2G mobile networks have one network plane for voice circuits and another network plane for signaling  Some elements reside only in the signaling plane ● HLR, VLR, SMS Center, … HLR MSC MSC SMS-SC VLR MSC Signaling Plane (SS7) Transport Plane (Voice) Signaling in Core Network • Based on SS7 • ISUP and specific Application Parts • GSM MAP and ANSI-41 services • mobility, call-handling, O&M, authentication, supplementary services, SMS, … • Location registers for mobility management • HLR: home location register has permanent data • VLR: visitor location register – local copy for roamers PSTN-to-Mobile Call PLMN PLMN (Visitor) (Home) PSTN (SCP) HLR Signaling over SS7 SCP Where is the subscriber? MAP/ IS41 (over TCAP) (STP) ISUP 4 Provide Roaming 2 3 5 Routing Info VMSC MS BSS (SSP) VLR 6 IAM 1 GMSC (SSP) (STP) IAM (SSP) 514 581 ... GSM 2G Architecture NSS BSS E Abis PSTN A PSTN B BSC MS BTS C MSC VLR D GMSC SS7 H HLR AuC BSS Base Station System NSS Network Sub-System BTS Base Transceiver Station MSC Mobile-service Switching Controller BSC Base Station Controller VLR Visitor Location Register MS Mobile Station HLR Home Location Register AuC Authentication Server GMSC Gateway MSC GSM Global System for Mobile communication 2.5G Architectural Detail 2G MS (voice only) NSS BSS E Abis PSTN A PSTN B BSC MS C MSC BTS Gs GMSC D VLR SS7 H Gb 2G+ MS (voice&data) Gr HLR AuC Gc Gn SGSN Gi IP PSDN GGSN BSS Base Station System NSS Network Sub-System SGSN Serving GPRS Support Node BTS Base Transceiver Station MSC Mobile-service Switching Controller GGSN Gateway GPRS Support Node BSC Base Station Controller VLR Visitor Location Register HLR Home Location Register AuC Authentication Server GMSC Gateway MSC GPRS General Packet Radio Service EDGE • Enhanced Data rates for Global Evolution • Increased data rates with GSM compatibility • still 200 KHz bands; still TDMA • 8-PSK modulation: 3 bits/symbol give 3X data rate • shorter range (more sensitive to noise/interference) • Migration path: IS-136 TDMA to GSM/EDGE • GAIT - GSM/ANSI-136 interoperability team • Allowed operators like AT&T and Cingular to migrate to GSM/EDGE using an evolved ANSI-41 core network Global Roaming Problems • Multiple vocoders (AMR, EVRC, SMV, …, WB?) • Many spectral bands • 450, 850, 900, 1700, 1800, 1900, 2100, 2500 … MHz • At least four modulation variants • GSM (TDMA), W-CDMA, CDMA2000, TD-SCMDA • “Universal” handset prospects • Still need: multiple antennas; improved batteries Different Flavors of 3G Wireless Migration Mobile Generations G 1 2 2.5 3 3.5 4 Summary Data Rates Analog Typical 2.4 Kbps; max 22 Kbps Digital – TDMA, CDMA 9.6 - 14.4 Kbps (circuit data) GPRS – mux packets in voice timeslots 15 - 40 Kbps Improved modulation, using CDMA variants 50 – 144 Kbps (1xRTT); 200 – 384 Kbps (UMTS); 500 Kbps – 2.4 Mbps (EVDO) More modulation tweaks 2–14 Mbps (HSPA) New modulation (OFDMA); Multi-path (MIMO); All IP LTE: >10 Mbps; eventual potential >100 Mbps Service Roadmap Improved performance, decreasing cost of delivery Broadband in wide area 3G-specific 3G-specific services services take take advantage advantage of of higher higher bandwidth bandwidth and/or and/or real-time real-time QoS QoS Video sharing Video telephony Real-time IP AA number number of of mobile mobile Multitasking multimedia and games services services are are bearer bearer WEB browsing Multicasting independent independent in in nature nature Corporate data access Streaming audio/video MMS picture / video xHTML browsing Application downloading E-mail Presence/location Voice & SMS Push-to-talk EGPRS 473 kbps WCDMA 2 Mbps CDMA 2000EVDV GPRS 171 kbps CDMA 2000EVDO GSM 9.6 kbps CDMA 2000 1x Typical average bit rates (peak rates higher) HSDPA 1-10 Mbps GSM Evolution to 3G High Speed Circuit Switched Data Dedicate up to 4 timeslots for data connection ~ 50 kbps Good for real-time applications c.w. GPRS Inefficient -> ties up resources, even when nothing sent Not as popular as GPRS (many skipping HSCSD) Enhanced Data Rates for Global GSM Evolution HSCSD 9.6kbps (one Uses 8PSK modulation timeslot) 3x improvement in data rate on short GSM Data distances Also called CSD Can fall back to GMSK for greater GSM GPRS distances Combine with GPRS (EGPRS) ~ 384 kbps WCDMA General Packet Radio Services Can also be combined with HSCSD Data rates up to ~ 115 kbps EDGE Max: 8 timeslots used as any one time Packet switched; resources not tied up all the time Contention based. Efficient, but variable delays 3G Overview • 3G is created by ITU-T and is called IMT2000 Core Network Architectures • Two widely deployed architectures today • 3GPP evolved from GSM-MAP • Used by GSM & 3GSM operators (87% of subs globally) • “Mobile Application Part” defines signaling for mobility, authentication, etc. • 3GPP2 evolved from ANSI-41 MAP • ANSI-41 used with AMPS, TDMA & CDMA 2000 • GAIT (GSM ANSI Interoperability Team) allowed interoperation, i.e., roaming • Evolving to common “all IP” vision based on 3GPP UMTS • UMTS is an upgrade from GSM via GPRS or EDGE • The standardization work for UMTS is carried out by Third Generation Partnership Project (3GPP) • Data rates of UMTS are: • 144 kbps for rural • 384 kbps for urban outdoor • 2048 kbps for indoor and low range outdoor • Virtual Home Environment (VHE) 3GPP2 Defines IS-41 Evolution  3rd Generation Partnership Project “Two” ● Evolution of IS-41 to “all IP” more direct (skips ATM stage), but not any faster ● Goal of ultimate merger (3GPP + 3GPP2) remains  1xRTT – IP packets (like GPRS)  1xEVDO – Evolution data-optimized  1xEVDV – abandoned  3x – Triples radio data rates  Universal Mobile Broadband (UMB) – abandoned Evolution of Cellular Networks 1G 2G 2.5G 3G 4G Evolution from 2G 2G 2.5G IS-95 GSM- GPRS IS-95B HSCSD Cdma2000-1xRTT 3G IS-136 & PDC EDGE W-CDMA EDGE Cdma2000-1xEV,DV,DO TD-SCDMA Cdma2000-3xRTT 3GPP2 3GPP UMTS Architecture GSM/GPRS network architecture Radio access network BSS GSM/GPRS core network MS MS BTS BTS GMSC GMSC VLR VLR BSC BSC HLR HLR PCU PCU AuC AuC SGSN SGSN BTS BTS IP Backbone EIR EIR GGSN GGSN database Internet PSTN, ISDN MSC MSC 3G rel99 Architecture (UMTS) 2G MS (voice only) CN BSS E Abis PSTN A PSTN B BSC Gb BTS C MSC Gs GMSC D VLR SS7 H 2G+ MS (voice & data) IuCS RNS Gr HLR ATM Iub IuPS RNC AuC Gc Gn SGSN Gi IP PSDN GGSN Node B 3G UE (voice & data) BSS Base Station System CN Core Network SGSN Serving GPRS Support Node BTS Base Transceiver Station MSC Mobile-service Switching Controller GGSN Gateway GPRS Support Node BSC Base Station Controller VLR Visitor Location Register HLR Home Location Register RNS Radio Network System RNC Radio Network Controller AuC Authentication Server GMSC Gateway MSC UMTS Universal Mobile Telecommunication System 3GPP Rel.’99 network architecture Radio access network UTRAN UE UE RNC RNC Iu CS BS BS MSC MSC GMSC GMSC VLR VLR HLR HLR Iur Uu Iub RNC RNC BS BS Iu PS AuC AuC SGSN SGSN Gn IP Backbone EIR EIR GGSN GGSN database Internet PSTN Iub Core network (GSM/GPRSbased) 3GPP Rel.’99 network architecture Radio access network UTRAN Iub UE UE RNC RNC BS BS Iur Uu Iub BS BS RNC RNC 2G => 3G MS => UE (User Equipment), often also called (user) terminal New air (radio) interface based on WCDMA access technology New RAN architecture (Iur interface is available for soft handover, BSC => RNC) 3GPP Rel.’99 network architecture Core network (GSM/GPRSbased) Changes in the core network: Iu CS SGSN is upgraded to 3G SGSN GMSC and GGSN remain the same AuC is upgraded (more security features in 3G) MSC MSC GMSC GMSC VLR VLR HLR HLR Iu PS AuC AuC SGSN SGSN Gn IP Backbone EIR EIR GGSN GGSN Internet PSTN MSC is upgraded to 3G MSC UMTS Network Architecture • UMTS network architecture consists of three domains • Core Network (CN): Provide switching, routing and transit for user traffic • UMTS Terrestrial Radio Access Network (UTRAN): Provides the air interface access method for user equipment. • User Equipment (UE): Terminals work as air interface counterpart for base stations. The various identities are: IMSI, TMSI, P-TMSI, TLLI, MSISDN, IMEI, IMEISV UTRAN • Wide band CDMA technology is selected for UTRAN air interface • WCDMA • TD-SCDMA • Base stations are referred to as Node-B and control equipment for Node-B is called as Radio Network Controller (RNC). • Functions of Node-B are • Air Interface Tx/Rx • Modulation/Demodulation • Functions of RNC are: • • • • • • Radio Resource Control Channel Allocation Power Control Settings Handover Control Ciphering Segmentation and reassembly Diverse Mobile Wireless Spectrum Release 99  Radio Bearer Negotiations  Traffic Classes  Complex Scrambling  Speech Codec – (eight) Adaptive Multi Rate (AMR)  Battery Life  Transmission “spatial/antenna” diversity  Compressed Mode • Measurements in multiple frequency • Use of transmission time reduction techniques  # PDP Contexts per IP Address  QPSK; coherent detection; Rake receiver  Short and Long Spreading Codes  Multicall – several simultaneous CS calls with dedicated bearers of independent traffic and performance characteristics  Customized Application for Mobile network Enhanced Logic (CAMEL) Phase 3 UMTS Frequency Spectrum • UMTS Band • 1900-2025 MHz and 2110-2200 MHz for 3G transmission • In the US, 1710–1755 MHz and 2110–2155 MHz will be used instead, as the 1900 MHz band was already used. 3G rel4 - Soft Switching 2G MS (voice only) CN CS-MGW A Abis Nc Mc BSC Gb BTS CS-MGW Nb BSS PSTN B C MSC Server Gs PSTN Mc GMSC server D VLR SS7 H 2G+ MS (voice & data) IuCS RNS Gr HLR ATM Iub IuPS RNC AuC IP/ATM Gc Gn SGSN Gi PSDN GGSN Node B 3G UE (voice & data) BSS Base Station System CN Core Network SGSN Serving GPRS Support Node BTS Base Transceiver Station MSC Mobile-service Switching Controller GGSN Gateway GPRS Support Node BSC Base Station Controller VLR Visitor Location Register HLR Home Location Register RNS Radio Network System AuC Authentication Server RNC Radio Network Controller GMSC Gateway MSC 3GPP Rel.4 network architecture UTRAN (UMTS Terrestrial Radio Access Network) Circuit Switched (CS) core network MSC MSC Server Server New option in Rel.4: GERAN (GSM and EDGE Radio Access Network) MGW MGW SGW SGW MGW MGW PS core as in Rel.’99 PSTN SGW SGW GMSC GMSC Server Server 3GPP Rel.4 network architecture MSC Server takes care of call control signalling The user connections are set up via MGW (Media GateWay) RANAP RANAP // ISUP ISUP SS7 SS7 MTP MTP IP IP Sigtran Sigtran MSC MSC Server Server SGW SGW MGW MGW core GMSC GMSC Server Server SGW SGW MGW MGW PS core as in Rel.’99 PSTN “Lower layer” protocol conversion in SGW (Signalling GateWay) Circuit Switched (CS) network Release 4  Bearer Independent Core Network  Tandem Free Operation (TFO), Transcoder Free Operation (TrFO), and Out of Band Transcoder Control (OoBTC)  Low Chip Rate TDD Operation  Network Assisted Cell Change  FDD Repeater  NodeB Synchronization for TDD  IPv6 packet switched network supporting both real time and non-real time traffic • Session Initiated Protocol (SIP) replacing SS7  Home Subscriber Server (HSS)  MSC/VLR -> MSC server (mobility management) and MGW (Connection management subtasks)  Multimedia Message Service (MMS) environment 3GPP rel5 ― IP Multimedia 2G MS (voice only) CN CS-MGW A/IuCS Abis Nc Mc BSC Gb/IuPS BTS CS-MGW Nb BSS 2G+ MS (voice & data) IuCS C VLR SS7 ATM Gr IuPS RNC GMSC server D H RNS Iub PSTN B MSC Server Gs PSTN Mc HSS AuC IP/ATM Gc Gn Gi SGSN GGSN Node B 3G UE (voice & data) IM-MGW IM Gs IM IP Multimedia sub-system PSTN MRF Media Resource Function IP CSCF Call State Control Function Mg MGCF Media Gateway Control Function (Mc=H248,Mg=SIP) MRF Mc MGCF IM-MGW IP Multimedia-MGW CSCF IP Network 3GPP Rel.5 network architecture New core network part: IMS IMS(IP (IP Multimedia Multimedia System) System) SGSN SGSN PS core MGW MGW HSS HSS GGSN GGSN Internet GERAN (GSM and EDGE Radio Access Network) CS core PSTN UTRAN (UMTS Terrestrial Radio Access Network) 3GPP Rel.5 network architecture Interworking with the PSTN may be required for some time ... MGW MGW IMS IMS(IP (IP Multimedia Multimedia System) System) SGSN SGSN PS core HSS HSS GGSN GGSN Internet / other IMS Call/session control using SIP (Session Initiating Protocol) CS core PSTN The IMS can establish multimedia sessions (using IP transport) via PS core between UE and Internet (or another IMS) Release 5  IP Transport in UTRAN  High Speed Downlink Packet Access (HSDPA) (upto 10 Mbps)  Intra Domain Connection to Multiple CN Nodes (Iuflex)  IP Multimedia CN Subsystem (IMS)  “Guaranteed” End to End (E2E) QoS in the PS domain  Global Text Telephony  Support for Real Time Services in packet domain  CAMEL Phase 4 UMTS Handoffs • W-CDMA • Handover • UMTS will use a soft handover technique • GSM used a hard handover technique • In a handover the device is always attached to at least one BS Node-B Node-B Node-B Node-B Node-B Node-B UMTS bearer service architecture TE MT UTRAN CN Iu edge node UE CN gateway Core network End-to-end service Local b.s. UMTS bearer service Radio access bearer service Radio b.s. Radio RadioBearer Bearer Iu b.s. Ext. b.s. CN b.s. Backbone Radio RadioAccess AccessBearer Bearer TE What is a bearer? Bearer: a bearer capability of defined capacity, delay and bit error rate, etc. (as defined in 3GPP specs.) Bearer is a flexible concept designating some kind of ”bit pipe” · at a certain network level (see previous slide) · between certain network entities · with certain QoS attributes, capacity, and traffic flow characteristics Four UMTS QoS Classes · conversational, streaming, interactive, background UMTS QoS (service) classes Conversational Conversational Streaming Streaming Interactive Interactive Background Background low delay reasonably low delay low round-trip delay delay is not critical low delay variation speech video telephony/ conferencing basic QoS requirements video streaming audio streaming www applications basic applications store-andforward applications (e-mail, SMS) file transfer Four UMTS QoS (service) classes Conversational Conversational Streaming Streaming Interactive Interactive Background Background • low delay (< 400 ms) and low delay variation • BER requirements not so stringent • in the radio network => real-time (RT) connections • speech (using AMR = Adaptive Multi-Rate speech coding) • video telephony / conferencing: ITU-T Rec. H.324 (over circuit switched connections) ITU-T Rec. H.323 or IETF SIP (over packet switched connections) Adaptive Multi-Rate coding Adaptive <=> During the call, the AMR bit rate can be changed, using the values at the right <=> Codec negotiation between transcoders kbit/s 12.2 (= GSM EFR) 10.2 7.95 7.40 (= US TDMA) 6.70 (= PDC EFR) 5.90 5.15 4.75 EFR = Enhanced Full Rate Transcoding UE UE MSC MSC TC TC GMSC GMSC User UserBB (e.g. in PSTN) Transcoder (AMR/PCM) should be located as far as possible to the right (transmission capacity savings) TC TC (possible only if same coding is used at both ends of connection) Transcoding should be avoided altogether (better signal quality) TFO = Tandem Free Operation (2G) TrFO = Transcoder Free Operation (3G) Four UMTS QoS (service) classes Conversational Conversational Streaming Streaming Interactive Interactive Background Background • reasonably low delay and delay variation • BER requirements quite stringent • traffic management important (variable bit rate) • in the radio network => real-time (RT) connections • video streaming • audio streaming UE UE Source Source Buffer video or audio information is buffered in the UE, large delay => buffer is running out of content! Four UMTS QoS (service) classes Conversational Conversational Streaming Streaming Interactive Interactive Background Background • low round-trip delay (< seconds) • delay variation is not important • BER requirements stringent • in the radio network => non-real-time (NRT) connections • web browsing • interactive games • location-based services (LCS) Four UMTS QoS (service) classes Conversational Conversational Streaming Streaming Interactive Interactive Background Background • delay / delay variation is not an important issue • BER requirements stringent • in the radio network => non-real-time (NRT) connections • SMS (Short Message Service) and other more advanced messaging services (EMS, MMS) • e-mail notification, e-mail download • file transfer UMTS protocols Different protocol stacks for user and control plane User plane (for transport of user data): Circuit switched domain: data within ”bit pipes” Packet switched domain: protocols for implementing various QoS or traffic engineering mechanisms Control plane (for signalling): Circuit switched domain: SS7 based (in core network) Packet switched domain: IP based (in core network) Radio access network: UTRAN protocols