PART 3 Introduction to GSM Lecture 3.0 History Giuseppe Bianchi History of wireless communication Î 1896: Marconi Ö first demonstration of wireless telegraphy Ö tx of radio waves to a ship at sea 29 km away Ö long wave transmission, high power req. (200 kW and +) Î 1901: Marconi Ö Telegraph across the atlantic ocean Ö Close to 3000 Km hop! Î 1907 Commercial transatlantic connections Ö huge ground stations (30 by100m antennas) Î 1915: Wireless telephony established Ö NY – S. Francisco Ö Virginia and Paris Î 1920 Marconi: Ö Discovery of short waves (< 100m) Ö reflection at the ionosphere Ö (cheaper) smaller sender and receiver, possible due to the invention of the vacuum tube (1906, Lee DeForest and Robert von Lieben) Giuseppe Bianchi 1 History of wireless communication Î 1920's: Radio broadcasting became popular Î 1928: many TV broadcast trials Î 1930's: TV broadcasting deployment Î 1946: First public mobile telephone service in US Ö St. Louis, Missouri Ö Single cell system Î 1960's: Bell Labs developed cellular concept Ö brought mobile telephony to masses Î 1960’s: Communications satellites launched Î Late 1970's: technology advances enable affordable cellular telephony Ö entering the modern cellular era Î 1974-1978: First field Trial for Cellular System Ö AMPS, Chicago Giuseppe Bianchi 1st generation mobile systems early deployment ÎFirst system: Ö NMT-450 (Nordic Mobile Telephone) ÆScandinavian standard; adopted in most of Europe Æ450 MHZ band ÆFirst european system (Sweden, october 1981) Î Italian history: Ö 1966: first experiments (CSELT) at 160 MHZ ÆRTMI (Radio Telefono Mobile Italiano) ÆMarket: 1973 Ö First italian cellular system: 1985 ÆRTMS (Radio Telefono Mobile di Seconda Generazione) Æ450 MHZ Ö Evolution: 1990, TACS ÆTotal Access Communication System Æ900 MHZ Giuseppe Bianchi 2 1st generation mobile systems ÎFirst generation: 1980’s ÎAnalog transmission ÎSeveral competing standards in Ö Frequency modulation different countries ÎVarious bands: Ö NMT (Nordic Mobile Telephone) Ö NMT: ÆScandinavian standard; adopted in most Æ450 MHz first of Europe Æ900 MHz later ÆFirst european system (Sweden, 1981) Ö TACS Ö TACS (Total Access Communication Æ900 MHz Systems), starts in 1985 Æ1230 bidirectional ÆUK standard; A few of Europe, Asia, channels (25KHz) Japan Ö AMPS Ö AMPS (Advanced Mobile Phone Æ800 MHz Service) ÆUS standard ÎToday still in use in low- Ö C-Netz (Only in Germany) technology countries Ö And not yet completely dismissed Ö Radiocom 2000 (Only in France) in high-tech countries Giuseppe Bianchi 2nd generation mobile systems Î4 systems ÎBasic bands: ÖGlobal System for Mobile (GSM) Ö900 MHz ÖDigital AMPS (D-AMPS), US Ö1800 MHz ÖCode Division Multiple Access Æ(Digital Cellular System: (IS-95) – Qualcomm,US DCS-1800) ÖPersonal Digital Cellular Ö1900 MHz (PDC),Japan Æ(Personal Communication ÎGSM by far the System:PCS-1900,US only) dominant one ÎSpecifications for ÖOriginally pan-european ÖGSM-400 (large areas) ÖDeployed worldwide ÖGSM-800 (north america) Æ(slow only in US) Giuseppe Bianchi 3 Timing Î1982: Start of GSM-specification in Europe (1982-1990) Î1983: Start of American AMPS widespread deployment Î1984 CT-1 standard (Europe) for cordless telephones Î1991 Specification of DECT ÖDigital European Cordless Telephone (today: Digital Enhanced Cordless Telecommunications) - ~100-500m range, 120 duplex channels, 1.2Mbit/s data transmission, voice encryption, authentication Î1992: Start of GSM operation Europe- wide Î1994: DCS-1800 Giuseppe Bianchi 2 ½ generation mobile systems GSM incremental extension ÎHigh speed circuit switched data (HSCSD) ÆCircuit switched data communication ÆUses up to 4 slots (1 slot = 9.6 or 14.4 Kbps) ÎGeneral Packet Radio Service (GPRS) ÆPacket data (use spectrum only when needed!) ÆUp to 115 Kbps (8 slots) ÎEnhanced Data-rates for Global Evolution (EDGE) ÆHigher data rate available on radio interface (3x) » Up to 384 Kbps (8 slots) » Thanks to new modulation scheme (8PSK) » May coexist with old GMSK Giuseppe Bianchi 4 3rd generation mobile systems ÎUMTS (Universal Mobile TelecommunicationSystem) ÆITU standard: IMT-2000 (International Mobile Telecommunication – 2000) ÆUMTS forum created in 1996 ÆLater on 3GPP forum (bears most of standardization activities) ÖWideband CDMA radio interface ÆBut several other proposals accepted as “compatible” ÖRadio spectrum: 1885-2025 & 2110-2200 MHz ÖAlready deployed in Japan ÖTime to market in Italy: 2004? Giuseppe Bianchi Facts about wireless communication ÎWho has a cellular phone? ÖUSA: Over 50% of US households ÖItaly: from 2001, more wireless lines than wired ÖWorld: from march 2002, 1 billion wireless cellular users ÆMuch faster than projections! ÆAugust 2000: 372 GSM networks, 362M customers ÎRevenues: Öglobal revenue from wireless portals predicted to grow from $700M to $42 billion by 2005 ÖWLAN revenues predicted at $785M by 2004 ÖForecasting a 59 percent growth rate for wireless usage in rural areas between 2000 and 2003 Giuseppe Bianchi 5 PART 3 Introduction to GSM Lecture 3.1 Architecture and components Giuseppe Bianchi GSM Network high-level view MSC = Mobile Switching Center = administrative region PSTNPSTN PublicPublic switched switched telephonetelephone network network MSC MSC Base Base Station Station PLMN Public Land Mobile Network MSC role: telephone switching central with special mobility management capabilities Giuseppe Bianchi 6 GSM system hierarchy MSC MSC region LOCATION BSC AREA MSC: Mobile Switching Center LA: Location Area BSC: Base Station Controller BTS BTS: Base Transceiver Station Hierarchy: MSC region Æ n x Location Areas Æ m x BSC Æ k x BTS Giuseppe Bianchi GSM essential components To fixed network OMC (PSTN, ISDN, PDN) GMSC EIR AUC HLR VLR MSC BSC BTS MS Mobile Station BTS BTS Base Transceiver Station BTS BSC Base Station Controller BTS BSC MSC Mobile Switching Center GMSC Gateway MSC BTS OMC Operation and Maintenance Center MS EIR Equipment Identity Register AUC Authentication Center HLR Home Location Register VLR Visitor Location Register Giuseppe Bianchi 7 Î Two components: GSM Sub-Systems Ö Fixed installed infrastructure Æ The network in the proper sense Ö Mobile subscribers Æ MS: Mobile Station Î Fixed infrastructure divided operator into three sub-systems Ö BSS: Base Station subsystem Æ Manages transmission path from MS to NSS External Ö NSS: Network Switching Subsystem Networks Æ Communication and interconnection with other nets OSS Ö OSS: Operational Subsystem Æ GSM network administration tools Users NSS BSS MS A Interface Radio Interface (Um) Giuseppe Bianchi PART 3 Introduction to GSM Lecture 3.2 Mobile Station and addresses Giuseppe Bianchi 8 Mobile Station (MS) GSM separates user mobility from equipment mobility, by defining two distinct components ÎMobile Equipment ÆThe cellular telephone itself (or the vehicular telephone) ÖAddress / identifier: ÆIMEI (International Mobile Equipment Identity) ÎSubscriber Identity Module (SIM) ÆFixed installed chip (plug-in SIM) or Æexchangeable card (SIM card) ÖAddresses / identifiers: ÆIMSI (International Mobile Subscriber Identity) ÆMSISDN (Mobile Subscriber ISDN number) » the telephone number! Giuseppe Bianchi Mobile Equipment structure TerminalTerminal MobileMobile EquipmentEquipment TerminationTermination Terminal Terminal Mobile Equipment Adaptor Termination Î Mobile Termination functions Ö tRadio interface (tx, rx, signalling) Mobile Equipment Î Terminal Equipment functions S Um Ö User interface (microphone, keyboard, speakers, etc); TE1 MT Ö Functions specific of services (telephony, fax, messaging, etc), R independent of GSM Î Terminal Adaptor functions TE2 TA MT Ö Interfaces MT with different types of terminals (PCs, Fax, etc.) Giuseppe Bianchi 9 Mobile Equipment Max Power 5 power classes max power Type of CLASS (watt) terminal I 20 vehicular II 8 vehicular III 5 portable Normally used IV 2 portable V 0.8 portable This was for 900 MHz – for 1800 MHz only two classes: 1W, and 0.25 W Giuseppe Bianchi IMEI International Mobile Equipment Identity Î Uniquely identifies the mobile equipment Î 15 digits hierarchical address Î assigned to ME during manifacturing and “type approval” testing Ö Type approval procedure: guarantees that the MS meets a minimum standard, regardless of the manifacturer Î IMEI structure: TAC – 6 digits FAC – 2 digits SNR – 6 digits SP – 1 digit (Type Approval Code) (Final Assembly Code) (Serial Number) (Spare Digit) centrally assigned assigned by assigned by Additional upon type approval manufacturer manufacturer digit available Identifies place Unique for given where ME was TAC+FAC assembled or combination manufactured Giuseppe Bianchi 10 IMEI management Î Protection against stolen and malfunctioning terminals Î Equipment Identity Register (EIR): 1 DataBase for each operator; keeps: ÖWHITE LIST: Ævalid IMEIs ÆCorresponding MEs may be used in the GSM network ÖBLACK LIST: ÆIMEIs of all MEs that must be barred from using the GSM network ÆException: emergency calls (to a set of emergency numbers) ÆBlack list periodically exchanged among different operators ÖGRAY LIST: ÆIMEIs that correspond to MEs that can be used, but that, for some reason (malfunctioning, obsolete SW, evaluation terminals, etc), need to be tracked by the operator ÆA call from a “gray” IMEI is reported to the operator personnel Giuseppe Bianchi SIM card Subscriber Identity Module Î Uniquely associated to a user Ö Not to an equipment, as in first generation cellular networks Î Stores user addresses Ö IMSI Ö MSISDN Ö Temporary addresses for location, roaming, etc Î authentication