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giới thiệu về mạng GSM, quá trình phát triển của mạng thông tin di động trên thế giới.In early networks, the emphasis was to provide radio coverage with little consideration for the number of calls to be carried
Copyright 2002 AIRCOM International Ltd All rights reserved AIRCOM Training is committed to providing our customers with quality instructor led Telecommunications Training. This documentation is protected by copyright. No part of the contents of this documentation may be reproduced in any form, or by any means, without the prior written consent of AIRCOM International. Document Number: P/TR/003/K011/4.4 This manual prepared by: AIRCOM International Grosvenor House 65-71 London Road Redhill, Surrey RH1 1LQ ENGLAND Telephone: Support Hotline: Fax: Web: +44 (0) 1737 775700 +44 (0) 1737 775777 +44 (0) 1737 775770 http://www.aircom.co.uk GSM TECHNOLOGY FOR ENGINEERS Table of Contents 1. Introduction to Cellular Systems 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Introduction .1 Cellular Radio st Generation Cellular Systems nd Generation Cellular Systems .5 GSM Development and Characteristics .7 Cellular Systems Subscriber Distribution .8 2.5G Characteristics 2. Architecture Overview 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Introduction . 11 GSM Identifiers 12 General Architecture Overview . 13 The GSM Mobile Station (MS) 14 The Base Station Subsystem (BSS). . 16 The Network Switching Subsystem (NSS) . 17 GSM Interfaces 22 Self-Assessment Exerecises 27 3. GSM Services 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Introduction 29 GSM Bearer Services . 30 Teleservices 32 Supplementary Services . 33 Circuit-Switched Data (CSD) Services . 34 Short Message Service . 35 USSD Data Services 37 Self-Assessment Exerecises 41 4. The Air Interface 4.1 4.2 4.3 4.4 4.5 Introduction . 43 GSM Frequency Spectrum Allocation 44 GSM Multiple Access Techniques . 50 GSM Air Interface Channels . 52 Frames and Multiframes . 56 Self-Assessment Exercises 63 5. Protocols 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 Introduction . 65 The ISO 7-Layer OSI Model . 66 GSM Protocols Overview . 67 GSM Transmission Protocols 69 GSM Signalling Protocols . 71 GSM Air (Um) Interface Protocols . 73 GSM A-bis Interface Protocols 75 The GSM A Interface Protocols . 78 6. Speech and Channel Coding 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 Introduction . 79 Speech Coding Techniques 80 GSM Speech Coding 81 Channel Coding Techniques . 83 GSM Channel Coding. . 88 Interleaving 89 Radio Burst Multiplexing…… ……………………………………………… 91 Summary of Coding Processes ………… ……………………………………………95 Radio Interface Modulation… …………… ……………………………………………95 GSM Technology for Engineers © AIRCOM International 2002 i 7. Mobility Management 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 Introduction . 99 Mobility Management Procedures . 100 Network Areas . 101 Mobility States . 103 IMSI Attach/Detach 104 Location Updating 107 Roaming . 109 TMSI Reallocation . 110 8. Radio Resource Management 8.1 8.2 8.3 8.4 Introduction . 113 Radio Resource Connection Setup . 114 Cell Selection and Reselection . 115 Handovers . 118 9. Call Management 9.1 9.2 9.3 9.4 9.5 Introduction . 123 Mobile Originated Calls 124 Mobile Terminated Calls . 125 Call Routing Examples . 127 Echo Cancelling . 129 Self-Assessment Exercises 131 10. GSM Security 10.1 10.2 10.3 10.4 10.5 10.6 Introduction . 133 Purposes of GSM Security 134 User Identity Confidentiality 134 Authentication 135 User Data Confidentiality - Encryption . 138 Signalling Data Confidentiality . 140 Self-Assessment Exercises 143 11. Billing Procedures Overview 11.1 11.2 11.3 11.4 11.5 11.6 11.7 Introduction . 145 Billing Principles . 146 Description of Call Components 146 Charge Advice Information (CAI) . 148 Advice of Charge (AoC) Calculations . 149 Call Detail Records 151 The Transferred Account Procedure (TAP) 152 12. GSM Evolution 12.1 12.2 12.3 12.4 Introduction . 155 High Speed Circuit Switched Data (HSCSD) 156 General Packet Radio Service (GPRS) 157 Enhanced Data for nGSM Evolution (EDGE) . 159 Appendix A - Solutions to Self Assessment Exercises Appendix B - Glossary of Terms ii GSM Technology for Engineers © AIRCOM International 2002 Course Objectives and Structure Course Objectives • Be familiar with the development of 2G mobile systems • Describe the architecture of a GSM network • Appreciate the main services provided within a GSM network • Understand the various facets of the GSM air interface including, Access structures, frequency allocations, physical and logical channels • Appreciate GSM transmission and signalling protocols • Describe the methods of speech and error coding on the air interface • Understand the principals mobility management • Understand the principles of radio resource management • Describe the processes involved in connection management • Appreciate the security measures implemented by GSM • Understand GSM mechanisms for customer billing • Be familiar with the future evolution of GSM including 2G+ technologies • Describe the evolution of GSM towards 3G systems Course Outline Day Day 1. Introduction to Cellular Systems 7. Radio Resource Management 2. Architecture Overview 8. Mobility Management 3. Services 9. Connection Management 4. The Air Interface 10. Security 5. GSM Protocols 11. Billing Procedures Overview 6. Speech and Channel Coding 12. GSM Evolution GSM Technology for Engineers © AIRCOM International 2002 iii Intentional Blank Page iv GSM Technology for Engineers © AIRCOM International 2002 1. Introduction to Cellular Systems 1. Introduction to Cellular Systems _________________________________________________________________________________ 1.1 Introduction This section reviews the characteristics of first and second generation cellular systems and is followed by an overview of the functional blocks of GSM architecture, and its functional entities. Topics covered include: • • • • • Cellular Radio st generation cellular characteristics and systems nd generation cellular characteristics and non-GSM systems GSM development and characteristics Worldwide roll-out of cellular systems and subscriber distribution GSM Technology for Engineers © AIRCOM International 2002 1. Introduction to Cellular Systems _________________________________________________________________________________ 1.2 Cellular Radio Mobile Radio Networks Cellular • There are three major types of terrestrial mobile communications technologies: • Paging: PSTN Brief numeric, alphanumeric or voice messages are sent to the subscriber typically using simultaneous broadcasting. MSC • Cordless Communication: Users are provided limited mobility from a dedicated base station Cordless Paging Control Centre • Cellular: Users are provided wide area mobility from multiple base stations with handover permitted Paging Area Paging Area Cellular Radio Network Characteristics • Mobile Radio Network based on cellular structure for areas coverage • Frequency reuse required due to limited frequency availability (frequency re-use patterns) • Mobility between cell areas possible (handover) GSM Technology for Engineers © AIRCOM International 2002 1. Introduction to Cellular Systems Cellular Generations The significant stages in the evolution of cellular radio systems is referred to in terms of generations: Data rate • 1st Generation or 1G • 2nd Generation or 2G • 2.5G • 3rd Generation or 3G • 4th Generation or 4G 1978 1992 2000 2002 ? time Progress of data rates with time and generation _________________________________________________________________________________ 1.3 1st Generation Cellular Systems 1st Generation Cellular Characteristics • Widespread Introduction in early 1980s • Analogue modulation • Frequency Division Multiple Access • Voice traffic only • No inter-network roaming possible The 1st Generation of Cellular Technology makes use of analogue modulation techniques such as FM • Insecure air interface GSM Technology for Engineers © AIRCOM International 2002 1. Introduction to Cellular Systems In early networks, the emphasis was to provide radio coverage with little consideration for the number of calls to be carried. As the subscriber base grew, the need to provide greater traffic capacity had to be addressed. 1st Generation Standards • AMPS (Analogue Advanced Mobile Phone System) • North American Standard in cellular band (800MHz) • TACS (Total Access Communications System) • UK originated Standard based on AMPS in 900MHz band • NMT (Nordic Mobile Telephony System) • Scandinavian Standard in 450MHz and 900MHz bands • C-450 • German Standard in 450MHz band Analogue/AMPS • JTACS (Japanese Total Access Communications System) Nokia 252 • Japanese Standard in 900MHz band 1st Generation Planning • Macrocellular • High sites for coverage driven planning • Antennas above roof height • Frequency planning required • For networks with more cells than frequencies these must be planned F1 F2 F5 • Large cell size F4 • Order 30km • Hard handover F3 • Mobile only ever connected to a single cell • Hexagonal Grid Representation The above diagram shows how different frequencies are used in different cells in a cellular network GSM Technology for Engineers © AIRCOM International 2002 Appendix A – Solutions to SAEs Appendix A Solutions to Self-Assessment Exercises Section Exercise 2.1 - GSM Network Architecture BTS 22 BSC VLR EIR BTS 23 MSC BSC BTS 24 BSC BTS 25 SS7 AuC PSTN HLR MSC VLR BTS 26 BTS 27 GSM Technology for Engineers © AIRCOM International 2002 A-1 Appendix A – Solutions to SAEs Intentional Blank Page A-2 GSM Technology for Engineers © AIRCOM International 2002 Appendix A – Solutions to SAEs Section Exercise 3.1 – Comparison of SMS and USSD USSD Advantages: • Up to seven times faster than SMS • Longer character messages than SMS (182 compared to 160) • Works on all existing GSM terminals • Supported by SIM Toolkit and WAP • Stage can provide WAP-like features (on existing handsets) USSD Disadvantages: • No Store-and-Forward. • Additional loading on signalling channels • Session-oriented (Traffic loading and costs compared to SMS). • Stage implementation not intuitive Exercise 3.2 – GSM Services and Data Transport The GSM services are divided into three categories • • • Bearer Services. GSM bearer services refer to those services provided to transport binary data across the GSM network. They represent the functionality of layers to of the OSI 7-layer model. Teleservices… Teleservices are generally end-to-end user applications and are therefore transparent to their transporting bearer services. Supplementary Services. A supplementary service modifies or supplements a basic teleservice. Consequently, it cannot be offered to a customer as a stand alone service, only in association with a basic teleservice. The same supplementary service may be applicable to a number of teleservices. The Basic GSM Phase Data Transport Services include: • • Circuit Switched Data (CSD). Circuit switched data falls within the Bearer Services category and more specifically to services (BS 21-26). Both asynchronous (BS 21-26) and synchronous (BS 31-34) options are available and each data rate (other than 1200bps synch) can operate in transparent or non-transparent mode (see above for explanation) Unstructured Supplementary Service Data (USSD). Unstructured Supplementary Services Data (USSD) is a means of transmitting information or instructions over a GSM network. USSD has some similarities with SMS since both use the GSM network's signalling path (the SDCCH). GSM Technology for Engineers © AIRCOM International 2002 A-3 Appendix A – Solutions to SAEs • A-4 Short Message Service (SMS). SMS is a service that allows subscribers to send short messages (up to 160 characters) to other mobile subscribers. Rather than having to set up a call on a traffic channel, SMS uses spare capacity on the Standalone Dedicated Control Channel (SDCCH). GSM Technology for Engineers © AIRCOM International 2002 Appendix A – Solutions to SAEs Section Exercise 4.1 - Radio Spectrum Allocation 1. Uplink 960 124 925 1023 915 975 1023 975 880 124 Downlink For E-GSM: Fu(n) = 890 + 0.2 n n=0: Fu(1) = 890 + 0.2 x = 890 MHz n = 124 : Fu(124) = 890 + 0.2 x 124 = 914.8 MHz Fu(n) = 890 + 0.2 (n –1024) n = 975 : Fu(n) = 890 + 0.2 x (975 – 1024) = 880.2 MHz n = 1023 : Fu(n) = 890 + 0.2 x (1023 – 1024) = 889.8 MHz The downlink frequencies are found by adding 45 MHz to each of these. 2. For DCS-1800 , Fu(n) = 1710.2 + 0.2 (n – 512) n = 601, Fu(601) = 1710.2 + 0.2 x (601 – 512) = 1728 MHz n = 625, Fu(625) = 1710.2 + 0.2 x (625 – 512) = 1732.8 MHz GSM Technology for Engineers © AIRCOM International 2002 A-5 Appendix A – Solutions to SAEs Intentional Blank Page A-6 GSM Technology for Engineers © AIRCOM International 2002 Appendix A – Solutions to SAEs Section Exercise 9.1 - Mobile Originated Call Location Area BSS Paging Call set up BSS Call set up Caller MS MSC BSS User MS Call routing Yes – in LA VLR Is user here? No – go to HLR to find which MSC VLR Which LA? User in LA MSC HLR Which MSC? User in MSC Location Area BSS Paging Call set up BSS User MS GSM Technology for Engineers © AIRCOM International 2002 A-7 Appendix A – Solutions to SAEs Intentional Blank Page A-8 GSM Technology for Engineers © AIRCOM International 2002 Appendix A – Solutions to SAEs Section 10 Exercise 10.1 – Security Parameters 1. Ki Key– This is an encryption key unique to individual MSs. It is stored only in the AuC and the MS’s SIM. It uses the A3 algorithm, together with the RAND to creation of the SRES for authentication purposes. 2. Kc Key. This is a data encryption key. It is generated by applying the Ki key and the RAND to the A8 Algorithm. It is then mixed with the clear user data using the A5 algorithm top produce encrypted data. 3. RAND. This is a random number generated within the AuC which is used in conjunction with the Ki key and the A3 algorithm to produce the SRES for authentication purposes. It is also used in conjunction with the Ki key and the A8 algorithm to produce the Kc Key. 4. SRES. This is the ‘Signed Result’ produced by applying the RAND and the Ki Key to the A3 algorithm. It is compared with the SRES generated within the MS for authentication purposes. 5. A3 Algorithm. The A3 algorithm is used in the authentication procedure. It takes the RAND and Ki Key inputs to produce the SRES output. 6. A5 Algorithm. The A5 algorithm is used in the encryption of user data. It takes the clear user data and the Kc Key as inputs to produce encrypted user data output. 7. A8 Algorithm. The A8 algorithm is used in the generation of the Kc data encryption Key. It takes the RAND and the Ki Key as inputs to produce the Kc Key output. GSM Technology for Engineers © AIRCOM International 2002 A-9 Appendix A – Solutions to SAEs Intentional Blank Page A-10 GSM Technology for Engineers © AIRCOM International 2002 Appendix B – Glossary of Terms Appendix B Glossary of Terms A3 A5 A8 A Abis ACK ADM ADPCM ADSL AMPS ARFCN ARQ ATM AuC BCCH BER BP BS BSC BSS BSSMAP BT BTS CAI CDMA CC CELP CEPT COST Authentication algorithm Ciphering algorithm Ciphering key computation Interface between MSC and BSC Interface between BSC and BTS Acknowledgement protocol Adaptive delta modulation Adaptive differential pulse-code modulation Asymmetric Digital Subscriber Line. A technique for dramatically increasing the data rates available on copper wiring. Analogue Mobile Phone System. The US analogue cellular standard. Absolute Radio Frequency Channel Number Automatic repeat request Asynchronous Transfer Mode Authentication Centre. The part of the GSM system responsible for authenticating the mobiles and providing ciphering keys. Broadcast Control Channel. A GSM logical control channel providing information to the mobile as to the channel configuration in the cell. Bit error rate Burst Period. The duration of a single burst, when one mobile transmits within the GSM framing structure. Base station. The part of the radio system which transmits the signal to the mobile. Base Station Controller. The part of the GSM system responsible for controlling the base stations. Base Station Sub-system. The combination of the BTS and BSC. BSS Management Part. The protocol used for BSS management on the Abis interface. Bandwidth-Time product. A means of measuring the amount of filtering applied to the pulse during the modulation process. Base Transceiver Station. Another name for BS. Common air interface – as in CT2 standard. Code Division Multiple Access. The use of different codes to allow users to access the same spectrum at the same time. Call Control. The protocol layer within GSM responsible for overall control of the call. Code-excited linear prediction, vocoder. European Committee for Post and Telecommunications. The European body Responsible for radio spectrum management. Co-operation in Science and Technology programme (Europe). GSM Technology for Engineers © AIRCOM International 2002 B-1 Appendix B – Glossary of Terms COST 231 CT-0 CT-1 CT-2 CT-3 CTM DCS DECT Downlink Duplex DTAP DTX EDGE 8PSK EIR ETR ETS ETSI FACCH FCCH FDMA FEC FH FPLMTS FSK FT GAP GFSK GIP G-MSC GMSK B-2 COST committee dealing with future mobile system. The original analogue VHF/LF cordless phone technology as used in UK, France and elsewhere. Cordless Telephone Generation One – 900MHz analogue FM cordless Technology standardised by CEPT. Cordless Telephone Generation 2. An early UK digital cordless standard. Early Swedish (Ericsson) digital cordless standard. Cordless terminal mobility – an application concept and an ETSI project. Digital cellular system (eg DCS1800). Digital European Cordless Telephone. The European cordless telephone standard. Transmission path from radio fixed part to portable part. Simultaneous two-way conversation. Direct Transfer Application Part. The protocol used on the Abis interface to Distinguish between messages for mobiles and for BTSs. Discontinuous transmission Enhanced Data rates for GSM Evolution. Method of increasing data rates in GSM by using 8PSK modulation Eight Phase Shift Keying. Modulation techniques encoding bits to each symbol. Equipment Identity Register. Part of the GSM system responsible for keeping details of the mobile units and their status. ETSI technical report. ETSI technical standard. European Telecommunications Standards Institute. Fast Associated Control Channel. A logical channel used for sending emergency information to the mobile by suppressing traffic information. Frequency Control Channel. A logical control channel within GSM used to allow the mobile to lock onto the transmitted signal. Frequency Division Multiple Access. The division of the radio frequency into narrow slots, each one being given to a different user. Forward error correction. Frequency Hopping. Changing rapidly from frequency to frequency to avoid problematic propagation effects. Future Public Land Mobile Telecommunications Service. The US name for third generation radio systems. Frequency-shift keying. Fixed termination. Generic access profile of DECT. Gaussian-filtered FSK modulation. GSM interworking profile of DECT. Gateway Mobile Switching Centre. The part of the GSM system providing the link into the PSTN. Gaussian Minimum Shift Keying. The modulation technique used in GSM, a form of phase modulation. GSM Technology for Engineers © AIRCOM International 2002 Appendix B – Glossary of Terms GoS GPRS GSM Handoff Handover HLR HSCSD IAP ISI IMEI IMSI IMT2000 IN IP IS54 IS95 ISDN ITU IWF IWP IWU LA LAC LAI LAPD LEO LLME LNA LOS LPC MAC MAP Grade of service. General Packet Radio Service. Global System for Mobile telecommunications. also Groupe Speciale Mobile Procedure whereby communications between a mobile handset and a base station is automatically routed via an alternative base station when necessary to maintain or improve communications. Another term for handoff. Home Location Register. The part of the GSM system responsible for holding records about mobiles and for keeping track of the parent MSC area. High Speed Circuit Switched Data. 2.5 G enhancement to GSM giving higher data rates ISDN access profile for DECT. Inter-Symbol Interference. A radio propagation effect whereby echoes of received signals cause previous symbols transmitted to interference with current symbols. International Mobile Equipment Identity. The GSM number given to each mobile. International Mobile Subscriber Identity. The phone numbering system used within GSM. International Mobile Telecommunications system for the year 2000. Intelligent Network. Internet Protocol, a layer network protocol US digital AMPS standard. US CDMA digital cellular standard. Integrated Services Digital Network. A protocol for sending digital information over copper landlines. International Telecommunications Union. The international body responsible for spectrum management. Inter-working function Inter-working profile Inter-working unit Location Area Location Area Code Location Area Identity Link Access Protocol on interface D. Part of the ISDN protocol stack also used in GSM. Low Earth Orbiting satellite system. A proposed communications system based on up to 66 satellites. Lower layer management entity (DECT). low noise amplifier. Line-Of-Sight Linear Predictive Coding. Medium Access Control. The means whereby mobiles access radio channels which are not permanently reserved for their own particular use. Mobile Application Part. Part of the SS7 protocol dealing with mobile services. GSM Technology for Engineers © AIRCOM International 2002 B-3 Appendix B – Glossary of Terms MM Mobility Management. The protocol layer within GSM responsible for keeping track of mobiles and performing security functions. MoU Memorandum of Understanding MS Mobile Station. MSC Mobile Switching Centre. The part of the GSM system responsible for switching calls. MSISDN Mobile Subscriber Integrated Services Digital Number. The numbering system used to contact GSM mobiles from other networks. MSK Minimum shift keying modulation. MTP Message Transfer Part. Part of the SS7 protocol stack. NADC North American Digital Cellular NCC National Colour Code NMT Nordic Mobile Telephone system. The Nordic analog cellular standard. O&M Operations and maintenance OAM Operations, administration and maintenance. OMC Operations and Maintenance Centre. The part of the GSM system responsible for monitoring network function. PABX private automatic branch exchange. PAGCH Paging and Access Grant Channel. A GSM logical control channel providing paging information and allowing mobiles to make access attempts. PBX Private Branch Exchange (today has same meaning as PABX). PCM Pulse Code Modulation. A simple form of speech coding. PCN Personal communications network. PCS1900 Personal Communications System at 1900 MHz. A variant of GSM working at 1900MHz designed for the US. PDC Personal Digital Cellular. The Japanese cellular standard. PHL Physical layer – lowest protocol layer. PHS Personal Handiphone System. The Japanese cordless telephone standard. PLMN Public Land Mobile Network. PMR Private (or Professional)Mobile Radio. A radio system owned by the users ` typically large companies. POTS Plain old telephone service. PP Portable part. PSK Phase shift keying modulation. PSTN Public Switched Telephone Network. PT Portable termination. QPSK Quadrature Phase Shift Keying. A form of modulation whereby orthogonal carriers are used to gain the maximum information from the channel. Quantisation A process of representing samples of an analogue waveform by the nearest whole number of predefined voltage steps. RACH Random Access Channel. A GSM logical control channel used for making uplink access attempts. RAP Radio access profile for DECT. RAN Radio Access Network RFP Radio fixed part. RIL Radio Interface Layer. The protocol within GSM responsible for maintenance of the radio interface. B-4 GSM Technology for Engineers © AIRCOM International 2002 Appendix B – Glossary of Terms RLAN RLL RPE-LTP RR RSSI SACCH SCCH SCCP SID SIM Simplex SMS SMS-SC SRES TA TACS TBR TCH TCAP TDD TDM TDMA TETRA TMN TMSI TRAU TRX UMTS Uplink UPT VAD Radio local area network. Radio local loop. Regular pulse excitation – long term predictor – speech coder user in GSM. Radio Resource. The protocol layer within GSM responsible for providing a service over the air interface. Received signal strength indication. Slow Associated Control Channel. A logical channel used alongside a traffic channel to send signalling information to and from the mobile. Synchronisation Control Channel. A GSM logical control channel providing synchronisation to the mobile. Signalling Control and Connection Part. Part of the SS7 protocol stack. Silence Descriptor Subscriber Identity Module. A small card within GSM mobiles which contains the subscriber identity. One-way communication. Short Message Service. A feature within GSM whereby messages of up to 160 characters can be transmitted to mobiles. SMS Service Centre. The part of the GSM system which handles short messages. Signed RESult . Produced by authentication algorithm. Timing Advance Total Access Communications System. The UK (and other European countries) analogue cellular standard. Technical basis for regulation – ETSI standards. Traffic Channel. The channel used in GSM to send subscriber information. Transaction Capability Application Part. Part of the SS7 protocol stack. time division duplex. Time division multiplex. Time Division Multiple Access. A system where users access all the frequency but only for a limited time. TErrestrial Trunk RAdio Telecommunications Management Network. The concept of managing the network from a single point using a networked operations and maintenance system. Temporary Mobile Subscriber Identity. A GSM number given to the mobile during an encrypted call to prevent eavesdroppers being able to located the mobile. Transcoder and Rate Adapter Unit Transmit/Receiver module. The GSM term for a single carrier card within a BTS. Universal Mobile Telecommunications Service. One name for the third generation mobile radio system. Communications path from portable part to fixed part. Universal Personal Telecommunications. The fixed network equivalent of third generation systems. Voice Activity Detection GSM Technology for Engineers © AIRCOM International 2002 B-5 Appendix B – Glossary of Terms VLR VSAT WAP WLL WPABX WPBX WRC WRS B-6 Visitors Location Register. The part of the GSM system responsible for keeping track of a mobile’s position to the nearest location area. Very Small Aperture Terminal. A satellite communication system based on dishes around 1m across. Wireless Application Protocol Wireless Local Loop. The use of radio to replace copper wiring as a means of connecting the home to the PSTN. Wireless PABX. Wireless PBX. World Radio Conference. The bi-annual international conferences to determine the use of the radio spectrum. Wireless relay station. GSM Technology for Engineers © AIRCOM International 2002 [...]... Power mW dBm GSM class 2 960 39 (8W) GSM class 3 600 37 (5W) GSM class 4 240 33 (2W) GSM class 5 96 29 (0.8W) DCS class 1 120 30 (1W) DCS class 2 30 24 (.25W) DCS class 3 480 36 (4W) GSM class 1 – deleted under GSM Phase 2 Specification Power ( mW) = Nominal maximum mean power output (milliwatts) Power (dBm) = Maximum power output in dBm (+watts) Source: ETSI GSM 02.06 (Version 4.5.2) GSM Technology... their connections GSM Technology for Engineers © AIRCOM International 2002 27 2 Architecture Overview Intentional Blank Page 28 GSM Technology for Engineers © AIRCOM International 2002 3 GSM Services 3 GSM Services _ 3.1 Introduction The services offered by GSM are based on those of the fixed-line ISDN services and are therefore, as with ISDN, the GSM services are divided... Cellular Systems • 2nd Generation Cellular Systems • GSM- specific Characteristics • Cellular User Distribution • 2.5 G Characteristics 10 GSM Technology for Engineers © AIRCOM International 2002 2 Architecture Overview 2 Architecture Overview _ 2.1 Introduction This section of the course provides an overview of the GSM network architecture This includes a brief explanation... in the 04- and 05-series of GSM Technical Specifications Summary This section has covered: • General GSM Architecture Overview • GSM Network Components including Air Interface (Um) • The Mobile Station • The Base Station Subsystem Abis Interface Abis A Interface OMC OMC MS HLR BSS BSS VLR MS MS TRX TRX BTS • The Network Subsystem MSC BSC BSC AuC • GSM Network Interfaces Overview • The Base Station... Sub-system MS PSTN EIR • The Network Switching System GSM Technology for Engineers © AIRCOM International 2002 25 2 Architecture Overview Intentional Blank Page 26 GSM Technology for Engineers © AIRCOM International 2002 2 Architecture Overview Section 2 Self-Assessment Exercises Exercise 2.1 – GSM Architecture The following exercises tests your understanding of GSM architecture as applied to a small network... _ 2.3 General Architecture Overview GSM Architecture Overview Air Interface Air (Um) (Um) Abis Interface Abis Interface A Interface A Interface OMC MS VLR VLR BSS MS HLR HLR TRX BTS BTS MSC BSC AuC AuC MS EIR NSS NSS PSTN GSM Technology for Engineers © AIRCOM International 2002 13 2 Architecture Overview A GSM network is made up of three subsystems: • The Mobile Station... Predominantly used in North and South America • Predominantly used in Asia • Planning Similar to GSM • ANSI-41 Core Network • Planning Similar to GSM TDMA and PDC phones 6 GSM Technology for Engineers © AIRCOM International 2002 1 Introduction to Cellular Systems 1.5 GSM Development and Characteristics Originally GSM referred to the European working party set up to establish a new standard (‘Groupe Speciale... include: • • • • • A General architecture overview The Mobile Station (MS) Subsystem and Elements The Base Station Subsystem (BSS) and Elements The Network Subsystem (NSS) and Elements Introduction to network interfaces GSM Technology for Engineers © AIRCOM International 2002 11 2 Architecture Overview 2.2 GSM Identifiers GSM Identifiers • IMEI – International... or stolen handsets 22 GSM Technology for Engineers © AIRCOM International 2002 2 Architecture Overview 2.7 GSM Interfaces GSM Network Interfaces D VLR VLR HLR HLR MS Um MS C B TRX BTS BTS Abis BSC A BSS H AuC AuC MSC F MS EIR NSS 2.7.1 THE A (MSC-BSS) INTERFACE The interface between the MSC and its BSS is specified in the 08-series of GSM Technical Specifications... data services offered by GSM including: • • • Circuit Switched Data (CSD) Unstructured Supplementary Service Data (USSD) Short Message Service (SMS) Each of these services will be described in this section of the course GSM Technology for Engineers © AIRCOM International 2002 29 3 GSM Services GSM Services Teleservices Bearer Services PLMN Section Section outside PLMN TE TE IWF TE GSM Network Transit Network . 5.3 GSM Protocols Overview 67 5.4 GSM Transmission Protocols 69 5.5 GSM Signalling Protocols 71 5.6 GSM Air (Um) Interface Protocols 73 5.7 GSM A-bis Interface Protocols 75 5.8 The GSM A. measures implemented by GSM • Understand GSM mechanisms for customer billing • Be familiar with the future evolution of GSM including 2G+ technologies • Describe the evolution of GSM towards 3G systems. Architecture Overview 12 GSM Technology for Engineers © AIRCOM International 2002 ________________________________________________________________________________ GSM IdentifiersGSM Identifiers •