MẠNG GSM - PHẦN 1 pot

04/2009 Overview 1. INTRODUCTION TO GSM 2. GSM ARCHITECTURE 3. GEOGRAPHICAL NETWORK ORGANIZATION 4. GSM NUMBERING 5. GSM CALLING (MOC, MTC) Overview 1. INTRODUCTION TO GSM a. What is GSM b. GSM services c. History d. GSM advantages and disadvantages What is GSM?  GSM (Global System for Mobile communication) is a Worldwide Digital Cellular Communications Network  formerly: Groupe Spéciale Mobile (founded 1982)  used in over 184 countries  The GSM network provides for  mobile voice communication  international roaming  mobile fax  text messaging  data services What is GSM?  GSM is a Second Generation (2G) digital radio cellular network  Time Division Multiplexing / Multiple access (TDM/TDMA) are employed  TDM / TDMA allows:  One frequency channel to be subdivided  Multiple conversations over a single physical channel GSM Subscriber Services Two basic types: 1. Telephony (Teleservices) Mainly voice services providing capability to communicate with other subscribers 2. Data (Bearer services) Capacity necessary to transmit appropriate data signals between two access points creating an interface to the network GSM Subscriber Services GSM supports the following subscriber services: 1. Dual tone multi frequency (DTMF) tone signaling scheme used for control purposes E.g. Remote control of an answering machine 2. Facsimile group III GSM supports CCITT group III Facsimile Special fax converter forms junction between standard analogue fax and GSM FAX GSM Subscriber Services 3. Short Message Services (SMS) Messaging facility consisting of maximum 160 alphanumeric characters to or from a mobile station to another 4. Cell Broadcast Variation of SMS where maximum number of alphanumeric characters is 93 Can be broadcast to users in a certain geographical area. E.g. Traffic congestion warnings GSM Subscriber Services 5. Voice Mail Answering machine within the network controlled by the subscriber Security code needed to access 6. Fax Mail Subscriber can receive fax messages at any fax machine 7. Emergency number common number mandatory for all service providers free of charge connection with the highest priority (pre-emption of other connections possible) GSM Supplementary Services  GSM supports comprehensive list of supplementary services supporting both data and voice services  The following compromises a partial list: 1. Call forwarding 2. Barring of outgoing calls 3. Advice of charge (AoC) [...]... offer added services such as Caller ID or Messaging 1st Generation Analogue Networks AMPS 19 83 USA, Australia C-Netz 19 81 Germany, Austria, Portugal, South Africa ETACS 19 87 UK, NMT450/900 19 81/ 86 Scandinavia + 30 other countries RadioCom 19 85 France RTMS 19 85 Italy TACS 19 85 UK, Ireland, Spain NTACS/JTACS 19 91 Japan NTT/NTT Hi Cap 19 78/88 Japan How did GSM get established  CEPT formed a technical study... “Olivia” - Hotline     Introduced in 19 89 Originally introduced in 19 89 for the NMT900, ETACS and AMPS networks Later adapted for GSM, and is the first Ericsson GSM phone First all digital mobile “Sandra”    First introduced by Ericsson in 19 91 First version used in NMT-900 networks, followed by version for ETACS, DAMPS/AMPS Adapted for GSM in 19 93 “Jane”   Introduced by Ericsson in 19 96 Several... AMPS, GSM, DCS, PCD1900 /GSM GSM Specification Frequency Band Uplink: 890 MHz – 915 MHz / 17 10 MHz – 17 85 MHz Downlink: 935 MHz – 960 MHz / 18 05 MHz – 18 80 MHz Duplex distance 45MHz / 95MHz Carrier Separation 200 kHz Modulation Gaussian Minimum Shift Keying (GMSK) Transmission rate 270 kbit/s Access Method Time Division Multiple Access (TDMA) (narrow band) Speech coder Regular Pulse Excitation - Long... Long Term Prediction (RPE-LPC) 13 kbit/s Diversity Channel coding, Interleaving, Frequency hopping, Adaptive equalization GSM compared to 1G Systems  Communication   Total mobility   better frequency efficiency, smaller cells, more customers per cell High transmission quality   one number, the network handles localization High capacity if needed   international access, chip-card enables use of... access control, authentication via chip-card and PIN What are some of disadvantages of GSM? There is no perfect system!!        no end-to-end encryption of user data reduced concentration while driving electromagnetic radiation abuse of private data possible roaming profiles accessible high complexity of the system several incompatibilities within the GSM standards What are the trends with mobile... pan-European mobile cellular radio system in 900MHz band Tackle the associated technical, economic and logistical problems Objectives of GSM    To provide a European “second generation” digital network standard Increase the market for Equipment Manufacturers Allow Manufacturing to establish economy of scale Development Timeline  19 85 – Digital Coded Speech over radio link chosen as basis for GSM. .. link chosen as basis for GSM  19 86 – Validation Trials held in Paris  19 88 – Following successful validation multiple invitations to tender issued  19 92 – Commercial Networks Launched First portable units   First portable units were really big and heavy Called transportables or “luggables” “Curt” – The Hotline Pocket    The first Ericsson Handheld introduced in 19 87 Adapted from a police radio.. .GSM Supplementary Services 4 Call hold 5 Call waiting 6 Multiparty service 7 Calling line identification presentation / restriction 8 Closed user groups (CUGs) Multiple incompatible networks  Before GSM, the technical incompatibilities between networks were due to:    operation on different radio . 04/2009 Overview 1. INTRODUCTION TO GSM 2. GSM ARCHITECTURE 3. GEOGRAPHICAL NETWORK ORGANIZATION 4. GSM NUMBERING 5. GSM CALLING (MOC, MTC) Overview 1. INTRODUCTION TO GSM a. What is GSM b. GSM services c Messaging 1 st Generation Analogue Networks Japan1978/88NTT/NTT Hi Cap Japan1991NTACS/JTACS UK, Ireland, Spain1985TACS Italy1985RTMS France1985RadioCom Scandinavia + 30 other countries19 81/ 86NMT450/900 UK,. Spain1985TACS Italy1985RTMS France1985RadioCom Scandinavia + 30 other countries19 81/ 86NMT450/900 UK, 19 87ETACS Germany, Austria, Portugal, South Africa 19 81C-Netz USA, Australia1983AMPS How did GSM get established  CEPT formed a technical study