GSM Network Architecture ELET 6302

Motivation

Outline Introduction and history. GSM architecture. Implementation. Technology and standards. Summary

Introduction Global System for Mobile Communication (GSM) Anybody – 500 million users (may 2001) Anywhere – 168 countries (may 2001) Any media – voice, messaging, data, multimedia Source: Hillebrand, 1

GSM Architecture Mobile switching center Base station controller Network Management Center Home Location Register BTS = Base Transceiver Station AuC = Authentication Center OMC = Operation and Maintenance Center PSTN = Public Switched Telephone Network ME = Mobile Equipment AuC Equipment ID OMC Visitor Location Register Subscriber Identity Module BTS Mobile switching center ME Data communication network Subscriber Identity Module Base station controller BTS ME Subscriber Identity Module BTS ME PSTN Source: Stallings, 313 Source: Mehrotra, 27

GSM Architecture MS Transmission Band : 890 – 915 MHZ BS Transmission Band : 935 – 960 MHZ 45 MHz Year Introduced 1990 Access method TDMA Channel Bandwidth 200 kHz Number of duplex channels 125 Users per channel 8 Speech coding bit rate 13 kbps Data coding bit rate 12 kbps Frame size 4.6 ms

SIM (Subscriber Identity Module) Billions of Calls Millions of Subscribers Thousand of Different Types of Telephones Hundreds of Countries Dozens of Manufacturers…. And only one Card: The SIM Administrative data Security data Subscriber data Roaming data PLMN (Public Land Mobile Network Source: Hillebrand, 369 http://ucables.com/products/simcards/

Implementation Receiver Transmitter SIM = Subscriber Identity Module >Channel Decoding >De-Interleaving >Re-formatting Voice decoding Deciphering Demodulation >Channel encoding >Interleaving >Burst generation Voice encoding Ciphering Modulation Amplifier Transmitter Central processor, clock and tone, internal bus system, keyboard (HMI) SIM = Subscriber Identity Module Source: Heine, 14

Implementation Block Diagram of a BTS with one TRX Source: Heine, 20 HF Transmitter (HF-TX) Output filter TRX Abis-Interface Slow frequency hopping Transmission system Digital signal processing (NF functionality) HF Receiver (HF-RX) Input filter O&M Module Operation and maintenance functionality/clock distribution Block Diagram of a BTS with one TRX Source: Heine, 20

GSM Variants Variant Uplink (MHz) Downlink (MHz) Total Bandwidth Duplex-frequency Channels GSM-400 451-458 and 479-486 461-468 and 489-496 Twice 14 MHz 10 MHz Twice 72 GSM-900 (primary band) 890-915 935-960 Twice 25 MHz 45 MHz Twice 124 Extended GSM-900 880-915 925-960 Twice 35 MHz Twice 174 GSM-R 876-880 921-925 Twice 4 MHz Twice 19 DCS-1800 1,710-1,785 1,805-1,880 Twice 75 MHz 95 MHz Twice 373 PCS-1900 1,850-1,910 1,930-1,990 Twice 60 MHz 80 MHz Twice 300 Source: Bekkers, 299

Summary Network architecture Implementation Voice application Data application

References Bekkers, Rudi. Mobile Communications Standards: GSM, UMTS, TETRA, and ERMES. Norwood, MA: Artech House, Inc., 2001. Halonen, Romero, and Melero. GSM, GPRS, and EDGE Performance: Evolution Towards 3G/UMTS. England: John Wiley & Sons Ltd., 2003. Hillebrand, Friedhelm. GSM and UMTS: The Creation of Global Mobile Communications. England: John Wiley & Sons Ltd., 2002. Heine, Gunnar. GSM Networks: Protocols, Terminology, and Implementation. Norwood, MA: Artech House, Inc., 1999. Mehrotra, Asha. GSM System Engineering. Norwood, MA: Artech House, Inc., 1997. Harte, Levine, and Livingston. GSM Superphones. United States: APDG Publishing, Inc. A Division of McGraw-Hill, 1999.