Downloaded 14 times
Uploaded bymanish kumawat
4 Gsm Net Architecture Manish Copy Copy
GSM is a global standard for mobile communications that has over 500 million subscribers in 168 countries. It uses TDMA and FDMA to allow multiple users to access the network simultaneously. The GSM architecture includes the BTS, BSC, MSC, HLR, VLR, AuC and other components. It operates in frequency bands such as 900 MHz and 1800 MHz with channel bandwidth of 200 kHz. GSM supports voice calls and data transmission and uses technologies like encryption, authentication and SIM cards.
4 Gsm Net Architecture Manish Copy Copy
- 1. GSM Network Architecture Presenter: Manish Kumawat All sections to appear here
- 2. Outline • Introduction and history. • GSM architecture. • Implementation. • Technology and standards. • Summary
- 3. Introduction • Global Systemfor Mobile Communication (GSM) – Anybody – 500 million users (may 2001) – Anywhere – 168 countries (may 2001) – Any media – voice, messaging, data, multimedia Source: Hillebrand, 1
- 4. GSM Specifications Carrier Separation - 200 kHz Duplex Distance - 45 MHz No. of RF Carriers - 124 Access Method - TDMA/FDMA Modulation Method - GMSK Transmission Rate - 270.833 Kbps Speech Coding - Full rate 13 Kbps Half rate 6.5 Kbps
- 5. GSM FDMA (Frequency Division Multiple Access) 890 915 935 960 25 MHz 25 MHz 0 1 2 0 1 2 Mobile to Base Base to Mobile (MHz) 890.2 890.4 890.6 935.2 935.4 935.6 200 kHz 200 kHz 45MHz Channel layout and frequency bands of operation
- 6. GSM TDMA (Time Division Multiple Access) Amplitude 45 MHz 7 8 7 8 5 6 5 6 4 4 3 3 2 2 1 1 Frequency F1 F2 F1’ F2’ (Cell Rx) (Cell transmit) Typical TDMA/ FDMA frame structure
- 7. FDMA/TDMA Scheme TIME BP2 BP1 BP8 BURST BP7 F BP6 BP5 R BP4 A BP3 M BP2 E BP1 FREQ 890.2 890.6 891.0 890.0 890.4 890.8 891.2 915.8 MHz
- 8. GSM Architecture Home Location Register Network Management BTS = Base Transceiver Station Center AuC AuC = Authentication Center Equipment ID OMC = Operation and Maintenance Center PSTN = Public Switched Telephone Network ME = Mobile Equipment Visitor Location OMC Register Subscriber B Identity ME T Mobile S Module Data switching communication center network Subscriber B Base station Identity ME T Module S controller Subscriber B Identity ME T PSTN S Module Source: Stallings, 313 Source: Mehrotra, 27
- 9. GSM Architecture MS Transmission BS Transmission Band : 890 – 915 Band : 935 – 960 MHZ MHZ 45 MHz Year Introduced 1990 1 Access method TDMA 2 3 Channel Bandwidth 200 kHz 4 5 Number of duplex 125 6 channels 7 F1 F2 F1' F2' 8 Users per channel 8 Frequency Speech coding bit 13 kbps rate Data coding bit rate 12 kbps Frame size 4.6 ms
- 10. SIM (Subscriber IdentityModule) Billions of Calls Millions of Subscribers Thousand of Different Types of Telephones Hundreds of Countries Dozens of Manufacturers…. •Administrative data And only one Card: The SIM •Security data •Subscriber data •Roaming data •PLMN (Public Land Mobile Network Source: Hillebrand, 369 http://ucables.com/products/simcards/
- 11. Implementation Receiver >Channel Decoding Voice decoding >De-Interleaving Deciphering Demodulation >Re-formatting >Channel encoding >Interleaving Voice encoding Ciphering Modulation Amplifier >Burst generation Transmitter Central processor, clock and tone, internal bus system, keyboard (HMI) SIM = Subscriber Identity Module Source: Heine, 14
- 12. Implementation Slow frequency Transmission HF Transmitter Output filter TRX Abis- (HF-TX) Interface system hopping Digital signal HF Receiver processing (NF Input filter (HF-RX) functionality) O&M Module Operation and maintenance functionality/clock distribution Block Diagram of a BTS with one TRX Source: Heine, 20
- 13. GSM Variants Variant Uplink Downlink Total Duplex- Channels (MHz) (MHz) Bandwidth frequency GSM-400 451-458 and 461-468 and Twice 14 MHz 10 MHz Twice 72 479-486 489-496 GSM-900 890-915 935-960 Twice 25 MHz 45 MHz Twice 124 (primary band) Extended 880-915 925-960 Twice 35 MHz 45 MHz Twice 174 GSM-900 GSM-R 876-880 921-925 Twice 4 MHz 45 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
- 14. References Bekkers, Rudi. MobileCommunications 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.