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Cellular and PCS Technical Issues

Cellular and PCS Technical Issues. COMT 220. Overview. Cell Layout Signaling Mobile Handset Operation. System Block Diagram. forward. Mobile. BTS. BSC. MTSO. PSTN. reverse. Data Bases. BTS Base Tranceiver Station BSC Base Station Controller MTSO Mobile Telephone Switching Office.

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Cellular and PCS Technical Issues

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  1. Cellular and PCS Technical Issues COMT 220

  2. Overview • Cell Layout • Signaling • Mobile Handset Operation

  3. System Block Diagram forward Mobile BTS BSC MTSO PSTN reverse Data Bases BTS Base Tranceiver Station BSC Base Station Controller MTSO Mobile Telephone Switching Office Radio Link Voice Trunk Data Trunk

  4. Frequency Reuse Pattern

  5. First Generation Standards • AMPS - United States • TACS - UK • NTT - Japan • NMT - Scandanavia • MATS-E - France • C-450 - Germany • GSM - global

  6. North American AMPS system • 50MHz spectrum • 30kHz per channel per direction • 832 total full-duplex channels • 4, 7, and 12 cell clusters used

  7. AMPS Specifics • 832 channels (2 frequencies per channel) • Forward: 869-894 MHz • Reverse: 824-849MHz • Forward/Reverse Spacing: 45MHz • Adjacent Channel Spacing: 30kHz • 21 Control Channels per group • Cell Sizes: 2-20km

  8. Mobile-Originated Call Mobile BTS BSC MTSO PSTN RCC MIN, ESN, dialed no validation FCC Ch No, SAT code, Power SAT FVC SAT RVC FVC Conversation RVC

  9. Call Handoff • Base Stations monitor the signal strength • If strength drops below hand-off level, all base stations are asked to look for the mobile; strongest becomes new BS • MTSO instructs the new base station to activate a voice channel to receive the handoff; BS starts transmitting the Supervisory Audio Tone.

  10. Call Handoff cont… • Current base station at MTSO command sends signal to mobile giving the new channel assignment. • Mobile send a signaling tone burst, and tunes to the new channel. • Previous base station clears the call path.

  11. Mobile Handset • ESN - Electronic Serial Number • Programmable NAM (Number Assignment Module) • Contains among other things • System ID • First control channel to scan • A/B system selection • MIN (Mobile Identification Number)

  12. Mobile Identification Number • MIN1 - Mobile System Id (3 digits) • US: Area Code • International: Mobil Carrier Identifcation • MIN2 - Station Number • US: NXX and line number • International: international mobile number

  13. Hand-Off MS MS BS BS MTSO

  14. Roaming MTSO Mobile MTSO Mobile Mobile Mobile Mobile Mobile Mobile Mobile Mobile

  15. Intersystem Hand-Off MS MS BS BS MTSO MTSO

  16. The “Shoe-Lace” Effect MS BS BS BS BS BS BS BS BS MS

  17. Multi-System Tandem MS MS BS BS MTSO MTSO MTSO MTSO MTSO

  18. Automatic Roaming MS BS Request MTSO MTSO Response HLR HLR VLR Current Location Temporary Directory Number Billing Information Service Profile

  19. The “Trombone” Effect MS BS MTSO MTSO Fixed Station

  20. Second Generation Systems COMT 220

  21. Classes of Standards • Analog Cellular • FDMA - Frequency Division Multiple Access • Digital Cellular • FDMA • TDMA - Time Division Multiple Access • CDMA - Code Division Multiple Access

  22. Frequency Frequency Time Time Frequency Time Access Methods FDMA TDMA CDMA

  23. Systems and Frequencies • Advanced mobile phone service (AMPS) • 824 to 849 MHz and 869 to 894 • Digital-advanced mobile phone service (D-AMPS) • 824 to 849 MHz and 869 to 894 • Global system for mobile communications (GSM) • 450 MHz, 890 to 960 MHz, 1.8 GHz, 1.9

  24. Systems cont. • Personal communications service (PCS) • 1.9 GHz • Nextel and other specialized mobile radio (SMR) • 816 MHz to 866 MHz • Cellular digital packet data (CDPD) • 824 to 894 MHz, 1.8 GHz to 1.9 GHz

  25. 3rd Generation Wireless Service COMT 220

  26. “3G” Definition • From the FCC Web Site: • 144 kbps (vehicular traffic) to 2 Mbps for indoor traffic • Common billing and user profile services • Bandwidth on demand • Fixed and variable bit rates • Multimedia store-and-forward messaging

  27. Background • ITU Specifications • FPLMTS (future public land mobile telecommunication systems) • IMT-2000 • Frequency bands identified at the 1992 and 200 World Radio Conferences

  28. Technical Specs • Wideband CDMA (5MHz channel) • CDMA2000 (1.25-15MHz channels) • Based on TIA/EIA 95 B • CMDA Time Division Duplex • TDMA Single Carrier • DECT (TDMA/FDMA)

  29. Frequencies • ITU Recommendations: • 1885-2025 MHz • 2110-2200 MHz • 806-960 MHz • 1710-1885 MHz (1755-1850 studied by NTIA) • 2500-2690 MHz (Studied by FCC)

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