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Telecommunication

Telecommunication

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Telecommunication

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  1. Dr. Dóra Maros Telecommunication Radiopropagation Pathloss Shadowing Multipathfading, ISI

  2. Cells EarthCell (satelite) Macrocell Size: 350m-20 km Outdoor, rural, roads Microcell Size: 50m-300 m Outdoor, city Picocell Size: some 10 m Indoor

  3. RadioPropagationin Mobile Networks

  4. GSM 900, 1800, 1900 bands(2G)

  5. UMTS GSM1800 DECT UMTS TDD UMTSFDD Műhold UMTS TDD UMTSFDD Műhold [MHz] 2100 2200 2500 2700 1800 1900 2000 2600 UMTS FrequencyBands • in2000, newfrequencybands • 806-960 MHz, 1710 - 1885 MHz (GSM bands!) • 2500 - 2690 MHz Channelbandwidth: 5,10, or20 MHz Pairedfr. bands Unpairedfr. bands

  6. LTEBands 30 bands: 21 FDD 9 TDD

  7. DirectionalAntennas Adjustableantennas GSM antennas

  8. Omniantennas Omni antenna mountedon mobile tower „Handy” omni antenna

  9. MicrowaveAntennas Micro antennas: connectionstowardsthecorenetwork (sometenGHz)

  10. 3G/4G Antennas Multiplesectorantennasinthesamecell MIMO antennas(LTE)

  11. IndoorAntennas (examples)

  12. RadiopropagationI. Frequency and wavelength • The wavelength is inverslyproportionaltothefrequency of elektromagneticwave : • λ = c/f, where • λ- wavelength(m) • c - velocity of electromagneticwave • (invacuum and inthe air about 3*108 m/s, accuratevalue: 299792458 m/s) • f - frequency(Hz) • Example: • 1. f=900 MHz (9*108 Hz) λ=? • 3*108 / 9*108 = 3/9 [m] ~ 0,33 [m] • f=2,6 GHz (2,6*109) • 3*108 / 2,6*109 = 1,154 * 10-1 ~ 0,1154 [m]

  13. Radiopropagation II. Pathloss Free spaceattenuation: RSL ReceivedSignalLevel (dB) a0 = 20 log (4Πd/λ) a0 = 20 log (df) + 28,14 d (distancefrom antenna)

  14. RadioPropagationIII. PropagationModels • Makrocellpropagationmodels: • Relativesmalltraffic (rural, road), highspeed of movement (>100 km/h) • Hata, COST231 • Mikrocellpropagation models: • Hightraffic (urban, suburban), smallerspeed of movement (30-80 km/h) • Walfish-Ikegami modell, COST 231 • Indoorpropagation models: • Mootley-Keenan (félempirikus) • Ray-tracing

  15. RadioPropagationIV. Shadowing BaseStation Mobile Equipment Meanvalue RSL (dB) d (distancefrom antenna) Slowfadingcausedbyshadowing

  16. RadioPropagationV. MultipathFading Mobile Equipment BaseStation Fastfadingcausedbyreflections