Lecture 2 - Sept 3 - Chapter2: Frequencies...

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2.1 Prof. Dr.-Ing. Jochen H. Schillerwww.jochenschiller.deMC - 2008 Mobile Communications Chapter 2: Wireless Transmission  Frequencies  Signals, antennas, signal propagation  Multiplexing  Spread spectrum, modulation  Cellular systems
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Prof. Dr.-Ing. Jochen H. Schillerwww.jochenschiller.deMC - 2008 2.2 Frequencies  for communication VLF = Very Low Frequency UHF = Ultra High Frequency LF = Low Frequency  SHF = Super High Frequency MF = Medium Frequency  EHF = Extra High Frequency HF = High Frequency  UV = Ultraviolet Light VHF = Very High Frequency Frequency and wave length   λ = c/f  wave length  λ , speed of light c   2245  3x10 8 m/s, frequency f 1 Mm 300 Hz 10 km 30 kHz 100 m 3 MHz 1 m 300 MHz 10 mm 30 GHz 100 μ m 3 THz 1 μ m 300 THz visible light VLF LF MF HF VHF UHF SHF EHF infrared UV optical transmission coax cable twisted pair
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Prof. Dr.-Ing. Jochen H. Schillerwww.jochenschiller.deMC - 2008 2.3 Frequencies for mobile communication VHF-/UHF-ranges for mobile radio simple, small antenna for cars deterministic propagation characteristics, reliable connections SHF and higher for directed radio links, satellite communication small antenna, beam forming large bandwidth available Wireless LANs use frequencies in UHF to SHF range some systems planned up to EHF limitations due to absorption by water and oxygen molecules  (resonance frequencies) weather dependent fading, signal loss caused by heavy rainfall etc. 
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Prof. Dr.-Ing. Jochen H. Schillerwww.jochenschiller.deMC - 2008 2.4 Frequencies and regulations ITU-R holds auctions for new frequencies, manages frequency bands  worldwide (WRC, World Radio Conferences) Examples Europe USA Japan Cellular phones GSM  880-915, 925-960,  1710-1785, 1805-1880 UMTS  1920-1980, 2110- 2170 AMPS, TDMA, CDMA,  GSM  824-849, 869-894 TDMA, CDMA, GSM,  UMTS  1850-1910, 1930- 1990 PDC, FOMA  810-888,  893-958 PDC  1429-1453, 1477- 1501 FOMA  1920-1980, 2110- 2170 Wireless LANs 802.11b/g  2412-2472 802.11b/g  2412-2462 802.11b  2412-2484 802.11g  2412-2472 Other RF  systems 27, 128, 418, 433, 868 315, 915 426, 868
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Prof. Dr.-Ing. Jochen H. Schillerwww.jochenschiller.deMC - 2008 2.5 Signals  I physical representation of data function of time and location signal parameters: parameters representing the value of data   classification continuous time/discrete time continuous values/discrete values analog signal = continuous time and continuous values digital signal = discrete time and discrete values signal parameters of periodic signals:  period T, frequency f=1/T, amplitude A, phase shift  ϕ sine wave as special periodic signal for a  carrier :  s(t) = A t  sin(2  π  f t +  ϕ t )
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Prof. Dr.-Ing. Jochen H. Schillerwww.jochenschiller.deMC - 2008 2.6 Signals
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Prof. Dr.-Ing. Jochen H. Schillerwww.jochenschiller.deMC - 2008
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This note was uploaded on 11/03/2009 for the course COMPUTERS CS537 taught by Professor Salman during the Spring '09 term at Texas A&M University–Commerce.

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Lecture 2 - Sept 3 - Chapter2: Frequencies...

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