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Overview of Computer Networks - College of Engineering

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					                      CPET 355
               2. The Physical Layer -
               Wireless Transmission

               Paul I-Hai Lin, Professor
        Electrical and Computer Engineering Technology
             Purdue University, Fort Wayne Campus




Feb. 2, 2004                Prof. Paul Lin               1
    The Electromagnetic Spectrum
    NASA
      • http://imagine.gsfc.nasa.gov/docs/science/kno
        w_l1/emspectrum.htm
      • http://imagers.gsfc.nasa.gov/ems/waves3.htm
        l
    Berkeley Lab: Electromagnetic
     Spectrumhttp://www.lbl.gov/MicroWorlds/
     ALSTool/EMSpec/EMSpec2.html
    Naval Spectrum Management Support-
     http://www.navemscen.navy.mil/index.ht
     m
Feb. 2, 2004             Prof. Paul Lin             2
               Frequency Allocation
      • Radio wave- < 3 x109 Hz
      • Microwave – 3.0x109 – 3x1012 Hz
      • Infrared    - 3.0x1012 – 4.3x1014 Hz
      • Visible     - 4.3x1014 – 7.5x1014 Hz
      • Ultraviolet - 7.5x1014 – 3.0x1017 Hz
      • X-Rays      - 3.0x1017 – 3.0x1019 Hz
      • Gamma Rays - > 3.0x1019 Hz
      f = c
      Wavelength*Frequency = speed of light
Feb. 2, 2004           Prof. Paul Lin          3
                 Wavelength
    f = c
      Wavelength*Frequency = speed of light
    Electromagnetic Wave
      • http://www.geo.mtu.edu/rs/back/spectr
        um/
    An Applet Example -
     http://lectureonline.cl.msu.edu/~mm
     p/applist/Spectrum/s.htm
Feb. 2, 2004          Prof. Paul Lin          4
               Spectrum for Wireless
                  Transmission
    Usable spectrum: Radio wave,
     Microwave, Infrared, and Visible light
     f = c            f = c/ 
     df/d = c/ 2    f = c  / 2
    Narrow frequency band
      f/f << 1, best reception (watts/Hz)
    Frequency hopping spread spectrum
      • Military application, 802.11, Bluetooth,
Feb. 2, 2004            Prof. Paul Lin             5
                   Wireless Transmission
    Federal Regulations
      • Wireless Telecommunication Bureau,
        http://wireless.fcc.gov/
    Emerging Wireless Technologies,
     http://www.fcc.gov/initiatives.html
                  3G Wireless
                  Broadband
                  Digital TV
                  Lower Power FM
                  Rural Wireless ISP
                  Voice Over IP
Feb. 2, 2004                            Prof. Paul Lin   6
               Wireless Transmission
    Radio Transmission
    Microwave Transmission
    Lightwave Transmission
    Satellite Communications




Feb. 2, 2004            Prof. Paul Lin   7
           Radio Transmission
   Omnidirectional systems
    •   For indoor and outdoor
    •   No need for physical alignment
    •   Can penetrate buildings easily
    •   Low bandwidth
   Examples
       • Paging – short message, 10s of k meters
       • Cordless telephone – analog/digital, 10s of
           meters
       • Cellular phone – analog/digital/data, k meters
       • Personal communication services – digital
                                   of
           voice and data, 100sPaul Lin meters
Feb. 2, 2004                 Prof.                        8
          Microwave Transmission
    Wave > 100 MHz can penetrate haze, light
     rain and snow, clouds, and smoke
    Do not passing through building well, and
     has multipath fading effect (some delay
     waves that may cancel the signals)
    Wave can travel in nearly straight line and
     can be narrowly focused for transmitting
     information (data & voice)
    100 meter tower, repeaters can be spaced
     by 80 km apart

Feb. 2, 2004           Prof. Paul Lin          9
          Microwave Transmission
    Microwave Spectrum
      • http://imagers.gsfc.nasa.gov/ems/micro.html
    ISM bands – Industrial, Scientific and
     Medical for unlicensed usage
      • International Telecommunication Union
        http://en.wikipedia.org/wiki/ITU-T
      • 900 MHz – crowded, not available world wide
      • 2.4 GHz – available worldwide; 802.11
        wireless LAN
      • 5.7 GHz – new; 802.11a use it
Feb. 2, 2004             Prof. Paul Lin               10
          Microwave Transmission
    Applications
      • Microwave cooking (about foot
        wavelength)
      • Transmitting information: data and
        phone (can penetrate haze, light rain
        and snow, clouds, and smoke)
      • Remote sensing – weather forecasting
      • Wireless LAN

Feb. 2, 2004           Prof. Paul Lin           11
           Lightwave Transmission
    IrDA Association -
     http://www.irda.org/
    Wavelength range – 850 nm to 900
     nm
    IrDA-C
      • 75 kbps, up to 8 meters
    IrDA-D
      • 115 kbps to 4Mbps, up to 1 meter
Feb. 2, 2004           Prof. Paul Lin      12
        Satellite Communications
    GOES (Geostationary Satellite)
     Systems
      • 36,000 km above the equator
      • Transponder data rate – 50 Mbps, at
        4/6. 11/14, and 20/30 GHz bands
    LEOS (Low-Earth Orbit Satellite)
     Systems
    MEOS (Multiple-mission Earth
     Observatory Satellite) Systems
Feb. 2, 2004          Prof. Paul Lin          13
                GOES Satellite
               Communications
 Significant satellite operators & Industries
http://www.3g-generation.com/satellite.htm
 GOES Satellites
  http://ww2010.atmos.uiuc.edu/(Gh)/guide
  s/rs/sat/goes/home.rxml
 GOES Science Projects
  http://rsd.gsfc.nasa.gov/goes/
 GOES Servers
      • http://www.goes.noaa.gov/
      • http://www.goes.noaa.gov/g8hu.html

Feb. 2, 2004            Prof. Paul Lin       14
        Satellite Communications
    Overview of LEO Satellite Systems
      • http://www.its.bldrdoc.gov/meetings/art/art99
        /slides99/red/red_s.pdf
    LEOS (Low-Earth Orbit Satellite)
      • Technologies and Trends -
        http://www.mindbranch.com/listing/product/R
        201-084.html
    Routing and Multicasting in LEO Satellite
     IP Networks
      • http://users.ece.gatech.edu/~cchen/routing/dr
        p.html
Feb. 2, 2004             Prof. Paul Lin             15
               MEOS Satellite
    Multiple-mission Earth Observatory
     Satellite
      • http://www.eumetsat.de/en/area2/proc
        eedings/eump33/pdf/session_5/softwar
        e/oynes.pdf




Feb. 2, 2004          Prof. Paul Lin       16
               Web References
    Hughes Network Systems, www.hns.com
      • http://research.mwjournal.com/data/detail?id
        =988922143_314&type=ORG
    NEC Optical Network Division
     http://www.necpng.com/press/
    Panduit Network Connectivity Solutions
     http://www.panduit.com/
    www.commscope.com
    Errcsson Microwave Systems AB
     http://www.ericsson.com/microwave/
    Northrop Grumman – California Microwave
     Systemshttp://sensor1.northgrum.com/calmw/
Feb. 2, 2004             Prof. Paul Lin                17

				
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