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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 Supporthttp://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 Feb. 2, 2004 3G Wireless Broadband Digital TV Lower Power FM Rural Wireless ISP Voice Over IP 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 voice and data, 100s of meters Feb. 2, 2004 Prof. Paul Lin 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