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Wireless SystemsIK1330Anders [email protected] 44
55
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IK1330 Wireless SystemsTEN1: 4,5 hec. A part theory, B part
problemsLAB1: 3 hec.Three labs, propagation and planning, WLAN,
measurements, Required reading:Stallings, W., Wireless
Communications and Network, Pearson, 2005Course
Webpage:http://www.kth.se/student/program-kurser/kurshemsidor/ict/cos/IK1330/VT10-1Book
Webpage:http://williamstallings.com/Wireless/Wireless2e.html
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Stallings: Wireless Communications and Networks[Stallings.,
2005]
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Radio CommunicationRadio or radio communication means any
transmission, emission, or reception of signs, signals, writing,
images, sounds or intelligence of any nature by means of
electromagnetic waves of frequencies lower than three thousand
gigacycles per second (3000 GHz) propagated in space without
artificial guide.Examples of radio communication systems:Radio
broadcasting.TV broadcasting.Satellite communication.Mobile
Cellular Telephony.Wireless LAN.Multimedia communication &
Mobile Internet[Slimane]
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History1864: Maxwell describes radio wave mathematically1888:
Hertz generates radio waves1890: Detection of radio waves1896:
Marconi makes the first radio transmission1915: Radio tubes are
invented1948: Shannons law1948: Transistor1960: Communication
Satellites1981: Cellular technology
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Classification of radio spectrum
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The Radio SpectrumThe frequency spectrum is a shared
resource.Radio propagation does not recognize geopolitical
boundaries.International cooperation and regulations are required
for an efficient use of the radio spectrum.The International
Telecommunication Union (ITU) is an agency, within the UN, that
takes care of this resource.Frequency
assignment.Standardization.Coordination and planning of the
international telecommunication services.
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Evolution of Wireless Systems[Stallings., 2005]
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Evolution of Cellular
Systems[Slimane]AMPSETACSNMTGSMGPRSEDGEUSDCIS-136CDPDTD-SCDMAWCDMACDMAIS-95CDMAoneIS-95BCDMA20001G2.5G2G3G
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Radio CommunicationThree main problems:The path lossNoiseSharing
the radio spectrum
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Communication SystemsSource of
informationInformationsinkTransmitterChannelReceiverMessage
signalEstimate of message signalTransmitted signalReceived
signal[Ahlin et. al., 2006]
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Analog Communication SystemSource of informationSignal
ProcessingModulatorRF-StageChannelRF-StageInformationsinkSignal
ProcessingDemodulator[Slimane]
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Digital Communication SystemSource of
InformationSourceEncoderModulatorRF-StageChannelRF-StageInformationSinkSourceDecoderDemodulatorChannelEncoderDigitalModulatorChannelDecoderDigitalDemodulator[Slimane]
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decibelsThe bel is a logarithmic unit of power ratios. One bel
corresponds to an increase of power by a factor of 10 relative to
some reference power, Pref.
The bel is a large unit, so that decibel (dB) is almost always
used:
The above equation may also be used to express a ratio of
voltages (or field strengths) provided that they appear across the
same impedance (or in a medium with the same wave impedance):
[Saunders, 1999]
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decibels[Saunders, 1999]
