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Wireless Telecommunications

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					Wireless Telecommunications


         Presented by:
        Susanne Cochez
         Nicole Clark
          Wade Brett
         Rojae Charity
               Introduction
•   History
•   Major Manufacturers
•   Cell Systems
•   Cell Access Technologies
•   Cells in the Future
•   Problems with Cell Phones
                             History
• 1947 - Researchers looked at crude mobile (car) phones and
  realized they could increase the traffic capacity of mobile phones
  substantially.

• 1948 - AT&T proposed that the FCC allocate a large number of
  radio-spectrum frequencies

• 1968 - FCC increased the frequencies allocation, freeing the
  airwaves for more mobile phones

• 1977 - AT&T and Bell Labs had constructed a prototype cellular
  system
• 1979 - In a separate venture, the first commercial cellular
  telephone system began operation in Tokyo.

• 1981 - Motorola and American Radio telephone started a
  second U.S. cellular radio-telephone system.

• 1983 - The first American commercial analog cellular
  service or AMPS (Advanced Mobile Phone Service) was
  made available in Chicago by Ameritech.

• 1987 - Cellular telephone subscribers exceeded one million
  and the airways were crowded.
        Major Manufacturers

•   Nokia
•   Motorola
•   Audiovox
•   Ericksson
                 Cell Systems

• Digital cell phones use the same radio technology as
  analog phones, but they use it in a different way.

• Analog systems do not fully utilize the signal between the
  phone and the cellular network -- analog signals cannot be
  compressed and manipulated as easily as a true digital
  signal.
 Cellular Access Technologies


• Frequency division multiple access (FDMA)
• Time division multiple access (TDMA)
• Code division multiple access (CDMA)
FDMA


  • FDMA puts each call on
    a separate frequency
TDMA


  • TDMA assigns each call a
    certain portion of time on
    a designated frequency
CDMA


  • CDMA gives a unique
    code to each call and
    spreads it over the
    available frequencies.
Cells in the Future
  • Third-generation wireless phones may
    look more like hand held computers, with
    features such as video-conferencing,
    advanced personal calendar functions and
    multi-player gaming.

  • Another futuristic feature, will include
    making every day purchases through
    cellular communication with computer
    operated systems.
   Problems with Cell Phones


• Cloning
• Hazardous while driving
• Radiation causing cancer
Questions?

				
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