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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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