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TDMA

    There are three standard technologies used by cellular phone networks for transmitting voice and data:

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

     FDMA is used for analog cellular phones. TDMA ( Time Division Multiple Access) is one of several technologies used in digital wireless transmission. It increases the efficiency of the network by allowing a greater number of simultaneous transmissions. Networks using TDMA assign 6 timeslots for each frequency channel.

 TDMA builds on FDMA (Frequency Division Multiple Access) by dividing conversations by frequency and time. Since digital allows for compression, TDMA can fit three digital conversations into a single FDMA/Analog channel. A digital system can sample (measuring the amplitude of an analog signal at a specified time) a persons voice for a certain amount of time and then send it in one third the time. This allows more than one user to share the same channel. TDMA is more secure with better voice quality over longer and shorter distances.

CDMA

    CDMA stands for Code Division Multiple Access. For cellular phone users, it's a transparent interface for a wireless digital network. CDMA was original developed by the military in the early 1960's. CDMA uses sequential code frequencies to funnel traffic channels within the same radio channels.

   In layman's terms, CDMA channels packets of voice and data over wireless radio frequencies so a cellular user can hear better, quicker and with more quality then ever before.

    CDMA uses wide-band spread spectrum techniques for signal transmission, as opposed to narrow-band channel techniques used in conventional analog systems. A perfect analogy of CDMA wide-band technology and narrow-band analog would be the Internet. Picture CDMA technology as a Cable or DSL Line, and analog technology as a dial-up Internet connection. Since DSL or cable lines are thicker and wider than a thinner phone line, it's faster and quicker, in both directions. CDMA is faster in transmitting and receiving data over a cellular phone.

    It 1993, CDMA went mainstream and was certified by the TIA (Telecommunications Industry Association) and adopted as the leading digital multiple access technique for cellular phones.

    The newer CDMA (Code Division Multiple Access) technology is more advanced than basic FDMA. Due to lower cost savings compared to CDMA, TDMA is the digital transmission of choice in today's cellular world. TDMA is more popular with cellular carriers and manufactures and is the adopted digital standard for most phones. TDMA can be viewed as modern technology, FDMA/Analog as older technology.
 

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