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TECHNOLOGY |
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Wireless phones access technologies |
| Know about the different access technologies
used by cell phones such as FDMA, TDMA and CDMA, showed up since the
creation of the wireless phone networks. |
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There
are nowadays three technologies used in networks for information
transmission: FDMA, TDMA and CDMA.
Although these technologies sound complicated you can
have an idea of how they work by examining each word in
their names.
The main difference lies in the access method,
which varies between:
Frequency, used in the FDMA technology.
Unique
Codes provided to each call in the CDMA technology.
The first part of the names of these three technologies
(Multiple access), mean that more than one user (multiple)
can use (access) each cell.
Without
entering into cumbersome technical details we detail how
each of the three technologies work: |
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FDMA
technology separates the spectrum in different
voice channels, by separating the bandwidth in uniform
widths (frequencies). The FDMA
technology is mainly used for analogical
transmission. This technology is not recommended
for digital transmissions, even though she is capable
of carrying digital information.
TDMA technology compress conversations
(digital), and sends each using the radio signal
just during a third of a unit time. The compression
of the voice signal is possible because the information
size can be reduced due to its digital nature, which
works on a binary system (ones and zeros). Due to
this compression, the TDMA technology has three
times as much capacity as an analogical
system using the same number of channels.
CDMA technology differs greatly
from the TDMA technology. CDMA, transmits through
the whole bandwidth available after digitalizing
the information. Many calls are juxtaposed on the
channel and each has a code of unique sequence.
Using the CDMA technology, it is possible
to compress between 8 and 10 digital calls in such a way that those will fill the same space
a single call would demand in the analogical system.
In theory, TDMA and CDMA technologies must be transparent
among themselves (they must not interfere or reduce
each other’s quality). Nevertheless, in practice
there are some minor inconveniences such as volume
and quality differences between both technologies. |
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| At Mobile Phone Download, you will find a great amount of resources for your cellular phone. Download ringtones, wallpapers, screensavers, games, themes and software for free. In addition, our editor's group selects the best articles, news and reviews on cellular/wireless technology, and the lastest launching features. |
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| Copyright© Mobile Phone Download 2006 |
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