Short for
Code-Division
Multiple Access, a digital
cellular technology that uses
spread-spectrum techniques. Unlike competing
systems, such as
GSM, that
use
TDMA, CDMA
does not assign a specific frequency to each user. Instead, every
channel uses the full
available spectrum. Individual conversations are encoded with a pseudo-random
digital sequence. CDMA consistently provides better capacity for voice
and data communications than other commercial mobile technologies, allowing more
subscribers to connect at any given time, and it is the common platform on which
3G technologies are built.
CDMA is a military technology first used during World
War II by English allies to foil German attempts at jamming transmissions.
The allies decided to transmit over several frequencies, instead of one, making
it difficult for the Germans to pick up the complete signal. Because Qualcomm
created communications chips for CDMA technology, it was privy to the classified
information. Once the information became public, Qualcomm claimed patents on the
technology and became the first to commercialize it.
IE 7
Firefox 2.0
