Sep 18, 2010

Code division multiple access (CDMA)

Code division multiple access (CDMA) is a form of pemultipleksan (not a pemodulasian scheme) and an access method that divides the channel simultaneously is not based on time (as in TDMA) or frequency (as in FDMA), but in a way encodes data with a code specifically associated with each channel that exists and use the constructive interference properties of the special codes to perform pemultipleksan.

In the mobile phone telecommunications technology developments especially those related to third-generation (3G), CDMA into future technology options [1].

CDMA also refers to digital cellular telephone systems that use this collaborative access scheme, such as that initiated by Qualcomm.

CDMA is a military technology first used during World War II by English allies to foil German business interfere with their transmissions. Allies decided to transmit not only on one frequency, but at some frequencies, make it difficult to catch the Germans complete signal.

Since that CDMA is used in many communications systems, including the Global Positioning System (GPS) and satellite systems OmniTRACS for transport logistics. Final system was designed and built by Qualcomm, and became the forerunner who helped Qualcomm engineers to find the Soft Handoff and power control quickly, the technology needed to make a practical and efficient CDMA for terrestrial mobile communications.

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