Friday, December 31, 2010

Evolution of the CDMA Standards

    The evolution process of the CDMA standards is roughly divided into the following stages :

   CdmaOne namely, IS-95A and IS-95B It mainly supports the voice service, belonging to 2G communications.

   cdma2000 1X: It can support both voice and data services. The max. Data rate can reach 153 kbps, belonging to 3G mobile communications.

   cdma2000 1xEV-DO: As the enhanced version of cdma2000 1X at stage 1, it supports data services, with max. forward rate being up to 2.4 Mbps.

   cdma2000 1xEV-DV: As the enhanced version of cdma2000 1X at stage 2, it supports both voice and data services, with max. data rate being up to 4 Mbps, and even higher.

       IS-95 is the first-released standard of the cdmaOne series standards. But the first CDMA standards really and widely applied in the world are IS-95A which supports the 8K code voice service and the STD-008 standard of the 1.9GHz CDMA PCS system. The 13K code voice service quality is already very close to the voice service quality of the wireline phone. With the increasing demands of the mobile communication for the data service, Qualcomm of the U.S.A. declared in February 1998 to apply the IS-95B standard to the basic platform of CDMA. With IS-95B standard, the CDMA system performance could be enhanced, the data flow of the user’s mobile communication equipment could be increased, and the 64 kbps data service could be supported. Later, cdma2000 became the transitional standard from the narrowband CDMA system to the 3G system.

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