22-10-2014, 04:31 PM
Abstracts: CODE DIVISION MULTIPLE ACCESS (CDMA) is a digital cellular technology that uses spread-spectrum .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. Worldwide resources are being devoted to third-generation CDMA technology, Including Multi-Carrier (cdma2000 1xMC and HDR in 1.25 MHz bandwidth), and Direct Spread (WCDMA in 5 MHz bandwidth). CDMA was adopted by the Telecommunications Industry Association (TIA) in 1993. In September 1998, only three years after the first commercial Deployment, there were 16 million subscribers on cdmaOne systems Worldwide. By May 2001 there were 35 million subscribers on cdmaOne Systems worldwide and there are now 60 million. Wideband CDMA that forms the basis of UMTS 3G networks, Developed originally by Qualcomm, CDMA is characterized by high capacity and small cell radius, employing spread-spectrum technology and a special coding scheme. Developed originally by Qualcomm and enhanced by Ericsson, CDMA is Characterized by high capacity and small cell radius, employing spread spectrum Technology and a special coding scheme.