Hi Santosh , In cellular service there are two main competing network technologies: Code Division Multiple Access (CDMA) and Global System for Mobile Communications (GSM)

In CDMA Both data and voice are separated from signals using codes and then transmited using a wide frequency range. Because of this, there are more space left for data transfer (this was one of the reasons why CDMA is the prefered technology for the 3G generation, which is broadband access and the use of big multimedia messages). 14% of the worldwide market goes to CDMA. For the 3G generation CDMA uses 1x EV-DO and EV-DV. It has a lot of users in Asia, specially in South Korea.

GSM, - it is sold as "the latest technology" in several countries, this technology is older than CDMA (and also TDMA). But keep in mind that this doesn't mean that GSM is inferior or worse than CDMA. Roaming readiness and fraud prevention are two major advantages from this technology. GSM is the most used cell phone technology in the ...more