First at all I would like to write more about different Technologies of Mobile phones in case if somebody still don't have any Idea about them:
CDMA:
CDMA stands for Code Division Multiple Access. 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:
stands for Global System Mobile. Even though it is sold as "the latest technology" in several countries, this technology is older than CDMA (and also TDMA). But I don'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 world, with 73% of the worldwide market. It has a very strong presence in Europe.
In the beginning, GSM was in fact superior. It had more services and allowed more data transfer. But CDMA, facing the advantages of the competitor standard, soon delivered the same features found on GSM. Nowadays, it is not possible to say that GSM services are better than CDMA. Multimedia messages, video, high-speed Internet access, digital camera and even PDA function are some of the features we can found on both technologies. The new CDMA 1XRTT technology, which previews what G3 cell phones will bring, is more advanced than EDGE, technology from the beginning of 3G generation, allowing higher transfer rates.Glossary
# AMPS: stands for Advanced Mobile Phone Service. Analog cell system.
# TDMA: stands for Time Division Multiple Access. It works by dividing the spectrum into frequency channels and each user uses each channel for a specific time, to avoid interference.
# CDMA 1XRTT: Second generation technology (2.5G, actually) which allows data transfers up to 144 Kbps.
# EDGE: stands for Enhanced Data Rates for Global Evolution. Technology promoted by GSM operators. Before migrating to WCDMA, EDGE will allow third generation data and voice access with 384 kbps transfer rate.
# EV-DO: Third generation (3G) from CDMA 1xEV-DO technology. "EV" comes from and "DO" from data-only. It uses a second channel, of 1.25 MHz, exclusively for data transmission. Some countries are already running this standard. In the USA, Verizon and Sprint started this technology in 2004. This tecnology allows hi-speed Internet access (2.4 Mbps) using the cell phone or using a wireless connection from a laptop or PDA.
# EV-DV: Evolution of EV-DO, but still under development. "DV" comes from data-and-voice. It uses the same channel for trasmiting data and voice. The transfer rate can reach 5.2 Mbps.
# WCDMA: Wideband CDMA. Third generation technology that will be adopted by GSM operators. Its European version is known as UMTS (Universal Mobile Telecommunications System). It can reach transfer rates up to 2 Mbps.