Third Generation Wireless(3G) contains a group of standards to support broadband voice, data and multi-media communications over wireless networks. IMT-2000, the 3G standards developed by ITU, will specify no less than five means of multiple access – CDMA2000, WCMA, a time division duplex version of WCDMA, 136HS (based on the UWCC's recommendation), and Digital Enhanced Cordless Telephone (DECT). The "family of standards" will be required to interoperate with both GSM MAP and IS-41 networks. Namely, the WCDMA specification will be required to allow interconnection with IS-41 and CDMA2000 will be required to interface with GSM MAP.
Currently, the second generation (2G) of wireless networks, such as GSM, CDMA (IS-95) and TDMA (IS-136) networks, are widely used in the wireless communications. The 2G networks can provide narrow band (up to 144kbps) voice and data services using circuit switching techniques. To conduct a smooth evolution from the 2G to 3G wireless networks, some transitional technologies, such as GPRS for GSM, 136 high-speed for TDMA or IS-95B for CDMA, are defined, which are sometimes called 2.5G wireless technologies.
The following table lists the comparison and evolution of Wireless Systems from 1G, 2G to 3G:
| 1G | 2G | 3G | |
| System | Analogue | Digital | Digital |
| Major Systems | AMPS, NMT and TACS | GSM, CDMA and TDMA | WCDMA, CDMA-2000 and TD-SCDMA |
| Application | Voice | Voice + little Circuit- switch Data | Voice + Packet-switch Data |
| Local Subscriber | Less than 500k | About 5.9M | More than 5M (Estimated) |
| Speed | Depends on Analogue Signal | 9.6kbps - 14.4kbps | 384kbps for mobile & 2Mbps for stationary |
| Properties | Unstable, incomplete coverage and poor sound quality | More secure, data services available, broader coverage, more stable, allow more user, better sound quality | Multimedia data, positioning capability, connection to Internet, always connected |
3G: Third Generation Wireless Technologies and Services
Related Terms: 2G, 2.5G, GPRS, CDMA, TDMA, CDMA2000, WCDMA, GSM, IMT-2000
Reference Links: http://www.cse.ohio-state.edu/~jain/cis788-99/ftp/3g_wireless/index.html: Evolution Toward Third Generation Wireless Networks