Introduction
3-G or 3G stands for Third Generation Technology. It is a service offered by mobile phone operators. 3G allows voice (phone call) and non-voice data (instant messaging, email etc) to be transmitted simultaneously. The technology is different from IEEE 802.11 networks as it offers wide area cellular networks. Video call or Video Telephone is an example of application of 3G technology.
The major hindrance faced by 3G technology was the licensing and equipment cost. In many countries license for 3G is still very expensive, for example in many European countries licensing are high. Moreover as its frequency is different from old-fashioned 2G, equipment also needs to be upgraded. Hence the technology faces a hard challenge in many countries.
3G services were introduces in United Kingdom in 2000, but it did not gained much popularity at that time due to high costs. Japan was the first country to introduce the technology on commercial basis. According to a survey 40% of mobile phone subscribers used 3G. Korea was also quick to adopt the technology. The main reason for 3G’s popularity in Japan was attributed to music downloads. Important stakeholders in music download services included Chaku Uta Full, and EZchakuuta.
Technical Aspects and Working of 3G
3G utilizes 5 megahertz channel carrier width for data transmission and reception. The allowed radio spectrum’s band is provided by ITU (International Telecommunications Unit) under International Mobile Telecommunications program, IMT-2000.
The basic principle of 3G is pretty much similar to that of 2G i.e. a mast (also known as base station) links individual 3G enabled devices (laptops mobile phones and PDAs) through radio signals. Base stations provide coverage to a certain geographical area known as a “cell”. The cells need to be overlapped to avoid disconnections in case of roaming mobile devices.
Radio waves used by 3G technology have a slightly higher frequency than that of 2G, resulting in a smaller cell size (less coverage). Moreover if a certain geographical area, covered by a cell, gets crowded by third gen. devices then the size of cell shrinks further. Hence the masts must be overlapped in a way that they offer minimum interference between their neighboring cells and provide best coverage.
The 3G technology allows speed as fast as 2Mbps for stationary and 384kbps for mobile systems. Future promises by third generation technology include faster speeds and international roaming between different 3G operators.
Standard interfaces for 3G services
IMT-2000 provides six radio interfaces for 3G services:
- DECT (Digital Enhanced Cordless Telecommunications)
- UWC-136 (EDGE)
- TD-CDMA (Time-Division, code division multiple access) / TD-SCDMA
- CDMA2000
- CDMA2001
- W-CDMA