What is the difference between 2G and 3G technologies?
When mobile telephones and Internet technology were first introduced as a means of communication, they used 1G technology. Such features as instant messaging were far into the future as well as many of the applications that we take for granted today. Now the technology has developed far beyond that having gone through 2G, 2.5G, 3G and in the very near future 4G.
What is 2G Network technology?
2G is a shortened form for the second generation of the Global System for Mobile Communication. It was the first attempt at developing technology to bring some kind of standard to the concept of modern digital cellular service. This standard was first brought to fruition in 1991 and since then it has improved very rapidly. By 1998 there were over 200 million subscribers to cell phone service all over the world. It made voice transmission so easy and convenient by means of handsets and this is the reason why it immediately became popular.
Handsets that are designed for the Global System for Mobile Communication (GSM) have an identifier that authenticates the set as belonging to a person who does have a paid subscription. This is called a Subscriber Identity Module (SIM). The handset uses multiple access technology which is a hybrid of Frequency Division Multiple Access (FDMA) and Time Division Multiple Access (TDMA). This access serves to increase the amount of support and access that subscribers can receive in any one cell. There are many different parts to a cell in this technology. Each one is a small part of a larger interface and is covered by 3 GSM antennae.
The radio interface of the GSM allows for a data rate of 270Kbps and the limit of the bandwidth for the voice channel is 200kHz. This is sufficient bandwidth to carry voice data. There are 14 bands in the allocated GSM spectrum. Of these 14, there are four GSM bands that get the greatest amount of usage: 850, 900, 1800 and 1900. In order for communication to take place, the uplink and the downlink each use distinct bands. For the GSM 900 band, for example, the duplex distance is 45MHz. This means that the uplink frequencies are 890 – 915MHz and the downlink frequencies are 935 – 960MHz. Each of these bands is further subdivided into 200 kHz channels.
The GSM spectrum bands used in Europe and Asia are 900 and 1800. The spectrum bands used in Canada and the United States are GSM 850 and GSM 1900.
What is 3G Network technology?
The growth of mobile networks led to the development of technology that allows more than voice data to be transmitted through mobile devices. Video calling, stream audio and video and video conferencing have now become commonplace. The standard for this technology is 3G and it is based on CDMA technology.
In order for a network to be classified as being 3G, it has to meet certain conditions that have been laid down by the International Telecommunications Union (ITU). These are:
- The data transfer rate for downlinks must be 144Kbps for mobile handsets
- The data transfer rate for downlinks must be 384Kbps for pedestrians
- The data transfer rate for downlinks must be 24Mbps in an indoor environment
Each user has full access to the bandwidth because each one is identified by a random code in the multiple use technology of CDMA.
Summary
- 2G is the standard for GSM mobile communication and only permits voice calls. 3G is the standard that provides for enhanced features, such as video calling.
- The technology used in 2G is FDMA and TDMA, while 3G relies on CDMA.
- The air interface date rate for 2G is 270Kbps. In 3G, the data rate is 2Mbps when stationary and 384Kbps when moving.
- 2G uses a ciphering algorithm, but the random code for 3G is more secure because it can authenticate the user.
- The channel bandwidth for 2G is 200 KHz for voice transmission. The channel for 3G is 1.25 Mhz.