Third Generation (3G) Wireless

What is 3G?

3G is the next generation of wireless network technology that provides high speed

bandwidth (high data transfer rates) to handheld devices. The high data transfer rates

will allow 3G networks to offer multimedia services combining voice and data.

Specifically, 3G wireless networks support the following maximum data transfer rates:

o 2.05 Mbits/second to stationary devices.

o 384 Kbits/second for slowly moving devices, such as a handset carried by a

walking user.

o 128 Kbits/second for fast moving devices, such as handsets in moving vehicles.

These data rates are the absolute maximum numbers. For example, in the

stationary case, the 2.05 Mb/second rate is for one user hogging the entire capacity of

the base station. This data rate will be far lower if there is voice traffic (the actual data

rate would depend upon the number of calls in progress).

The maximum data rate of 128Kbits/second for moving devices is about ten times

faster than that available with the current 2G wireless networks. Unlike 3G networks,

2G networks were designed to carry voice but not data.

3G wireless networks have the bandwidth to provide converged voice and data

services. 3G services will seamlessly combine superior voice quality telephony, highspeed mobile IP services, information technology, rich media, and offer diverse content.

Some characteristics of 3G services that have been proposed are:

o Always-on connectivity. 3G networks use IP connectivity, which is packet

based.

o Multi-media services with streaming audio and video.

o Email with full-fledged attachments such as PowerPoint files.

o Instant messaging with video/audio clips.

o Fast downloads of large files such as faxes and PowerPoint files.

o Access to corporate applications.






Is there a 3G Standard?

The International Telecommunication Union (ITU) is responsible for standardizing

3G. After trying to establish a single 3G standard, ITU finally approved a family of five

3G standards, which are part of the 3G framework known as IMT-2000:

o Three standards based on CDMA, namely CDMA2000, WCDMA, and TDSCDMA.

o Two standards based on based on TDMA, namely, FDMA/TDMA and TDMA-SC

(EDGE).

The CDMA standards are the leading 3G standards.

Europe, Japan, and Asia have agreed upon a 3G standard called the Universal

Mobile Telecommunications System (UMTS), which is WCDMA operating at 2.1GHz.

Note that UMTS and WCDMA are often used as synonyms. In the USA and other parts

of Americas, WCDMA will have to use another part of the radio spectrum. Incidentally,

most of the world’s wireless operators have chosen to use UMTS.

What are the Advantages of 3G?

3G networks offer users advantages such as:

o New radio spectrum to relieve overcrowding in existing systems.

o More bandwidth, security, and reliability.

o Interoperability between service providers.

o Fixed and variable data rates.

o Asymmetric data rates.

o Backward compatibility of devices with existing networks.

o Always-online devices. 3G will use IP connectivity, IP is packet based (not

circuit based).

o Rich multimedia services.

What are Some Disadvantages of 3G?

There are some issues in deploying 3G:

o The cost of upgrading base stations and cellular infrastructure to 3G is very

high.

o Requires different handsets and there is the issue of handset availability. 3G

handsets will be a complex product. Roaming and making both data/voice work

has not yet been demonstrated. Also the higher power requirements (more bits

with the same energy/bit) demand a larger handset, shorter talk time, and

larger batteries)

o Base stations need to be closer to each other (more cost).

o Tremendous spectrum-license costs, network deployment costs, handset

subsidies to subscribers, etc.

o Wireless service providers in Germany and Britain who won spectrum licenses

in auctions, paid astronomical prices for them. As a result, they have little money left for building the infrastructure. Consequently, deployment of 3G in

Germany and Britain will be delayed.