CHAPTER 25

THIRD- GENERATION (3G) WIRELESS SYSTEM

The 3G (UMTS and CDMA2000) research and development projects started in 1992. In 1999, ITU approved five radio interfaces for IMT-2000 as a part of the ITU-R M.1457 Recommendation; WiMAX was added in 2007.

There are evolutionary standards (EDGE and CDMA) that are backwards-compatible extensions to pre-existing 2G networks as well as revolutionary standards that require all-new network hardware and frequency allocations. The cell phones used utilise UMTS in combination with 2G GSM standards and bandwidths, but do not support EDGE. The latter group is the UMTS family, which consists of standards developed for IMT-2000, as well as the independently developed standards DECT and WiMAX, which were included because they fit the IMT-2000 definition.

3G systems will provide access, by means of one or more radio links, to a wide range of telecommunication services supported by the fixed telecommunication networks and to other services that are specific to mobile users. A range of mobile terminal types will be encompassed, linking to terrestrial and/or satellite-based networks, and the terminals may be designed for mobile or fixed use.

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:

1. 2.05 Mbits/second to stationary devices.

2. 384 Kbits/second for slowly moving devices, such as a handset carried by a

walking user.

3. 128 Kbits/second for fast moving devices, such as handsets in moving vehicles.

3G networks offer users advantages such as:

1. New radio spectrum to relieve overcrowding in existing systems.

2.More bandwidth, security, and reliability.

3. Interoperability between service providers.

4. Fixed and variable data rates.

5. Asymmetric data rates.

6. Backward compatibility of devices with existing networks.

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

circuit based).

8. Rich multimedia services.

UMTS offers teleservices (like speech or SMS) and bearer services, which provide the capability for information transfer between access points. It is possible to negotiate and renegotiate the characteristics of a bearer service at session or connection establishment and during ongoing session or connection. Both connection oriented and connectionless services are offered for Point-to-Point and Point-to-Multipoint communication.

Bearer services have different QoS parameters for maximum transfer delay, delay variation and bit error rate. Offered data rate targets are:

1.144 kbits/s satellite and rural outdoor

2.384 kbits/s urban outdoor

3.2048 kbits/s indoor and low range outdoor

UMTS network services have different QoS classes for four types of traffic:

> Conversational class (voice, video telephony, video gaming)

> Streaming class (multimedia, video on demand, webcast)

> Interactive class (web browsing, network gaming, database access)

> Background class (email, SMS, downloading)

UMTS will also have a Virtual Home Environment (VHE). It is a concept for personal service environment portability across network boundaries and between terminals. Personal service environment means that users are consistently presented with the same personalised features, User Interface customisation and services in whatever network or terminal, wherever the user may be located. UMTS also has improved network security and location based services.

http://www.umtsworld.com/technology/overview.htm

http://transition.fcc.gov/3G/

http://www.silicon-press.com/briefs/brief.3g/brief.pdf