TD-SCDMA Forum Joins 3GPP

Europe : The Organizational Partners of the Third Generation Partnership Project (3GPP™) have approved an application by the TD-SCDMA Forum to become a Market Representation Partner within the project. 3GPP develops specifications for a 3rd Generation mobile technology which is being embodied in communications systems which offer users access to multimedia services on the move, wherever they are in the world.

Market Representation Partners provide a market dimension to the specification work of 3GPP, ensuring that the project consistently responds to the needs of the mobile communications industry. Established in December 2000, the TD-SCDMA Forum brings to 3GPP its commitment to promote the Time Division – Synchronous Code Division Multiple Access technology (TD-SCDMA) as part of the global family of 3rd Generation technologies. TD-SCDMA has been developed by the Chinese Wireless Telecommunications Standards group, CWTS, with the support of a number of manufacturers, and has been included in the specifications of 3GPP since 2001.

The radio interface defined by 3GPP for communication between the User Equipment and the base station is known as UTRA – Universal Terrestrial Radio Access – and it is the principal distinguishing feature of the 3GPP technology. It is defined for two basic modes of operation: Frequency Division Duplex (FDD) and Time Division Duplex (TDD). Each mode has its particular strengths, according to the type of traffic to be carried. TDD has a particular attraction in that it can be implemented in unpaired spectrum (and is well suited to asymmetric traffic), whilst FDD always needs paired frequency bands. Spectrum is always a rare resource so, as frequencies are made available in future for 3G, it is likely that much of it will be unpaired.

Both modes were initially defined by 3GPP to use spreading codes with a chip rate of 3.84 Mcps (mega chips per second). Subsequently, proposals from CWTS were adopted by 3GPP to define a second TDD mode that uses a chip rate of 1.28 Mcps, one consequence of which is the ability to use narrower frequency bands than for basic TDD or FDD. This mode is therefore known as "Low Chip Rate TDD" or "Narrow-band TDD". All three modes (FDD and the two TDD modes) have been agreed by the International Telecommunication Union (ITU) as part of its IMT-2000 family of radio interface technologies.

By fully integrating this technology within the TDD specification, 3GPP is ensuring that no unnecessary disparity occurs and that the maximum commonality between the modes is maintained. Narrow-band TDD can be supported on unpaired frequency bands of 1.6MHz, making it possible to accommodate very conveniently on existing GSM™ frequency allocations. Given that 3GPP has sought to define its 3G system as an evolution, as far as possible, of GSM, Narrow-band TDD is an attractive option for bringing 3G capability to existing GSM networks relatively inexpensively.

The TD-SCDMA Forum is headquartered in Beijing, China, and is strongly supported by Chinese industry. Nevertheless, it is eager to share its technology with mobile operators and manufacturers world-wide, a fact reflected in its logo.

The Forum's Secretary-General, Jin Guo Qiang, explained:

"The design of the logo embodies many messages, notably the global, open and vigorous nature of the TD-SCDMA standard. In addition, the three colour ribbons form the Chinese character "today", stressing the timeliness of the technology, whilst their outward flow represents its enormous future potential."

Dr Asok Chatterjee, Chairman of the 3GPP Project Co-ordination Group and representative of the USA's T1 Standards Committee, warmly welcomed the decision of the Organizational Partners to accept the Forum's application:

"I am delighted that the developers and supporters of the TD-SCDMA technology, many of them Chinese organizations, have chosen to promote it through 3GPP. The fact that the technology has also been approved by the ITU is a sign of its world-wide potential, and I am happy to assure the Forum of our commitment to help promote TD-SCDMA as a fully recognized member of the top-quality set of 3GPP global standards."

The addition of the TD-SCDMA Forum to the 3rd Generation Partnership Project brings the number of Market Representation Partners to six.