Radio Access

There are multiple radio access technologies used in IMT. As of WRC-07, the list is:

- CDMA-Direct Spread (Universal Terrestrial Radio Access-UTRA)

- CDMA-Multi Carrier (CDMA2000)

- CDMA TDD (UTRA TDD)

- TDMA Single Carrier (UWC (Universal Wireless Communication)-136)

- FDMA/TDMA (Digital Enhanced Cordless Communications-DECT)

- OFDMA TDD WMAN (WiMAX)

Currently under study are technologies for Long Term Evolution (LTE) and LTE-Advanced (LTE-A.)

ITU-R Recommendation M.1457-8 (May 2009) clause 5 indicates the radio interfaces for the terrestrial component of IMT-2000 as listed above. Subsequent text provides additional detail and cross references to the national and regional standards that define these radio access systems. The level of detail in these subsequent sections is relevant to  those who are deeply immersed in the implementation of the technologies, or are doing research and development in their various aspects.

Other resources are available that usefully provide substantive but less detailed information on the radio access technologies. Wikipedia is one such, but this should not be interpreted as an endorsement of these articles by the ITU, and in particular these references should be treated as informative and unsuitable for decision making or specifying purchases. Some relevant articles which provide substantial information on the principles and design in each of these may be accessed at:

- CDMA is a general article on code division multiple access technology

- CDMA-Direct Spread is also known as W-CDMA, UMTS-FDD, UTRA-FDD

- CDMA-Multi Carrier (CDMA2000) is an article specific to this technology

- CDMA TDD (UTRA TDD)

- TDMA Single Carrier (UWC (Universal Wireless Communication)-136)

- FDMA/TDMA (Digital Enhanced Cordless Communications-DECT)

- OFDMA TDD WMAN (WiMAX)

Information on LTE and LTE-A can be found at the ITU-R’s LTE web page. This page includes links to a considerable amount of information on process and procedures for evaluation of a radio access technology. The useful part at the intermediate level is the portion on the LTE workshops:

- 1st Workshop on IMT-Advanced - Kyoto, 22 May 2007 (The presentations can be obtained by following the appropriate links but a TIES account is needed and must be authorized for access to the material.)

- 2nd Workshop on IMT-Advanced - Seoul, 7 October 2008 ( The presentations can be obtained by following the appropriate links.)

- 3rd Workshop on IMT-Advanced - Dresden, 15 October 2009 (This event had not yet taken place as this web page was being prepared.)