The International Telecommunication Unions globally co-ordinated definition of 3G that includes five radio access technologies in the IMT-2000 family of standards:

• IMT-DS Direct Sequence (referred to as UTRA-FDD, W-CDMA, UMTS-FDD);
• IMT-MC Multi-Carrier (referred to as CDMA2000);
• IMT-TC Time Code (referred to as UTRA-TDD) and China's TD-SCDMA;
• IMT-SC Single Carrier (referred to as UWC-136/EDGE);
• IMT-FT Frequency Time (referred to as DECT).