Time Division Synchronous Code Division Multiple Access (TD-SCDMA) is originally a joint development of Siemens and the China Academy of Telecommunications Technology (CATT). It is one of the five IMT-2000 standards for the third generation of mobile communications (3G) accepted by the ITU. The standard is also accepted by the 3G Partnership Project (3GPP). TD-SCDMA forms part of the UMTS standard as of UMTS Release 4. In the UMTS standard the system is also referred to as UMTS TDD Low Chip Rate.
The main characteristics of TD-SCDMA are:
TD-SCDMA is based on radio channels with a bandwidth of 1.6 MHz. The uplink and the downlink use the same radio channel. So there is no need for paired spectrum. Three channels can be accomodated in a 5 MHz UMTS TDD radio channel.