TD-SCDMA

Time Division Synchronous Code Division Multiple Access (TD-SCDMA) or UTRA TDD 1.28 mcps low chip rate (UTRA-TDD LCR) is an air interface found in UMTS mobile telecommunications networks in China as an alternative to W-CDMA.

The term "TD-SCDMA" is misleading. While it suggests covering only a channel access method, it is actually the common name for the whole air interface specification.

Together with TD-CDMA, it is one of the two time-division duplex (TDD) UMTS air interfaces (UTRAs), known commonly as UMTS-TDD or more formally as IMT-2000 CDMA-TDD or IMT 2000 Time-Division (IMT-TD). Both air interfaces use a combination of two channel access methods, code division multiple access (CDMA) and time division multiple access (TDMA): the frequency band is divided into time slots (TDMA), which are further divided into channels using CDMA spreading codes. These air interfaces are classified as TDD, because time slots can be allocated to either uplink or downlink traffic.

TD-SCDMA / UMTS-TDD (LCR) networks are incompatible with W-CDMA / UMTS-FDD and TD-CDMA / UMTS-TDD (HCR) networks.