TD-SCDMA
Technology Overview
TD-SCDMA (time division - synchronous code division multiple access) is a cellular technology based on the combination of a TDMA (time division multiple access) component and a CDMA (code division multiple access) component. Additionally, unique synchronization mechanisms are foreseen for optimizing the time division duplex (TDD) mode of operation. The uplink and downlink are separated in time, i.e. specific timeslots within one time frame are assigned separately to uplink and downlink transmission.
Deployment Scenario
TD-SCDMA can be deployed as a 1.28 Mcps TDD mode in UMTS TDD bands. The standard also foresees integration with UMTS WCDMA (FDD) and GSM/GPRS networks, i.e. mobility between the various technologies is supported.
Key Parameters
| TD-SCDMA | |
|---|---|
| Frequency Range |
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|
| Modulation | QPSK, 8PSK, 16QAM (HSPA only) |
| Multiple Access | TD-SCDMA |
| Duplex (Uplink/Downlink) | TDD |
| Channel Bandwidth | 1.6 MHz |
| Peak Data Rate | 2 Mbit/s
2.8 Mbit/s (HSPA) |
Standardization
TD-SCDMA was introduced as a UMTS low chip rate TDD mode (1.28 Mcps TDD) in Release 4 specifications of 3GPP (3rd Generation Partnership Project).
Further enhancements such as high speed downlink packet access (HSDPA) and enhanced uplink (high speed uplink packet access, HSUPA) for 1.28 Mcps TDD mode were introduced in 3GPP Releases 5 and 7, respectively.
UMTS Long Term Evolution (LTE) as specified in 3GPP Release 8 will provide the long term evolution path for TD-SCDMA. The following link provides access to 3GPP specifications: http://www.3gpp.org/ftp/Specs/
