TD-SCDMA Standard

TD-SCDMA is a Chinese contribution to the international family of Mobile Radio Systems for 3G services of UMTS and IMT 2000. It is now one option of UTRA-TDD, called 1.28Mcps TDD or low chip rate (LCR) TDD. It is an advanced CDMA/TDMA/TDD system with an adaptive synchronous operation.

TD-SCDMA system simulation models based on the 3GPP TDD LCR standard demonstrate signal generation capabilities; basic measurements are considered. TD-SCDMA aligns with the same version of the specification used by the Agilent ESG-C, PSA II and VSA.

Physical Layer

The frame structure in the following illustration recognizes new smart antenna and uplink synchronization technologies.

Physical Channel Signal Format

Uplink and downlink time slots in each frame are separated by a switching point. There are two switching points in each sub-frame: TS0 is always allocated as downlink; TS1 is always allocated as uplink. There are three special time slots:

• DwPTS: downlink pilot time slot, 96 chip duration
• UpPTS: uplink pilot time slot, 160 chip duration
• GP: main guard period for TDD operation, 96 chip duration

The system can operate on symmetric and asymmetric modes by properly configuring the number of downlink and uplink time slots. The burst structure is illustrated in the following image.

Burst Structure

The transmitter structure of a physical channel is illustrated in the following image.

Physical Channel Transmitter Structure

There are two kinds of receiver algorithm for TD-SCDMA: Rake and Joint Detection.
Physical channels have a 3-layer structure.

• Time slot: 675 usec slot consisting of a number of Symbols. Time slots are used in a TDMA component to separate different user signals in time and code domain.
• Radio frame: 5 msec frame consisting of 7 time slots
• System frame numbering

DesignGuide Examples Overview

Example designs are provided in the /examples/tdscdma directory. Projects and their corresponding design examples are:
The TDSCDMA_BER project demonstrates BER and BLER performance.

• BER and BLER performance of a 12.2k uplink channel with AWGN: TDSCDMA_12_2_UL_AWGN.dsn
• BER and BLER performance of a 12.2k uplink reference fading channel with joint detection receiver: TDSCDMA_12_2_UL_Fading_JD.dsn
• BER and BLER performance of a 12.2k downlink fading channel with joint detection receiver: TDSCDMA_12_2_DL_Fading_JD.dsn

The TD-SCDMA_LinkTest project demonstrates the characteristics of ADS and instrument links.

• Base station signal generated using ADS-ESGc link measured by VSA89600: TDSCDMA_DL_Link.dsn.
• User equipment signal generated using ADS-ESGc link measured by VSA89600: TDSCDMA_UL_Link.dsn.

The TDSCDMA_PA_Test project includes these design examples.

• Characterization of peak average power ratio versus probability: TDSCDMA_DL_CCDF.dsn.
• Instant and average power versus time measurements: TDSCDMA_UL_Power_vs_Time.dsn.
• CCDF and spectrum of multi-carrier signal measurements: TDSCDMA_MC_Test.dsn.

The TDSCDMA_Rx project demonstrates user equipment and base station characteristics.

• BTS reference sensitivity level: TDSCDMA_UL_Sensitivity.dsn.
• UE adjacent channel selectivity: TDSCDMA_DL_AdjacentChannel.dsn.

The TDSCDMA_SignalSource project demonstrates the special transient characteristics of TD-SCDMA signals from time and frequency domains.

• Uplink signal characteristics: TDSCDMA_UL_Spectrum.dsn.
• Downlink signal characteristics: TDSCDMA_DL_ACLR.dsn.

The TDSCDMA_Tx project demonstrates user equipment and base station characteristics.

• Base station error vector magnitude: TDSCDMA_DL_EVM.dsn.
• User equipment code domain power: TDSCDMA_UL_CDP.dsn.