TD-SCDMA Transmitter Designs

Introduction

The TDSCDMA_Tx project demonstrates user equipment and base station characteristics. Design examples in this project are described in the following sections:

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

Base Station Error Vector Magnitude

TDSCDMA_DL_EVM.dsn

Description

This design demonstrates the base station error vector magnitude measurement to determine the difference between the reference waveform and the measured waveform. This difference is called the error vector. Both waveforms pass through a matched root raised-cosine filter with a bandwidth corresponding to the considered chip rate and roll-off a =0.22. Both waveforms are then further modified by selecting the frequency, absolute phase, absolute amplitude and chip clock timing so as to minimize the error vector. The EVM result is defined as the square root of the ratio of the mean error vector power to the mean reference power expressed as a percentage. The measurement interval is one time slot. The error vector magnitude (EVM) cannot exceed 12.5%. The requirement is valid over the total power dynamic range as specified in subclause 6.4.3 of TS 25.105.
The top-level schematic for this design is shown in TDSCDMA_DL_EVM.dsn schematic.

• TDSCDMA_DL_RF is used to generate a 12.2 kbps uplink RF signal.
• TDSCDMA_EVM is used to measure the EVM value of the RF signal. The algorithm is the same as that of VSA89600.
  

  TDSCDMA_DL_EVM.dsn schematic

Simulation Results

Simulation results are shown in TDSCDMA_DL_EVM.dsn Simulation Results.

TDSCDMA_DL_EVM.dsn Simulation Results

Benchmark

• Hardware Platform: Pentium II 400 MHz, 512 MB memory
• Software Platform: Windows NT 4.0, ADS 2003A
• Simulation Time: 1 minute

References

1. 3GPP Technical Specification TS 25.142 V4.5.0 "3rd Generation Partnership Project; Technical Specification Group Radio Access Networks; Base station Conformance (TDD) (Release 4)" June, 2002.

User Equipment Code Domain Power

TDSCDMA_UL_CDP.dsn

Description

This design demonstrates the code domain power measurement of user equipment. Code domain power is the part of the mean power which correlates with a particular (OVSF) code channel. The sum of all powers in the code domain equals the mean power in a bandwidth of (1+ a) times the chip rate of the radio access mode.
The top-level schematic for this design is shown in TDSCDMA_UL_Link.dsn Schematic.

• TDSCDMA_DL_RF is used to generate an uplink RF signal.
• VSA_89600_1_Sink is used to start the VSA89600 software to measure the RF signal.
• ESG_E4438C_Sink is used to send I, Q data to ESG.
  

  TDSCDMA_UL_Link.dsn Schematic

Simulation Results

Simulation results are displayed in a VSA89600 window are shown in TDSCDMA_UL_Link.dsn Simulation Results.

TDSCDMA_UL_Link.dsn Simulation Results

Benchmark

• Hardware Platform: Pentium II 400 MHz, 512 MB memory
• Software Platform: Windows NT4.0, ADS 2002C, VSA89600 4.00x2_BETA
• Simulation Time: 1 minute

References

1. 3GPP Technical Specification TS 25.142 V4.5.0 "3rd Generation Partnership Project; Technical Specification Group Radio Access Networks; Base station Conformance (TDD) (Release 4)" June, 2002.