TD-SCDMA Signal Source Designs

Introduction

The TDSCDMA_SignalSource project demonstrates the special transient characteristics of TD-SCDMA signals from time and frequency domains, as well as rate matching calculation. Design examples in this project are described in the following sections:

• Uplink signal characteristics: TDSCDMA_UL_Spectrum.dsn.
• Downlink signal characteristics: TDSCDMA_DL_ACLR.dsn.
• Rate matching calculator demonstration: TDSCDMA_RM_Cal_Demo.dsn

Uplink Signal Characteristics

TDSCDMA_UL_Spectrum.dsn

Description

This design demonstrates user equipment out-of-band emissions; these are unwanted emissions immediately outside the nominal channel that result from the modulation process and non-linearity in the transmitter but excluding spurious emissions. This out-of-band emission limit is specified in terms of a spectrum emission mask and adjacent channel power.
The spectrum emission mask of the user equipment applies to carrier frequencies that are between 0.8 and 4.0 MHz. The out-of-channel emission is specified relative to the user equipment output power measured in a 1.28 MHz bandwidth. The power of any user equipment emission cannot exceed the levels specified in Spectrum Emission Mask Requirements.

Spectrum Emission Mask Requirements

f in MHz†	Minimum Requirements	Measurement Bandwidth
0.8	-35 dBc	30 kHz ††
0.8 - 1.8		30 kHz ††
1.8 - 2.4		30 kHz ††
2.4 - 4.0	-49 dBc	1 MHz †††

† f is the separation between the carrier frequency and the center of the measuring filter.
†† The first and last measurement positions with a 30 kHz filter at !dgtdscdma-7-1-05.gif!f equals 0.815 and 2.385 MHz.
††† The first and last measurement positions with a 1 MHz filter at !dgtdscdma-7-1-06.gif!f equals 2.9 and 3.5 MHz.
The lower limit must be -55dBm/1.28MHz or the minimum requirement presented in this table, whichever is higher.

The top-level schematic for this design is shown in TDSCDMA_UL_Spectrum Schematic.

• TDSCDMA_UL_RF generates a 12.2 kbps uplink RF signal source that includes one DPCH.
• The SpectrumMeasure subnetwork, SpectrumMeasure Subnetwork Schematic, measures the out-of-band emission spectrum and the average power measured in a 1.28 MHz bandwidth centered at the carrier frequency.
  

  TDSCDMA_UL_Spectrum Schematic

  

  SpectrumMeasure Subnetwork Schematic

Simulation Results

Simulation results displayed in the TDSCDMA_UL_Spectrum.dds data display window are shown in Simulation Results.

Simulation Results

Benchmark

• Hardware Platform: Pentium III 800 MHz, 512 MB memory
• Software Platform: Windows 2000, ADS 2002
• Simulation Time: approximately 1 hour

References

1. 3GPP Technical Specification TS 25.102 V4.2.0 "3rd Generation Partnership Project; Technical Specification Group Radio Access Networks; UTRA(UE) TDD; Radio Transmission and Reception (Release 4)" 2000-12.

Adjacent Channel Power Leakage Ratio

TDSCDMA_DL_ACLR.dsn

Features

• ACLR measurements for TD-SCDMA downlink
• 12.2 kbps downlink reference measurement channel
• Roll-off α = 0.22 root raised-cosine filter

Description

This example measures ACLR for TD-SCDMA downlink.
The schematic for this design is shown in TDSCDMA_DL_ACLR Schematic. TDSCDMA_DL_RF generates the 12.2 kbps downlink reference channel for the measurement. The SpectrumMeasure subnetwork implements average power measurement through a root raised-cosine filter. By offsetting the center frequency of the root raised-cosine filter, power leakage on the adjacent channel is measured.

TDSCDMA_DL_ACLR Schematic

Simulation Results

Simulation results displayed in the TDSCDMA_DL_ACLR.dds data display window are shown in ACLR Measurements for TD-SCDMA Downlink.

ACLR Measurements for TD-SCDMA Downlink

Benchmark

• Hardware Platform: Pentium II 400MHz, 523MB memory
• Software Platform: Windows NT Workstation 4.0, ADS 2002
• Simulation Time: approximately 20 minutes

References

1. .3GPP TS 25.105, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; UTRA(BS) TDD; Radio transmission and Reception (Release 4), version 4.3.0, Dec., 2001.

Rate Match Calculator

TDSCDMA_RM_Cal_Demo.dsn

Description

This design demonstrates the use of TDSCDMA_RM_Cal rate matching calculator model. The puncture limit and rate match attributes are specified by users when they configure TDSCDMA Design Library models related to rate matching.
In TDSCDMA specifications, frame sizes before and after rate matching are supplied for reference measurement channels only. TDSCDMA_RM_Cal calculates the puncture limit and rate match attributes from the given frame sizes.
The schematic for this design is shown in TDSCDMA_RM_Cal_Demo Schematic.

TDSCDMA_RM_Cal_Demo Schematic

Simulation Results

Simulation results displayed in TDSCDMA_RM_Cal_Demo.dds are shown in Puncture Limit and Rate Match for each Transport Channel.

Puncture Limit and Rate Match for each Transport Channel

Benchmark

• Hardware Platform: Pentium IV 2.26 GHz, 512 MB memory
• Software Platform: Windows 2000, ADS 2003C
• Simulation Time: 4 seconds

References

1. 3GPP Technical Specification TS 25.222 V4.4.0, Multiplexing and channel coding (TDD) Release 4.