3GPP FDD Base Station Receiver Test

3GPPFDD_BS_RX is the test bench for 3GPP FDD base station receiver testing. The test bench provides a way for users to connect to an RF circuit device under test and determine its performance using pre-defined test bench measurements. This test bench provides signal measurements for reference sensitivity level, dynamic range, adjacent channel selectivity, and blocking and intermodulation characteristics.

The signal and the measurements are designed according to 3GPP Technical Specifications TS 25.104 and TS 25.141. Versions supported are 2000-03, 2000-12, and 2002-03.

This 3GPP FDD signal model is compatible with Agilent E4438C ESG Vector Signal Generator, Option 400 (3GPP W-CDMA Firmware Option for the E4438C ESG Vector Signal Generator). Details regarding Agilent E4438C ESG are included at the website http://www.agilent.com/find/esg.

This test bench includes a TX DSP section, an RF modulator, RF output source resistance, an RF DUT connection, RF receivers, and DSP measurement blocks as illustrated in the following figure. The generated test signal is sent to the DUT.

Receiver Wireless Test Bench Block Diagram

The 3GPPFDD_BS_RX test bench uses the uplink 12.2kbps reference measurement channel. One 12.2kbps DTCH (dedicated transport channel) and one 2.4 kbps DCCH (dedicated control channel) are multiplexed into one 60 kbps DPDCH (dedicated physical data channel). The 60kbps DPDCH and 15kbps DPCCH (dedicated physical control channel) are I/Q multiplexed into one data stream using different spread factors (64 for DPDCH, 256 for DPCCH), then scrambled with the specified scrambling code. The amplitude ratio of DPCCH/DPDCH is 0.7333 according to the TS25.104 Annex A. All measurements provide BER results for DCCH and DTCH.

Test Bench Basics

A template is provided for this test bench.

3GPPFDD Base Station Receiver Test Bench

To access the template:

1. In an Analog/RF schematic window select Insert > Template.
2. In the Insert > Template dialog box, choose 3GPPFDD_BS_RX_test, click OK; click left to place the template in the schematic window.

An example design using this template is available; from the ADS Main window click File > Example Project > WCDMA3G_RF_Verification_prj > 3GPPFDD_BS_RX_test .dsn.

The basics for using the test bench are:

• Connect to an RF DUT that is suitable for this test bench.
• CE_TimeStep, FSource, SourcePower, and FMeasurement parameter default values are typically accepted; if not, set values based on your requirements.
• Activate/deactivate measurement(s) based on your requirements.
• Run the simulation and view Data Display page(s) for your measurement(s).

For details, refer to Test Bench Details.

Test Bench Details

The following sections provide details for setting up a test bench, setting measurement parameters for more control of the test bench, simulation measurement displays, and baseline performance.

Open and use the template:

1. In an Analog/RF schematic window select Insert > Template.
2. In the Insert > Template dialog box, choose 3GPPFDD_BS_RX_test , click OK ; click left to place the template in the schematic window.

Test bench setup is detailed here.

1. Replace the DUT (Amplifier2 is provided with this template) with an RF DUT that is suitable for this test bench.
   For general information regarding using certain types of DUTs, see Appendix A, RF DUT Limitations.
2. Set the Required Parameters .

   Note Refer to 3GPPFDD_BS_RX for a complete list of parameters for this test bench.

   Generally, default values can be accepted; otherwise, values can be changed by the user as needed.

   • Set CE_TimeStep.
     Cosimulation occurs between the test bench (using Agilent ADS Ptolemy Data Flow simulation technology) and the DUT (using Circuit Envelope simulation technology). Each technology requires its own simulation time step with time-step coordination occurring in the interface between the technologies.
     CE_TimeStep defines the Circuit Envelope simulation time step to be used with this DUT. The CE_TimeStep must be set to a value equal to or a submultiple of (less than) WTB_TimeStep; otherwise, simulation will stop and an error message will be displayed.
     The CE_TimeStep value is exported to the Choosing Analyses window in the Circuit Envelope Time Step field when the user clicks OK in the Wireless Test Bench Setup window.
     Note that WTB_TimeStep is not user-settable. Its value is derived from other test bench parameter values; with default settings WTB_TimeStep=1/(3.84e6 × 8) sec. The value is displayed in the Data Display pages as TimeStep.

     WTB_TimeStep = 1/(ChipRate × SamplesPerChip)

     where

     ChipRate is the non-settable value (3.84 MHz)
     SamplesPerChip is the number of waveform sampling points during pulse forming.

   • Set FSource, SourcePower, and FMeasurement.
     • FSource defines the RF frequency for the signal input to the RF DUT.
     • SourcePower defines the power level for FSource. SourcePower is defined as the average power during the non-idle time of the signal.
     • FMeasurement defines the RF frequency output from the DUT to be measured.
   • MeasType specifies the type of measurement.
     Pre-defined measurement settings (according to 3GPP specifications) are provided for signal power, AWGN interference, CW interference, and modulated interference.
3. Activate/deactivate ( YES / NO ) test bench measurements (refer to 3GPPFDD_BS_RX ). At least one measurement must be enabled.
4. More control of the test bench can be achieved by setting Basic Parameters , Signal Parameters , and parameters for each activated measurement. For details refer to Parameter Settings.
5. The RF modulator (shown in the block diagram in Receiver Wireless Test Bench Block Diagram) uses FSource, SourcePower ( Required Parameters ), MirrorSourceSpectrum ( Basic Parameters) , GainImbalance, PhaseImbalance, I OriginOffset, Q OriginOffset, and IQ Rotation ( Signal Parameters ).
   The RF output resistance uses SourceR, SourceTemp, and EnableSourceNoise ( Basic Parameters ). The RF output signal source has a 50-ohm (default) output resistance defined by SourceR.
   RF output (and input to the RF DUT) is at the frequency specified (FSource), with the specified source resistance (SourceR) and with power (SourcePower) delivered into a matched load of resistance SourceR. The RF signal has additive Gaussian noise power set by resistor temperature (SourceTemp) (when EnableSourceNoise=YES).
   Note that the Meas_in point of the test bench provides a resistive load to the RF DUT set by the MeasR value (50-ohm default) ( Basic Parameters ).
   The Meas signal contains linear and nonlinear signal distortions and time delays associated with the RF DUT input to output characteristics.
   The TX DSP block (shown in the block diagram in Receiver Wireless Test Bench Block Diagram) uses other Signal Parameters.
6. More control of Circuit Envelope analysis can be achieved by setting Envelope controller parameters. These settings include Enable Fast Cosim, which may speed the RF DUT simulation more than 10×. Setting these simulation options is described in Setting Fast Cosimulation Parameters and Setting Circuit Envelope Analysis Parameters in the Wireless Test Bench Simulation documentation.
7. To run a simulation, choose Simulation > Run in the Analog Design Environment main window.
   For details, refer to R unning a Simulation in the Wireless Test Bench Simulation documentation.
8. Simulation results will appear in a Data Display window for each measurement. Simulation Measurement Displays describes results for each measurement available for this test bench.
   For details on Viewing Results refer to the Wireless Test Bench Simulation documentation.