Agilent - 89600 Vector Signal Analysis Software for W-CDMA & HSPA+ Evaluation & Troubleshooting

8/22/2019 Agilent - 89600 Vector Signal Analysis Software for W-CDMA & HSPA+ Evaluation & Troubleshooting

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Agilent

89600 Vector Signal Analysis Software

for W-CDMA and HSPA+

Evaluation and Troubleshooting

Technical Overview and Self-Guided Demonstration

Measure, evaluate, and troubleshoot

W-CDMA and High Speed Packet

Access compatible signals with the

89600 vector signal analysis (VSA)

software and Option B7U.

This software works with a variety of

measurement hardware, including Agilentspectrum and signal analyzers, Infiniium

and Infiniivision scopes, logic analyzers,

ADS simulation software, the 89600S VXI

based VSA systems, and more.


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Introduction......................................................................................................... 3

W-CDMA/HSPA/HSPA+ Modulation Analysis Features .......................... 4

Physical Layer of W-CDMA Signals.................................................................... 5

Setting up the demonstration .................................................................................. 6

Measurement and Troubleshooting Sequence ................................................ 7

W-CDMA Downlink Analysis ................................................................................. 8

Spectrum and Time Domain Measurements.................................................... 9

Measuring occupied bandwidth ............................................................................11

Measuring band power............................................................................................ 12

Basic Digital Demodulation ..................................................................................14

Error Vector Magnitude (EVM) measurements ..................................................18

Additional CDP and CDE measurements ............................................................. 20

Advanced Demodulation.........................................................................................23

Measuring a single channel ................................................................................... 23

W-CDMA uplink analysis ........................................................................................25

HSPA+ analysis ......................................................................................................... 27

Summary .......................................................................................................................30

Ordering Information................................................................................................31

Glossary.........................................................................................................................33

Related Literature......................................................................................................34

Table of Contents


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Gain greater insight into HSPA+ signals with industry-leading HSPA+ analysis

capabilities designed to help you dig deeper into your signal.

The flexible 89600 VSA with Option B7U, which supports W-CDMA(3GPP) and

enhanced HSPA demodulation capabilities, enables descrambling, despreading,

and demodulation of W-CDMA and HSPA+ uplink and downlink signals. This

solution incorporates advanced technology that does not require coherent carriersignals or symbol-clock timing signals. Additionally, the analyzer automatically

identifies all active channels regardless of the symbol rate or spread-code-

length. It includes a built-in root raised-cosine filter with a user-definable alpha

(defines roll-off factor for chip shaping). Signal locking requires only that the

carrier frequency, chip rate, uplink/downlink direction, sync type (CPICH/SCH),

and scramble code be input. The demodulator uses the measured signal, called

I/Q Meas Time, to generate an ideal reference signal, called I/Q Ref Time.

The software uses these signals to allow you to gather more data on signal

problems by providing comparison data, modulation quality data, results, and

error summary data.

Explore signals further with modulation analysis capabilities, including composite

code domain power, composite time and channel specific analysis. Measurementresults may be shown in several trace display formats as well as numeric error

data formats. Flexible display scaling and marker functionality enhance these

measurement capabilities.

Measurement result data includes: time and frequency domain trace data,

code domain power data (composite or layer specific), code domain error data

(composite or layer specific), channel data results, and overall error summary

results.

If you have measurement hardware with two baseband channels, the

89600 VSA software provides IQ baseband measurement capability. You can

also perform measurements on data from a file or the stream interface, i.e. ADS

simulation or The MathWorks Simulink program. This example of versatility can

be seen by the 89600 VSAs compatibility with spectrum and signal analyzers,

Infiniium and Infiniivision scopes and logic analyzers. As you go through this

demo guide, remember that all of the measurements and displays can be made

anywhere from simulation to antenna, from baseband to RF, using the unique

89600 VSA compatibility with a wide range of front end inputs.

Introduction


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These features are applicable to W-CDMA modulation analysis:

Standard presets for

W-CDMA (3GPP) uplink (mobile station or user equipment)

W-CDMA (3GPP) downlink (mobile station)

Variable, user-definable chip rate (3.84 MHz standard preset)

Single code domain layer or composite code-domain power andcode-domain error displays (the composite display shows all code layers

simultaneously). You can normalize code-domain power to display the

code-domain relative to the total signal power in the code domain.

Code domain offsets table which shows time and phase offset of each

active Walsh code channel

Single channel time-domain displays, such as IQ measured, IQ reference,

IQ magnitude/phase error, and error vector traces

Composite time-domain displays, such as IQ measured time, IQ magnitude

or phase error, and error vector time traces

Adjustable filter alpha (default .22)

Mirrored (flipped) frequency spectrums can be used to remove the effects

of high-side mixing

Measurement offset and interval (similar to time gating) used to select

specific data slots for analysis

Flexible active channel identification for code domain power (CDP) and

composite results

Active channel identification may be gated to analyze signals with

Adaptive Modulation Coding (AMC)

Predefined 3GPP Test Models 1 through 4

Variable active channel threshold

Averaging for code domain trace data applied to the numeric error

summary data in the symbol table

Averaging for pre-demodulated spectrum, CDP, and code domain error

trace data results

HSPA modulation and HSPA+ modulation are extensions to the Universal

Mobile Telecommunications System (UMTS) standard published by 3GPP.

These additional Option B7U features are available:

HSDPA and HSUPA uplink and downlink channel modulation analysis

Automatic modulation scheme detection for HS-PDSCH channels using

QPSK, 16QAM, or 64QAM

Manual or automatic control of modulation scheme for despread

HS-PDSCH channels

Automatic modulation scheme detection for E-DPDCH channels using

BPSK, or 4PAM

Predefined Test Model 5 and Test Model 6 setup options (as defined in

Section 6.1.1 of 3GPP TS.25.141 V5.7.0 (2003-06) Rel 5 technical specification). HSPA+ capabilities include 64 QAM analysis for downlink and 16QAM/

4PAM analysis for uplink.

The built-in Help text consists of over 2900 help topics. Additional information

regarding any of the mentioned features above and more can be found in the

Help text.

W-CDMA/HSPA/

HSPA+ Modulation

Analysis Features


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There are two parameters used to specify which segment of the Result Length

data is used for data analysis: Measurement Interval and Measurement Offset.

When these two parameters are changed, the analyzer computes the new trace

data results from the current measurement data (Result Length) and does not

require a new measurement cycle. Figure 1is a representation of a typical

frame structure for a W-CDMA(3GPP)/HSPA signal.

Figure 1. Typical W-CDMA(3GPP)/HSPA Frame Structure.

Result Length: Determines the signal capture length.

This is the data used by the analyzer for demodulation and signal analysis.

When you are making your own measurements, you should ensure that the

result length is long enough to capture the desired data. Result Length is

specified in terms of an integer number of slots or PCGs, as determined by the

specific modulation type. In the case of W-CDMA(3GPP)/HSPA, they are

referred to as Slots. Note:Result Length

may be specified as an integernumber of slots, frames or time. If you choose to specify it in seconds, the

analyzer will automatically increment the time as necessary to obtain an

integer number of slots.

Measurement Interval: Determines the time length of the Result Length data

that is used for computing and displaying the trace data results.

Measurement Offset: Determines the start position of the Measurement

Interval within the Result Length.

Slot: One W-CDMA(3GPP) time slot is equal to 2560 chips (666.7 s at the

default chip rate). One frame is 15 slots (10 ms at the default chip rate).

Physical Layer of

W-CDMA Signals


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Setting up the demonstration

Table 1 describes the minimum hardware required to run the 89600 VSA software.

Table 2describes the 89600 VSA software required to use this demonstration

guide. If you do not already have a copy of the software, you can download a

free trial version atwww.agilent.com/find/89600.

Table 2. Software requirements

Version89600 version 9.00 or higher

(89601A, 89601AN, 89601N12)

Options (89601A, 89601AN only)

-200 Basic vector signal analysis

-300Hardware connectivity

(required only if using measurement hardware)

-B7U

or

-B7N

W-CDMA(3GPP)/HSPA modulation analysis

or

3G modulation analysis bundle

Table 1. System requirements

Operating System MicrosoftWindows XP Professional,

Service Pack 2

Microsoft Windows Vista Business, Enterprise,

or Ultimate

CPU600 MHz Pentium or AMD-K6 > 600 MHz

(> 2 GHz recommended)1 GHz 32-bit (x86) (> 2 GHz recommended)

Empty slots

(desktop)

1 PCI-bus slot

(Two recommended VXI hardware only)

1 PCI-bus slot

(Two recommended VXI hardware only)

Empty slots (laptop) 1 CardBus Type II slot (Integrated FireWire

recommended for VXI hardware only1)

1 CardBus Type II slot (Integrated FireWire

recommended for VXI hardware only1)

RAM 512 MB (1 GB recommended) 1 GB (2 GB recommended)

Video RAM 4 MB (16 MB recommended) 128 MB (512 MB recommended)

Hard disk 512 MB available 512 MB available

Additional drives CD-ROM to load the software; license transfer

requires a 3.5 inch floppy disk drive, network

access, or USB memory stick

CD-ROM to load the software; license transfer

requires a 3.5 inch floppy disk drive, network

access, or USB memory stick

Interface support LAN, GPIB, USB, or FireWire1 interface

(VXI HW only)

LAN, GPIB, USB, or FireWire1 interface

(VXI HW only)

1. For a list of supported IEEE-1394 (FireWire) interfaces, visitwww.agilent.com/find/89600 and search the FAQs for information on

What type of IEEE-1394 interface can I use in my computer to connect to the 89600 S VXI hardware?


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When measuring and troubleshooting digitally modulated systems, it is

tempting to go directly to digital modulation and the measurement tools. It is

usually better to follow a measurement sequence: one that begins with basic

spectrum measurements and continues with vector (combined frequency and

time) measurements, before switching to basic digital modulation analysis, and,

finally, to advanced and/or standard-specific analysis. This is the sequence we

will use in this demo guide. This sequence of measurements is especially usefulbecause it reduces the chance that important signal problems will be missed.

Step 1: Spectrum and time domain measurements

These measurements give the basic parameters of the signal in the frequency

and time domain so that correct demodulation can take place in step 2.

Parameters such as center frequency, bandwidth, symbol timing, power,

and spectral characteristics are investigated.

Step 2: Basic digital demodulation

These measurements evaluate the quality of the constellation. Along with

a display of the constellation, they include static parameters such as EVM,I/Q offset, frequency error, and symbol clock error.

Step 3: Advanced digital demodulation

These measurements are used to investigate the causes of errors uncovered

in the basic modulation parameters, particularly EVM errors. These include

dynamic parameters such as error vector frequency, error vector time, and

selective error analysis.

The 89600 VSA software has the advantage that you can recall saved time

capture recordings and analyze the signal as though you were acquiring data

from hardware. In the following pages, we will recall and analyze WCDMA/

HSPA+ signals available on the 89600 VSA software demo CD.

Measurement and

Troubleshooting

Sequence

Spectrum and time domain measurementsGet basics right, find major problems

Basic digital demodulation

Signal quality numbers, constellation, basic error vector measurement

Advanced digital demodulationFind specific problems and causes

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To begin our first measurements, lets analyze a W-CDMA downlink signal.

Figure 2. Spectrum and main time display of a W-CDMA downlink signal.

Trace A: This trace shows the signals spectrum. It also displays the center

frequency, span, resolution bandwidth, time length, and range of the signal.

Note: Depending on when the trace was auto scaled at different points in the

recording, your Y-scale values may appear to be different than the figure.

However, you should still obtain the same trace data.

Trace B: Displays a block of time-record samples of the signal waveform from

which time, frequency, and modulation domain data is derived.

W-CDMA Downlink

Analysis

Table 3. Recall the signal

Instructions: 89600 VSA software Toolbar menus

Preset the software Click File > Preset > Preset All

Note: Using Preset Allwill cause all saved user state information to be lost. If this

is a concern, save the current state before using Preset All.

ClickFile > Save > Setup

Recall the recording of a W-CDMA

downlink signal

Click File > Recall > Recall Recording

Navigate to the directory and load the signal: (c:\Program Files\Agilent\89600

VSA\Help\Signals\3GPPDown.sdf)

Start the measurement Click the restart button (toolbar, left side)

Auto scale Trace A Right click Trace A

Select Y Auto Scale

Auto scale Trace B Right click Trace B

Select Y Auto ScaleYour display should look similar to Figure 2.


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The first step in the troubleshooting process is to set up the signal measure-

ment parameters. Since this signal is not burst, triggering will not be necessary.

However, other parameters such as the range, scaling, center frequency, span,

and bandwidth measurements are all spectral and time domain measurements

that take place before demodulation. For this demonstration, the center

frequency and span are already set to the appropriate values. Setting theinput range is also not required for a pre-recorded signal. However, this

demonstration guide will set these values as an example to illustrate how to

make spectrum and time domain measurements as a reference.

Spectrum and Time

Domain MeasurementsSpectrum and time domain measurementsGet basics right, find major problems




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Table 4. RF parameters setup


Set center frequency and frequency spanClick MeasSetup > Frequency

Enter 1GHz in the Center text box

Enter 5MHz in the Span text box

Click Close

Set input range Click Input > Range

Enter 0 dBm in the Range: text box

Note: You may notice that the Rangeparameter can be changed to any value and will

not alter the actual range value located at the top right corner of the trace. This is

because the recording was made at a range of 0 dBm, and thus this value cannot be

changed manually.


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It is important to ensure your signal is spectrally clean before you begin

demodulation. The following section will show you how to measure the

occupied bandwidth. But first, we need to change the RBW filter and main time

length so we can view the signal in more detail.

Figure 3. Spectrum and time display.

Table 5. Increasing resolution and time length


Change the RBW filter and increase the frequency

points for better resolution. The Auto frequency

points selection chooses the best resolution for the

given time capture.

Click MeasSetup > ResBW > ResBW Mode > Arbitrary (pull down menu)

Check Auto for the Frequency Points parameter

Click Time (tab) and set Main Time Length to 900 usec

Click Close

Auto scale Trace A and Trace B Right click in Trace A

Click Y Auto Scale

Right click in Trace B

Click Y Auto Scale

Your display should look similar to Figure 3.


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Measuring occupied bandwidth

The Occupied Bandwidth (OBW) measurement, coupled with the OBW

Summary table, can quickly and accurately report many useful results. Follow

the steps in Table 6to display the OBW along with the corresponding table of

results. Trace B in Figure 4 displays several important measurements quickly,

including the occupied bandwidth, band power, and power ratio. This signal has

a nominal bandwidth of 5 MHz to allow for full viewing of the signal, while the

actual bandwidth is measured at approximately 4.4 MHz.

Figure 4. Occupied bandwidth measurement with summary data table.

Table 6. Measuring OBW


Display OBW marker Right click Trace A

Select Show OBW

Activate OBW Summary table Double click the Trace B title (B: Ch1 Main Time)

Select Marker from the Type menu on the left-hand side of the box

Select Obw Summary TrcA from the Data menu on the right-hand side of the box

ClickOK

Pause the measurement to

read the table values

Click the Pause button



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We will not need the OBW measurement from this point forward. Follow the

steps in Table 7to clear the OBW measurement.

Measuring band power

The band power marker feature measures the power of the modulated signal,

or channel power, by integrating over a specified bandwidth in the frequency

domain. Follow the steps in Table 8 to set up band power markers.

Table 7. Clear OBW measurement

Instructions: 89600 VSA software Toolbar menusClear the OBW marker Double click the Trace B title (B: TrcA OBW Summary Data)

Select Channel 1 from the Type menu on the left-hand side of the box that appears

Select Main Time from the Data menu on the right-hand side of the box

Click OK

Right click Trace A

De-select Show OBW

Table 8. Setting up band power marker


Select the band power marker tool Click Markers > Tools > Band Power

(Or, alternatively, you can click the band power marker button on the menu toolbar)

Drop the band power marker

on Trace A

On Trace A, move the mouse to the center frequency of the band to be measured

Click to drop the marker

Expand the band power marker Place the mouse pointer on the vertical band power marker and click and drag/expand

the marker so it includes the entire signal

Note: Adjust the center frequency of the band power marker by clicking and holding on

the dashed center line and dragging it to the right frequency.



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Figure 5. Band power marker display.

The band power should be displayed at the bottom of the window. This is the

total power inside the bandwidth of the band power marker. You can expand or

shrink the width of the marker to measure the power over specific frequencies.

You can control the band power marker more precisely by opening the Markers

Properties window. Click Markers > Calculation to access user-settable text

boxes for setting the center and width of the band power marker.

We will not need the band power marker any further. To turn it off, simply right-

click anywhere in Trace A and de-select Show Band Power. This shortcut can

also be used to toggle the band power marker on/off. You may also want to

return the mouse curser to a pointer. Click the Pointer button in the toolbar.


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Once you have examined your signal and verified that there are no major spec-

tral or time problems, the next step is to demodulate it. You should always view

the signal spectrum first to be sure that the signal is present, and that the cen-

ter frequency, span, and input range are correct before selecting a demodulator.

Follow the steps in Table 9to setup the demodulator.

Basic Digital

DemodulationSpectrum and time domain measurementsGet basics right, find major problems




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Table 9. Demodulation setup


Select the demodulator Click MeasSetup> Demodulator > 3G Cellular > W-CDMA(3GPP)/HSPA

Preset the demodulator parameters

for downlink analysis

Click MeasSetup > Demod Properties > Format (tab) > Preset to Default > Downlink

Click Close

Change display layout to Grid 3x2 Click Display > Layout > Grid 3x2

(Or, alternatively, you can click on the drop down menu near the top of themenu toolbar. Select Grid 3x2 from the available options).

Restart the measurement Click the Restart button

Auto scale Traces A, B and C Right click on Trace A

Select Y Auto Scale

Do the same for Trace BandC.

Pause the measurement to read

the table results

Click the Pause button



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Figure 6. Six trace display of demodulated composite signal.

Under different circumstances, you need to verify that the Chip Rate, Scramble

Code, Scramble Type, and Sync Type parameters are set correctly. However,

since we are making measurements on a pre-recorded signal, the default

settings for these parameters are adequate.

Trace A: Code Domain Power (CDP) trace that shows the power in each channel

for the composite signal.

This trace is an analysis of the distribution of signal power across the set of

Code Channels normalized to the total signal power. The data is shown in a

multi-color format that assigns a unique color to each code layer and related

active Code Channels. This allows you to easily identify and distinguish the

active Code Channels for a given code layer (Spread Code Length). Note: You

can change the channel colors by clicking Display > Appearanceto open the

Display Appearancewindow.

Trace C: Shows the time data results of the IQ measured signal in a vector

constellation format.

The trace data is computed from the first slot in the Measurement Interval after

the Measurement Offset. A typical downlink W-CDMA signal contains many

channels, 16 in this situation. Each channel is QPSK modulated, as seen by

Trace F. This leads to a constellation that looks quite noisy.


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Trace D: Composite error summary table shows the composite error summary

data.

Common error parameters, such as EVM and frequency error (Freq Err), provide

quick indicators that represent the signal quality error summary information for

the composite signal.

Trace E: Shows the symbol table and error summary trace data for the specified

Code Channel and Spread Code length.

The error summary data results are shown in the upper section of the channel

symbol table display.

Trace F: Shows the demodulated constellation time data results for the

measured input signal, sampled at the chip times, for the specified Code

Channel and code layer (Spread Code Length). Specifically, it is Channel 0 on

the Spread Code Length 256 (S256(0)).

Due to size constraints, both Trace D and Trace E do not show all of the table

results in Figure 6. Figure 7shows all of the table results.

Figure 7. Channel symbol table and composite error summary table.


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Below is a list of table results found in the composite error summary table:

Composite EVM(EVM):The error vector magnitude for the composite signal,

including all spread code lengths and code channels. The table shows RMS

percentage EVM, the peak (largest) percentage EVM, and the chip number with

the peak percentage EVM. This parameter is computed at the chip rate.

Composite magnitude error(Mag Err): The difference in amplitude between the

I/Q measured signal and the I/Q reference signal for the composite signal. The

display shows these magnitude error values: the RMS percentage magnitude

error, the peak percentage magnitude error, and the chip number with the peak

percentage magnitude error.

Composite phase error(Phase Err): The difference, in phase, between the I/Q

reference signal and the I/Q measured signal for composite signal, including all

spread code lengths and code channels. The display shows these phase error

values (in degrees): the RMS phase error, the peak phase error, and the chip

number with the peak phase error.

Composite IQ offset(IQ Offset): Also known as I/Q origin offset, indicates the

magnitude of the carrier feed-through signal. When there is no carrier feed-

through, IQ offset is zero (infinity dB).

Composite frequency error(Freq Err): Shows the composite signal carrier

frequency error relative to the analyzers center frequency. This parameter is

displayed in Hertz and is the amount of frequency shift, from the analyzers

center frequency, that the analyzer must perform to achieve carrier lock.

Composite rho (Rho): The normalized correlation coefficient between the

measured and ideal reference signals and is designated as the waveform

quality factor. The maximum value of rho is 1.0, which means the measured

signal and reference signal are identical.

Composite slot(Slot): Identifies the time slot used for the composite measure-

ments. The composite slot ignores the measurement offset.

Composite T trigger(T trigger): Shows the amount of time, in chips, from the

trigger to the start of the frame. If you select a trigger that starts the measure-

ment at the beginning of a PCG, the T trigger value is zero chips. The T trigger

value is displayed only for triggered measurements.

Composite peak active CDE(Peak Active CDE): The largest active code channel

code domain error (in dB). This is the largest measured CDE of all active code

channels in the composite signal.

Composite peak CDE(Peak CDE): The largest measured code channel code

domain error. This is the largest measured CDE for allcode channels (activeand inactive) in the base code layer (the code layer with the smallest symbol

rate) in the composite signal.

If averaging is on, averaging is applied to most numeric error data in the error

summary data, with the following exceptions. The peak data values, such as

peak EVM, peak magnitude, and peak phase error, are averaged only for the

continuous peak hold averaging type.


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Error Vector Magnitude (EVM) measurements

Two useful displays for evaluating the behavior of the composite signal are

error vector time and error vector spectrum. Each trace also has its own set of

markers. You can quickly set marker locations, manually re-position them,

locate peak values, and couple the markers between traces to show common

values. Follow the steps shown in Table 10to setup these measurements.

Table 10. EVM and markers setup


Change Trace A to show error vector time Double click on Trace A title (A: Ch1 Composite CDP)

Under the Type: column, select Channel 1 Comp

Under the Data: column, select Error Vector Time

Click OK

Change Trace B to show error vector

spectrum

Double click on Trace B title (B: Ch1 Spectrum)

Under the Type: column, select Channel 1 Comp

Under the Data: column, select Error Vector Spec

Click OK

Change the display layout to Stacked 2 Select Stacked 2 from the layout drop down menu on the menu toolbar

Enable markers in both traces Right click on Trace A and select Show Marker

Do the same for Trace B

Find the peak EVM value in both traces Right click on Trace A and select Peak

Do the same forTrace B



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Figure 8. Error vector spectrum and error vector time displays.

Trace A: Depending on when you paused your recording, you may have a

different peak location in Trace A. This trace displays error vector time, which

represents the EVM behavior over time, where chips represent time. You can

view EVM time data as EVM, error vector phase, the I component, or the Q

component. This feature is used to find impulsive errors such as a transient

overload event or a spiking clock circuit. It is also useful for finding low

frequency errors caused by close-in phase noise.

Trace B: This trace shows the error vector spectrum, which is the FFT of the

EVM time trace and shows the frequency content of the EVM. Trace B shows a

high error signal at 1 GHz (Trace B marker value at bottom of display). This is

the signal carrier frequency and represents carrier feed through. Carrier feed

through is not the only signal the EVM spectrum trace will show. Any spurious

signal will show up as a discrete peak in the composite error vector spectrum

trace.

Markers are a great tool for troubleshooting, and can be coupled between

traces for even more convenient troubleshooting. You will see an example of

this later in this demonstration.


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Additional CDP and CDE measurements

CDP (code domain power) and CDE (code domain error) measure the power and

error of the signal by code channel. They provide more detail on the signal

behavior and modulation quality than the composite EVM or rho. We will

continue to use markers, to determine the color assigned to each code layer.

Follow the steps shown in Table 11to set up these measurements.

Figure 9. Composite CDP and CDE measurements.

Table 11. Setup of CDP and CDE.


Change Trace A to show composite CDP Double click on Trace A title (A: Ch1 Composite Err Vect Time)

Under the Type: column, select Channel 1 CDP

Under the Data: column, select CDP Composite

Click OK

Change Trace B to show composite CDE Double click on Trace B title (B: Ch1 Composite Err Vect Spectrum)

Under the Type: column, select Channel 1 CDP

Under the Data: column, select CDE Composite

Click OK

Auto scale TracesA and B Right click on Trace A

Select Y Auto Scale

Do the same for Trace B



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For W-CDMA/HSPA modulation, the CDP and CDE displays assign a unique

color to each code layer and related active code-channels for a given code layer

(Spread-Code-Length). If you place the marker on each color, the marker read-

out at the bottom of the display will show the code layer and code channel for

that color. Follow the steps in Table 12.

Table 12. Marker coupling setup


Change the code order in TraceB to Hadamard Select Trace B by clicking anywhere in the trace

Click Trace > Digital Demod

Under the Code Order (drop down menu), selectHadamard

Click Close

Couple markers. Now all information displayed will

be for the same point in each trace. As you move

the marker in a selected trace, it will track in all

the other grids.

Click Markers > Couple Markers

Select the orange colored channel Click on Trace A

Drag the marker to the top of the right-most orange colored channel. Note:

Depending on the size of your window, you may not be able to see this chan-

nel. Size your window appropriately until the orange channels can be seen

(left side).

Your display should like similar to Figure 10.


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Figure 10. Composite signal traces with markers.

Trace A: The bit-reversed generation of code channels displays related code

channels adjacent to each other. The marker is on an orange colored channel

and shows the following values (bottom of screen):

Symbol rate: 15 ksym/s

Spread code length: 256

Code number: 16

The asterisk (*) indicates the marker is positioned on an active channel

Trace B: This trace shows the code channels in the Hadamard order. Note that

the marker automatically points to all of the other parts of the code channel as

it is spread by the Hadamard ordering, as seen by the small triangle markers.

Note: if you do not see the multiple triangle markers, you may need to use your

right/left arrow keys to exactly position the marker.

From this point forward, we will not need markers on Trace B. Right click on

Trace B and de-select Show Marker.


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Measuring a single channel

The instructions in Table 13show how to use markers and the Copy Marker to

Despread Chan function to quickly view a single channel in your W-CDMA/

HSPA signal. You can also go directly to the desired channel by entering its

parameters in the Demod Properties menu.

Advanced

DemodulationSpectrum and time domain measurementsGet basics right, find major problems




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Table 13. Markers with despread channel feature


Change the display layout to Grid 2x2 Select Grid 2x2 from the layout drop down menu on the menu toolbar

Change Trace B to display the Error Vector

Time trace for the selected channel

Double click Trace B title (B: Ch 1 Composite CDE)

Under the Type: column, select Channel 1 Chan

Under the Data: column, select Error Vector Time

Click OK

Auto scale Trace B Right click on Trace B and select Y Auto Scale

Change Trace C to display the vector dia-gram for the selected channel

Double click Trace C title (C: Composite Meas Time)Under the Type: column, select Channel 1 Chan

Under the Data: column, select IQ Meas Time

Click OK

Change Trace D to display the symbol

table for the selected channel

Double click on Trace D title (D: Ch1 Composite Error Summary)

Under the Type: column, select Channel 1 Chan

Under the Data: column, select Syms/Errs

Click OK

Select one of the blue colored channels Click on Trace A and position the marker so it is selecting one of the blue colored

traces which are any of the visible peaks (your color scheme maybe different)

Select the marked channel for more

detailed analysis

Right click on Trace A and select Copy Mkr to Despread Chan



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Figure 11. Single channel measurement.

Copy Marker to Despread Chan: This feature sets the despread channel

parameters including: spread code length, code channel, and IQ branch. These

parameters enable the following measurements: channel error vector, channel

IQ measurement time, channel IQ reference time, channel mag error, channel

phase error, and channel systems/error trace data.

Trace B: This trace shows how the EVM changes with time (where symbols

represent time) for a single code-channel within a specified code layer (Spread-

Code-Length/Symbol Rate).

The error vector time trace is made up of complex time-domain data. Each point

in the trace has two components: I and Q. To make sense of the data, you must

select an appropriate trace data format (Trace > Format > Format: drop down

list). The selections in this list allow you to set what trace data format you want

the trace to plot.

Trace C: This shows the Channel IQ Meas trace, which is the demodulated

time data, re-sampled at the chip times, for the specified code-channel and

code layer (Spread-Code-Length). The data is corrected for IQ origin offset, burst

amplitude droop compensation, filtering, and system gain normalization. This

particular channel (as well as the others) shows a modulation scheme of QPSK,

as shown by the 2x2 constellation.

Trace D: This symbol table provides both error summary information and demodu-

lated bits for the selected channel. For W-CDMA downlink signals, the symbol

table also shows information about the demodulated channel, such as the num-

ber of pilot bits detected in the DPCH channel, the tDPCH timing value for the

DPCH channel, and the first slot used in the measurement. For additional details

regarding the symbol table, see the online Help About the Channel Symbol Table

(W-CDMA). For additional details about error information in the symbol table,

see online Help About Channel Error Summary Data (W-CDMA).


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W-CDMA uplink analysis

The 89600 VSA software also supports uplink analysis. Pre-demodulation

measurements are similar to that of downlink, so we will not repeat those

measurements. However, a demodulated uplink signal has significant differences

in its composite displays. Follow the steps in Table 14to set up a W-CDMA

uplink demodulation.

Table 14. Uplink demodulation



Recall the recording of a W-CDMA

uplink signal


Navigate to the directory and load the signal: (c:\Program Files\Agilent\89600 VSA\

Help\Signals\3GPPUp.sdf)

Setup the demodulator Click MeasSetup > Demodulator > 3G Cellular > W-CDMA(3GPP)/HSPA

Set the demodulator for uplink analysis Click MeasSetup > Demod Properties > Format (tab) > Preset to Default > Uplink

Click Close

Change the display layout to a Grid 2x2 Click on the layout drop down menu on the menu toolbar and select Grid 3x2

Restart the measurement Click the Restart button

Place a marker on an uplink channel

and copy the marker to despread

channel

Right click on Trace A

Select Show Marker

Click on the upper left green box

Right click on Trace A

Select Copy Mkr to Despread Chan



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Figure 12. W-CDMA uplink demodulation.

By default, TracesA, C and D show you composite displays of your signal.

Composite displays show you the results of all channels and layers in your

signal, and include data for both I and Q.

Trace A: Notice that Trace A, Ch1 Composite CDP display, looks different than

it did for the W-CDMA downlink signal. This is because uplink signals separate

channels for I, data channels, and Q, control channels. The Ch1 Composite CDPdisplay shows the I channels above the x-axis and the Q channels below the

x-axis. In this situation, two channels are being transmitted on I and one

channel on Q.

Trace C: You may have also noticed that the constellation diagram in Trace C

looks significantly different than the downlink signal. In this situation, each

channel has a modulation scheme of BPSK, as seen in Trace F. Since there are

only three channels being analyzed, versus the 16 in the downlink recording,

the constellation will look more defined.

Trace F: This trace is similar to TraceC in Figure 11, however, this particular

channel has a modulation scheme of BPSK, as seen by the two constellation

points.


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HSPA+ analysis

The newest standard for HSPA signals is Enhanced HSPA (HSPA+). HSPA

features apply to HSPA+ signals. The 89600 VSA software has a downlink

HSPA+ recording that can be demodulated using the Enable HSPA Analysis

feature. Table 15sets the demodulation parameters such that it is measuring

Code Channel 6 in Spread Code Length 16. This specific channels modulation

scheme is automatically detected as 64 QAM.

Table 15. Begin downlink HSPA+ demodulation setup



Recall the recording of an HSPA downlink

signal


Navigate to the directory and load the signal: (c:\Program Files\Agilent\89600 VSA\

Help\Signals\3GPPDownHSPA+.sdf)

Setup the demodulator Click MeasSetup > Demodulator > 3G Cellular > W-CDMA(3GPP)/HSPA

Set up the demodulation parameters Click MeasSetup > Demod Properties > Format (tab)

Click Preset to Default> DownlinkGo to Channel/Layer (tab)

Change the Spread Code Length (drop down menu)to 16 (240.0ksym/s)

Change the Code Channel to 6

Click Close

Change the display layout to a Grid 3x2 In the toolbar click on the layout drop down menu and select Grid 3x2

Start the measurement Click the restart button (toolbar, left side)

Auto scale TracesA, B, C and F Right click on Trace A

Select Y Auto Scale

Do the same for TracesB, CandF



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Figure 13. Demodulated downlink HSPA+ signal without HSPA analysis enabled.

Notice TracesE and F show an error labeled as INACTIVE CHAN. This error

states that the specified CDMA channel, S16(6), is inactive. You can also note

that the constellation diagram in Trace F is consistently different than a

standard 64 QAM constellation. The high EVM values listed in Traces D and E

obviously indicate a problem with the demodulation. Follow the steps in Table

16 to enable HSPA analysis.

Table 16. Downlink HSPA+ with HSPA analysis enabled


Set up the demodulation parameters Click MeasSetup > Demod Properties

Go to Format (tab)

Check Enable HSPA analysis

Click Close



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Figure 14. Demodulated downlink HSPA+ signal with HSPA analysis enabled.

You should notice significant changes in all of the demodulation traces. Before

HSPA analysis was enabled, some of the channels were not being detected.

EVM results in TracesD and E should be significantly better and show values

< 1% rms. The constellation in Trace F is more stable with all of the constella-

tion points falling close to the ideal constellation targets, represented as the

small gray circles.


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The 89600 VSA software with Option B7U for W-CDMA/HSPA modulation

analysis, along with the standard 89600 VSA features, such as the occupied

bandwidth and band power measurements, provide all of the necessary tools to

measure and troubleshoot W-CDMA and HSPA downlink and uplink signals as

well as HSPA+ signals.

With this solution, you can gain greater insight by showing as many as sixtraces simultaneously, with complete control over the content of those traces.

Additionally, you can gather more data on signal problems with the versatile

demodulator that can measure the entire composite signal, or utilize the Copy

Marker to Despread Channel feature and measure specific channels, allowing

you to observe and characterize any aspect of the signal. The analysis of HSPA

channels lets you reach deeper into your signals and identify and track down

errors.

The 89600 VSA software supports a multitude of platforms, including Agilent

spectrum and signal analyzers, Infiniium and Infiniivision oscilloscopes, logic

analyzers, and ADS simulation software. From baseband to RF, simulation to

antenna, it provides the greatest versatility for all measurements. For further

detailed information on any of the features mentioned in this demonstrationguide, check the built-in Help text.

Summary


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89601A Vector signal analysis software

Note:For initial purchases including Option 200, a discount item, D12, will be

applied to provide a discount corresponding to 1 year of software update service.

Options Option 200 required; Option 012 or 024 required at initial order.

89601A-200 Basic vector signal analysis software

89601A-012 12 months bundled software update subscription service

(qualifies for 12 month discount)

89601A-024 24 months bundled software update subscription service


89601A-300 Hardware connectivity

89601A-AYA Flexible modulation analysis

89601A-B7N 3G modulation analysis bundle

89601A-B7T cdma2000/1xEV-DV modulation analysis

89601A-B7U W-CDMA/HSPA modulation analysis

89601A-B7W 1xEV-DO modulation analysis

89601A-B7X TD-SCDMA modulation analysis

89601A-B7R WLAN modulation analysis

89601A-B7S IEEE 802.16-2004 OFDM modulation analysis

89601A-B7Y IEEE 802.16 OFDMA modulation analysis

89601A-B7Z IEEE 802.11n modulation analysis

89601A-BHA TETRA modulation analysis and test

89601A-BHB MB-OFDM ultra-wideband modulation analysis

89601A-BHC RFID modulation analysis

89601A-BHD LTE modulation analysis

89601A-105 Dynamic link to EEsof/ADS

89601A-106 Dynamic link to The MathWorks Simulink Model-Based Design

Ordering Information


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89601AN Vector signal analysis software (floating license for 1 server) Note:For initial purchases including Option 200, a discount item, D12, will be

applied to provide a discount corresponding to 1 year of software update service.

Options Note:Multiple quantities of one option may be ordered per each server.Option 200 required. Every user must have Option 200, so the maximum quantity of

any option may not exceed the quantity of Option 200. For multiple servers, order

additional 89601AN. Either Option 012 or 024 required at initial order.

89601AN-012 12 months bundled software update subscription service


89601AN-024 24 months bundled software update subscription service


89601AN-200 Basic vector signal analysis software

89601AN-300 Hardware connectivity89601AN-AYA Flexible modulation analysis

89601AN-B7N 3G modulation analysis bundle

89601AN-B7T cdma2000/1xEV-DV modulation analysis

89601AN-B7U W-CDMA/HSPA modulation analysis

89601AN-B7W 1xEV-DO modulation analysis

89601AN-B7X TD-SCDMA modulation analysis

89601AN-B7R WLAN modulation analysis

89601AN-B7S IEEE 802.16-2004 OFDM modulation analysis

89601AN-B7Y IEEE 802.16 OFDMA modulation analysis89601AN-B7Z IEEE 802.11n MIMO modulation analysis

89601AN-BHA TEDS modulation analysis and test

89601AN-BHB MB-OFDM ultra-wideband modulation analysis

89601AN-BHC RFID modulation analysis

89601AN-BHD LTE modulation analysis

89601AN-105 Dynamic link to EEsof/ADS

89601AN-106 Dynamic link to The MathWorks Simulink Model-Based Design

Ordering Information(Continued...)


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3GPP Third Generation Partnership Project

3G Third Generation

ADS Advanced Design System

(Agilent EEsof design simulation software)

AMC Adaptive Modulation Coding

BPSK Binary Phase Shift Keying

CDE Code Domain Error

CDP Code Domain Power

CPICH Common Pilot Channel

DPCH Dedicated Physical Channel

E-DPDCH Enhanced Dedicated Physical Data Channel

EVM Error Vector Magnitude

HSDPA High Speed Downlink Packet Access

HSPA High Speed Packet Access

HSPA+ Enhanced High Speed Packet Access

HS-PDSCH High Speed Physical Downlink Shared Channel

HSUPA High Speed Uplink Packet Access

I/Q In-phase/Quadrature

OBW Occupied Bandwidth

QAM Quadrature Amplitude Modulation

QPSK Quadrature Phase Shift Keying

RBW Resolution Bandwidth

RF Radio Frequency

SCH Synchronization Channel

tDPCH Timing offset value for Dedicated Physical Channel

W-CDMA Wideband Code Domain Multiple Access

Glossary


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89600 Series Vector Signal Analysis Software,

Technical Overview, 5989-1679EN

89600 Series Vector Signal Analysis 89601A/89601AN/89601N12 Software,

Data Sheet, 5989-1786EN

89600 Vector Signal Analysis demo software, CD, 5980-1989E

Hardware Measurement Platforms for the Agilent 89600 Series Vector Signal

Analysis Software, Data Sheet, 5989-1753EN

89600S Series VXI-based Vector Signal Analyzers, Configuration Guide,

5968-9350E

Option B7U W-CDMA/HSPA Modulation Analysis for the Agilent 89600 Series

Vector Signal Analysis Software, Brochure,5989-8080EN

www.agilent.com/find/89600

www.agilent.com/find/HSPA

www.agilent.com/find/WCDMA

Related Literature

For more info:


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Revised: October 1, 2008

Product specifications and descriptions

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Agilent Technologies, Inc. 2008

Printed in USA, October 10, 2008

5989-0679EN

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Agilent - 89600 Vector Signal Analysis Software for W-CDMA & HSPA+ Evaluation & Troubleshooting

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