Rohde&Schwarz R&S®VSE-K10x LTE DL User Manual
R&S®VSE-K10x (LTE Downlink)
LTE Downlink Measurements
User Manual
(;ÚçÞ2)
1176898002
Version 11
This manual applies to the following software, version 2.20 and later:
●
R&S®VSE Enterprise Edition base software (1345.1105.06)
●
R&S®VSE Basic Edition base software (1345.1011.06)
This manual describes functionality of the following R&S®VSE options:
●
R&S®VSE-K100 (EUTRA/LTE FDD uplink and downlink measurement application) (1320.7545.02)
●
R&S®VSE-K102 (EUTRA/LTE Advanced and MIMO measurement application) (1320.7551.02)
●
R&S®VSE-K104 (EUTRA/LTE TDD uplink and downlink measurement application) (1320.7568.02)
●
R&S®VSE-K175 (O-RAN Measurements) (1350.7020.02)
●
R&S®VSE-KT100 (EUTRA/LTE FDD uplink and downlink measurement application) (1345.1786.02)
●
R&S®VSE-KT102 (EUTRA/LTE Advanced and MIMO measurement application) (1345.7770.02)
●
R&S®VSE-KT104 (EUTRA/LTE TDD uplink and downlink measurement application) (1345.1763.02)
●
R&S®VSE-KT175 (O-RAN measurements) (1345.2076.02)
© 2022 Rohde & Schwarz GmbH & Co. KG
Muehldorfstr. 15, 81671 Muenchen, Germany
Phone: +49 89 41 29 - 0
Email: info@rohde-schwarz.com
Internet: www.rohde-schwarz.com
Subject to change – data without tolerance limits is not binding.
R&S® is a registered trademark of Rohde & Schwarz GmbH & Co. KG.
Trade names are trademarks of the owners.
1176.8980.02 | Version 11 | R&S®VSE-K10x (LTE Downlink)
Throughout this manual, products from Rohde & Schwarz are indicated without the ® symbol , e.g. R&S®VSE is indicated as
R&S VSE.
R&S®VSE-K10x (LTE Downlink)
Contents
1 Preface.................................................................................................... 7
1.1 About this manual.........................................................................................................7
1.2 Documentation overview..............................................................................................7
1.3 Typographical conventions..........................................................................................8
2 Welcome to the LTE measurement application.................................10
2.1 LTE measurement application selection...................................................................10
2.2 Display information.....................................................................................................11
3 Measurements and result displays.................................................... 13
3.1 Selecting measurements............................................................................................13
3.2 Selecting result displays............................................................................................ 14
Contents
3.3 Performing measurements.........................................................................................14
3.4 I/Q measurements....................................................................................................... 15
3.5 Time alignment error measurements........................................................................ 37
3.6 3GPP test scenarios................................................................................................... 39
4 Measurement basics............................................................................41
4.1 Symbols and variables............................................................................................... 41
4.2 Overview...................................................................................................................... 42
4.3 The LTE downlink analysis measurement application............................................ 42
4.3.1 Synchronization.............................................................................................................42
4.3.2 Channel estimation and equalization............................................................................ 44
4.3.3 Analysis.........................................................................................................................44
4.4 MIMO measurement guide......................................................................................... 45
4.4.1 MIMO measurements with signal analyzers................................................................. 46
4.4.2 MIMO measurements with oscilloscopes......................................................................49
4.5 Calibrating beamforming measurements................................................................. 51
4.6 Performing time alignment measurements.............................................................. 54
4.7 O-RAN measurement guide....................................................................................... 55
5 Configuration........................................................................................57
5.1 Configuring I/Q measurements..................................................................................57
5.1.1 Configuration overview..................................................................................................58
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5.1.2 Signal characteristics.................................................................................................... 60
5.1.3 Test scenarios............................................................................................................... 66
5.1.4 Configuring MIMO setups............................................................................................. 67
5.1.5 PDSCH demodulation................................................................................................... 71
5.1.6 PDSCH subframe configuration.................................................................................... 72
5.1.7 Global signal characteristics......................................................................................... 79
5.1.8 Synchronization signal configuration.............................................................................80
5.1.9 Reference signal configuration......................................................................................81
5.1.10 Positioning reference signal configuration.................................................................... 82
5.1.11 Channel state information reference signal configuration............................................. 84
5.1.12 PDSCH resource block symbol offset........................................................................... 86
5.1.13 PBCH configuration.......................................................................................................87
5.1.14 PCFICH configuration................................................................................................... 88
Contents
5.1.15 PHICH configuration..................................................................................................... 89
5.1.16 PDCCH configuration....................................................................................................92
5.1.17 EPDCCH configuration................................................................................................. 93
5.1.18 Shared channel configuration....................................................................................... 95
5.1.19 MBSFN characteristics..................................................................................................95
5.1.20 Selecting the input and output source...........................................................................98
5.1.21 Frequency configuration..............................................................................................102
5.1.22 Amplitude configuration...............................................................................................103
5.1.23 Data capture................................................................................................................106
5.1.24 Trigger configuration................................................................................................... 108
5.1.25 Parameter estimation and tracking..............................................................................111
5.1.26 Measurement error compensation...............................................................................112
5.1.27 Demodulation.............................................................................................................. 113
5.1.28 Automatic configuration...............................................................................................115
5.2 Configuring time alignment error measurements..................................................116
6 Analysis...............................................................................................117
6.1 General analysis tools.............................................................................................. 117
6.1.1 Data export..................................................................................................................117
6.1.2 Microservice export..................................................................................................... 118
6.1.3 Diagram scale..............................................................................................................118
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6.1.4 Zoom........................................................................................................................... 119
6.1.5 Markers........................................................................................................................119
6.2 Analysis tools for I/Q measurements......................................................................120
6.2.1 Layout of numerical results......................................................................................... 120
6.2.2 Evaluation range......................................................................................................... 121
6.2.3 Result settings.............................................................................................................123
7 Remote control...................................................................................126
7.1 Common suffixes...................................................................................................... 126
7.2 Introduction............................................................................................................... 127
7.2.1 Conventions used in descriptions............................................................................... 127
7.2.2 Long and short form.................................................................................................... 128
7.2.3 Numeric suffixes..........................................................................................................128
Contents
7.2.4 Optional keywords.......................................................................................................129
7.2.5 Alternative keywords................................................................................................... 129
7.2.6 SCPI parameters.........................................................................................................129
7.3 LTE application selection......................................................................................... 132
7.4 Screen layout.............................................................................................................132
7.4.1 General layout.............................................................................................................132
7.4.2 Layout over all channels............................................................................................. 133
7.4.3 Layout of a single channel.......................................................................................... 137
7.5 Trace data readout.................................................................................................... 144
7.5.1 Using the TRACe[:DATA] command........................................................................... 144
7.6 Numeric result readout.............................................................................................161
7.6.1 Frame results.............................................................................................................. 161
7.6.2 Result for selection......................................................................................................163
7.6.3 Time alignment error................................................................................................... 169
7.6.4 Marker table................................................................................................................ 170
7.6.5 CCDF table................................................................................................................. 173
7.7 Limit check result readout....................................................................................... 174
7.7.1 Limits for numerical result display............................................................................... 174
7.8 Remote commands to configure the application...................................................182
7.8.1 General configuration..................................................................................................182
7.8.2 Configuring I/Q measurements................................................................................... 184
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7.8.3 Configuring time alignment measurements.................................................................244
7.9 Analysis..................................................................................................................... 245
7.9.1 Trace export................................................................................................................ 245
7.9.2 Microservice export..................................................................................................... 247
7.9.3 Evaluation range......................................................................................................... 247
7.9.4 Y-axis scale................................................................................................................. 251
7.9.5 Result settings.............................................................................................................253
Annex.................................................................................................. 255
A Annex: reference................................................................................255
A.1 Menu reference..........................................................................................................255
A.1.1 Common R&S VSE menus......................................................................................... 255
A.1.2 LTE measurement menus........................................................................................... 257
Contents
A.2 Reference of toolbar functions................................................................................ 259
List of commands.............................................................................. 264
Index....................................................................................................270
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1 Preface
1.1 About this manual
This User Manual describes information specific to measurements in the LTE measurement application. All other applications are described in the corresponding appli-
cation manuals.
The main focus in this manual is on the measurement results and the tasks required to
obtain them. The following topics are included:
●
Welcome to the R&S VSE
Introduction to and getting familiar with the software
●
Measurements and Results
Descriptions of the measurement types available in the R&S VSE software
●
Controlling Instruments and Capturing I/Q Data
Methods of data acquisition and description of basic instrument control functions
●
LTE Measurements
Description of the settings and functions provided to analyze results with the software and the corresponding remote control commands
●
Remote Commands for LTE Measurements
Remote commands required to configure and perform measurements in a remote
environment, sorted by tasks
Remote commands required to set up the environment and to perform common
tasks in the software, sorted by tasks
Programming examples demonstrate the use of many commands and can usually
be executed directly for test purposes
●
List of Commands
Alphabetical list of all remote commands described in the manual
●
Index
Preface
Documentation overview
1.2 Documentation overview
The user documentation for the R&S VSE consists of the following parts:
●
"Getting Started" printed manual
●
Online Help system in the software
●
CD-ROM including the following documentation:
– Getting Started
– User Manuals for base software and options
– Service Manual
– Release Notes
– Data sheet and product brochures
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Online Help
The Online Help is embedded in the software. It offers quick, context-sensitive access
to the complete information needed for operation and programming. Online help is
available using the icon on the toolbar of the R&S VSE.
Getting Started
This manual is delivered with the software in printed form and in PDF format on the
CD. It provides the information needed to set up and start working with the software.
Basic operations and handling are described. Safety information is also included.
User Manuals
User manuals are provided for the base software and each additional (software)
option.
The user manuals are available in PDF format - in printable form - on the CD-ROM
delivered with the software. In the user manuals, all software functions are described in
detail. Furthermore, they provide a complete description of the remote control commands with programming examples.
Preface
Typographical conventions
The user manual for the base software provides basic information on operating the
R&S VSE in general, and the I/Q Analyzer application in particular. Furthermore, the
software functions that enhance the basic functionality for various applications are
described here. An introduction to remote control is provided, as well as information on
troubleshooting.
In the individual application manuals, the specific software functions of the application
are described in detail. For additional information on default settings and parameters,
refer to the data sheets. Basic information on operating the R&S VSE is not included in
the application manuals.
Release Notes
The release notes describe the installation of the software, new and modified functions,
eliminated problems, and last minute changes to the documentation. The corresponding software version is indicated on the title page of the release notes.
Application Notes
Application notes, application cards, white papers and educational notes are further
publications that provide more comprehensive descriptions and background information. The latest versions are available for download from the Rohde & Schwarz website, at www.rohde-schwarz.com/appnote/.
1.3 Typographical conventions
The following text markers are used throughout this documentation:
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Convention Description
Preface
Typographical conventions
"Graphical user interface elements"
[Keys] Key and knob names are enclosed by square brackets.
Filenames, commands,
program code
Input Input to be entered by the user is displayed in italics.
Links Links that you can click are displayed in blue font.
"References" References to other parts of the documentation are enclosed by quota-
All names of graphical user interface elements on the screen, such as
dialog boxes, menus, options, buttons, and softkeys are enclosed by
quotation marks.
Filenames, commands, coding samples and screen output are distinguished by their font.
tion marks.
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2 Welcome to the LTE measurement applica-
tion
The LTE measurement application is a firmware application that adds functionality to
perform measurements on LTE signals according to the 3GPP standard to the
R&S VSE.
This user manual contains a description of the functionality that the application provides, including remote control operation. Functions that are not discussed in this manual are the same as in the spectrum application and are described in the R&S VSE
User Manual. The latest versions of the manuals are available for download at the
product homepage.
https://www.rohde-schwarz.com/manual/vse.
● LTE measurement application selection................................................................. 10
● Display information..................................................................................................11
Welcome to the LTE measurement application
LTE measurement application selection
2.1 LTE measurement application selection
The LTE measurement application adds a new application to the R&S VSE.
Starting the application
1.
Select the "Add Channel" function in the "Sequence" tool window.
A dialog box opens that contains all operating modes and applications currently
available in your R&S VSE.
2. Select the "LTE" item.
The R&S VSE opens a new measurement channel for the LTE application.
The application starts with the default settings. You can configure measurements with
the items in the "Meas Setup" menu.
For more information see Chapter 5, "Configuration", on page 57.
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2.2 Display information
The following figure shows a typical measurement diagram of the LTE application. All
different information areas are labeled. They are explained in more detail in the following sections.
1 2 3 4 5
Welcome to the LTE measurement application
Display information
1 = Window title bar with information about the diagram and its traces
2 = Channel bar with measurement settings
3 = Diagram area
4 = Diagram footer with information about the contents of the diagram
5 = Color code for windows of the same channel (here: red)
Channel bar information
In the LTE measurement application, the R&S VSE shows the following settings:
Table 2-1: Information displayed in the channel bar in the LTE measurement application
Ref Level Reference level
Att Mechanical and electronic RF attenuation
Freq Frequency
Mode LTE standard
MIMO Number of Tx and Rx antennas in the measurement setup
Capture Time Signal length that has been captured
Frame Count Number of frames that have been captured
Selected Subframe Subframe considered in the signal analysis
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In addition, the channel bar also displays information on instrument settings that affect
the measurement results even though this is not immediately apparent from the display
of the measured values (e.g. transducer or trigger settings). This information is displayed only when applicable for the current measurement. For a comprhensive
description, refer to the user manual of the R&S VSE.
Window title bar information
The information in the window title bar depends on the result display.
The "Constellation Diagram", for example, shows the number of points that have been
measured.
Status bar information
Global instrument settings, the instrument status and any irregularities are indicated in
the status bar beneath the diagram. Furthermore, the progress of the current operation
is displayed in the status bar.
Regarding the synchronization state, the application shows the following labels.
●
Sync OK
The synchronization was successful. The status bar is green.
●
Sync Failed
The synchronization was not successful. The status bar is red.
There can be three different synchronization errors.
– Sync Failed (Cyclic Prefix): The cyclic prefix correlation failed.
– Sync Failed (P-SYNC): The P-SYNC correlation failed.
– Sync Failed (S-SYNC): The S-SYNC correlation failed.
Welcome to the LTE measurement application
Display information
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3 Measurements and result displays
The LTE measurement application measures and analyzes various aspects of an LTE
signal.
It features several measurements and result displays. Measurements represent different ways of processing the captured data during the digital signal processing. Result
displays are different representations of the measurement results. They may be diagrams that show the results as a graph or tables that show the results as numbers.
Remote command:
Measurement selection: CONFigure[:LTE]:MEASurement on page 183
Result display selection: LAYout:ADD[:WINDow]? on page 137
● Selecting measurements.........................................................................................13
● Selecting result displays..........................................................................................14
● Performing measurements......................................................................................14
● I/Q measurements...................................................................................................15
● Time alignment error measurements...................................................................... 37
● 3GPP test scenarios............................................................................................... 39
Measurements and result displays
Selecting measurements
3.1 Selecting measurements
Access: "Overview" > "Select Measurement"
The "Select Measurement" dialog box contains several buttons. Each button represents a measurement. A measurement in turn is a set of result displays that thematically belong together and that have a particular display configuration. If these predefined display configurations do not suit your requirements, you can add or remove
result displays as you like. For more information about selecting result displays, see
Chapter 3.2, "Selecting result displays", on page 14.
Depending on the measurement, the R&S VSE changes the way it captures and processes the raw signal data.
EVM
EVM measurements record, process and demodulate the signal's I/Q data. The result
displays available for EVM measurements show various aspects of the LTE signal
quality.
For EVM measurements, you can combine the result displays in any way.
For more information on the result displays, see Chapter 3.4, "I/Q measurements",
on page 15.
Remote command:
CONFigure[:LTE]:MEASurement on page 183
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Time alignment error
Time alignment error (TAE) measurements record, process and demodulate the signal's I/Q data. The result displays available for TAE measurements indicate how well
the antennas in a multi-antenna system are aligned.
For TAE measurements, you can combine the result displays in any way.
For more information on the result displays, see Chapter 3.5, "Time alignment error
measurements", on page 37.
Remote command:
CONFigure[:LTE]:MEASurement on page 183
3.2 Selecting result displays
Access: or "Window" > "New Window"
The R&S VSE opens a menu to select result displays. Depending on the number of
LTE channels you are currently using, there is a submenu that contains all available
result displays for each LTE channel.
Measurements and result displays
Performing measurements
In the default state of the application, it shows several conventional result displays.
●
Capture Buffer
●
EVM vs Carrier
●
Power Spectrum
●
Result Summary
●
Constellation Diagram
From that predefined state, add and remove result displays to the channels as you like
from the "Window" menu.
Remote command: LAYout:ADD[:WINDow]? on page 137
Measuring several data streams
When you capture more than one data stream (for example component carriers), each
result display is made up out of several tabs.
The first tab shows the results for all data streams. The other tabs show the results for
each individual data stream. By default, the tabs are coupled to one another - if you
select a certain data stream in one display, the application also selects this data stream
in the other result displays (see Subwindow Coupling).
The number of tabs depends on the number of data streams.
3.3 Performing measurements
By default, the application measures the signal continuously. In "Continuous Sweep"
mode, the R&S VSE captures and analyzes the data again and again.
●
For I/Q measurements, the amount of captured data depends on the capture time.
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●
For frequency sweep measurement, the amount of captured data depends on the
sweep time.
In "Single Sweep" mode, the R&S VSE stops measuring after it has captured the data
once. The amount of data again depends on the capture time.
Refreshing captured data
You can also repeat a measurement based on the data that has already been captured
with the "Refresh" function. Repeating a measurement with the same data can be useful, for example, if you want to apply different modulation settings to the same I/Q data.
For more information, see the documentation of the R&S VSE.
3.4 I/Q measurements
Access: [MEAS] > "EVM/Frequency Err/Power"
You can select the result displays from the evaluation bar and arrange them as you like
with the SmartGrid functionality.
Measurements and result displays
I/Q measurements
Remote command:
Measurement selection: CONFigure[:LTE]:MEASurement on page 183
Result display selection: LAYout:ADD[:WINDow]? on page 137
Capture Buffer...............................................................................................................16
EVM vs Carrier..............................................................................................................17
EVM vs Symbol.............................................................................................................18
EVM vs RB....................................................................................................................19
EVM vs Subframe......................................................................................................... 19
Frequency Error vs Symbol...........................................................................................20
Power Spectrum............................................................................................................21
Power vs Resource Block PDSCH................................................................................21
Power vs Resource Block RS....................................................................................... 22
Channel Flatness.......................................................................................................... 22
Group Delay..................................................................................................................23
Channel Flatness Difference.........................................................................................23
Constellation Diagram...................................................................................................23
CCDF............................................................................................................................ 24
Allocation Summary...................................................................................................... 25
Bitstream.......................................................................................................................26
Channel Decoder Results............................................................................................. 27
EVM vs Symbol x Carrier..............................................................................................28
Power vs Symbol x Carrier............................................................................................29
Allocation ID vs Symbol x Carrier..................................................................................29
UE RS Magnitude......................................................................................................... 30
UE RS Phase................................................................................................................30
Cell RS Magnitude........................................................................................................ 31
Cell RS Phase...............................................................................................................32
CSI RS Magnitude........................................................................................................ 32
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CSI RS Phase...............................................................................................................33
Beamform Allocation Summary.....................................................................................33
Result Summary............................................................................................................34
Marker Table................................................................................................................. 37
Capture Buffer
The "Capture Buffer" shows the complete range of captured data for the last data capture.
The x-axis represents time. The maximum value of the x-axis is equal to the Capture
Time.
The y-axis represents the amplitude of the captured I/Q data in dBm (for RF input).
The capture buffer uses the auto peak detector to evaluate the measurement data. The
auto peak detector determines the maximum and the minimum value of the measured
levels for each measurement point and combines both values in one sample point.
Measurements and result displays
I/Q measurements
Figure 3-1: Capture buffer without zoom
A colored bar at the bottom of the diagram represents the frame that is currently analyzed. Different colors indicate the OFDM symbol type.
●
Indicates the data stream.
●
Indicates the reference signal and data.
●
Indicates the P-Sync and data.
●
Indicates the S-Sync and data.
A green vertical line at the beginning of the green bar in the capture buffer represents
the subframe start. The diagram also contains the "Start Offset" value. This value is the
time difference between the subframe start and capture buffer start.
When you zoom into the diagram, you will see that the bar is interrupted at certain
positions. Each small bar indicates the useful parts of the OFDM symbol.
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Figure 3-2: Capture buffer after a zoom has been applied
Remote command:
Selection: LAY:ADD ? '1',LEFT,CBUF
Query (y-axis): TRACe:DATA?
Query (x-axis): TRACe<n>[:DATA]:X? on page 160
Subframe start offset: FETCh[:CC<cc>]:SUMMary:TFRame? on page 169
Measurements and result displays
I/Q measurements
EVM vs Carrier
The "EVM vs Carrier" result display shows the error vector magnitude (EVM) of the
subcarriers. With the help of a marker, you can use it as a debugging technique to
identify any subcarriers whose EVM is too high.
The results are based on an average EVM that is calculated over the resource elements for each subcarrier. This average subcarrier EVM is determined for each analyzed subframe in the capture buffer.
If you analyze all subframes, the result display contains three traces.
●
Average EVM
This trace shows the subcarrier EVM, averaged over all subframes.
●
Minimum EVM
This trace shows the lowest (average) subcarrier EVM that has been found over
the analyzed subframes.
●
Maximum EVM
This trace shows the highest (average) subcarrier EVM that has been found over
the analyzed subframes.
If you select and analyze one subframe only, the result display contains one trace that
shows the subcarrier EVM for that subframe only. Average, minimum and maximum
values in that case are the same. For more information, see "Subframe Selection"
on page 121.
The x-axis represents the center frequencies of the subcarriers. The y-axis shows the
EVM in % or in dB, depending on the EVM Unit.
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Remote command:
Selection LAY:ADD ? '1',LEFT,EVCA
Query (y-axis): TRACe:DATA?
Query (x-axis): TRACe<n>[:DATA]:X? on page 160
EVM vs Symbol
The "EVM vs Symbol" result display shows the error vector magnitude (EVM) of the
OFDM symbols. You can use it as a debugging technique to identify any symbols
whose EVM is too high.
The results are based on an average EVM that is calculated over all subcarriers that
are part of a certain OFDM symbol. This average OFDM symbol EVM is determined for
all OFDM symbols in each analyzed subframe.
The x-axis represents the OFDM symbols, with each symbol represented by a dot on
the line. Any missing connections from one dot to another mean that the R&S VSE
could not determine the EVM for that symbol.
The number of displayed symbols depends on the subframe selection and the length of
the cyclic prefix.
For TDD signals, the result display does not show OFDM symbols that are not part of
the measured link direction.
On the y-axis, the EVM is plotted either in % or in dB, depending on the EVM Unit.
Measurements and result displays
I/Q measurements
Remote command:
Selection: LAY:ADD ? '1',LEFT,EVSY
Query (y-axis): TRACe:DATA?
Query (x-axis): TRACe<n>[:DATA]:X? on page 160
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EVM vs RB
The "EVM vs RB" result display shows the Error Vector Magnitude (EVM) for all
resource blocks that can be occupied by the PDSCH.
The results are based on an average EVM that is calculated over all resource elements
in the resource block. This average resource block EVM is determined for each analyzed subframe. If you analyze all subframes, the result display contains three traces.
●
Average EVM
This trace shows the resource block EVM, averaged over all subframes.
●
Minimum EVM
This trace shows the lowest (average) resource block EVM that has been found
over the analyzed subframes.
●
Maximum EVM
This trace shows the highest (average) resource block EVM that has been found
over the analyzed subframes.
If you select and analyze one subframe only, the result display contains one trace that
shows the resource block EVM for that subframe only. Average, minimum and maximum values in that case are the same. For more information, see "Subframe Selec-
tion" on page 121.
The x-axis represents the PDSCH resource blocks. On the y-axis, the EVM is plotted
either in % or in dB, depending on the EVM Unit.
Measurements and result displays
I/Q measurements
Remote command:
Selection: LAY:ADD ? '1',LEFT,EVRP
Query (y-axis): TRACe:DATA?
Query (x-axis): TRACe<n>[:DATA]:X? on page 160
EVM vs Subframe
The "EVM vs Subframe" result display shows the Error Vector Magnitude (EVM) for
each subframe. You can use it as a debugging technique to identify a subframe whose
EVM is too high.
The result is an average over all subcarriers and symbols of a specific subframe.
The x-axis represents the subframes, with the number of displayed subframes being
10.
On the y-axis, the EVM is plotted either in % or in dB, depending on the EVM Unit.
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Remote command:
Selection: LAY:ADD ? '1',LEFT,EVSU
Query (y-axis): TRACe:DATA?
Query (x-axis): TRACe<n>[:DATA]:X? on page 160
Frequency Error vs Symbol
Th e "Frequency Error vs Symbol" result display shows the frequency error of each
symbol. You can use it as a debugging technique to identify any frequency errors within
symbols.
The result is an average over all subcarriers in the symbol.
The x-axis represents the OFDM symbols, with each symbol represented by a dot on
the line. The number of displayed symbols depends on the subframe selection and the
length of the cyclic prefix. Any missing connections from one dot to another mean that
the R&S VSE could not determine the frequency error for that symbol.
Measurements and result displays
I/Q measurements
On the y-axis, the frequency error is plotted in Hz.
Note that the variance of the measurement results in this result display can be much
higher compared to the frequency error display in the numerical result summary,
depending on the PDSCH and control channel configuration. The potential difference is
caused by the number of available resource elements for the measurement on symbol
level.
Remote command:
Selection: LAY:ADD ? '1',LEFT,FEVS
Query (y-axis): TRACe:DATA?
Query (x-axis): TRACe<n>[:DATA]:X? on page 160
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Power Spectrum
The "Power Spectrum" shows the power density of the complete capture buffer in
dBm/Hz.
The displayed bandwidth depends on the selected channel bandwidth.
The x-axis represents the frequency. On the y-axis, the power level is plotted.
Remote command:
Selection: LAY:ADD ? '1',LEFT,PSPE
Query (y-axis): TRACe:DATA?
Query (x-axis): TRACe<n>[:DATA]:X? on page 160
Measurements and result displays
I/Q measurements
Power vs Resource Block PDSCH
The "Power vs Resource Block PDSCH" result display shows the power of the physical
downlink shared channel per resource element averaged over one resource block.
By default, three traces are shown. One trace shows the average power. The second
and the third traces show the minimum and maximum powers respectively. You can
select to display the power for a specific subframe in the Subframe Selection dialog
box. In that case, the application shows the powers of that subframe only.
The x-axis represents the resource blocks. The displayed number of resource blocks
depends on the channel bandwidth or number of resource blocks you have set. On the
y-axis, the power is plotted in dBm.
Remote command:
Selection: LAY:ADD ? '1',LEFT,PCRP
Query (y-axis): TRACe:DATA?
Query (x-axis): TRACe<n>[:DATA]:X? on page 160
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Power vs Resource Block RS
The "Power vs Resource Block RS" result display shows the power of the reference
signal per resource element averaged over one resource block.
By default, three traces are shown. One trace shows the average power. The second
and the third traces show the minimum and maximum powers respectively. You can
select to display the power for a specific subframe in the Subframe Selection dialog
box. In that case, the application shows the power of that subframe only.
The x-axis represents the resource blocks. The displayed number of resource blocks
depends on the channel bandwidth or number of resource blocks you have set. On the
y-axis, the power is plotted in dBm.
Measurements and result displays
I/Q measurements
Remote command:
Selection: LAY:ADD ? '1',LEFT,PVRR
Query (y-axis): TRACe:DATA?
Query (x-axis): TRACe<n>[:DATA]:X? on page 160
Channel Flatness
The "Channel Flatness" shows the relative power offset caused by the transmit channel.
The currently selected subframe depends on your selection.
The x-axis represents the frequency. On the y-axis, the channel flatness is plotted in
dB.
Remote command:
Selection: LAY:ADD ? '1',LEFT,FLAT
Query (y-axis): TRACe:DATA?
Query (x-axis): TRACe<n>[:DATA]:X? on page 160
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Group Delay
This "Group Delay" shows the group delay of each subcarrier.
The measurement is evaluated over the currently selected slot in the currently selected
subframe.
The currently selected subframe depends on your selection.
The x-axis represents the frequency. On the y-axis, the group delay is plotted in ns.
Remote command:
Selection: LAY:ADD ? '1',LEFT,GDEL
Query (y-axis): TRACe:DATA?
Query (x-axis): TRACe<n>[:DATA]:X? on page 160
Measurements and result displays
I/Q measurements
Channel Flatness Difference
The "Channel Flatness Difference" shows the level difference in the spectrum flatness
result between two adjacent physical subcarriers.
The currently selected subframe depends on your selection.
The x-axis represents the frequency. On the y-axis, the power is plotted in dB.
Remote command:
Selection: LAY:ADD ? '1',LEFT,FDIF
Query (y-axis): TRACe:DATA?
Query (x-axis): TRACe<n>[:DATA]:X? on page 160
Constellation Diagram
The "Constellation Diagram" shows the in-phase and quadrature phase results and is
an indicator of the quality of the modulation of the signal.
In the default state, the result display evaluates the full range of the measured input
data.
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Each color represents a modulation type.
●
●
●
●
●
●
●
●
●
You can filter the results by changing the evaluation range.
: BPSK
: RBPSK
: MIXTURE
: QPSK
: 16QAM
: 64QAM
: 256QAM
: 1024QAM
: PSK (CAZAC)
Measurements and result displays
I/Q measurements
The constellation diagram also contains information about the current evaluation
range, including the number of points that are displayed in the diagram.
Remote command:
Selection: LAY:ADD ? '1',LEFT,CONS
Query: TRACe:DATA?
CCDF
The "Complementary Cumulative Distribution Function (CCDF)" shows the probability
of an amplitude exceeding the mean power. For the measurement, the complete capture buffer is used.
The x-axis represents the power relative to the measured mean power. On the y-axis,
the probability is plotted in %.
In addition to the diagram, the results for the CCDF measurement are summarized in
the CCDF table.
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Mean Mean power
Peak Peak power
Crest Crest factor (peak power – mean power)
10 % 10 % probability that the level exceeds mean power + [x] dB
1 % 1 % probability that the level exceeds mean power + [x] dB
0.1 % 0.1 % probability that the level exceeds mean power + [x] dB
0.01 % 0.01 % probability that the level exceeds mean power + [x] dB
Remote command:
Selection: LAY:ADD ? '1',LEFT,CCDF
Query (y-axis): TRACe:DATA?
Numerical results: CALCulate<n>:STATistics:CCDF:X<t>? on page 173
Numerical results: CALCulate<n>:STATistics:RESult<res>? on page 174
Allocation Summary
The "Allocation Summary" shows various parameters of the measured allocations in a
table.
Each row in the allocation table corresponds to an allocation. A set of several allocations make up a subframe. A horizontal line indicates the beginning of a new subframe.
Special allocations summarize the characteristics of all allocations in a subframe
("ALL") and the complete frame (allocation "ALL" at the end of the table).
Measurements and result displays
I/Q measurements
The columns of the table show the following properties for each allocation.
●
The location of the allocation (subframe number).
●
The ID of the allocation (channel type).
●
Number of resource blocks used by the allocation.
●
The relative power of the allocation in dB.
The R&S VSE does not calculate the PHICH power if you turn on boosting estima-
tion.
●
The modulation of the allocation.
●
The power of each resource element in the allocation in dBm.
●
The EVM of the allocation.
The unit depends on the EVM unit
●
The EVM over all codewords in a layer. The layer EVM is calculated for all data
allocations, and not for the DMRS or other physical signals.
The unit depends on the EVM unit
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For PDSCH allocations that use beamforming, the table contains two values. One for
the PDSCH, and one for the UE-specific reference signal (UE RS).
Click once on the header row to open a dialog box that allows you to add and remove
columns.
Remote command:
Selection: LAY:ADD ? '1',LEFT,ASUM
Query: TRACe:DATA?
Bitstream
The "Bitstream" shows the demodulated data stream for the data allocations.
At the end of the table is a summary of all total number of bits, total number of coded
bits, total number of bit errors and bit error rate in %. The totals are calculated over all
PDSCH allocations that contribute to the bitstream. The results are shown when you
select an ORAN test case.
Depending on the bitstream format, the numbers represent either bits (bit order) or
symbols (symbol order).
●
For the bit format, each number represents one raw bit.
●
For the symbol format, the bits that belong to one symbol are shown as hexadecimal numbers with two digits.
(1024QAM: hexadecimal number with three digits)
Resource elements that do not contain data or are not part of the transmission are represented by a "-".
If a symbol could not be decoded because the number of layers exceeds the number
of receive antennas, the application shows a "#" sign.
Measurements and result displays
I/Q measurements
The table contains the following information:
●
Subframe
Number of the subframe the bits belong to.
●
Allocation ID
Channel the bits belong to.
●
Codeword
Code word of the allocation.
●
Modulation
Modulation type of the channels.
●
Symbol Index or Bit Index
Indicates the position of the table row's first bit or symbol within the complete
stream.
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●
Bit Stream
The actual bit stream.
Remote command:
Selection: LAY:ADD ? '1',LEFT,BSTR
Query: TRACe:DATA?
Channel Decoder Results
The "Channel Decoder" result display is a numerical result display that shows the characteristics of various channels for a specific subframe.
●
Protocol information of the PBCH, PCFICH and PHICH.
●
Information about the DCIs in the PDCCH.
●
Decoded bitstream for each PDCCH.
●
Decoded bitstream for each PDSCH.
The size of the table thus depends on the number of subframes in the signal.
Note that a complete set of results for the control channels is available only under cer-
tain circumstances.
●
The corresponding control channel (PBCH, PCFICH or PHICH) has to be present
and enabled.
●
Each channel must have a certain configuration (see list below).
Measurements and result displays
I/Q measurements
For each channel, the table shows a different set of values.
●
PBCH
For the PBCH, the Channel Decoder provides the following results.
– The MIMO configuration of the DUT (1, 2 or 4 TX antennas)
– The Transmission bandwidth
– The Duration of the PHICH (normal or extended)
– The PHICH resource which is the same as PHICH Ng (1/6, 1/2, 1 or 2)
– System frame number
If the CRC is not valid, a corresponding message is shown instead of the results.
Results for the PBCH can only be determined if the PHICH Duration or the PHICH
N_g are automatically determined ("Auto") or if automatic decoding of all control
channels is turned on.
●
PCFICH
For the PCFICH, the Channel Decoder provides the number of OFDM symbols that
are used for PDCCH at the beginning of a subframe.
●
PHICH
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The PHICH carries the hybrid-ARQ ACK/NACK. Multiple PHICHs mapped to the
same set of resource elements are a PHICH group. The PHICHs within one group
are separated by different orthogonal sequences.
For the PHICH, the Channel Decoder provides the ACK/NACK pattern for the
PHICH group and the relative power for each PHICH in the PHICH group. Each
line in the result table represents one PHICH group. The columns on the left show
the ACK/NACK pattern of the PHICH group. The columns on the right show the rel-
ative powers for each PHICH.
If a PHICH is not transmitted, the table contains a "-" sign. Otherwise, the ACK/
NACK pattern is either a "1" (acknowledgement) or a "0" (not acknowledged). The
relative power is a numeric value in dB.
●
PDCCH
For each PDCCH that has been detected, the Channel Decoder shows several
results. Each line in the table represents one PDCCH.
– RNTI
– DCI Format
Shows the Downlink Control Information (DCI) format. The DCI contains information about the resource assignment for the UEs.
The following DCI formats are supported: 0, 1, 1A, 1B, 1C, 2, 2A, 2C, 2D, 3,
3A.
The DCI format is determined by the length of the DCI. Because they have the
same length, the Channel Decoder is not able to distinguish formats 0, 3 and
3A. Note that a DCI that consist of only zero bits cannot be decoded.
– PDCCH format used to transmit the DCI
– CCE Offset
The CCE Offset represents the position of the current DCI in the PDCCH bit
stream.
– Rel. Power
Relative power of the corresponding PDCCH.
Results for the PDCCH can only be determined if the PDSCH subframe configura-
tion is detected by the "PDCCH Protocol" or if automatic decoding of all control
channels is turned on.
●
PDSCH
For each decoded PDSCH allocation, there is a PDCCH DCI. The DCI contains
parameters that are required for the decoding process. If the channel could be
decoded successfully, the result display shows the bit stream for each codeword.
If the Cyclic Redundancy Check (CRC) fails, the result display shows an error message instead.
Results for the PDSCH can only be determined if the PDSCH subframe configura-
tion is detected by the "PDCCH Protocol" or if automatic decoding of all control
channels is turned on.
Remote command:
Selection: LAY:ADD ? '1',LEFT,CDEC
Query: TRACe:DATA?
Measurements and result displays
I/Q measurements
EVM vs Symbol x Carrier
The "EVM vs Symbol x Carrier" result display shows the EVM for each carrier in each
symbol.
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The x-axis represents the symbols. The y-axis represents the subcarriers. Different colors in the diagram area represent the EVM. A color map in the diagram header indicates the corresponding power levels.
Remote command:
Selection: LAY:ADD ? '1',LEFT,EVSC
Query: TRACe:DATA?
Power vs Symbol x Carrier
The "Power vs Symbol x Carrier" result display shows the power for each carrier in
each symbol.
The x-axis represents the symbols. The y-axis represents the subcarriers. Different colors in the diagram area represent the power. A color map in the diagram header indicates the corresponding power levels.
Measurements and result displays
I/Q measurements
Remote command:
Selection: LAY:ADD ? '1',LEFT,PVSC
Query: TRACe:DATA?
Allocation ID vs Symbol x Carrier
The "Allocation ID vs Symbol x Carrier" result display is a graphical representation of
the structure of the analyzed frame. It shows the allocation type of each subcarrier in
each symbol of the received signal.
The x-axis represents the OFDM symbols. The y-axis represents the subcarriers.
Each type of allocation is represented by a different color. The legend above the dia-
gram indicates the colors used for each allocation. You can also use a marker to get
more information about the type of allocation.
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Remote command:
Selection: LAY:ADD ? '1',LEFT,AISC
Query: TRACe:DATA?
UE RS Magnitude
The "UE RS Weights Magnitude" result display shows the magnitude of the measured
weights of the UE-specific reference signal carriers. You can use it to calculate the
magnitude difference between different antenna ports.
The x-axis represents the frequency, with the unit depending on your selection. The yaxis shows the amplitude of each reference signal in dB.
Because the beamforming configuration can change between the subframes of one
frame, the contents of this result display for Subframe Selection = 'All' might be invalid.
Thus, it is recommended to select the precise subframe to be evaluated in order to get
valid results.
You can select the antenna port you want to show the information for from the corresponding beamforming selection dropdown menu.
Measurements and result displays
I/Q measurements
Remote command:
Selection: LAY:ADD ? '1',LEFT,URWM
Querying results: TRACe:DATA?
UE RS Phase
The "UE RS Weights Phase" result display shows the phase of the measured weights
of the UE specific reference signal carriers. You can use it to calculate the phase difference between different antenna ports.
The x-axis represents the frequency, with the unit depending on your selection. The yaxis shows the phase of each reference signal in degree.
30User Manual 1176.8980.02 ─ 11
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