R&S®FPS-K106
LTE NB-IoT Measurement Application
(Downlink)
User Manual
(;ÜÉÀ2)
1178595002
Version 04
This manual applies to the following R&S®FPS models with firmware version 1.70 and higher:
●
R&S®FPS4 (1319.2008K04)
●
R&S®FPS7 (1319.2008K07)
●
R&S®FPS13 (1319.2008K13)
●
R&S®FPS30 (1319.2008K30)
●
R&S®FPS40 (1319.2008K40)
The following firmware options are described:
●
R&S®FPS-K106 LTE NB-IoT Downlink Measurement Application (1331.3246.02)
© 2021 Rohde & Schwarz GmbH & Co. KG
Mühldorfstr. 15, 81671 München, 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.
1178.5950.02 | Version 04 | R&S®FPS-K106
Throughout this manual, products from Rohde & Schwarz are indicated without the ® symbol , e.g. R&S®FPS is indicated as
R&S FPS.
R&S®FPS-K106
1 Preface.................................................................................................... 7
1.1 About this Manual......................................................................................................... 7
1.2 Typographical Conventions......................................................................................... 7
2 Welcome to the LTE NB-IoT measurement application......................8
2.1 Installation..................................................................................................................... 8
2.2 Starting the LTE NB-IoT measurement application....................................................8
2.3 Understanding the Display Information......................................................................9
3 Measurements and Result Displays...................................................11
3.1 Selecting Measurements............................................................................................ 11
3.2 Selecting Result Displays.......................................................................................... 12
Contents
Contents
3.3 Performing Measurements.........................................................................................13
3.4 Selecting the Operating Mode................................................................................... 13
3.5 I/Q Measurements....................................................................................................... 14
3.6 Time Alignment Error..................................................................................................27
3.7 Frequency Sweep Measurements............................................................................. 28
4 Configuration........................................................................................32
4.1 Configuration Overview..............................................................................................32
4.2 I/Q Measurements....................................................................................................... 34
4.2.1 Defining Signal Characteristics..................................................................................... 34
4.2.2 Configuring MIMO Setups.............................................................................................38
4.2.3 Configuring the Control Channel...................................................................................39
4.2.4 Input Source Configuration........................................................................................... 39
4.2.5 Frequency Configuration...............................................................................................40
4.2.6 Amplitude Configuration................................................................................................41
4.2.7 Configuring the Data Capture....................................................................................... 44
4.2.8 Trigger Configuration.....................................................................................................46
4.2.9 Parameter Estimation and Tracking..............................................................................47
4.2.10 Configuring Demodulation Parameters......................................................................... 49
4.3 Time Alignment Error Measurement......................................................................... 50
4.4 Frequency Sweep Measurements............................................................................. 51
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4.4.1 ACLR Signal Description...............................................................................................51
4.4.2 SEM Signal Description................................................................................................ 51
5 Analysis................................................................................................ 54
5.1 General Analysis Tools...............................................................................................54
5.1.1 Data Export................................................................................................................... 54
5.1.2 Microservice Export.......................................................................................................55
5.1.3 Diagram Scale...............................................................................................................55
5.1.4 Zoom............................................................................................................................. 56
5.1.5 Markers......................................................................................................................... 56
5.2 Analysis Tools for I/Q Measurements....................................................................... 57
5.2.1 Layout of Numerical Results......................................................................................... 57
5.2.2 Evaluation Range..........................................................................................................58
Contents
5.2.3 Result Settings.............................................................................................................. 60
5.3 Analysis Tools for Frequency Sweep Measurements..............................................60
6 Remote Control.................................................................................... 62
6.1 Common Suffixes........................................................................................................62
6.2 Introduction................................................................................................................. 63
6.2.1 Conventions used in Descriptions.................................................................................63
6.2.2 Long and Short Form.................................................................................................... 64
6.2.3 Numeric Suffixes........................................................................................................... 64
6.2.4 Optional Keywords........................................................................................................ 65
6.2.5 Alternative Keywords.................................................................................................... 65
6.2.6 SCPI Parameters.......................................................................................................... 65
6.3 NB-IoT Application Selection.....................................................................................68
6.4 Screen Layout............................................................................................................. 71
6.4.1 General Layout..............................................................................................................71
6.4.2 Layout of a Single Channel........................................................................................... 73
6.5 Measurement Control................................................................................................. 80
6.5.1 Measurements.............................................................................................................. 80
6.5.2 Measurement Sequences............................................................................................. 82
6.6 Trace Data Readout.....................................................................................................83
6.6.1 The TRACe[:DATA] Command......................................................................................83
6.6.2 Result Readout............................................................................................................. 94
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6.7 Numeric Result Readout............................................................................................ 95
6.7.1 Result for Selection....................................................................................................... 95
6.7.2 Time Alignment Error.................................................................................................. 101
6.7.3 Marker Table............................................................................................................... 102
6.7.4 CCDF Table.................................................................................................................105
6.8 Configuration.............................................................................................................106
6.8.1 General Configuration................................................................................................. 106
6.8.2 I/Q Measurements.......................................................................................................108
6.8.3 Time Alignment Error Measurements..........................................................................132
6.8.4 Frequency Sweep Measurements.............................................................................. 133
6.9 Analysis..................................................................................................................... 135
6.9.1 Trace Export................................................................................................................135
6.9.2 Microservice Export.....................................................................................................136
Contents
6.9.3 Evaluation Range........................................................................................................137
6.9.4 Y-Axis Scale................................................................................................................ 139
6.9.5 Result Settings............................................................................................................ 141
Annex.................................................................................................. 143
A Performing Time Alignment Measurements....................................143
List of commands.............................................................................. 144
Index....................................................................................................148
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Contents
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1 Preface
1.1 About this Manual
Preface
Typographical Conventions
This NB-IoT User Manual provides all the information specific to the application. All
general instrument functions and settings common to all applications and operating
modes are described in the main R&S FPS User Manual.
The main focus in this manual is on the NB-IoT measurement results and the tasks
required to obtain them. The following topics are included:
●
Welcome to the NB-IoT application
Introduction to and getting familiar with the application
●
Measurements and result displays
Details on supported NB-IoT measurements and their result types
●
Configuration and analysis
A concise description of all functions and settings available to configure and analyze NB-IoT measurements with their corresponding remote control command
●
Remote commands for NB-IoT measurements
Remote commands required to configure and perform NB-IoT measurements in a
remote environment, sorted by tasks
(Commands required to set up the environment or to perform common tasks on the
instrument are provided in the main R&S FPS User Manual)
●
List of remote commands
Alpahabetical list of all remote commands described in the manual
●
Index
1.2 Typographical Conventions
The following text markers are used throughout this documentation:
Convention Description
"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 NB-IoT measurement
Welcome to the LTE NB-IoT measurement application
Starting the LTE NB-IoT measurement application
application
The LTE NB-IoT measurement application is a firmware application that adds functionality to measure on NB-IoT signals according to the 3GPP standard to the R&S FPS.
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 FPS
user manual. The latest versions of the manuals are available for download at the
product homepage.
https://www.rohde-schwarz.com/manual/fps.
● Installation.................................................................................................................8
● Starting the LTE NB-IoT measurement application...................................................8
● Understanding the Display Information.....................................................................9
2.1 Installation
Find detailed installing instructions in the getting started or the release notes of the
R&S FPS.
2.2 Starting the LTE NB-IoT measurement application
The LTE NB-IoT measurement application adds a new application to the R&S FPS.
Manual operation via an external monitor and mouse
Although the R&S FPS does not have a built-in display, it is possible to operate it interactively in manual mode using a graphical user interface with an external monitor and
a mouse connected.
It is recommended that you use the manual mode initially to get familiar with the instrument and its functions before using it in pure remote mode. Thus, this document
describes in detail how to operate the instrument manually using an external monitor
and mouse. The remote commands are described in the second part of the document.
For details on manual operation, see the R&S FPS Getting Started manual.
Starting the NB-IoT application
1. Press the [MODE] key on the front panel of the R&S FPS.
A dialog box opens that contains all operating modes and applications currently
available on your R&S FPS.
2. Select the "NB-IoT" item.
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2.3 Understanding the Display Information
Welcome to the LTE NB-IoT measurement application
Understanding the Display Information
The R&S FPS opens a new measurement channel for the NB-IoT measurement
application.
The application is started with the default settings. It can be configured in the "Overview" dialog box, which is displayed when you select the "Overview" softkey from the
"Meas Setup" menu.
For more information, see Chapter 4, "Configuration", on page 32.
The following figure shows a measurement diagram during NB-IoT operation. All different information areas are labeled. They are explained in more detail in the following
sections.
1 2 3 4 5 6
1
= Toolbar
2 = Channel bar
3 = Diagram header
4 = Result display
5 = Status bar
6 = Softkeys
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Welcome to the LTE NB-IoT measurement application
Understanding the Display Information
Channel bar information
In the LTE NB-IoT measurement application, the R&S FPS shows the following settings:
Table 2-1: Information displayed in the channel bar in the NB-IoT measurement application
Ref Level Reference level
Att Mechanical and electronic RF attenuation
Offset Reference level offset
Freq
E-UTRA Freq
Mode NB-IoT standard
MIMO Number of Tx and Rx antennas in the measurement setup
Capture Time Length of the signal that has been captured
Frame Count Number of frames that have been captured
Subframe Subframe considered in the signal analysis
Frequency
Center frequency of the LTE channel (in-band deployment only)
In addition, the channel bar displays information on instrument settings that affect the
measurement results even though this is not immediately apparent from the display of
the measured values (for example trigger settings). This information is displayed only
when applicable for the current measurement. For details, see the R&S FPS getting
started manual.
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 (NPSS)": The NPSS correlation failed.
– "Sync Failed (NSSS)": The NSSS correlation failed.
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3 Measurements and Result Displays
Measurements and Result Displays
Selecting Measurements
The LTE NB-IoT measurement application measures and analyzes various aspects of
an LTE NB-IoT 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 can 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 107
Result display selection: LAYout:ADD[:WINDow]? on page 73
● Selecting Measurements.........................................................................................11
● Selecting Result Displays........................................................................................12
● Performing Measurements......................................................................................13
● Selecting the Operating Mode.................................................................................13
● I/Q Measurements...................................................................................................14
● Time Alignment Error.............................................................................................. 27
● Frequency Sweep Measurements.......................................................................... 28
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 12.
Depending on the measurement, the R&S FPS 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 NB-IoT signal
quality.
For EVM measurements, you can combine the result displays in any way.
For more information on the result displays, see Chapter 3.5, "I/Q Measurements",
on page 14.
Remote command:
CONFigure[:LTE]:MEASurement on page 107
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Measurements and Result Displays
Selecting Result Displays
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 3.6, "Time Alignment Error",
on page 27.
Remote command:
CONFigure[:LTE]:MEASurement on page 107
Channel power ACLR
ACLR measurements sweep the frequency spectrum instead of processing I/Q data.
The ACLR measurements evaluates the leakage ratio of neighboring channels and
evaluates if the signal is within the defined limits. The measurement provides several
result displays. You can combine the result displays in any way.
For more information on the result displays, see Chapter 3.7, "Frequency Sweep Mea-
surements", on page 28.
Remote command:
CONFigure[:LTE]:MEASurement on page 107
SEM
SEM measurements sweep the frequency spectrum instead of processing I/Q data.
The SEM measurements tests the signal against a spectrum emission mask and eval-
uates if the signal is within the defined limits. The measurement provides several result
displays. You can combine the result displays in any way.
For more information on the result displays, see Chapter 3.7, "Frequency Sweep Mea-
surements", on page 28.
Remote command:
CONFigure[:LTE]:MEASurement on page 107
3.2 Selecting Result Displays
Access:
The R&S FPS opens a menu (the SmartGrid) to select result displays. For more information on the SmartGrid functionality, see the R&S FPS Getting Started.
In the default state of the application, it shows several conventional result displays.
●
Capture Buffer
●
Power vs Symbol X Carrier
●
Constellation Diagram
●
Power Spectrum
●
Result Summary
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3.3 Performing Measurements
Measurements and Result Displays
Selecting the Operating Mode
From that predefined state, add and remove result displays as you like from the SmartGrid menu.
Remote command: LAYout:ADD[:WINDow]? on page 73
By default, the application measures the signal continuously. In "Continuous Sweep"
mode, the R&S FPS captures and analyzes the data again and again.
●
For I/Q measurements, the amount of captured data depends on the capture time.
●
For frequency sweep measurement, the amount of captured data depends on the
sweep time.
In "Single Sweep" mode, the R&S FPS 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 FPS.
3.4 Selecting the Operating Mode
Access: [MODE] > "Multi-Standard Radio Analyzer Tab"
The NB-IoT application is supported by the Multi Standard Radio Analyzer (MSRA).
The MSRA mode supports all I/Q measurements and result displays available with the
NB-IoT application, except the frequency sweep measurements (SEM and ACLR).
In MSRA operating mode, only the MSRA master actually captures data. The application receives an extract of the captured data for analysis, referred to as the application
data. The application data range is defined by the same settings used to define the
signal capture in "Signal and Spectrum Analyzer" mode. In addition, a capture offset
can be defined, i.e. an offset from the start of the captured data to the start of the
analysis interval.
If a signal contains multiple data channels for multiple standards, separate applications
are used to analyze each data channel. Thus, it is of interest to know which application
is analyzing which data channel. The MSRA master display indicates the data covered
by each application by vertical blue lines labeled with the application name. The blue
lines correspond to the channel bandwidth.
However, the individual result displays of the application need not analyze the complete data range. The data range that is actually analyzed by the individual result display is referred to as the analysis interval.
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Measurements and Result Displays
I/Q Measurements
The analysis interval is automatically determined according to the Capture Time you
have defined. The analysis interval cannot be edited directly in the NB-IoT application,
but is changed automatically when you change the evaluation range. The currently
used analysis interval (in seconds, related to capture buffer start) is indicated in the
window header for each result display.
A frequent question when analyzing multi-standard signals is how each data channel is
correlated (in time) to others. Thus, an analysis line has been introduced. The analysis
line is a common time marker for all MSRA client applications. It can be positioned in
any MSRA client application or the MSRA Master and is then adjusted in all other client
applications. Thus, you can easily analyze the results at a specific time in the measurement in all client applications and determine correlations.
If the marked point in time is contained in the analysis interval of the client application,
the line is indicated in all time-based result displays, such as time, symbol, slot or bit
diagrams. By default, the analysis line is displayed, however, it can be hidden from
view manually. In all result displays, the "AL" label in the window title bar indicates
whether the analysis line lies within the analysis interval or not:
●
orange "AL": the line lies within the interval
●
white "AL": the line lies within the interval, but is not displayed (hidden)
●
no "AL": the line lies outside the interval
For details on the MSRA operating mode, see the R&S FPS MSRA documentation.
3.5 I/Q Measurements
Access: "Overview" > "Select Measurement" > "EVM/Frequency Err/Power"
You can select the result displays from the evaluation bar and arrange them as you like
with the SmartGrid functionality.
Remote command:
Measurement selection: CONFigure[:LTE]:MEASurement on page 107
Result display selection: LAYout:ADD[:WINDow]? on page 73
Capture Buffer...............................................................................................................15
EVM vs Carrier..............................................................................................................16
EVM vs Symbol.............................................................................................................17
EVM vs Subframe......................................................................................................... 18
Frequency Error vs Symbol...........................................................................................18
Power Spectrum............................................................................................................19
Channel Flatness.......................................................................................................... 19
Group Delay..................................................................................................................20
Channel Flatness Difference.........................................................................................20
Constellation Diagram...................................................................................................20
CCDF............................................................................................................................ 21
Allocation Summary...................................................................................................... 22
EVM vs Symbol x Carrier..............................................................................................23
Power vs Symbol x Carrier............................................................................................23
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Measurements and Result Displays
I/Q Measurements
Allocation ID vs Symbol x Carrier..................................................................................24
Result Summary............................................................................................................24
Marker Table ................................................................................................................ 26
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).
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 NPSS and data.
●
Indicates the NSSS 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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Measurements and Result Displays
I/Q Measurements
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 93
Subframe start offset: FETCh[:CC<cc>]:SUMMary:TFRame? on page 100
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 58.
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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I/Q Measurements
Remote command:
Selection LAY:ADD ? '1',LEFT,EVCA
Query (y-axis): TRACe:DATA?
Query (x-axis): TRACe<n>[:DATA]:X? on page 93
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 FPS
could not determine the EVM for that symbol.
The number of displayed symbols depends on the subframe selection.
On the y-axis, the EVM is plotted either in % or in dB, depending on the EVM Unit.
Remote command:
Selection: LAY:ADD ? '1',LEFT,EVSY
Query (y-axis): TRACe:DATA?
Query (x-axis): TRACe<n>[:DATA]:X? on page 93
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Measurements and Result Displays
I/Q Measurements
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.
Remote command:
Selection: LAY:ADD ? '1',LEFT,EVSU
Query (y-axis): TRACe:DATA?
Query (x-axis): TRACe<n>[:DATA]:X? on page 93
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.
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 NPDSCH and control channel configuration. The potential difference
is caused by the number of available resource elements for the measurement on symbol level.
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I/Q Measurements
Remote command:
Selection: LAY:ADD ? '1',LEFT,FEVS
Query (y-axis): TRACe:DATA?
Query (x-axis): TRACe<n>[:DATA]:X? on page 93
Power Spectrum
The "Power Spectrum" shows the power density of the complete capture buffer in
dBm/Hz.
The displayed bandwidth is always 7.68 MHz.
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 93
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 93
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Measurements and Result Displays
I/Q Measurements
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 93
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 93
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.
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I/Q Measurements
In the default state, the result display evaluates the full range of the measured input
data.
Each color represents a modulation type.
●
●
●
●
●
You can filter the results by changing the evaluation range.
: BPSK
: RBPSK
: MIXTURE
: QPSK
: PSK (CAZAC)
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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I/Q Measurements
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 105
Numerical results: CALCulate<n>:STATistics:RESult<res>? on page 106
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).
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 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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Measurements and Result Displays
I/Q Measurements
Remote command:
Selection: LAY:ADD ? '1',LEFT,ASUM
Query: TRACe:DATA?
EVM vs Symbol x Carrier
The "EVM vs Symbol x Carrier" result display shows the EVM 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 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.
Remote command:
Selection: LAY:ADD ? '1',LEFT,PVSC
Query: TRACe:DATA?
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Measurements and Result Displays
I/Q Measurements
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.
Remote command:
Selection: LAY:ADD ? '1',LEFT,AISC
Query: TRACe:DATA?
Result Summary
The Result Summary shows all relevant measurement results in numerical form, combined in one table.
Remote command:
LAY:ADD ? '1',LEFT,RSUM
Contents of the result summary
The table shows results that refer to the complete frame. For each result, the minimum,
mean and maximum values are displayed. It also indicates limit values as defined in
the NB-IoT standard and limit check results where available. The font of 'Pass' results
is green and that of 'Fail' results is red.
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I/Q Measurements
In addition to the red font, the application also puts a red star ( ) in front of
failed results.
By default, all EVM results are in %. To view the EVM results in dB, change the EVM
Unit.
The second part of the table shows results that refer to a specific selection of the
frame.
The statistic is always evaluated over the subframes.
The header row of the table contains information about the selection you have made
(like the subframe).
EVM All Shows the EVM for all resource elements in the analyzed frame.
FETCh[:CC<cc>]:SUMMary:EVM[:ALL][:AVERage]? on page 96
EVM Phys Channel Shows the EVM for all physical channel resource elements in the analyzed
frame.
A physical channel corresponds to a set of resource elements carrying infor-
mation from higher layers. NPDSCH, NPBCH or NPDCCH, for example, are
physical channels. For more information, see 3GPP 36.211.
FETCh[:CC<cc>]:SUMMary:EVM:PCHannel[:AVERage]? on page 97
EVM Phys Signal Shows the EVM for all physical signal resource elements in the analyzed
frame.
The reference signal, for example, is a physical signal. For more information,
see 3GPP 36.211.
FETCh[:CC<cc>]:SUMMary:EVM:PSIGnal[:AVERage]? on page 97
Frequency Error Shows the difference in the measured center frequency and the reference
center frequency.
FETCh[:CC<cc>]:SUMMary:FERRor[:AVERage]? on page 97
Sampling Error Shows the difference in measured symbol clock and reference symbol clock
relative to the system sampling rate.
FETCh[:CC<cc>]:SUMMary:SERRor[:AVERage]? on page 100
RSTP Shows the reference signal transmit power as defined in 3GPP TS 36.141. It
is required for the "DL RS Power" test.
It is an average power and accumulates the powers of the reference symbols
within a subframe divided by the number of reference symbols within a subframe.
FETCh[:CC<cc>]:SUMMary:RSTP[:AVERage]? on page 100
OSTP Shows the OFDM symbol transmit power as defined in 3GPP TS 36.141.
It accumulates all subcarrier powers of the 4th OFDM symbol. The 4th (out of
14 OFDM symbols within a subframe (for frame type 1, normal CP length))
contains exclusively NPDSCH.
FETCh[:CC<cc>]:SUMMary:OSTP[:AVERage]? on page 98
RSSI Shows the Received Signal Strength Indicator. The RSSI is the complete sig-
nal power of the channel that has been measured, regardless of the origin of
the signal.
FETCh[:CC<cc>]:SUMMary:RSSI[:AVERage]? on page 99
Power Shows the average time domain power of the analyzed signal.
FETCh[:CC<cc>]:SUMMary:POWer[:AVERage]? on page 98
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I/Q Measurements
NB-IoT Power Shows the power of all resource elements used by NB-IoT.
FETCh[:CC<cc>]:SUMMary:NBPower[:AVERage]? on page 99
Crest Factor Shows the peak-to-average power ratio of captured signal.
FETCh[:CC<cc>]:SUMMary:CRESt[:AVERage]? on page 96
Marker Table
Displays a table with the current marker values for the active markers.
This table is displayed automatically if configured accordingly.
Wnd Shows the window the marker is in.
Type Shows the marker type and number ("M" for a nor-
mal marker, "D" for a delta marker).
Trc Shows the trace that the marker is positioned on.
Ref Shows the reference marker that a delta marker
refers to.
X- / Y-Value Shows the marker coordinates (usually frequency
and level).
Z-EVM
Z-Power
Z-Alloc ID
Shows the EVM, power and allocation type at the
marker position.
Only in 3D result displays (for example "EVM vs
Symbol x Carrier").
Remote command:
LAY:ADD? '1',RIGH, MTAB, see LAYout:ADD[:WINDow]? on page 73
Results:
CALCulate<n>:MARKer<m>:X on page 103
CALCulate<n>:MARKer<m>:Y on page 103
CALCulate<n>:MARKer<m>:Z? on page 104
CALCulate<n>:MARKer<m>:Z:ALL? on page 104
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3.6 Time Alignment Error
Measurements and Result Displays
Time Alignment Error
Access: "Overview" > "Select Measurement" > "Time Alignment"
The time alignment error measurement captures and analyzes new I/Q data when you
select it.
The time alignment error measurement only works under the following conditions:
●
It is only available in a MIMO setup (2 antennas).
Therefore, you have to mix the signal of the antennas into one cable that you can
connect to the R&S FPS. For more information on configuring and performing a
time alignment measurement, see Chapter A, "Performing Time Alignment Mea-
surements", on page 143.
●
It is only available for the stand alone deployment.
In addition to the result displays mentioned in this section, the time alignment measurement also supports the following result displays described elsewhere.
●
"Capture Buffer" on page 15
●
"Power Spectrum" on page 19
●
" Marker Table " on page 26
You can select the result displays from the evaluation bar and arrange them as you like
with the SmartGrid functionality.
Remote command:
Measurement selection: CONFigure[:LTE]:MEASurement on page 107
Result display selection: LAYout:ADD[:WINDow]? on page 73
Time Alignment Error.................................................................................................... 27
Time Alignment Error
The time alignment is an indicator of how well the transmission antennas in a MIMO
system are synchronized. The time alignment error is the time delay between a reference antenna (for example antenna 1) and another antenna.
The application shows the results in a table.
Each row in the table represents one antenna. The reference antenna is not shown.
For each antenna, the maximum, minimum and average time delay that has been
measured is shown. The minimum and maximum results are calculated only if the
measurement covers more than one subframe.
In any case, results are only displayed if the transmission power of both antennas is
within 15 dB of each other. Likewise, if only one antenna transmits a signal, results will
not be displayed (for example if the cabling on one antenna is faulty).
For more information on configuring this measurement, see Chapter 4.3, "Time Align-
ment Error Measurement", on page 50.
The "Limit" value shown in the result display is the maximum time delay that may occur
for each antenna (only displayed for systems without carrier aggregation).
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Measurements and Result Displays
Frequency Sweep Measurements
You can select the reference antenna from the dropdown menu in the result display.
You can also select the reference antenna in the MIMO Setup - if you change them in
one place, they are also changed in the other.
In the default layout, the application also shows the "Capture Buffer" and "Power Spectrum" result displays for each component carrier.
Remote command:
Selection: LAY:ADD ? '1',LEFT,TAL
Query: FETCh:TAERror[:CC<cc>]:ANTenna<ant>[:AVERage]? on page 101
Reference antenna: CONFigure[:LTE]:DL[:CC<cc>]:MIMO:ASELection
on page 114
3.7 Frequency Sweep Measurements
Access (ACLR): "Meas Setup" > "Select Measurement" > "Channel Power ACLR"
Access (SEM): "Meas Setup" > "Select Measurement" > "Spectrum Emission Mask"
The NB-IoT aplication supports the following frequency sweep measurements.
●
Adjacent channel leakage ratio (ACLR)
●
Spectrum emission mask (SEM)
Instead of using I/Q data, the frequency sweep measurements sweep the spectrum
every time you run a new measurement. Therefore, it is mandatory to feed a signal into
the RF input for these measurements. Using previously acquired I/Q data for the frequency sweep measurements is not possible (and vice-versa).
Because each of the frequency sweep measurements uses different settings to obtain
signal data it is also not possible to run a frequency sweep measurement and view the
results in another frequency sweep measurement.
Make sure to have sufficient bandwidth to be able to capture the whole signal, including neighboring channels.
Features of the frequency sweep measurements:
●
Frequency sweep measurements are only available for the stand alone deploy-
ment.
In addition to the specific diagrams and table (see description below), frequency sweep
measurements support the following result displays.
●
" Marker Table " on page 26
●
Marker peak list
Both result displays have the same contents as the spectrum application.
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Measurements and Result Displays
Frequency Sweep Measurements
Remote command:
Measurement selection: CONFigure[:LTE]:MEASurement on page 107
Result display selection: LAYout:ADD[:WINDow]? on page 73
Adjacent Channel Leakage Ratio (ACLR).....................................................................29
└ Result diagram................................................................................................29
└ Result summary..............................................................................................29
Spectrum Emission Mask (SEM).................................................................................. 30
└ Result diagram................................................................................................30
└ Result summary..............................................................................................30
Marker Peak List .......................................................................................................... 31
Adjacent Channel Leakage Ratio (ACLR)
The adjacent channel leakage ratio (ACLR) measurement is designed to analyze signals that contain multiple signals for different radio standards. Using the ACLR measurement, you can determine the power of the transmit (Tx) channel and the power of
the neighboring (adjacent) channels to the left and right of the Tx channel. Thus, the
ACLR measurement provides information about the power in the adjacent channels as
well as the leakage into these adjacent channels.
When you measure the ACLR in the NB-IoT application, the R&S FPS automatically
selects appropriate ACLR settings based on the selected channel bandwidth.
For a comprehensive description of the ACLR measurement, refer to the user manual
of the R&S FPS.
Remote command:
Selection: CONF:MEAS ACLR
Result diagram ← Adjacent Channel Leakage Ratio (ACLR)
The result diagram is a graphic representation of the signals with a trace that shows
the measured signal. Individual channels (Tx and adjacent channels) are indicated by
vertical lines and corresponding labels.
In addition, the R&S FPS highlights the channels (blue: Tx channel, green: adjacent
channels).
The x-axis represents the frequency with a frequency span that relates to the specified
NB-IoT channel and adjacent channel bandwidths. On the y-axis, the power is plotted
in dBm.
The power for the Tx channel is an absolute value in dBm. The power of the adjacent
channels is relative to the power of the Tx channel.
In addition, the R&S FPS tests the ACLR measurement results against the limits
defined by 3GPP.
Remote command:
Result query: TRACe:DATA?
Result summary ← Adjacent Channel Leakage Ratio (ACLR)
The result summary shows the signal characteristics in numerical form. Each row in
the table corresponds to a certain channel type (Tx, adjacent channel). The columns
contain the channel characteristics.
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Measurements and Result Displays
Frequency Sweep Measurements
●
Channel
Shows the channel type (Tx, adjacent or alternate channel).
●
Bandwidth
Shows the channel bandwidth.
●
Offset
Shows the channel spacing.
●
Power
Shows the power of the Tx channel.
●
Lower / Upper
Shows the relative power of the lower and upper adjacent and alternate channels.
The values turn red if the power violates the limits.
Remote command:
Result query: CALCulate<n>:MARKer<m>:FUNCtion:POWer<sb>:RESult[:
CURRent]?
Spectrum Emission Mask (SEM)
The "Spectrum Emission Mask" (SEM) measurement shows the quality of the measured signal by comparing the power values in the frequency range near the carrier
against a spectral mask that is defined by the 3GPP specifications. In this way, you can
test the performance of the DUT and identify the emissions and their distance to the
limit.
For a comprehensive description of the SEM measurement, refer to the user manual of
the R&S FPS.
Remote command:
Selection (SEM): CONF:MEAS ESP
Result diagram ← Spectrum Emission Mask (SEM)
The result diagram is a graphic representation of the signal with a trace that shows the
measured signal. The SEM is represented by a red line.
If any measured power levels are above that limit line, the test fails. If all power levels
are inside the specified limits, the test passes. The application labels the limit line to
indicate whether the limit check has passed or failed.
The x-axis represents the frequency with a frequency span that relates to the specified
NB-IoT channel bandwidths. The y-axis shows the signal power in dBm.
Remote command:
Result query: TRACe:DATA?
Result summary ← Spectrum Emission Mask (SEM)
The result summary shows the signal characteristics in numerical form. Each row in
the table corresponds to a certain SEM range. The columns contain the range characteristics. If a limit fails, the range characteristics turn red.
●
Start / Stop Freq Rel
Shows the start and stop frequency of each section of the spectrum emission mask
relative to the center frequency.
●
RBW
Shows the resolution bandwidth of each section of the spectrum emission mask.
●
Freq at Δ to Limit
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