Application Card | Version 01.00
R&S®CMWcards, an intuitive and user-friendly
software application, makes it possible to recreate
field testing in a lab environment.
NB-IoT field-to-
lab testing with
R&S®CMWcards
Your task
Narrowband IoT (NB-IoT) is a low power wide area net-
work (LPWAN) radio technology initially standardized by
3GPP in Release 13. It operates in a limited bandwidth of
200kHz and can be deployed in three operating modes:
standalone, guard band and in-band. NB-IoT provides ser-
vices that span various vertical industries, e.g. logistics
tracking, smart home, smart city, etc.
Outstanding indoor coverage even under poor radio condi-
tions, reliable mobility performance and minimum power
consumption are just a few of the key performance indica-
tors of NB-IoT modules.
It is essential to thoroughly verify the performance of the
NB-IoT module in various mobile operator networks be-
fore product launch. Sometimes it is even necessary to
conduct benchmarking tests to ensure the market leading
position of your product. Field tests play a very important
role in this context.
Field tests enable users to test the module in real network
environments, providing the necessary level of confidence
in the functionality and reliability of the NB-IoT product. Is-
sues seen during field tests are usually hard to reproduce
due to the dynamic nature of real-world conditions. This
makes it hard to verify fixes.
Rohde & Schwarz solution
¸CMWcards is a graphic test script creation tool that
runs on the ¸CMW500 and requires no prior program-
ming knowledge. Just by setting up a hand of cards, you
can create various signaling test scripts to simulate a va-
riety of test scenarios and verify your device’s protocol
behavior. Each card comprises a predefined protocol pro-
cedure, yet is flexible enough to allow users to adjust the
signaling parameters. The built-in error checking function-
ality of each card ensures the conformity of the signaling
flows.
The field-to-lab (F2L) application works closely with
¸CMWcards and allows users to reproduce the real
network scenario in the lab environment. The majority of
the field-related issues can then be investigated in a con-
trollable, repeatable and deterministic way.
¸CMWcards with F2L is a powerful tool for verifying
field behavior. It extracts the network configurations from
the field logs and imports them into ¸CMWcards to
simulate the test scenario with live network configurations,
including cell information, RRC and NAS messages.
It can replace specific layer 3 (L3) messages in the test
script with the one from the field log in order to easily test
how this L3 message content impacts module behavior.
Field RF conditions, e.g. RF power and quality, can also
be extracted with optional synchronization with downlink
messages and reproduced in the test script. In the future,
it will be possible to extend the variable radio conditions to
simulate the fading condition.
CMWcards-NB-IoT-field-to-lab-testing_ac_en_3609-0866-92_v0100.indd 1 15.02.2019 11:56:48
Outline of NB-IoT field-to-lab test concept
1
Field test logfile
F2L wizard
2
3 5
4
Field-to-lab
Layer 3 messages
RF parameters
Network configurations
Network profile
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Trade names are trademarks of the owners
PD 3609.0866.92 | Version 01.00 | February 2019 (jr)
NB-IoT eld-to-lab testing with R&S®CMWcards
Data without tolerance limits is not binding | Subject to change
© 2019 Rohde & Schwarz GmbH & Co.KG | 81671 Munich, Germany
3609.0866.92 01.00 PDP 1 en
360
9086692
Designation Type Order No.
R&S®CMWcards framework R&S®CMW-KP091 1211.0540.02
R&S®CMWcards R&S®CMW-KT022 1207.9301.02
R&S®CMWcards advanced extension R&S®CMW-KT026 1209.1750.02
R&S®CMWcards field-to-lab signaling extension R&S®CMW-KT030 1211.2850.02
Field-to-lab power/quality extension R&S®CMW-KT041 1532.5015.02
Create an R&S®CMWcards test script that reflects the
test sequence of your field test. For example, as shown
in the script below, the NB-IoT DUT registered with user
plane cellular IoT (cIoT) EPS optimization resumes the data
connection on another NB-IoT cell after a radio link failure.
Select the network profile created in step 3. The net-
work profile will automatically replace the cards in the test
script you created in step 4.
After step 5, the R&S®CMWcards test scenario simu-
lates the live network conditions in a lab environment
(R&S®CMW500).
The R&S®CMWcards and F2L combination offers a unique
and powerful way to recreate and eventually resolve
NB-IoT field test problems in the lab. This approach greatly
increases debugging efficiency, optimizing your OPEX.
See also
www.rohde-schwarz.com/CMWcards
Application workflow
The figure below shows a typical use case of the
R&S®CMWcards F2L feature for NB-IoT application.
To debug a field test problem, first a field test log
file is needed. This kind of log file can be obtained by a
Rohde & Schwarz network scanner or captured via the
UEtraces.
Feed the field log as input to the F2L application wizard.
The wizard automatically analyzes the log file. Based on
the analysis output, the user determines the network
parameters and the L3 message contents that need to be
further investigated.
The F2L wizard generates a network profile that con-
tains the network configurations, layer 3 messages and RF
parameters extracted from the field log. The network pro-
file is a set of cards where the parameters of each card are
configured like those in the real network.
CMWcards-NB-IoT-field-to-lab-testing_ac_en_3609-0866-92_v0100.indd 2 15.02.2019 11:56:49