ETSI GR F5G-TEST 041 V1.1.1 (2026-09)

• Abstract:

  DGR/F5G-0041

• Status: Not Published
• Technical Committee: F5G TEST - TEST
• Current Stage: 12 - Citation in the OJ (auto-insert)
• Due Date: 11-Oct-2026
• Completion Date: 14-Sep-2026

GROUP REPORT
Fifth Generation Fixed Network (F5G);
F5G-A Methodology for Hybrid Measurement-Simulation of
FTTR
Disclaimer
The present document has been produced and approved by the Fifth Generation Fixed Network (F5G) ETSI Industry
Specification Group (ISG) and represents the views of those members who participated in this ISG.
It does not necessarily represent the views of the entire ETSI membership.

2 ETSI GR F5G-TEST 041 V1.1.1 (2026-09)

Reference
DGR/F5G-0041
Keywords
F5G Advanced, FTTR, measurement, simulation,
testing, WLAN
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: [phone]  Fax: [phone]

Siret N° 348 623 562 00017 - APE 7112B
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° w061004871

Important notice
The present document can be downloaded from the
ETSI Search & Browse Standards application.
The present document may be made available in electronic versions and/or in print. The content of any electronic and/or
print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any
existing or perceived difference in contents between such versions and/or in print, the prevailing version of an ETSI
deliverable is the one made publicly available in PDF format on ETSI deliver repository.
Users should be aware that the present document may be revised or have its status changed,
this information is available in the Milestones listing.
If you find errors in the present document, please send your comments to
the relevant service listed under Committee Support Staff.
If you find a security vulnerability in the present document, please report it through our
Coordinated Vulnerability Disclosure (CVD) program.
Notice of disclaimer & limitation of liability
The information provided in the present deliverable is directed solely to professionals who have the appropriate degree of
experience to understand and interpret its content in accordance with generally accepted engineering or
other professional standard and applicable regulations.
No recommendation as to products and services or vendors is made or should be implied.
No representation or warranty is made that this deliverable is technically accurate or sufficient or conforms to any law
and/or governmental rule and/or regulation and further, no representation or warranty is made of merchantability or fitness
for any particular purpose or against infringement of intellectual property rights.
In no event shall ETSI be held liable for loss of profits or any other incidental or consequential damages.

Any software contained in this deliverable is provided "AS IS" with no warranties, express or implied, including but not
limited to, the warranties of merchantability, fitness for a particular purpose and non-infringement of intellectual property
rights and ETSI shall not be held liable in any event for any damages whatsoever (including, without limitation, damages
for loss of profits, business interruption, loss of information, or any other pecuniary loss) arising out of or related to the use
of or inability to use the software.
Copyright Notification
No part of this document may be reproduced in any form, by any means and in any media, without the prior written
authorization of ETSI and except as expressly permitted below.
By way of exception and when the document is a normative deliverable (European Standard (EN),
Technical Specification (TS), Group Specification (GS) or ETSI Standard (ES)), ETSI authorizes to reproduce
and incorporate into products, services and technical documentation only those extracts (e.g. templates) that are strictly
necessary for the technical implementation of the normative deliverable, to ensure compliance with the latter.
Nothing in this notice shall be construed as limiting any mandatory exceptions to copyright provided by applicable law.

© ETSI 2026.
All rights reserved.
ETSI
3 ETSI GR F5G-TEST 041 V1.1.1 (2026-09)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Executive summary . 5
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 7
3 Definition of terms, symbols and abbreviations . 8
3.1 Terms . 8
3.2 Symbols . 8
3.3 Abbreviations . 9
4 Reference Model and Test Environment . 9
4.1 Overview . 9
4.2 Measurement Subsystem . 10
4.3 Simulation Subsystem (Digital Twin) . 10
4.4 Data Integration and Validation Flow . 10
4.5 Uncertainty and Repeatability Considerations . 11
5 Test Case . 11
5.1 Test Purpose . 11
5.2 Test Configuration . 12
5.3 Test Procedure . 12
5.3.1 Phases . 12
5.3.2 Measurement Phase . 12
5.3.3 Equivalent Source Calculation Phase . 13
5.3.4 Simulation-Based Performance Evaluation Phase . 13
5.4 Expected Result . 13
5.4.1 Overview . 13
5.4.2 Performance Criteria . 13
5.4.3 Reference antenna and threshold-range adaptation . 15
5.4.4 Physical relations . 17
Annex A: Comparison of Hybrid Measurement-Simulation Methodology with Conventional
Test Approaches . 19
A.1 Overview of FTTR Performance Evaluation Approaches . 19
A.2 Shielded and Radiated OTA Testing . 19
A.3 Real Home and Field Testing . 19
A.4 Simulation-Only Performance Evaluation . 20
A.5 Hybrid Measurement-Simulation Methodology. 20
A.6 Qualitative Comparison Summary . 20
Annex B: Reference Residential Digital Twin Environment Framework . 22
B.1 Purpose and Scope . 22
B.2 Reference Geometry Model . 22
B.3 Reference Material Classes . 22
B.4 Coordinate System and Device Placement . 23
ETSI
4 ETSI GR F5G-TEST 041 V1.1.1 (2026-09)
B.5 Evaluation Location Grid . 23
B.6 Reproducibility and Documentation Principles . 23
Annex C: Illustrative validation and application of the hybrid measurement-simulation
methodology . 24
C.1 Purpose . 24
C.2 Test and Simulation Configuration . 24
C.3 Free-space Radiation Comparison . 24
C.4 Validation of the Indoor Digital Twin . 25
C.5 Hybrid Indoor Coverage Evaluation . 27
C.5.1 Introduction . 27
C.5.2 Coverage Maps . 28
C.5.3 Evaluation at 44 Receiver Positions . 28
C.6 Summary . 30
Annex D: Change history . 31
History . 32

ETSI
5 ETSI GR F5G-TEST 041 V1.1.1 (2026-09)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables (European Standard (EN), Technical Specification (TS),
Group Specification (GS) or ETSI Standard (ES)) may have been declared to ETSI. The declarations pertaining to these
essential IPRs, if any, are publicly available for ETSI members and non-members, and can be found in
ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the
ETSI IPR online database.
Pursuant to the ETSI Directives including the ETSI IPR Policy, no investigation regarding the essentiality of IPRs,
including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not
referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become,
essential to the present document.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
DECT™, PLUGTESTS™, UMTS™ and the ETSI logo are trademarks of ETSI registered for the benefit of its
Members. 3GPP™, LTE™ and 5G™ logo are trademarks of ETSI registered for the benefit of its Members and of the
3GPP Organizational Partners. oneM2M™ logo is a trademark of ETSI registered for the benefit of its Members and of ®
the oneM2M Partners. GSM and the GSM logo are trademarks registered and owned by the GSM Association.
Foreword
This Group Report (GR) has been produced by ETSI Industry Specification Group (ISG) Fifth Generation Fixed
Network (F5G).
Modal verbs terminology
In the present document "should", "should not", "may", "need not", "will", "will not", "can" and "cannot" are to be
interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Executive summary
The present document presents a hybrid measurement-simulation methodology for the performance evaluation of
Fiber-to-the-Room (FTTR) wireless devices in residential indoor environments. The methodology combines physical
electromagnetic field measurements with numerical simulation techniques in a digital twin representation of the
deployment environment.
FTTR systems combine optical access with multiple distributed wireless access points, creating complex indoor
propagation conditions that are difficult to characterize using conventional testing approaches alone.
ETSI
6 ETSI GR F5G-TEST 041 V1.1.1 (2026-09)
Conventional wireless testing approaches include fully physical measurement setups and purely numerical simulation
models. While physical measurements provide traceability and realism, they are often constrained by test environment
limitations and measurement effort. Simulation-based approaches offer flexibility and scalability, but their accuracy
strongly depends on modelling assumptions. The hybrid methodology introduced in the present document aims to
combine the strengths of both approaches by integrating measured field data into electromagnetic simulation
workflows. The methodology is designed to facilitate realistic indoor performance evaluation while maintaining
traceability and technical repeatability across different test environments.
The proposed framework enables the evaluation of key radio performance indicators such as received signal strength,
power density distribution, and spatial coverage under realistic indoor conditions. By leveraging near-field
measurement techniques and equivalent source modelling, the methodology allows the extension of physical
measurements into representative digital twin environments, improving repeatability and reducing overall test
complexity and measurement time.
The present document defines the reference model, data integration flow, validation principles, and a representative test
case structure for hybrid measurement-simulation based FTTR performance evaluation. It is intended to support test
laboratories, fixed network operators and service providers, and equipment designers in the development and
application of consistent and reproducible hybrid testing methodologies.

ETSI
7 ETSI GR F5G-TEST 041 V1.1.1 (2026-09)
1 Scope
The present document describes a hybrid measurement-simulation methodology for evaluating the wireless
performance of Fiber-to-the-Room (FTTR) devices in residential indoor environments. The methodology applies to Sub
FTTR Units (SFU) and Main FTTR Units (MFU) operating as access points within FTTR deployments.
2 References
2.1 Normative references
Normative references are not applicable in the present document.
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long-term validity.
The following referenced documents may be useful in implementing an ETSI deliverable or add to the reader's
understanding, but are not required for conformance to the present document.
[i.1] CTIA Certification: "Test Plan for Wireless Device Over-the-Air Performance, Multi-Probe
Anechoic Chamber Methodology (CTIA 01.40)", Version 6.0.1.
[i.2] ETSI TR 137 977 (V19.0.0): "Universal Mobile Telecommunications System (UMTS); LTE;
Universal Terrestrial Radio Access (UTRA) and Evolved Universal Terrestrial Radio Access
(E-UTRA); Verification of radiated multi-antenna reception performance of User Equipment (UE)
(3GPP TR 37.977 version 19.0.0 Release 19)".
[i.3] IEEE Std 1720™: "IEEE Recommended Practice for Near-Field Antenna Measurements".
[i.4] IEC 61000-4-21:2011: "Electromagnetic compatibility (EMC) - Part 4-21: Testing and
measurement techniques - Reverberation chamber test methods".
[i.5] S. Gregson, J. McCormick, C. Parini: "Principles of Planar Near-Field Antenna Measurements",
IET, 2023.
[i.6] L.J. Foged et al.: "Antenna measurement systems using multi-probe technology", 2015 IEEE™
Conference on Antenna Measurements & Applications (CAMA).
[i.7] S.-H. Park, G.-H. Jang, Y.-H. Seo, H.-S. Keum and S.-I. Bang: "High-Speed Antenna
Measurement System Using Multi-Probe Array Technique for 5G Applications", Electronics,
Vol. 11, No. 21, 2022, Article 3435.
[i.8] K. Persson and M. Gustafsson: "Reconstruction of equivalent currents using near-field data
transformation with radome applications", Progress In Electromagnetics Research, Vol. 54, 2005,
pp. 179–198.
[i.9] R. Bagheriasl et al.: "Toward Standardization of Phasor Near-field OTA Testing for Connected
Devices – How RF Phasor Arrays Enable Augmented Measurements", IEEE™ Conference on
Antenna Measurements & Applications (CAMA), 2025.
[i.10] Broadband Forum TR-398 Issue 3 Corrigendum 1: "Wi-Fi Residential & SOHO Performance
Testing", May 2025.
[i.11] IEEE Std 145™-2025: "IEEE Standard for Definitions of Terms for Antennas".
ETSI
8 ETSI GR F5G-TEST 041 V1.1.1 (2026-09)
[i.12] ETSI TS 138 161 (V19.3.0): "5G; NR; User Equipment (UE) TRP (Total Radiated Power) and
TRS (Total Radiated Sensitivity) requirements; Range 1 Standalone and Range 1 Interworking
operation with other radios (3GPP TS 38.161 version 19.3.0 Release 19) ".
[i.13] IEEE Std 802.11ax™-2021: "IEEE Standard for Information Technology--Telecommunications
and Information Exchange between Systems Local and Metropolitan Area Networks--Specific
Requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY)
Specifications Amendment 1: Enhancements for High-Efficiency WLAN".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:
digital twin: numerical model of a physical environment used to emulate realistic indoor propagation conditions and
enable repeatable simulation of electromagnetic fields in that environment
equivalent electromagnetic source model: numerical representation derived from measured near-field data that
reproduces the radiated field behaviour of the device under test in the region outside the equivalent-source region
hybrid measurement: combination of physical field measurement and electromagnetic simulation, where measured
data are coupled with numerical computation to determine electromagnetic field distributions and performance metrics
across defined test environments
measurement surface: geometrical surface associated with the spatial locations at which complex near-field
electromagnetic field samples are acquired
near-field: region in the vicinity of an antenna corresponding to near-field conditions
NOTE: See IEEE Std 145-2025 [i.11] for antenna terminology.
3.2 Symbols
For the purposes of the present document, the following symbols apply:
� effective aperture of the receiving antenna (m )
�
� effective aperture of an isotropic antenna (m )
���
� percentage of evaluation locations with received signal strength greater than or equal to � (%)
�
� percentage of evaluation locations classified as acceptable or strong (%)
�������
� percentage of evaluation locations classified as strong (%)
������
� percentage of evaluation locations classified as acceptable (%)
����������
� percentage of evaluation locations classified as weak (%)
����
� minimum required percentage of evaluation locations classified as acceptable or strong for the
���
selected test scenario (%)
� receiving-antenna gain in linear units, including radiation efficiency and excluding impedance
mismatch at the receiver interface
� linear gain of the lossless half-wave dipole receiving antenna
���
� linear gain of alternative receiving antenna
���
�(.) indicator function, equal to 1 when its argument is true and 0 otherwise
� polarization mismatch factor between the incident electromagnetic field and the receiving antenna,
���
in linear units, with 0≤ � ≤1
���
� polarization mismatch factor for the lossless half-wave dipole reference antenna
���,���
� polarization mismatch factor for the alternative receiving antenna
���,���
� impedance mismatch efficiency between the receiving antenna and the receiver input, in linear
�
units, with 0≤ � ≤1
�
� impedance mismatch efficiency of the half-wave dipole reference receiving antenna
�, dip
� impedance mismatch efficiency of the alternative receiving antenna
�, ant
ETSI
9 ETSI GR F5G-TEST 041 V1.1.1 (2026-09)
� number of evaluation locations
�� scalar power density, corresponding to the magnitude of the time-averaged Poynting vector
(W/m²)
� available received power from the receiving antenna, defined as the maximum power that can be
��
delivered at the antenna terminals to a conjugate-matched receiver input (W)
� actual received power delivered to the receiver input at the defined receiver reference plane (W)
�
� actual received power delivered to the receiver input at evaluation location i (W)
�,�
�
� average power delivered to the receiver input, computed across all evaluation locations (W)
�
��� received signal strength at evaluation location � (dBm)
�
��� average received signal strength (dBm)
���
� received signal strength threshold used for spatial coverage evaluation (dBm)
� minimum acceptable RSS boundary for the selected receiving antenna (dBm)
min
� strong received signal strength boundary for the selected receiving antenna (dBm)
strong
� minimum required linear-power-averaged received signal strength for the selected test scenario
avg
and receiving antenna (dBm)
� minimum acceptable RSS boundary for the lossless half-wave dipole reference antenna (dBm)
���,���
� strong RSS boundary for the lossless half-wave dipole reference antenna (dBm)
������,���
� average received signal strength threshold for the half-wave dipole reference receiving antenna
���,���
(dBm)
� minimum acceptable RSS boundary adapted to the alternative receiving antenna (dBm)
���,���
� strong RSS boundary adapted to the alternative receiving antenna (dBm)
strong, ant
� average received signal strength threshold adapted to the alternative receiving antenna (dBm)
avg, ant
� wavelength (m)
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
LAN Local Area Network
MCS Modulation and Coding Scheme
MFU Main FTTR Unit
OTA Over-The-Air
PD Power Density
RF Radio Frequency
RSS Received Signal Strength
RSSI Received Signal Strength Indicator
SFU Sub FTTR Unit
TRP Total Radiated Power
UDP User Datagram Protocol
UE User Equipment
WLAN Wireless Local Area Network
4 Reference Model and Test Environment
4.1 Overview
Clause 4 defines the reference model used for the hybrid measurement-simulation methodology. The reference model
describes the roles of the measurement and simulation subsystems and the data integration flow between them.
The framework enables the transformation of measured electromagnetic field data into equivalent numerical excitation
sources for use within a digital twin representation of the indoor environment. This approach allows physically
measured device behaviour to be propagated into representative deployment scenarios while maintaining consistency
with electromagnetic theory.
ETSI
10 ETSI GR F5G-TEST 041 V1.1.1 (2026-09)
The reference model is intended to remain implementation-independent and technology-neutral. It does not prescribe
specific measurement hardware, numerical solvers, or commercial tools, but instead defines the functional blocks and
data integration flow needed to support reproducible hybrid testing. The reference model does not define an overall
system architecture for implementing the hybrid measurement-simulation methodology; such an architecture is for
further study.
4.2 Measurement Subsystem
The measurement subsystem is responsible for acquiring electromagnetic field data from the device under test under
controlled transmission conditions. Its primary objective is to capture physically representative field information that
can be used as input for subsequent numerical simulation stages.
Near-field measurements are used to sample the complex electromagnetic field (amplitude and phase) in the vicinity of
the device under test. The availability of phase-resolved field data is essential for the accurate computation of
equivalent electromagnetic sources. These measurements are performed on one or more surfaces around the device,
such as planar, cylindrical, spherical, cuboid or other suitable measurement geometries. The combined measurement
geometry provides sufficient spatial coverage and sampling density to support the equivalent source computation.
During data acquisition, the device under test is operated under continuous transmission conditions using controlled
wireless traffic generation. This ensures stable radiated emission behaviour throughout the measurement process and
minimizes time-domain variations of the transmitted signals.
The measurement subsystem supports acquisition of complex electromagnetic field data, including both amplitude and
phase, in order to enable equivalent source calculation and subsequent numerical simulation. This capability is achieved
using measurement systems capable of coherent field sampling. Measurement systems using multiple probes enable
parallel acquisition of field samples and can significantly reduce overall measurement time compared with sequential
single-probe scanning approaches (see [i.6] and [i.7]).
EXAMPLE: Near-field phasor probe arrays are an example of measurement systems capable of coherent field
sampling.
The present document does not prescribe specific probe designs, array geometries, scanner architectures, or mechanical
positioning solutions. These implementation aspects may vary depending on laboratory infrastructure, provided that the
measurement system satisfies the functional need of coherent complex-field acquisition with sufficient spatial sampling
density.
4.3 Simulation Subsystem (Digital Twin)
The simulation subsystem provides the numerical representation of the environment used in the hybrid measurement-
simulation methodology. It consists of a digital twin representing the indoor environment, combined with an
electromagnetic solver capable of computing field propagation and spatial performance metrics.
The digital twin environment models the geometric layout and material characteristics of representative residential
indoor deployment scenarios. The digital twin may include walls, floors, ceilings, and major furniture structures that
influence radio wave propagation. The level of geometric and material detail may be adapted according to the intended
accuracy and computational complexity of the simulation.
Equivalent electromagnetic sources derived from the measurement subsystem are integrated into the digital twin
environment, either directly or through a compatible radiation representation derived from them, to reproduce the
radiated behaviour of the device under test.
The simulation subsystem enables the computation of spatial field distributions and performance indicators, such as
power density and received signal strength, at predefined locations within the digital twin environment.
4.4 Data Integration and Validation Flow
The data integration flow defines the process by which measured electromagnetic field data are transformed into
numerical excitation models suitable for simulation within the digital twin environment. This transformation is
performed using equivalent source modelling techniques that construct a source representation capable of reproducing
the measured fields outside the measurement surface.
ETSI
11 ETSI GR F5G-TEST 041 V1.1.1 (2026-09)
The data integration flow consists of the following stages:
• Acquisition of near-field measurement data around the device under test.
• Computation of equivalent electromagnetic source models based on the measured data.
• Integration of the equivalent sources into the numerical simulation environment, either directly or through a
compatible radiation representation derived from them.
• Computation of spatial electromagnetic field distributions and extraction of performance metrics.
The equivalent source calculation is validated using reference antennas with known electromagnetic characteristics [i.9]
by comparing field quantities obtained from the constructed equivalent sources with reference values for those
antennas. The digital-twin propagation model may be validated separately by comparing simulated and measured field
quantities at corresponding locations in the physical and digital environments. This staged validation provides
additional diagnostic information and helps identify the main source of any discrepancy observed in the overall
end-to-end comparison (see Annex C for an example).
4.5 Uncertainty and Repeatability Considerations
The accuracy and repeatability of hybrid measurement-simulation results depend on multiple factors spanning both the
measurement and simulation domains. Measurement-related uncertainty contributors include measurement probe
calibration, positioning accuracy, measurement system repeatability, and environmental stability during acquisition.
Digital twin uncertainty contributors include differences between the physical environment and its geometric
representation, uncertainty in the electromagnetic properties assigned to materials, transmitter and receiver placement
and propagation model configuration and numerical settings, such as discretization parameters.
These contributions can act simultaneously, and their individual effects cannot in general be determined from the final
RSS difference alone. A quantitative combined uncertainty requires separate characterization of the relevant
contributors and their interactions. In the present methodology, the end-to-end comparison between simulated and
measured RSS at corresponding receiver positions provides a practical assessment of their aggregate uncertainty effect.
The hybrid measurement-simulation methodology aims to support reproducible performance evaluation by defining
consistent reference models, validation procedures, and data processing workflows. The development of a quantitative
uncertainty budget, including the identification and characterization of dominant error sources, is foreseen as part of
future refinements of the methodology and is for further study.
Laboratories applying the hybrid approach need to document relevant configuration parameters and environmental
conditions to support result traceability and inter-laboratory comparison.
5 Test Case
5.1 Test Purpose
Clause 5 defines a hybrid measurement-simulation test case for the performance evaluation of FTTR devices in
residential indoor environments. The test case is intended to demonstrate the application of the proposed methodology
and to provide a reference workflow that can be reproduced. Extensions are for further study.
The purpose of the test case is to evaluate the wireless performance of Sub FTTR Units (SFU) and Main FTTR Units
(MFU) under the indoor deployment conditions using the hybrid measurement-simulation methodology.
The test aims to characterize the spatial distribution of electromagnetic field quantities and radio performance
indicators, such as received signal strength and power density, within a digital twin representation of the residential
environment. The results are used to assess indoor coverage behaviour and to verify the consistency of the hybrid
testing workflow.
ETSI
12 ETSI GR F5G-TEST 041 V1.1.1 (2026-09)
5.2 Test Configuration
The test configuration consists of a device under test, which may be an SFU or an MFU, a wireless terminal, a traffic
generator, and the measurement subsystem. The device under test is configured to operate under continuous
transmission conditions using controlled wireless traffic in order to ensure stable radiated emission during
measurement.
During the measurement phase, the device under test is positioned in a controlled near-field measurement setup, with
measurements performed on multiple surfaces around the device. Figure 1 illustrates an implementation using six
surfaces defining a rectangular cuboid. Near-field phasor probe arrays are used to acquire complex electromagnetic
field samples on these surfaces.
The wireless terminal is positioned at a distance of 1 m from the device under test and remains connected throughout
the measurement process. The traffic generator is connected on the LAN or uplink side and is used to generate
continuous traffic.
5.3 Test Procedure
5.3.1 Phases
The hybrid performance evaluation test procedure is divided into three main phases:
1) Measurement phase;
2) Equivalent source calculation phase; and
3) Simulation-based performance evaluation phase.
The detailed workflow is described below.
5.3.2 Measurement Phase
1) One WLAN terminal is connected to the SFU/MFU under test and positioned at a distance of 1 m. The WLAN
terminal remains connected during the entire test.
2) Unless otherwise described in this procedure, the WLAN parameters (mode, channel, authentication and
encryption method, etc.) of the MFU and SFU use the manufacturer default settings. The channel bandwidth is
set to 20 MHz for both 2,4 GHz and 5 GHz. Other channel bandwidths supported by the MFU/SFU may be
evaluated using the same procedure. For the test case described here, the number of spatial streams is set to
two (Nss = 2), where supported by the device under test, using IEEE 802.11ax [i.13]. If two spatial streams are
not supported, a supported spatial-stream configuration is used and documented. Other supported spatial-
stream configurations or WLAN protocols may be evaluated using the same procedure. Any alternative
WLAN configuration is evaluated as a separate test run. The WLAN configuration used for each test run is
documented to support comparability and repeatability.
3) Generate continuous UDP traffic between the device under test and the WLAN terminal so that the device
under test remains actively transmitting during the measurement.
NOTE: UDP is used in the reference test setup for ease of continuous traffic generation and monitoring. The UDP
traffic may be carried over Ethernet on the wired side of the setup. Other means of generating a controlled
continuous traffic stream may be used, provided that the device under test remains actively transmitting
throughout the measurement.
4) After initiating data transmission, wait at least 120 seconds as a stabilization period to allow the wireless link
and transmission to reach steady-state operation before measurement begins.
5) Maintain the data transmission continuously throughout the entire data acquisition process.
6) Measure near-field phasor data (both phase and amplitude) on multiple surfaces around the SFU/MFU.
EXAMPLE: Measurements can be performed on six surfaces defining a rectangular cuboid around the
SFU/MFU as shown in figure 1.
ETSI
13 ETSI GR F5G-TEST 041 V1.1.1 (2026-09)

Figure 1: Example rectangular cuboid surrounding SFU/MFU:
(a) with external antennas; (b) with internal antennas
7) During step 6 of the measurement phase, continuously monitor the throughput at the terminal to ensure that the
device under test remains actively transmitting; values near zero indicate that the intended traffic condition is
not maintained. If this occurs, re-establish the traffic condition starting from Step 3 and the stabilization period
is repeated before the affected data are acquired again.
5.3.3 Equivalent Source Calculation Phase
1) Process the measured near-field data to compute an equivalent electromagnetic source representation of the
device under test. The equivalent source model is selected to enable accurate reproduction of the measured
field distribution outside the measurement surfaces and compatibility with the selected numerical simulation
environment.
5.3.4 Simulation-Based Performance Evaluation Phase
1) Integrate the equivalent sources derived from clause 5.3.3 into the digital twin environment, either directly or
through a compatible radiation representation derived from them.
2) Perform numerical electromagnetic simulations to compute power density and received signal strength, at
evaluation locations defined according to clause B.5.
3) Generate and report spatial performance maps and coverage indicators. These results form the basis for the
performance evaluation of the SFU or MFU under test.
5.4 Expected Result
5.4.1 Overview
The following physical quantities are considered:
• Power Density (PD): magnitude of the time-averaged Poynting vector at each evaluation location.
• Received Signal Strength (RSS): actual power delivered to the receiver input at each evaluation location,
expressed in dBm and evaluated at a documented receiver reference plane using a receiving antenna model
with documented gain, polarization, orientation, and impedance-matching assumptions.
5.4.2 Performance Criteria
Performance evaluation is based on two complementary characteristics:
• the spatial distribution of received signal strength across the predefined evaluation locations; and
• the linear-power-averaged received signal strength across the same evaluation locations.
ETSI
14 ETSI GR F5G-TEST 041 V1.1.1 (2026-09)
For a selected received signal strength threshold �, the corresponding spatial coverage percentage is calculated as:
���
�
∑ � � � �
� = � ��� ≥ � 1
� ��� �
�
where ��� is the received signal strength at evaluation location �, �is the number of evaluation locations, and �(⋅) is
�
the indicator function, which is equal to 1 when the stated condition is satisfied and 0 otherwise.
To characterize the spatial received signal strength distribution, two threshold boundaries are selected before the test: a
minimum acceptable boundary � and a strong-signal boundary � , where:
��� �����
� < �
��� �����
Each evaluation location is classified according to the following ranges:
• Strong: ��� ≥ �
� �����
• Acceptable: � ≤ ��� < �
��� � �����
• Weak: ��� < �
� ���
The corresponding spatial percentages are defined as follows:
• � = � , representing the percentage of locations classified as acceptable or strong;
covered �
���
• � = � representing the percentage of locations classified as strong;
strong �
strong
• � = � − � , representing the percentage of locations classified as acceptable;
acceptable covered strong
• � = 100 % − � , representing the percentage of locations classified as weak.
weak covered
The spatial coverage criterion is:
� ≥ � �2�
covered req
where � is the minimum needed percentage of covered evaluation locations classified as acceptable or strong for the
�!"
selected test scenario.
The linear-power-averaged received signal strength is calculated by first converting the received signal strength at each
evaluation location from dBm to linear received power:
� �
��� ��� ���
�
��
� ��� =10 �3�
�,�
where � is the actual power delivered to the receiver input at the defined receiver reference plane for evaluation
�,�
location �. The linear received powers are then averaged:
�
�
�
� = ∑ � �4�
� �,�
���
�
and the resulting average received power is converted back to dBm:
�
� � � � � �
��� ��� =10log � [�] + 30 5
��� �� �
‾
The quantities ��� , � , � , and ��� refer to power delivered to the receiver input at the defined receiver reference
� �,� � #$
plane. Receiving-antenna gain, polarization mismatch, and impedance mismatch are therefore already reflected in the
calculated RSS values. These factors are not applied again during the averaging process. The corresponding aggregate
mean-power criterion is:
� �
��� ≥ � 6
avg avg
where � is the minimum needed linear-power-averaged received signal strength for the selected test scenario.
#$
The device configuration satisfies the selected performance criteria only if both the spatial coverage criterion and the
mean-power criterion are satisfied, hence:
� ≥ �    and   ��� ≥ � �7�

covered req avg avg
ETSI
15 ETS
...