In the framework of metrology for the new emerging wireless standards such 5G New Radio (NR), the traceable calibration of 5G NR measuring receivers is presented in this contribution. A reference setup to measure the power of cell-specific synchronization resource elements in downlink 5G NR signals is introduced, providing the traceability of the measurements to the International System of Units (SIs). This setup can be used to calibrate 5G code-selective measuring receivers that are utilized for the measurements of the radiation from base stations for mobile communication. This setup can also be used to calibrate not only the 5G signal receivers, but also the 5G generators. The method relies on the traceable measurements of the downlink signal generator by using an oscilloscope. It employs offline digital signal processing demodulation algorithms that account for digital down-conversion, timing synchronization, frequency synchronization, phase synchronization, and robust 5G cell identification to generate the downlink time-frequency 5G grid. The applicability of this method for both sub 6 GHz and millimeter wave frequency ranges is proven with experiments. Experimental results from conducted test scenarios demonstrate calibration capabilities with typical uncertainties of 0.05 dB (k = 2). Moreover, the application of this method for the calibration of two commercial product and also the RF exposure assessment considerations are also explained in detail.

With new emerging wireless standards, the planning of RF exposure from base station and its compliance measurements are becoming even more difficult tasks due to the introduction of new techniques, such as beamforming, to improve the signal quality and enhance the user experience. The consistence of the exposure measurements with planned RF exposure values could be even harder to reach. This issue was experienced during a recent RF exposure measurement campaign. There, the effective electric field strength was found to be significantly higher than the calculated values for some locations. The reason was found out to be the diffraction of the electromagnetic radiation through an open window, which resulted in the amplification of the electric field strength at a focus point located behind the window opening. In this publication, this phenomenon is presented in terms of theory, simulations and measurements in the context of RF exposure from base stations. Moreover, the effect of diffraction and its implications for the RF exposure planning for 5G and beyond are discussed for more insight.

In this publication, an improved measurement method is proposed for the quantification of the radio frequency exposure from 5G NR base stations in sub-6 GHz frequency range. The method is based on the code selective measurements of all resource elements in the resource grid and enables an estimation of the exposure at maximum data transmission. In particular, it allows the quantification of the ratio between traffic resource elements and synchronization resource elements. The use of this method is presented in this publication and some preliminary results of the laboratory measurements are demonstrated, which were performed using a code selective measuring receiver implementing the proposed method for analyzing the full 5G resource grid.

Main text The results of the supplementary comparison in the area of magnetic field probe calibration of the field strength are presented. This supplementary comparison has been discussed to organize a comparison on magnetic field strength measurements during the EURAMET TC-EM Subcommittee Radiofrequency and Microwave (SC-MW) meeting, including an EMC meeting, organized as a virtual (online) meeting on 20-21 April 2021. The comparison was conducted in accordance with the Technical Protocol of "Comparison of Magnetic Field Strength Measurements for Frequencies up to 30 MHz, EURAMET Project No 1538, EURAMET.EM.RF-S46", which was prepared by the TÜBİTAK UME and approved by the participants. The measurements started in January 2022 and were completed in May 2023. Measurement results reported by nine participants for magnetic field strength values were compared and degrees of equivalence are reported. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Emerging wireless technologies with Gbps connectivity, such as the 5th generation (5G) and 6th generation (6G) of mobile networks, require improved and substantiating documentation for the wireless standards concerning the radio signals, systems, transmission environments used, and the radio frequency exposures created. Current challenges faced by the telecommunications sector include the lack of accurate, fast, low-cost, and traceable methods for manufacturers to demonstrate 5G and 6G product verifications matching customer specifications. This paper gives an update on the recent research and development activities from an EU Joint Research Project entitled metrology for emerging wireless standards (MEWS) in support of the above.

Interlaboratory comparisons and proficiency testing are receiving increasing attention by electromagnetic compatibility (EMC) test and calibration laboratories due to the need for accreditation according to ISO/IEC 17025. In EMC, the proficiency testing offer is restricted to a few test standards, mostly emission. In order to increase this offer, we recently developed a novel equipment that enables the assessment of the test capabilities of laboratories for IEC 61000-4-5 (surge immunity). This article presents an overview of this reference equipment and its capabilities, as well as the interlaboratory comparison recently realized in Switzerland.

Since 2016, METAS organized numerous proficiency testing schemes for EMC laboratories. This experience demonstrated the benefit of the proficiency testing. This publication aims to provide some examples of the problems, or of the inappropriate application of the EMC testing, that were observed during the interlaboratory comparison campaigns. It can be emphasised that these findings have always been discussed with the participants and that it led to an improvement of their test setups and procedures. These examples might also be beneficial to the whole EMC community.

Zusammenfassung Eine der neuesten Entwicklungen im Bereich der mobilen Kommunikation heißt 5G, für Mobilfunksystem der fünften Generation. In Europa hat die Einführung der 5G-Technologie viele Ängste in der Bevölkerung hervorgerufen. Die Technologie ist komplex und erfordert Spezialwissen. Der Nachweis, dass eine Basisstation die Anforderungen an die Strahlenbegrenzung erfüllt, erfordert zuverlässige Messmethoden. Die Messunsicherheit, die jedoch schwer abzuschätzen ist, spielt dabei eine wichtige Rolle. Dieser Artikel behandelt die Problematik der Konformitätsbewertung komplexer Systeme am Beispiel einer 5G-Basisstation.

One of the latest developments in the field of mobile communication is called 5G, for fifth generation mobile communication system. In Europe, the introduction of 5G technology has raised many fears among the population. The technology is complex and requires specialized knowledge. Proof of a base station's compliance with radiation limitation requirements requires reliable measurement methods. Measurement uncertainty, however, is difficult to estimate and plays an important role. This article discusses the issues of conformity assessment of complex systems based on the example of a 5G base station.

After the realisation of an improved reference device for Proficiency Testing according to IEC 61000-4-3, an interlaboratory comparison in Switzerland was conducted in 2021. The complete study of this comparison is published here. First, the reference device is briefly presented. The measurands for the comparison and the evaluation method are listed in detail. The performance of the participants are analysed and commented. Finally, the didactic learnings of this comparison are presented and discussed.

Main text RF current monitoring probes are commonly utilized in measurements of disturbance currents of cables without making direct conductive contact with the source conductor and without modification of its circuit. They must be calibrated by National Metrology Institutes (NMIs) or accredited calibration laboratories in accordance with international standards such as CISPR 16-1-2 or ISO 11452-4. The RF current monitor probe comparison measurements were conducted with 8 participants; five national metrology institutes (NMIs), two designated institutes (DI) and one commercial calibration laboratory at the frequencies 0.01 MHz, 0.1 MHz, 1 MHz, 10 MHz, 100 MHz, 200 MHz, 300 MHz, 400 MHz and 500 MHz in order to obtain the transfer impedance of the RF current monitoring probe. The comparison measurements started in September 2019 and were completed in June 2020. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

In order to improve and to standardize the quality in EMC testing services, increasing efforts have been given in the organisation of interlaboratory comparisons and proficiency testing. Several devices have been designed and realized for this purpose for various emission and immunity tests. In this publication, we pursue this development and propose a new reference device for interlaboratory comparisons and proficiency testing services in electrical fast transients/burst immunity testing according to IEC 61000-4-4. The device is equipped with adapted detecting circuitry to measure and record the burst pulses and relevant parameters for offline evaluation. The concept and the architecture of the device and its operation principles are explained in detail. The preliminary evaluation of its stability and linearity is performed and its capabilities to detect errors in a typical testing scenario is explained.

In order to organize interlaboratory comparisons and provide proficiency testing services in radiated immunity testing according to IEC 61000-4-3, a high quality reference device is developed. This device is adapted for the frequency range of 80 MHz to 6 GHz, and it is equipped with appropriate detecting mechanisms that record the required parameters for comparisons. This device is a significant improvement compared to a previous device already developed few years ago. The device architecture and the principles of operation are presented in detail, as well as a preliminary evaluation of its stability and linearity.

Coupling-decoupling networks (CDN) are used in electromagnetic compatibility (EMC) conducted immunity testing according to IEC 61000-4-6. This standard defines the requirements for CDNs to achieve a good reproducibility [1]. However, during the analysis of a recent international interlaboratory comparison (proficiency testing) on conducted immunity testing [2], we observed some deviations in the participant results that could not be explained by evident reasons such as bad earth connection, broken cable or faulty setup. A careful analysis has demonstrated that CDNs from different manufacturers might behave significantly differently with given equipment under test (EUT), despite the fact that they are all compliant with the standard IEC 61000-4-6.

This contribution presents a reference setup to measure the power of the cell-specific resource elements present in downlink long term evolution (LTE) signals in a way that the measurements are traceable to the international system of units. This setup can be used to calibrate the LTE code-selective field probes that are used to measure the radiation of base stations for mobile telephony. It can also be used to calibrate LTE signal generators and receivers. The method is based on traceable scope measurements performed directly at the output of a measuring antenna. It implements offline digital signal processing demodulation algorithms that consider the digital down-conversion, timing synchronization, frequency synchronization, phase synchronization and robust LTE cell identification to produce the downlink time-frequency LTE grid. Experimental results on conducted test scenarios, both single-input–single-output and multiple-input–multiple-output antenna configuration, show promising results confirming measurement uncertainties of the order of 0.05 dB with a coverage factor of 2.

Electromagnetic compatibility (EMC) testing is a complex activity that requires adequate infrastructure, skilled personal, and correct working procedures. One of the most efficient ways to validate the testing capabilities of a laboratory is the proficiency testing or interlaboratory comparison. In contrast to proficiency testing in EMC emission, which can be realized, for example, by using a comb generator with an antenna as test object, proficiency testing in EMC immunity is not very common today, mainly because there is no device that is specially designed for this purpose. In this contribution, we present a proficiency testing performed with a device that is specially developed to assess the field immunity testing capabilities of EMC laboratories according to IEC 61000-4-3. We also propose a method for the evaluation of this comparison. Improvements for the next implementations are finally discussed.

In this publication, we present a reference device for surge immunity inter-laboratory comparison. With the help of this device, the capabilities of the test laboratories regarding the correct interpretation and implementation of the standard IEC 61000-4-5 [1] can be assessed. This device is intended to be tested as a normal EUT in surge immunity testing, and it has the ability to record the applied test parameters. The architecture and a first evaluation of this device are presented. The device stability and the measurement repeatability issues are thoroughly investigated.

Constellation modulation (CM) is introduced as a new degree of freedom to increase the spectral efficiency and to further approach the Shannon limit. Constellation modulation is the art of encoding information not only in the symbols within a constellation but also by encoding information by selecting a constellation from a set of constellations that are switched from time to time. The set of constellations is not limited to sets of partitions from a given constellation but can e.g., be obtained from an existing constellation by applying geometrical transformations such as rotations, translations, scaling, or even more abstract transformations. The architecture of the transmitter and the receiver allows for constellation modulation to be used on top of existing modulations with little penalties on the bit-error ratio (BER) or on the required signal-to-noise ratio (SNR). The spectral bandwidth used by this modulation scheme is identical to the original modulation. Simulations demonstrate a particular advantage of the scheme for low SNR situations. So, for instance, it is demonstrated by simulation that a spectral efficiency increases by up to 33% and 20% can be obtained at a BER of 10-3 and 2×10-2 for a regular BPSK modulation format, respectively. Applying constellation modulation, we derive a most power efficient 4D-CM-BPSK modulation format that provides a spectral efficiency of 0.7 bit/s/Hz for an SNR of 0.2 dB at a BER of 2 × 10-2.

The CCEM international antenna gain comparison CCEM.RF- K23.F was initiated by the Working Group on Radio Frequency quantities (GT_RF) on the Consultative Committee for Electricity and Magnetism. This key comparison report presents results of measurements of on-axis gain of two Ku-band pyramidal horns at 12.4, 15, and 18 GHz. Participants making corrections for mismatch were asked to provide a table of the real and imaginary parts of the reflection coefficients of the antennas. Optionally, participants could measure the swept frequency gain from 12.4 to 18 GHz. Twelve national laboratories participated. The National Institute of Standards and Technology from the United States was the pilot lab. The purpose of the comparison was to evaluate the consistency between the participating laboratories in the measurement of the boresight gain of horn antennas in the WR-62 band. Main text To reach the main text of this paper, click on Final Report . Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/ . The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).