5G NR Base Station Exposure of the General Public: Comparison of Assessment Methods

Abstract

5G NR Base Station Exposure of the General Public: Comparison of Assessment Methods Kenneth Deprez, Leen Verloock, Loek Colussi, Sam Aerts, Matthias Van den Bossche, Jos Kamer, John Bolte, Luc Martens, David Plets, Wout Joseph. In-Situ 5G NR Base Station Exposure of the General Public: Comparison of Assessment Methods. Radiat Prot Dosimetry. 2022 May 3;ncac061. doi: 10.1093/rpd/ncac061. Abstract New measurement methods and equipment for correct 5G New Radio (NR) electromagnetic field (EMF) in-situ exposure assessment of instantaneous time-averaged exposure (Eavg) and maximum extrapolated field exposure (Emax) are proposed. The different options are investigated with in-situ measurements around 5G NR base stations (FR1) in different countries. The maximum electric field values satisfy the ICNIRP 2020 limit (maximum 7.7%). The difference between Emax and Eavg is <3 dB for the different measurement equipment at multiple sites in case there is only self-generated traffic. However, in a more realistic scenario, Eavg cannot be used to assess the exposure correctly due to influence of other users as the spatial distribution of user equipment (UE) influences Eavg, while Emax is not affected. However, when multiple UEs are collocated, there is no influence of the number of UEs. A broadband measurement can give a first impression of the RF-EMF exposure up to 700 m, but is not enough to assess the 5G-NR exposure. Conclusions and Future Work This paper provides an overview of different measurement equipment and optimal settings that can be used to correctly perform in-situ 5G NR electromagnetic field exposure assessment at 3.5 GHz (FR1). Both time-averaged exposure and maximum extrapolated field exposure assessment are proposed and investigated with in-situ measurements in different countries. The maximum electric field values satisfy the ICNIRP 2020 limit (i.e. maximum 7.7%). Furthermore, in a low-traffic environment, one UE is sufficient to attract the beam towards the measurement equipment. The difference between Emax and Eavg is <3 dB for the different measurement equipment at multiple sites. Hence, the current setups are to be recommended in 5G-NR exposure assessment in the current low-traffic scenarios. In a more realistic scenario, not all measurement methods are valid and must thus be adapted. When Eavg is used as metric, the exposure assessment drops with 6 dB when four UEs are spatially separated. However, Emax is not affected by the spatially separated UEs (difference of 0.60 dB between the various measurements) and is the recommended metric to use for exposure assessment in high- traffic environments. A broadband measurement can give a first impression of the RF-EMF environment up to 700 m (deviations of 0.05–4.86 dB), but is limited in use (larger separations) and not enough to assess the 5G-NR field exposure. The future work can be divided into two main parts. The first part is to test the measurement methods and equipment in more realistic, higher traffic environments. This will give a more accurate view on the impact of 5G NR on everyday RF-EMF exposure. The second part is to test the measurement methods for the frequency range 2 of 5G-NR (FR2), i.e. mm-waves. Here, more beams, higher bandwidths and more traffic are expected. pubmed.ncbi.nlm.nih.gov

AI evidence extraction

Main findings

In in-situ measurements around 5G NR base stations (FR1) in different countries, maximum electric field values were reported to satisfy the ICNIRP 2020 limit (maximum 7.7%). Under low-traffic/self-generated traffic conditions, the difference between Emax and Eavg was <3 dB across equipment at multiple sites, but in more realistic scenarios Eavg was influenced by other users while Emax was not; broadband measurements provided only a first impression up to 700 m and were not sufficient to assess 5G NR exposure.

Outcomes measured

• In-situ electric field exposure metrics (Eavg, Emax) around 5G NR base stations (FR1)
• Compliance with ICNIRP 2020 limit (maximum electric field as % of limit)
• Differences between Emax and Eavg under different traffic/user equipment (UE) scenarios
• Performance/limitations of broadband measurements for assessing 5G NR exposure

Limitations

• Sample size/number of sites not stated in the abstract
• Findings noted to depend on traffic conditions; current setups recommended mainly for current low-traffic scenarios
• Broadband measurements described as limited and not sufficient for 5G-NR exposure assessment
• Future work indicates need for testing in higher-traffic environments and in FR2 (mmWave), implying current results are limited to FR1 (3.5 GHz)

Suggested hubs

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  Study evaluates in-situ exposure assessment methods for 5G NR base stations and reports compliance relative to ICNIRP limits.
• who-icnirp (0.72)
  Explicit comparison to ICNIRP 2020 exposure limit and discussion of compliance.

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    "study_type": "exposure_assessment",
    "exposure": {
        "band": "RF",
        "source": "5G NR base station",
        "frequency_mhz": 3500,
        "sar_wkg": null,
        "duration": null
    },
    "population": "General public",
    "sample_size": null,
    "outcomes": [
        "In-situ electric field exposure metrics (Eavg, Emax) around 5G NR base stations (FR1)",
        "Compliance with ICNIRP 2020 limit (maximum electric field as % of limit)",
        "Differences between Emax and Eavg under different traffic/user equipment (UE) scenarios",
        "Performance/limitations of broadband measurements for assessing 5G NR exposure"
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    "main_findings": "In in-situ measurements around 5G NR base stations (FR1) in different countries, maximum electric field values were reported to satisfy the ICNIRP 2020 limit (maximum 7.7%). Under low-traffic/self-generated traffic conditions, the difference between Emax and Eavg was <3 dB across equipment at multiple sites, but in more realistic scenarios Eavg was influenced by other users while Emax was not; broadband measurements provided only a first impression up to 700 m and were not sufficient to assess 5G NR exposure.",
    "effect_direction": "no_effect",
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        "Broadband measurements described as limited and not sufficient for 5G-NR exposure assessment",
        "Future work indicates need for testing in higher-traffic environments and in FR2 (mmWave), implying current results are limited to FR1 (3.5 GHz)"
    ],
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    "peer_reviewed_likely": "yes",
    "keywords": [
        "5G NR",
        "base station",
        "FR1",
        "3.5 GHz",
        "in-situ measurements",
        "RF-EMF exposure assessment",
        "Eavg",
        "Emax",
        "ICNIRP 2020",
        "broadband measurement",
        "user equipment (UE)",
        "beamforming"
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