Realistic Human Exposure at 3.5 GHz and 28 GHz for Distributed and Collocated MaMIMO in Indoor Environments

2022 · No effect · Low evidence

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No effectLow evidencePaper 622

Study snapshot

Publicationmanual · 2022

Study typeexposure_assessment

Reported directionNo effect

Evidence ratingLow

Abstract

Realistic Human Exposure at 3.5 GHz and 28 GHz for Distributed and Collocated MaMIMO in Indoor Environments R. Wydaeghe et al. Realistic Human Exposure at 3.5 GHz and 28 GHz for Distributed and Collocated MaMIMO in Indoor Environments using Hybrid Ray-Tracing and FDTD. IEEE Access, doi: 10.1109/ACCESS.2022.3227107. Abstract Realistic human downlink exposure at 3.5 and 28 GHz to electromagnetic fields is evaluated for distributed and collocated base stations using a hybrid ray-tracing/finite-difference time-domain method. For the first time, the absorbed power density is computed for distributed massive multiple-input multiple-output (DMaMIMO) 6G base stations (BS) at 28 GHz. The results are compared with 3.5 GHz 5G base stations. Computational costs are drastically increased at 28 GHz. A large analysis is realized by speed improvements and using two configurations. In the first, exposure distributions of DMaMIMO BS show clusters of low and high exposure. These clusters disappear when results are normalized with respect to the incoming power at the user. In the second, the influence of BS to user distance in line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios shows expected results. This includes a power law relationship in LOS and shadowing in NLOS. The vast majority of exposure quantities are less than 4% of the limits of the International Commission for Non-Ionizing Radiation. Basic restrictions are respected when reference quantities are set to their limits. With equal power, distributed base stations contribute 2 to 3 times less to exposure than collocated base stations. Expressed as a ratio to their limits set by ICNIRP, the basic quantities are 5 to 10 dB lower than the reference quantities. ieeexplore.ieee.org

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeexposure_assessment

Effect directionno_effect

PopulationNot supplied

Sample sizeNot supplied

ExposureRF

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Human downlink exposure at 3.5 and 28 GHz was evaluated for distributed and collocated base stations using a hybrid ray-tracing/FDTD method. The vast majority of exposure quantities were reported as less than 4% of ICNIRP limits, and with equal power distributed base stations contributed 2–3 times less to exposure than collocated base stations; basic quantities were 5–10 dB lower than reference quantities when expressed as ratios to ICNIRP limits.

Outcomes measured

absorbed power density
downlink exposure at 3.5 GHz and 28 GHz
exposure vs ICNIRP limits
effect of base station configuration (distributed vs collocated) on exposure
effect of BS-user distance in LOS/NLOS on exposure

Limitations

Computational costs were reported as drastically increased at 28 GHz.
Details on population characteristics and sample size are not provided in the abstract.
Exposure metrics are based on modeling (hybrid ray-tracing/FDTD) rather than direct measurements.

View raw extracted JSON

{
  "study_type": "exposure_assessment",
  "exposure": {
    "band": "RF",
    "source": "base station",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "absorbed power density",
    "downlink exposure at 3.5 GHz and 28 GHz",
    "exposure vs ICNIRP limits",
    "effect of base station configuration (distributed vs collocated) on exposure",
    "effect of BS-user distance in LOS/NLOS on exposure"
  ],
  "main_findings": "Human downlink exposure at 3.5 and 28 GHz was evaluated for distributed and collocated base stations using a hybrid ray-tracing/FDTD method. The vast majority of exposure quantities were reported as less than 4% of ICNIRP limits, and with equal power distributed base stations contributed 2–3 times less to exposure than collocated base stations; basic quantities were 5–10 dB lower than reference quantities when expressed as ratios to ICNIRP limits.",
  "effect_direction": "no_effect",
  "limitations": [
    "Computational costs were reported as drastically increased at 28 GHz.",
    "Details on population characteristics and sample size are not provided in the abstract.",
    "Exposure metrics are based on modeling (hybrid ray-tracing/FDTD) rather than direct measurements."
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "3.5 GHz",
    "28 GHz",
    "5G",
    "6G",
    "massive MIMO",
    "distributed MaMIMO",
    "collocated base stations",
    "indoor environments",
    "ray-tracing",
    "finite-difference time-domain",
    "absorbed power density",
    "ICNIRP limits",
    "LOS",
    "NLOS"
  ],
  "suggested_hubs": [
    {
      "slug": "who-icnirp",
      "weight": 0.86,
      "reason": "Results are repeatedly expressed relative to ICNIRP limits and reference quantities/basic restrictions."
    },
    {
      "slug": "5g-policy",
      "weight": 0.55,
      "reason": "Assesses exposure for 3.5 GHz 5G base stations and compares with 28 GHz systems."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1109/access.2022.3227107
PubMed: Not supplied

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