Associations between Individual and Geospatial Characteristics and Power of 4G Signals Received by Mobile Phones

Abstract

Category: Epidemiology Tags: 4G, LTE, RSSI, antenna density, electromagnetic fields, geospatial analysis, smartphone exposure DOI: 10.1016/j.envres.2025.123030 URL: pubmed.ncbi.nlm.nih.gov Overview The study investigates how individual, technical, and geospatial factors impact the received signal strength indicator (RSSI) for 4G LTE networks as measured by smartphones. Background - Received Signal Strength Indicator (RSSI): Measures downlink signal intensity received by smartphones in 4th Generation LTE networks. Objective To evaluate how individual, technical, and spatial variables influence LTE-RSSI during daily activities. Methods - Adults in France (November 2022 – October 2023) logged RSSI and GPS data using the XMobiSensePlus Android application. - Distance to the nearest cellphone antenna, population density, antenna density, and urbanicity were assessed with geographic information systems. - An autoregressive mixed model with restricted cubic splines analyzed determinants of RSSI. - Environmental exposures were estimated at 1800 MHz using conversion factors. Findings - Data from 1,969,913 records and 187 participants (measurements every 30 seconds for an average of 7.9 days). - Mean LTE-RSSI was -79.3 dBm; estimated electric field strength was 0.12 V/m (with high uncertainty). - Median distance to nearest antenna: 536 meters. - Proximity to antenna and higher antenna density increased RSSI (+0.37 dBm per additional antenna per km²). - RSSI was lower in evening and night, particularly in urban areas. - Technical factors (Android version, System-on-a-Chip) influenced RSSI; operator did not. - Proximity to antennas had greater impact in rural settings. Conclusion Urbanicity, distance to nearest 4G antenna, antenna density, time of day, and technical smartphone parameters impacted RSSI levels in 4G networks in France, while the operator was not a significant factor in RSSI variations. ⚠️ Note: Variations in RSSI, influenced by proximity and density of antennas, directly relate to the level of electromagnetic field (EMF) exposure individuals receive from 4G networks. The scientific consensus highlights the importance of continued investigation into health risks associated with EMF exposure, especially in relation to proximity to network infrastructure and specific population settings such as urban versus rural areas.

AI evidence extraction

Main findings

Using smartphone-logged RSSI and GPS data (1,969,913 records from 187 adults), mean LTE-RSSI was -79.3 dBm and the estimated electric field strength was 0.12 V/m (noted as highly uncertain). RSSI increased with proximity to the nearest antenna and with higher antenna density (+0.37 dBm per additional antenna per km²), was lower in evening/night (especially in urban areas), and was influenced by technical factors (Android version, System-on-a-Chip) while operator was not a significant factor; proximity effects were greater in rural settings.

Outcomes measured

• 4G LTE received signal strength indicator (RSSI)
• Estimated electric field strength (V/m)
• Associations of RSSI with distance to nearest antenna, antenna density, population density, urbanicity, time of day, and technical smartphone parameters

Limitations

• Electric field strength estimates were reported as having high uncertainty
• Results depend on smartphone/app-based RSSI and GPS logging and technical phone parameters (e.g., Android version, System-on-a-Chip) that influenced RSSI

Suggested hubs

• occupational-exposure (0.1)
  Not occupational; included only if the portal groups adult daily-activity exposure assessments here (weak match).

{
    "study_type": "exposure_assessment",
    "exposure": {
        "band": "RF",
        "source": "mobile phone",
        "frequency_mhz": 1800,
        "sar_wkg": null,
        "duration": "Measurements every 30 seconds for an average of 7.9 days (Nov 2022–Oct 2023)"
    },
    "population": "Adults in France",
    "sample_size": 187,
    "outcomes": [
        "4G LTE received signal strength indicator (RSSI)",
        "Estimated electric field strength (V/m)",
        "Associations of RSSI with distance to nearest antenna, antenna density, population density, urbanicity, time of day, and technical smartphone parameters"
    ],
    "main_findings": "Using smartphone-logged RSSI and GPS data (1,969,913 records from 187 adults), mean LTE-RSSI was -79.3 dBm and the estimated electric field strength was 0.12 V/m (noted as highly uncertain). RSSI increased with proximity to the nearest antenna and with higher antenna density (+0.37 dBm per additional antenna per km²), was lower in evening/night (especially in urban areas), and was influenced by technical factors (Android version, System-on-a-Chip) while operator was not a significant factor; proximity effects were greater in rural settings.",
    "effect_direction": "unclear",
    "limitations": [
        "Electric field strength estimates were reported as having high uncertainty",
        "Results depend on smartphone/app-based RSSI and GPS logging and technical phone parameters (e.g., Android version, System-on-a-Chip) that influenced RSSI"
    ],
    "evidence_strength": "insufficient",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "4G",
        "LTE",
        "RSSI",
        "antenna density",
        "distance to antenna",
        "urbanicity",
        "geospatial analysis",
        "smartphone measurements",
        "RF-EMF",
        "France",
        "1800 MHz"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.1000000000000000055511151231257827021181583404541015625,
            "reason": "Not occupational; included only if the portal groups adult daily-activity exposure assessments here (weak match)."
        }
    ]
}

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