In Situ Assessment of Uplink Duty Cycles for 4G and 5G Wireless Communications.

{
  "study_type": "exposure_assessment",
  "exposure": {
    "band": "RF",
    "source": "mobile phone",
    "frequency_mhz": 3700,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Uplink duty cycle (time %) for 5G NR and 4G LTE across use cases",
    "UL-allotted time differences related to TDD (5G NR at 3.7 GHz)"
  ],
  "main_findings": "In situ measurements of a smartphone near a 4G/5G base-station site (Belgium) found uplink duty cycles varying by application and technology. For Twitch, VoLTE, and WhatsApp, duty cycles ranged from 4% to 22% for both 4G and 5G; Ping showed median duty cycles of 2% (5G NR) versus 50% (4G LTE); FTP upload and iPerf produced duty cycles close to 100%. For 5G NR, the reported duty cycles corresponded to higher UL-allotted time due to TDD at 3.7 GHz.",
  "effect_direction": "unclear",
  "limitations": [
    "Sample size not reported in abstract",
    "Only ten measurement positions near a single 4G/5G base-station site in Belgium are described",
    "Results limited to six specific use cases (voice, video, data) and the tested smartphone/network conditions"
  ],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "in situ",
    "uplink",
    "duty cycle",
    "smartphone",
    "5G NR",
    "4G LTE",
    "TDD",
    "3.7 GHz",
    "VoLTE",
    "WhatsApp",
    "Twitch",
    "Ping",
    "FTP upload",
    "iPerf",
    "Belgium"
  ],
  "suggested_hubs": [
    {
      "slug": "5g-policy",
      "weight": 0.55,
      "reason": "Assesses 5G NR uplink duty cycles in situ, relevant to 5G exposure characterization."
    }
  ]
}