FCC opens entire 6 GHz band to low power device operations

Original Article ↗ Hacker News Discussion ↗

Regulatory details and power limits

  • “Very Low Power” (VLP) devices are defined for parts of 5.9–7.1 GHz with integrated antennas and no AP control requirement.
  • New rules set VLP at 14 dBm EIRP (~25 mW) with a power spectral density of –5 dBm/MHz, spread over wide channels (e.g., 80 MHz).
  • Commenters note modern regs use EIRP and spectral masks rather than raw transmitter wattage.
  • 6 GHz now has three regimes:
    • VLP: very low power, indoor/outdoor, now across full 1,200 MHz.
    • Low Power Indoor (LPI): up to 1 W for indoor APs, already across full band.
    • Standard Power (SP): up to 4 W EIRP with cloud‑based frequency coordination, only in 850 MHz subset.

Implications for Wi‑Fi and devices

  • No new 6 GHz channels for regular Wi‑Fi routers; change is only for VLP.
  • Enables more and wider (e.g., 320 MHz) channels for short‑range links like AR/VR, wearables, phone‑to‑laptop, in‑vehicle systems.
  • Some hope this will boost Bluetooth‑like and UWB‑style high‑bandwidth personal‑area links.

Propagation and range

  • 6 GHz behavior seen as similar to 5 GHz: good for line‑of‑sight, easily attenuated by walls, unsuitable for long‑range except with directional links.
  • “Fragility” is seen as a feature in dense environments because it limits interference; multiple low‑power APs per home are suggested over one high‑power unit.
  • Multi‑hop wireless backhaul adds significant latency; Ethernet to APs remains preferred for low‑latency.

Spectrum allocation context

  • 6 GHz incumbents include satellite and point‑to‑point microwave; some radar usage is mentioned.
  • Comparisons made to heavily fragmented, much narrower bands (AM/FM, TV, amateur); commenters argue those are too narrow or low‑frequency to be as useful for high‑throughput unlicensed systems.
  • Some express hope other jurisdictions mirror the FCC to enable cheaper global hardware.

Enforcement, hacking culture, and compliance

  • Debate over cranking up Wi‑Fi power:
    • One side: “real limit” is when someone complains; FCC vans respond mainly to interference reports.
    • Others emphasize lab certification, existing enforcement (pirate radio, cell jammers), and ethical responsibility to follow limits to preserve shared spectrum and avoid pushing regulators toward locked‑down firmware.

Health and biological effects

  • Consensus from several commenters: at these non‑ionizing frequencies and very low powers, main risk is tissue heating, and 25 mW is far below levels of concern.
  • Others cite papers on polarization, ion channels, TRPV1, and DNA dynamics to argue possible non‑thermal biological effects are not fully ruled out; responses range from strong skepticism to “needs more research.”
  • Overall, no agreement; thread notes that safety standards focus on heating because that’s what is well‑characterized.

Other bands and related proposals

  • Discussion of existing 5.9 GHz vehicle‑to‑vehicle (DSRC, C‑V2X) spectrum and why V2V hasn’t taken off (security, reliance on cellular gatekeepers).
  • Concern about proposals to reorganize 900 MHz, potentially displacing LoRa, RFID, tolling, and amateur uses; some see it as a corporate land‑grab, others as part of broader spectrum‑security concerns.

Beamforming and EIRP debate

  • Some argue EIRP‑based limits discourage phased arrays and spatial selectivity; they’d prefer limits on total radiated power.
  • Counterargument: EIRP is what matters for interference and safety; concentrated beams from high‑gain antennas could “blind” nearby receivers even at low total power, so EIRP limits are appropriate.