Silex Unwired

FCC Announces New Rules for U-NII in 5 GHz Band

5GhzBandIn the Federal Register Vol 79, No.84 of May 01, 2014, FCC has announced that Unlicensed National Information Infrastructure (U-NII) for the 5 GHz band would undergo some changes starting June 2nd, 2014. This change eliminates a loophole where a device could be certified under 15.247 but then illegally modified to operate in the U-NII DFS bands which interfered with Terminal Doppler Weather Radar (TDWR).

There will be a two year transition period before the changes are enforced.

  •  All new certifications and permissive changes must be approved under the new 15.407 rules after June 2nd, 2015.
  • For products certified under 15.247,  5 GHz band cannot be sold unless they are re-tested and re-certified under 15.407 rules after June 2nd 2016.

Changes to U-NII-3

  • 5.725 – 5.850 GHz band to be removed from part 15.247 rules (except for frequency hopping systems) and consolidated in part 15.407 rules. This is to better support the use of wideband digital modulation techniques for high-data-rate mobile and fixed communications, which are supported by 802.11ac.
  • Maximum conducted output power for this band remains at 1 watt.
  • Unwanted emission limits less than 1 GHz must comply with the 15.209 limits which are stricter than the 15.247 limits.

Changes to U-NII-1

  • 5.150 - 5.250 GHz band can now be used outdoors.
  • Maximum conducted output power is increased to 1 watt (4 watts EIRP) for Access Points and 250 mW (23.9 dBm) for mobile/portable clients with maximum 6 dBi antenna gain.
  • Power must be reduced by 1 dB for every dB that the antenna gain exceeds 6 dBi.
  • For outdoor AP use, EIRP power in the upwards direction above 30 degrees is limited to 125 mW (20.9 dBm) to reduce interference for Mobile Satellite Service and no reduction for indoor use.

Changes to DFS Sensing Requirements

 Dynamic Frequency Selection (DFS) sensing requirements have changed so re-testing will need to be completed by June 02, 2016.

  • The DFS sensing requirement expands to cover 100 percent instead of 80 percent of the U-NII-2A and U-NII-2C signal bandwidth.
  • The new sensing threshold for high power devices is -64 dBm, and is -62 dBm for lower power devices but a Power Spectral Density (PSD) limit is introduced.
  • The simulated radar waveforms have been updated for Bin-1 radar which should help alleviate interference to the Terminal Doppler Weather Radar (TDWR) and other radar systems.
  • The MPEG streaming video requirement for Channel Loading has been removed since some units cannot support this type of data.  Other appropriate tests will be substituted.

What does this mean to you?

  • 2.4 GHz band might not need to get re-tested. Meaning you could still use the subpart C test reports for 15.247.
  • For subpart E, 15.407, you will need to re-test all products that use 5GHz.
  • Any C2PC’s done after June 2nd 2015, will require re-testing* of the 5GHz radio.
  • All products with 5GHz radio must be in compliance with the new rules by June 2nd 2016.

* Tests include transmit power, power density, DFS, spurious emissions below and above 1 GHz, etc.

Additionally, manufacturers must ensure that parameters including output power, restricted channels and DFS functionality, in the 5 GHz U-NII bands cannot be changed by third parties. This is to restrict the module to operate outside the parameters it was certified with. Documentation must also be provided during the certification application process explaining how modification to these parameters is restricted.

 Note: the FCC is currently considering whether to add two more U-NII bands in the 5 GHz band.  This would be U-NII-2B, 5.350 – 5.470 GHz and U-NII-4, 5.850 – 5.925 GHz.

Silex Technology does provide certification services and can help you obtain FCC certification for your products, as well as compliance with other international regulatory standards. Please contact for more information on the services we provide.



 The complete Federal Register / Vol 79, No. 84 / Rules and Regulations is available at: