MIMO antennas extend the easily usable frequencies well beyond the 4.9 GHz band. The FCC took the first step with a Notice of Proposed Rulemaking. Claus Hetting of Wi-Fi Now kindly allowed me to reprint his report.
The FCC wants to introduce four new unlicensed subbands aptly named U-NII-5 to U-NII-8. In the case of U-NII-5 and U-NII-7 (a total of 800 MHz) a new scheme called AFC (‘Automated Frequency Control’) will protect some incumbent 6 GHz users (mostly point-to-point microwave links) from harmful interference, the FCC says. In these two subbands the FCC wants to allow the operation of ‘standard-power access points’ equivalent to current rules for U-NII-1 and U-NII-3 subbands.
Four new subbands and (some) new rules
Meanwhile the U-NII-6 and U-NII-8 subbands (a total of 350 MHz) should only be used indoors, says the FCC. The use of these two bands will also only be permitted at low power levels equivalent to those of the current U-NII-2 band. The idea is that such restrictions will be sufficient to protect fixed microwave links, mobile stations, and some satellite incumbent users in these bands.
The exact subband structure would then look like this:
- U-NII-5: 5925-6425 MHz (standard power levels, AFC applies)
- U-NII-6: 6425-6525 MHz (low power, indoor only)
- U-NII-7: 6525-6875 MHz (standard power levels, AFC applies)
- U-NII-8: 6875-7125 MHz (low power, indoor only)
“The Commission tentatively concludes that this two-class approach can expand unlicensed use without causing harmful interference to the incumbent services that will continue to be authorised to use this spectrum,” the FCC says in the document. The U-NII-5 band is also currently under study by the European Commission as a candidate for expansion of Wi-Fi bands in Europe."