Latest Ofcom regulations in the 5 GHz band

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The advent of 802.11ac and its new 80- and 160-MHz channels brings to the table the issue of lack of available channels in the UK to take advantage of this technology. The UK regulator (Ofcom) issued this document in 2017 to announce the opening up of an additional 125 MHz band (5.725 – 5.850 GHz) for Wi-Fi use. This band is equivalent to the U-NII-3 band in the US, and introduces five new 20 MHz channels: 149, 153, 157, 161, 165.

The immediate consequence of these new 20 MHz channels is two new 40 MHz channels (151, 159), and one new 80 MHz channel (155) available in the UK. All these changes are effective from 11th August 2017.

Additionally, the new band allows for the 20-MHz channel 144 to be also available. This is important for various reasons:

  • Channel 144 (5.710 – 5.730 GHz) is the last channel in the U-NII-2c band and bridges the gap between this band and the newly allocated U-NII-3.
  • Channel 144 allows for one new 40-MHz channel (142) and one new 80-MHz channel (138).

All in all, the changes introduced by Ofcom translate into the following available spectrum in the UK:

  • 25x 20-MHz channels (previously 19)
  • 12x 40-MHz channels ( previously 9)
  • 6x 80-MHz channels (previously 4)
  • 2x 160-MHz channels (no new channels in this category)

Additional bandwidth is always welcome, but the lack of a variety of 160-MHz channels makes this channel width effectively not usable in corporate environments, being relegated to home applications and some corner case scenarios.

Future considerations

The Ofcom document mentioned above also announces that it is considering opening up yet more bands for Wi-Fi use:

  • Medium term: 5.850 – 5.925 GHz (equivalent to U-NII-4)
  • Longer term: 5.350 – 5.470 GHz (equivalent to U-NII-2B)

While opening up U-NII-4 would add three new 20-MHz channels (173, 177, 181), it would also allow for channel 169 (5.835 – 5.855 GHz), which straddles across bands U-NII-3 and U-NII-4. The result is a contiguous block of twenty one 20-MHz channels (from the current seventeen), starting from channel 100 in the U-NII-2C band. This would allow for one additional 160-MHz channel (163) to be added to the other two (50, 114) currently available, making this channel width a feasible option in corporate environments.

Even more important would be the opening up of the U-NII-2B band (eight 20-MHz channels, 68-96). With this addition, all the 5 GHz spectrum starting from channel 36 all the way to channel 181 would be available to Wi-Fi, and one new 160-MHz channel (82) would be available, with a total of four channels of this width.