By Claus Hetting, WiFi NOW CEO & Chairman
Both mobile and Wi-Fi industries covet the 6 GHz band – but can the interest of competing industry factions be reconciled? A new consultation document released by UK regulator Ofcom last week is proposing that the upper half of 6 GHz band (eventually) be shared between mobile and Wi-Fi while the lower half is opened up for standard power Wi-Fi with AFC. As it stands, both parts of the proposal arguably favour Wi-Fi.
UK regulator Ofcom’s approach to 6 GHz spectrum regulation has thus far diverged substantially from those of the FCC and the EU. But this now appears to be changing as Ofcom last week issued a new consultation document outlining new schemes for the unlicensed use of the 6 GHz band.
In short Ofcom suggests the adoption of a phased ‘shared’ approach to low power indoor Wi-Fi (at 250 mW) operation in the top half (6425–7125 MHz) of the band while AFC-controlled Wi-Fi should be permitted to operate at standard power (4 Watts) in the lower half of the band (5925–6425 MHz) indoors and out. Ofcom’s approach to the top half of the band is somewhat complex in that it posits two possible mobile/Wi-Fi sharing schemes the details of which are still not entirely clear.
Thankfully Ofcom is proposing that any final sharing scheme – the intention of which is to allow mobile services to use the band to some extent – only enters into the picture in a later phase. This means that Wi-Fi would initially be allowed to operate in the full 6 GHz band (up to 7125 MHz) at 250 milliwatts of power until such a scheme can be established. The sharing scheme – says Ofcom – should be harmonised with European regulation expected to be finalised in 2027.
Further good news is that Ofcom wants to permit low power indoor Wi-Fi operation in the full 6 GHz band already this year, which would give the Wi-Fi industry at least 2 years of non-shared full 6 GHz operation. So while the UK waits for Europe’s decision and potential deployments of shared spectrum mobile networks, UK consumers and businesses will benefit from access to the entire 6 GHz band. Add to this that it is anyone’s guess whether or not a sharing mechanism will ever actually be adopted and deployed by the mobile industry – even if Ofcom were to go ahead and write this possibility into law.
As far as the 6 GHz sharing mechanism is concerned, two approaches have been proposed: ‘Prioritised spectrum split’ or ‘indoor/outdoor’ split. Neither of the proposed solutions has any precedent and plenty of details still need to be worked out. The solution also needs to be agreed upon by the competing parties. ‘Prioritised spectrum split’ gives Wi-Fi priority in the lower half of the band while mobile receives priority in the upper half (see graphic below).
Either can then employ the entire band (or parts of it) when the other is not using it. No mention so far on what mechanisms would be used to manage the splits but of course in either case avoiding interference is paramount. Therefore both Wi-Fi and mobile networks would somehow need to access each others’ deployment data in order to make the right informed decisions.
The indoor/outdoor split method involves controlling mobile power in such a way that it allows interference-free operation of Wi-Fi indoors in the same band. It is unclear (and frankly doubtful) if this approach – which appears to be suggesting that a simple limit on mobile 6 GHz power will suffice – will be any easier to implement and control that the first option (also see graphic below).
Thankfully, Ofcom’s proposal for standard power Wi-Fi (indoor or outdoor) in the lower 6 GHz band is a straight-forward AFC implementation similar (or perhaps in practice virtually identical) to the scheme already implemented and available in the US and Canada. Since AFC regulation, technology, and deployments already exist, this approach will arguably be fairly simple to introduce in contrast to the proposed spectrum sharing schemes.
So what sharing solution will prevail for the upper 6 GHz band? The good news from a Wi-Fi point of view is that the answer to that question doesn’t matter a great deal at this point. What is important is that full-band indoor 6 GHz Wi-Fi (at 250 mW) is all but guaranteed to happen in the United Kingdom as is lower half standard power Wi-Fi with AFC. Ofcom’s consultation document suggests that another big win is in the making for the Wi-Fi industry – and not least for consumers and businesses in the UK.
/Claus.
