Changes to New Zealand's radio frequency spectrum regulation mooted, in the wake of Aussie warship-induced internet outages

When the Royal Australian Navy's HMAS Canberra (pictured above) sailed close to New Zealand shores recently, wireless internet in parts of Taranaki, Blenheim and Marlborough buckled. Local users saw dropouts and slowdowns, and there were plenty of media stories about the incident.

What happened was that the wireless network technology worked how it is supposed to work, when pinged by radar. 

So, the service interruption was not the Aussies’ fault. The HMAS Canberra didn’t break the internet as such, but the way fixed wireless access is configured in the affected areas is, shall we say, suboptimal. In fact, as it's a surprise that the service interruptions haven't come to the fore earlier. Let's look at why that is.

Radar realities

Technically the issue stems from Wireless Internet Providers (WISPs) using unlicensed radio frequency spectrum in the 5 gigahertz band to provide broadband connectivity to their customers. The 5 GHz band is also used for Wi-Fi indoors.

Apart from being free to use, 5 GHz provides a good mix of lots of bandwidth (around 500 megahertz in total for outdoor use) and long reach for WISPs, meaning they can offer decent performance service for customers in locations that are otherwise difficult to service with other technologies.

However, the shared 5 GHz radio frequency band is used for maritime and ground radar as well. Like, on warships which can have transmitters in the hundreds of kilowatt range (which is absolutely heaps compared to broadband radios), and by the Metservice. 

Radar takes precedence over Wi-Fi and wireless broadband networks, for obvious reasons.

For that reason, 5 GHz radio equipment has a security feature called dynamic frequency selection (DFS): if radar signals are detected by the 5 GHz radio, DFS kicks in and moves the frequencies used to other channels, to avoid interference.

Moving frequencies isn't always smooth and painless. Shifting to a channel that is not impacted by radar could make it crowded, and degrade performance for customers. 

As a related side note, radios configured to the New Zealand jurisdiction use DFS. It’s also possible to incorrectly (and illegally) configure transmitters to ignore radar detection, which could lead to a full service outage. Whether that happened is not clear at this stage.

It wouldn’t have been a fun time for WISPs, with alerts going off in the small hours of the morning as their broadband service offerings became degraded.

You could look at it as the WISPs taking their chances, running a business in shared radio spectrum which can as we’ve seen be interrupted by ships like HMAS Canberra popping across the Tasman for a visit.

As always, there are some interesting nuances to consider however.

Making the case for 6 GHz outdoors

Clearly, having maritime radar making a mess of customers' internet connectivity isn't acceptable. However, the options for WISPs to move out of 5 GHz are slim to non-existent due to New Zealand's regulatory regime for spectrum.

Wireless providers are now casting side-eyes on the 6 GHz shared frequency band which is used for Wi-Fi 6E and Wi-Fi 7.

The 6 GHz band is relatively new. A United States led effort began in 2017 to make the 6 GHz band freely available for Wi-Fi, and it was backed by the technology industry and the regulator, the Federal Communications Commission.

In 2020, the US and Canada designated the 6 GHz band for shared, unlicensed use.

That decision meant a whopping 1200 MHz of bandwidth became available, and you could have up to three fat 320 MHz wide channels.

The long story short here is that more bandwidth equals better performance; newer Wi-Fi 6E and 7 access points and clients can talk to each other wirelessly at speeds in the gigabits per second range.

This is great for New Zealand's UFB fast fibre to the premises connections, but also excellent if you can make 6 GHz go the distance outdoors, maybe using it instead of the maritime-radar allergic 5 GHz band.

Here's the sad trombone though: New Zealand did not take the North American route. Instead, the Ministry of Business, Innovation and Employment’s Radio Spectrum Management (RSM) agency decided to follow the European Union and Australian examples. Our Wi-Fi 6E and Wi-Fi 7 equipment only have 500 MHz of 6 GHz spectrum at their disposal, courtesy of regulation. This means only one 320 MHz combo channel is possible instead of three.

Why did that happen? Reading the submissions in 2021 on making 6 GHz available in New Zealand (which happened in 2023), shows that tech companies like Apple, Cisco, Microsoft, Broadcom and others wanted the whole 1200 MHz to be available in New Zealand.

New Zealand telcos did not. They were keen to get the 6 GHz band for 5G and only agreed that the lower 500 MHz of the band should be available for Wi-Fi. Their equipment vendors Ericsson, Nokia and Huawei supported that, which is not really surprising.

Satellite companies meanwhile were adamant that the upper 6 GHz band must not be allowed to have Wi-Fi in it, because their feeder uplinks used it. 

Low power means short range

Still, having 500 MHz of additional bandwidth in 6 GHz could’ve been useful for wireless providers… had it not been for the low transmission power allowed currently for the band. 

The conservative approach taken by RSM means transmission power for 6 GHz is very limited for outdoor use. In fact, you can run indoors Wi-Fi 6E/7 with 250 milliwatt; outdoors, it’s a puny 25 mW. That's due to fear of interference, particularly in the upper half of the 6 GHz band.

Meanwhile, North Americans get up to 4 Watt to play so providers there can set up links that reach several kilometres. With New Zealand power limit outdoors we're talking signal reach in the tens of metres instead.

For 6 GHz, the higher power limit outdoors provides about 1 Gbps over a couple of kilometres distance. 

To avoid interference between networks, the US and Canada uses a system called Automatic Frequency Coordination (AFC) for 6 GHz. This feature does what the name says, and picks clear frequencies when it detects interference. It’s not cheap to implement, and requires global positioning system (GPS) functionality in the 6 GHz radios.

Australia, where everything is bigger, including budgets, is now trialling AFC. This is so they can put more of the upper 6 GHz band to use and to increase transmission power for longer signal reach.

There are some question marks around ACMA's decision to configure the upper 6 GHz band in a non-standard fashion which is unique to Australia. A bit of 6 GHz will be sliced off for 5G use it seems, so the whole band won't be used for Wi-Fi like in North America which could lead to equipment compatibility issues. That's radio engineer nerd stuff though.

While the RSM has left the door open for AFC, there are no plans to currently to introduce such a system in New Zealand.

That said, a small market like New Zealand might not need AFC. Jon Brewer, one of New Zealand's Approved Radio Engineers (AREs) suggested the 6 GHz allocations could be coordinated by radio engineers, like in many other parts of New Zealand.

More free, shared spectrum wanted

NZ WISPs using 5 GHz are now looking at the 6 GHz spectrum their Aussie counterparts are about to receive, and want New Zealand to head down that route too. Australia also has a different regime for parts of the 3.4 to 4 GHz spectrum, with inexpensive licensing that provides access to large swathes of bandwidth. There's nothing similar in New Zealand.

It's not a quick and easy fix though. Changing regulatory tack like that requires political nous to bend the government's ear. The powers to be need to be persuaded that a different approach that allows for greater use of free, or cheaply licensed spectrum can have substantial economic benefits.

Overseas experiences suggests that is the case. If the United States NCTA Internet and Television Association is to be believed, the shared spectrum use it advocates for adds bilions to the US economy, along with millions of jobs, particularly for Wi-Fi technologies.

The demand for connectivity is definitely there because in 2025, fast Internet access is nearly mandatory to lead a normal life. This is what Starlink has been able to capitalise on, with the satellite broadband provider rapidly building up a big customer base that's probably going hit 40,000 soon.

Starlink isn't going away, and the risk here is that it and other Low Earth Orbit (LEO) satellite providers will be seen by the government as the easy option rather than embarking on slow and complex regulatory reconfiguration.