Rural broadband problem we're not talking about

We’ve all heard about the digital divide. It’s about how disadvantaged New Zealanders don’t have the same access to broadband as their better-off neighbours.

We also know about the rural-urban digital divide. People who live outside the UFB fibre areas have fewer broadband options and none of them are as good as fibre. Rural New Zealanders can end up paying more, for inferior broadband. Many of these people are covered by the Rural Broadband Initiative (RBI).

There’s another digital divide that you hear about less often. That’s the performance gap between two classes of Rural Broadband Initiative (RBI) customers.

Fixed wireless rural broadband

Fixed wireless broadband serves RBI customers. It may not be as good as fibre, but on a good day the service isn’t bad. When it works well, RBI customers can see speeds that are more than adequate for most applications. That includes streaming high resolution video.

The problem is that some people, the people on the wrong side of New Zealand’s third digital divide don’t have good broadband days. Not ever.

It’s a complex topic, so while engineering types may disagree with this explanation, here’s the problem described for non-experts.

Vodafone and Spark mainly use 4G mobile technology for their first generation RBI towers. This is often called RBI1.

Carriers have two sets of spectrum. The 700 MHz band connects people who live further away from towers. The 700 MHz signals reach further, in some cases over 20km from a tower and they do a better job of dealing with obstacles. You don’t need line of sight.

Urban standard, but in the bush

RBI towers often also include antennae using, for the want of a better term, ‘urban 4G spectrum’. This tends to work only where the customer can actually see the tower. Or as they say in wireless communications circles, where there is “line-of-sight”.

In effect the urban spectrum delivers much the same fixed wireless broadband performance that customers will get if they live in a city or town.

It tends to be faster and is more reliable, which means fewer drop outs.

There are nuances. Wireless performance depends on a number of factors; distance, the nature of obstacles and, in some cases, atmospheric conditions, can all play a part.

Some more remote RBI1 customers are lucky. Others are not. It’s a lottery.

Customers connected to the same tower can see a huge difference in performance. While some who live nearby may be able to enjoy Netflix, others who live further away may struggle to get their email out.

Overload

A second, related problem, is that carriers engineered and managed their RBI towers to cope with the levels of demand they saw before the Covid-19 lockdown. This included limiting the number of connections on a tower so that users get a reasonable experience and managing download limits to minimise congestion.

Fixed wireless bandwidth is shared. When too many customers connect at the same time there isn’t enough to go around. It requires a careful balancing act. The calculations used to manage customer and download numbers date from before the lockdown. Since the lockdown broadband demand has increased dramatically.

Which means towers that were coping before are now under pressure. Rural broadband can not scale up to meet increased demand the way fibre can.

We don’t hear much discussion about the gulf between different classes of RBI1 users connected to the same tower, but the problems are real. Fixing it won’t be easy.