NBN changes to combat fixed-wireless congestion

Australia's National Broadband Network (NBN) company has amended its network design rules to reduce the number of premises able to connect to each fixed-wireless cell, as well as updating the maximum bandwidth capacity available.

The new Network Design Rules [PDF] -- first spotted by Kenneth Tsang -- provided to the Australian Competition and Consumer Commission (ACCC) at the end of June, will see maximum bandwidth move from 900Mbps to 4Gbps and maximum connected premises per sector be capped at 56.

"The planned maximum number of connected premises in a sector has typically been 110 premises but is now moving towards 56 premises in each sector, driving the need for additional sectors to support capacity demand (this may vary depending on the exact positions and radio conditions of the served premises)," the document says.

"The maximum bandwidth planned for the microwave hub site back to a FAN [fibre access node] site has been 900Mbps, but is now moving to 4Gbps to support capacity growth, allowing for the aggregation of up to eight eNodeBs [base stations], with a maximum of 2,640 end users."

The largest wireless serving areas will have up to 24 wireless serving area modules connected to a FAN, while the maximum number of end users in an access aggregation region is 25,000.

The changes follow criticisms about congestion on the fixed-wireless network, with CEO Bill Morrow last month telling the Joint Standing Committee on the National Broadband Network that the company is considering implementing a Fair Use policy capping download allowances for "extreme" or "super" users.

"Our average consumption across the NBN network is just under 200 gigabytes per month, and when you look at the fixed-wireless network it's substantially less than that, so these aren't as heavy of users; however, in the fixed-wireless there's a large portion that are using terabytes of data," the outgoing CEO explained.

"One of the things that we're evaluating ... [is] a form of Fair Use policy to say we would groom these extreme users ... the grooming could be that during the busy period of the day, when these heavy users are impacting the majority, that they actually get throttled back to where they are taking down whatever everybody else is taking down, and during the non-congested or busy periods, they're free to go for as much data as they want to pull down."

According to Morrow, there's enough extreme usage happening that there would be a "substantial lift" in peak speeds for other fixed-wireless users if NBN did groom the super users, which he described as being "gamers predominantly".

Morrow further claimed that the 100Mbps fixed-wireless product was always more aimed at businesses than residential users, arguing that it was killed off because it could cost AU$1 billion to offer, due to requiring additional towers, backhaul, and spectrum.

NBN in May revealed in response to Senate Estimates Questions on Notice that it is targeting fixed-wireless congestion at priority cells where speeds are less than 3Mbps during peak periods, with nine towers targeted at the end of November.

In June, the ACCC told the same joint standing committee that it would need an additional AU$6 million to extend its speed-monitoring program to fixed-wireless services.

According to the ACCC's Sean Riordan, the decision to exclude fixed-wireless from the speed-monitoring reports had been made by the watchdog itself.

"It was done on the basis that we felt there was a need to act quickly in the fixed-line footprint where most of the services were an issue; there was certainly more acceptance by RSPs of testing of the fixed-line footprint," he said.

"There is a lot of nervousness from the retailers about the fixed-wireless services coming into the scope of the program."

Riordan also described two ways in which NBN could improve visibility over how it is tracking and addressing its fixed-wireless network, including publishing which cells are congested.

"Commence in their dashboard reporting or similar how they're tracking in addressing the cells which don't currently qualify or meet their own design standard for the 6 megabit per second per end user in the busy hour -- that would be one simple step which they could take, and that would at least give people an informed information base to make some policy and other decisions," he suggested.

"The other work that we would like to do is to look to see what consumers are being advised at the time they're making their purchase decisions, whether they're being advised that the service that they're looking to acquire is actually in a cell which is congested."

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