Australia’s national broadband service NBN says its lab trials of Nokia’s XG.FAST have reached speeds of 8 Gbps at 30 meters and 5 Gbps at 70 meters. Alcatel-Lucent was well-underway in developing XG.FAST when Nokia acquired it – and XG.FAST and G.fast are turning out to be jewels. NBN, whose trials are conducted at its Sydney headquarters, is one of only three telcos that have conducted XG.FAST trials – the other two being BT and DT (Deutsche Telekom).
XG.FAST is essentially a higher-speed version of G.fast, which supercharges copper-line connections by increasing the frequency range over which broadband signals travel.
Using G.fast technology, BT aims to provide services of at least 300 Mbit/s to around 10 million UK homes and businesses by 2020, while NBN has said it might use both G.fast and XG.FAST during a deployment of fiber-to-the-distribution point (FTTdp) technology targeting about 700,000 premises.
G.fast’s main drawback is that it loses effectiveness over longer distances due to signal attenuation. It was originally intended for use at distribution points near customer premises, as NBN is planning, but BT reckons that ongoing technology improvements will support installation at street cabinets up to 350 meters from homes.
However, because XG.FAST works in even higher frequency ranges than G.fast, it seems unlikely to feature in cabinet-based deployments at all.
“Given that it’s a 500MHz system, I don’t think it will be going too far away from the fiber,” said Trevor Linney, BT’s head of access network research, during a conversation with Light Reading at last year’s Broadband World Forum in London.
The rollout of gigabit broadband access networks is spreading. Find out what’s happening where in our dedicated Gigabit Cities content channel here on Light Reading.
NBN says its FTTdp deployment could provide a platform for the rollout of both G.fast and XG.FAST while appearing to have ruled out the use of cabinet-based G.fast whatsoever.
“BT’s cabinets are about 300 meters from premises but the average distance in Australia is about twice as much,” said Daniel Willis, NBN’s principal technology officer for FTTx, at this year’s Broadband World Forum.
Critics of the state-backed wholesale operator believe the use of copper-based technologies is shortsighted and have urged NBN to invest in fiber. Yet NBN is also under pressure to minimize the cost of providing a high-speed broadband network across the whole of Australia.
In Germany, Deutsche Telekom has yet to announce any firm commitment to G.fast, although it previously told Light Reading it was considering using the technology in building basements.
Deutsche Telekom claimed to have reached even higher speeds than NBN during its own trials of XG.FAST, achieving 11 Gbps over a distance of 50 meters in February.
The German operator’s trials were also carried out with Nokia Corp.