BT says trials prove gigabit potential of G.fast technology

BT has completed field trials to show that "ultrafast" broadband – with combined downstream and upstream speeds of up to 1 Gbps – can be delivered via a mix of copper and fiber-optic cable.

BT has completed field trials to show that "ultrafast" broadband – with combined downstream and upstream speeds of up to 1 Gbps – can be delivered via a mix of copper and fiber-optic cable.

The UK operator, which is due to open a new ultrafast broadband lab at its Adastral Park R&D center in Ipswich, says it is "greatly encouraged" by the potential of fiber-to-the-distribution point (FTTdp) in combination with G.fast technology.

With FTTdp the fiber cable is rolled out to telephone poles or junction (footway) boxes located within about 100 m of homes and businesses. G.fast technology is then used to maximize data capacity over the copper by using much higher electronic frequencies plus advanced crosstalk cancellation techniques to deliver ultrafast speeds.

During the G.fast trials, downstream speeds of around 800 Mbps were achieved over a 19-m length of copper, combined with upstream speeds of more than 200 Mbps. Speeds of around 700/200 Mbps were also achieved over longer lines of 66 m, a distance that encompasses around 80% of potential connections in the real world, according to BT.

FTTdp is potentially a more cost-effective way to deliver ultra-high speeds than both fiber to the premises (FTTP) and dedicated business Ethernet lines, the operator claims. Less civil engineering works are required to install new cable and, since the cable terminates outside the property, it is likely that FTTdp could be a "self-install" product with no need for home engineering visits. As well as delivering ultrafast speeds, the technology also offers the flexibility to tailor the downstream/upstream allocation of the total 1-Gbps speed according to the user’s needs.

"We see G.fast as a very promising technology with significant potential – that's why we’re putting some of our best minds on the case to assess it fully in a purpose-built facility," said Dr. Tim Whitley, MD of research and innovation, BT Group.

Over the coming months BT researchers will use the new laboratory to study the full technical capabilities of G.fast hardware designed by system vendors such as ADTRAN Inc. (NASDAQ: ADTN), Alcatel-Lucent (Euronext Paris and NYSE: ALU), and Huawei Technologies Co Ltd. (watch, for example "ADTRAN makes the case for VDSL2, G.fast alongside FTTH"). The operator didn’t identify which equipment was used in the current field trial; however, last year BT said it was testing G.fast equipment from Huawei (see "BT to field trial G.fast fiber to the distribution point technology from Huawei").

"Our fiber rollout is making a huge positive difference to this country, already helping 82% of people have access to superfast broadband," said Joe Garner, CEO Openreach. "Businesses obviously demand even greater bandwidth and can already access speeds of up to 10 Gbps via dedicated business lines that we provide across the country. But customer needs will continue to change, and that’s why we’re deploying a mix of current technologies as well as testing new ones. We will continue to innovate so that we meet our customers’ needs today, and in the future."

While commercial G.fast technology is still immature, the specifications are stable and final approval of the G.9701 recommendation is expected in December. Widespread embrace of G.fast would dim the hopes of advocates of FTTP that service providers such as BT would move to all-fiber networks as competitors deployed 1-Gbps services based on FTTP.

For more information on FTTx/access systems and suppliers, visit the Lightwave Buyer’s Guide.

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