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BT: 100Mbps on FTTC vectoring anti-noise tech trials extended

BT customers won’t see FTTC speeds pushing past 100Mbps this year after the telecoms firm extended trials of noise-cancelling ‘vectoring’ technology.

Vectoring could help push download speeds on BT’s Infinity FTTC (fibre-to-the-cabinet) broadband products over 100Mbps, working like noise-cancelling headphones to reduce crosstalk interference between copper lines running side-by-side.

BT Openreach engineers have been testing the tech in Barnet and Braintree with download speed improvements of around 10-15Mbps over short distances, and will now evaulate an enhanced vectoring system.

BT: 100Mbps on FTTC delayed to 2015 as vectoring tech trials continue
No Terry, I said cut the blue wire

BT said: “We know vectoring will have most impact on lines between 50m and 500m. Beyond 500m vectoring impact reduces with very little gain being seen beyond 1.5km. The trial certainly evidenced speed improvements for some longer lines impacted by cross-talk however. 

“Openreach is planning a further trial in summer 2014 to evaluate an enhanced vectoring engine (ASIC) capable of cancelling out significantly more cross-talk interference per line.”

BT Openreach said the trial would test out an enhanced vectoring engine (ASIC) that would cancel out even more crosstalk, pushing up speeds again.

It will also test out Physical Retransmission (G.INP) and Seamless-Rate-Adaptation (SRA) technologies, which BT Openreach hopes will bring further improvements in tandem with vectoring.

SRA was previously been ruled out by Openreach for older ADSL2+ lines, and is more reliable at varying line speeds based on line quality.

This trial will run through Summer 2014 and is likely to last three months, using the same six DSLAM fibre cabinets in Braintree and Barnet.

Broadband industry news site has been following the BT vectoring trials since they began in 2013, as well as similar tests being conducted overseas, where researchers are pushing copper phone lines towards gigabit speeds.

Huang Bai, senior engineering director of Jiangsu Posts & Telecommunications Planning and Designing Institute said in a blog post that a combination of vectoring for crosstalk elimination, SuperMIMO for channel expansion, and bonding technology will enable high-bandwidth connection over copper.

“This has been seen in the industry’s first DSL prototype, which can deliver one gigabit per second, making DSL a technology to keep an eye on,” he added.

BT hasn’t yet decided whether to roll out vectoring to cabinets across the country, but it could be under pressure to remain competitive as Virgin Media’s network reaches 152MbpsSky and TalkTalk plan a rival fibre network in selected cities, and community rural fibre schemes grow in number.


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