NBN hails 'game-changing' DOCSIS 3.1 gigabit speeds on HFC

NBN has said that new technology allowing for the utilisation of DOCSIS 3.1 brings HFC alongside FttP in terms of broadband speeds available to users.
Written by Corinne Reichert, Contributor

The National Broadband Network (NBN) company has hailed new technology unveiled by worldwide hybrid fibre-coaxial (HFC) technology standards group CableLabs will facilitate DOCSIS 3.1 on HFC networks which would allow symmetrical multi-gigabit speeds for users.

Data Over Cable Service Interface Specification (DOCSIS) 3.1 supersedes the current DOCSIS 3.0 standard, allowing for faster speeds by freeing up around 50 percent capacity on the cable through more efficient transmission of data over the available spectrum.

"A newly unveiled project at CableLabs illustrates how DOCSIS 3.1 technology provides the basis for continued evolution of system capacities by supporting symmetric multi-gigabit service over the cable network," CableLabs vice president of Research and Development in Wireless Technologies Belal Hamzeh wrote.

In comparison to frequency-division duplex (FDD) and time-division duplex (TDD), full duplex DOCSIS sees both downstream and upstream traffic share the same spectrum. Symmetrical multi-gigabit broadband services are hence made possible through DOCSIS 3.1 technology when combined with full duplex DOCSIS.

"A DOCSIS 3.1 Full Duplex network provides the peak speeds and flexibility of TDD solutions, but one-ups both TDD and FDD with double the capacity," Hamzeh said.

"Using a combination of Passive HFC and the self-interference cancellation and intelligent scheduling of DOCSIS 3.1 technology, CableLabs has built a solution that proves the viability of full duplex communication. Its approach significantly increases upstream data capacity in order to enable symmetric multi-gigabit broadband data services for consumers and the enterprise.

"These developments are expected to yield DOCSIS 3.1 network performance of up to 10Gbps symmetrical on 1GHz HFC networks, with the potential for even higher performance by utilizing spectrum that is currently available for future expansion above 1GHz."

Full duplex DOCSIS won't be launched for some time, with HFC spectrum bands to be opened up to 6GHz for this.

"Although it is still very early days, the arrival of Full Duplex DOCSIS 3.1 is extremely exciting news for NBN, and a real game-changing moment in the ultra-fast broadband market," said NBN CTO Dennis Steiger, who is currently in the US with CableLabs for the announcement.

"We will be working closely with CableLabs to track the development of this technology, and are excited about the potential this offers for the 4 million premises that will receive their NBN services via our HFC network.

"Previously, it was only possible to deliver multi-gigabit symmetrical broadband if you deployed an FttP network -- but HFC is now right up there in terms of being able to deliver these kinds of speeds.

"We now have the pathway to deliver these ultra-fast symmetrical speeds to our HFC end users both very cost effectively and far more conveniently than we could if we had to deliver fibre all the way to their homes."

According to NBN, DOCSIS 3.1 will work across both Telstra and Optus' HFC networks, despite a leaked draft from NBN revealing in November that Optus' HFC network is "not fully fit for purpose", with 470,000 premises in the footprint needing to be overbuilt by either Telstra HFC or fibre services.

A Q&A on DOCSIS 3.1, published on the website of Australian Communications Minister cum Prime Minister Malcolm Turnbull a year ago said the technology would be coming to the NBN HFC network by 2017.

"We plan to run DOCSIS 3.1 trials in 2016 and we plan to have DOCSIS 3.1 services commercially available in 2017," Turnbull wrote.

"Bringing DOCSIS 3.1 on board is the cherry on the cake that will give us even more capacity and really make sure that there is plenty of bandwidth for everyone on the network to have a great experience."

According to reports, however, the highest throughput ever recorded using a single coherent receiver across a fibre network saw speeds of 1.125 Tbps.

In October, NBN announced that it had conducted a trial of G.fast fibre-to-the-basement (FttB) technology, attaining throughput speeds of 800Mbps.

The wide-scale rollout of NBN HFC was approved by the Australian Competition and Consumer Commission (ACCC) in June, with a revised AU$11 billion deal allowing NBN to take ownership of Telstra's HFC and copper assets and Optus' HFC network.

The new deal came about as a result of NBN moving away from Labor's full FttP rollout following the Coalition's election at the end of 2013 to the present so-called multi-technology mix (MTM), which proposes to cover 20 percent of the population with FttP; 38 percent with fibre-to-the-node (FttN) and FttB; 34 percent with HFC; 5 percent with fixed wireless; and 3 percent with satellite services.

In December, Telstra and NBN announced they had entered a memorandum of understanding for a "significant contract" to manage the design, engineering, procuring, and construction of NBN's HFC network, which will include Telstra updating HFC to DOCSIS 3.1 technology in order to deliver end users speeds of up to 1Gbps.

Telstra is also set to prepare exchange locations and planning and design prior to and during the contract's negotiation. Telstra has already been continually building out its HFC network despite its impending transfer of ownership to NBN.

HFC will connect 4 million Australian premises in total, with 3.6 million of these coming from the old Telstra HFC network. The network will also be extended and infilled, with the Optus network likely to be infilled and overbuilt in the remaining 400,000 premises.

NBN is currently conducting a 4,500-premises HFC trial in Redcliffe, Queensland, and said it has not found any "unexpected" technical issues with the Optus network.

The HFC network will be launched by June 2016, and completed along with the rest of the NBN by 2020.

Making good on its own promise in January 2015 to offer 1Gbps speeds across its HFC network in 2015, US cable company Comcast announced in December that it had installed the world's first commercial DOCSIS 3.1 modem for a customer in Philadelphia.

"The beauty of DOCSIS 3.1 is that it is backwards compatible, so no digging up streets or backyards," Comcast said.

"This technology, when combined with the extensive upgrades we have already completed on our advanced hybrid fiber-coaxial network, will provide more gigabit choices for our customers."

Comcast then said in January that customers in Atlanta and Nashville would be the first to receive DOCSIS 3.1 internet services within the first half of 2016, with Chicago, Detroit, and Miami to follow in the latter half of the year.

Last month, Chinese technology giant Huawei announced that it will upgrade Denmark's fixed broadband network to deliver download speeds of up to 1 gigabit per second by the end of 2017.

Under a deal with Tele Danmark Communications (TDC), Denmark will become the first nation to upgrade a broadband network in its entirety to Giga Coax technology, with the upgrade to begin in June 2016.

Denmark was also the first country in Europe to have a DOCSIS 3.0 network deployed, which was installed by incumbent multi-service operator TDC.

Denmark's new DOCSIS 3.1 Giga Coax network implements orthogonal frequency-division multiplexing (OFDM), which carries data on multiple parallel data streams to increase transmission by 50 percent in comparison to DOCSIS 3.0.

Existing coaxial cables can be upgraded to DOCSIS 3.1 to offer bandwidth of up to 10Gbps down and 2Gbps up.

Huawei is providing its distributed DOCSIS 3.1 Distributed Converged Cable Access Platform (D-CCAP) solution [PDF] in order to digitise and reuse existing optical fibres and analog components in the network, making flexible and reliable capacity expansion possible. D-CCAP can also be used on the same platform as FttP technology.

According to Zha Jun, president of Huawei's Fixed Network Product Line, the Chinese company has been dedicating research and development resources to DOCSIS 3.1 networks since 2012, with the goal of modernising fixed-line networks to compete with FttP networks.

"Huawei's cooperation with TDC and other industry players to build industry-leading Giga Coax networks will greatly promote DOCSIS 3.1 commercialisation worldwide, and help establish a mature industry ecosystem," Zha Jun said.

Nokia followed this up at the start of February with a demonstration in its labs of XG-Fast technology, which delivered 11Gbps over a 50-metre run on two bonded pairs of Category 6 cable.

Using a standard drop cable, Nokia, in partnership with Deutsche Telekom, said XG-Fast is capable of delivering an aggregate rate in excess of 8Gbps on 50-metre runs.

Tests conducted with UK telco BT in October showed that XG-Fast is able to carry 5Gbps on 35m two-pair copper cable, and 1.8Gbps over the distance of 100m of two-pair copper.

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