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gfast map nov

Dark Green: Firm commitments from incumbent: BT (10M), Belgacom, Australian NBN, Swisscom,  Austria, Bezeq Israel, Chunghwa Taiwan, Telus Canada, Telekom South Africa, SK Korea, (U.S.) AT&T, Century, Frontier, Windstream, Belgium, Omantel

Mid Pink: Smaller carriers in Germany, Norway, Finland, Japan

Light Green: Incumbent likely:  France, Germany, Italy

Cavium OCTEONToday's fronthaul CPRI usually requires 2.4Gb/s to 7.2Gb/s, too much for Today's wireless network often has a single Baseband Unit (BBU) supporting multiple Radio Units (RU), also called remote radio heads. Cellular speeds are just now rising from 100-150 megabits to 300-450 megabits, well within the capacity of My initial reaction was "ho-hum," but BT's Richard Knowles pointed out what I had missed. Most fronthaul uses the Common Public Radio Interface, which requires much higher speeds. BT and Cavium found an alternative that brought fronthaul requirements down to speeds.

 They may be spread across a building for better indoor coverage or may be kilometers away. The connection from a BBU in the field to the remotes is called "fronthaul." Backhaul is from BBU to the high capacity of the telco network. CPRI fronthaul speeds require fiber today. 

Cavium and BT are developing an alternative to CPRI that requires less bandwidth.

Knowles writes, "By splitting the base station functionality above the physical layer we have successfully demonstrated a ‘Mid-haul’ solution which requires 10% overhead above the line rate. Using CPRI, the front haul would require 2.4Gb/s to support 150Mb/s,  using the novel functional split this is reduced to 170Mb/s. Angel Atondo of Cavium explains what they are testing. "This trial splits the LTE L1-L2 protocol and significantly reduces the required fronthaul bandwidth."

There could be large savings in some locations up to 400 meters with copper available. 150 megabits won't be sufficient for long in many places because LTE is quickly moving to two and three carriers and higher order MIMO. Data rates of 300-800 megabits will become common.

Cavium and BT hope will bring down the effective cost of small cells, especially 5G in high frequencies. Five years ago, most of us expected substantial deployments of small cells and femtocells. It hasn't happened and some once very promising companies are no longer with us. The backhaul costs were just too high. Sometimes, real estate was also prohibitive. "The lab based demonstration showed successful operation of this concept over, a major milestone in our research," BT writes.

Here's the pr.

BT partners with Cavium in Cloud RAN trials

BT announced today that it has successfully used technology to deliver a ‘Cloud Radio Access Network’ (C-RAN) cellular network service over copper, in an experiment believed to be a world first.

C-RAN is a new network architecture used to connect cellular base-stations to mobile operators’ core networks. A traditional approach to C-RAN requires a dedicated fibre link to connect transmitters at the top of a cell tower to complex signal-processing equipment deeper in the network. This can involve complex and costly engineering work if no fibre is present in the ground to carry the signal.

Researchers at BT’s Adastral Park Labs in Ipswich, in collaboration with US-based semiconductor manufacturer Cavium, Inc. (NASDAQ: CAVM), have demonstrated that they can use technology to deliver cellular data over copper lines at speeds of 150 – 200Mbps. 

This removes the need for mobile operators to invest in costly, high capacity backhaul links over dedicated fibre connections.  By providing a far more economic “fronthaul” connection between the base station and the mobile operators’ core network, a C-RAN service delivered over would significantly lower the cost of deployment for mobile operators building out 4G networks today and 5G architectures in the future.

Dr Tim Whitley, MD for Research & Innovation at BT said: “Using to deliver a cellular network is an exciting breakthrough for C-RAN and yet another world first for our team of researchers at Adastral Park.

“These technologies will play a key role in 4G networks and will be fundamental to 5G architectures. The trials are another step towards a fixed and mobile network which will support customers’ increasing demands for data.”

“We are very excited to collaborate with BT, using Cavium OCTEON Fusion-M™ basestation and ThunderX® server processor technology to validate this new class of Radio Access application with technology.” said Raj Singh, General Manager of Cavium’s Wireless Broadband Group. 

“Our successful testing has laid the groundwork for enabling LTE deployments today and 5G deployments in the future using”

As well as exploring the role that may play in helping operators to roll out their 4G/5G networks, Openreach, BT’s local access network division, is also trialling as an access technology in Huntingdon and Gosforth, alongside a further BT technical trial in Swansea. is significant because by building on current Fibre-to-the-Cabinet (FTTC) technology, it allows Openreach to bring ultrafast speeds to a wide footprint far more rapidly and without the expense and disruption of running fibre directly into a home or business. 

If the trials prove successful – and if UK regulation continues to encourage investment – the company has pledged to provide ultrafast speeds to 10m homes by 2020 and to the majority of the UK within a decade. 
BT has invested c£500 million that in R&D every year. The company is one of the largest investors in R&D of any company in the UK and globally in the telecoms sector, and currently holds an astonishing 4,560 patents. 



FrontHaul for indoor coverage

Indoor spaces isolated from macrocell coverage may have peak traffic at different times than those that occur outdoors, especially weekends and evenings. Examples of such areas are usually indoor stadiums, shopping centers, cafés/bars, convention centers, and government offices, covered by indoor lampsites, hotel BBUs, etc. Indoor small cells placed on ceilings or interior walls can use existing FTTx or Ethernet resources as per the availability.

However, wired solutions can play a useful role in small cell backhaul, and of course, the overall backhaul solution can be a hybrid of wired and wireless (such as short-length microwave connectivity).

FrontHaul for outdoor coverage

For outdoor FrontHaul coverage areas, microwave technologies, including E-Band (71 to 76GHz), V-Band (60GHz), and Sub Link (Sub 6GHz) are usually best for supporting the LOS/n-LOS/N-LOS terrains. This accelerates rollout and makes O&M quite a bit easier, while enabling full outdoor assembly and unified NMS solution. It is more adaptable in terms of site location (walls, rooftops, poles, etc.). PMP application is useful as it eliminates the need for line-of-sight, making it useful for hotspot areas, while PTP application, with its longer transmission distance (though line-of-sight) can connect PMP hub modules with macro sites.

BT's Richard Knowles 

The Site for gfast 230 News

I’m still working through remarkable presentations from the Broadband Forum events. Michael Weissman, Bernd Hesse and team did a remarkable job choosing the speakers.

Deutsche Telecom: 35b Supervectoring Delayed to 2019
Broadcom is now over 3 years late. DT briefed German reporters after their financial call and revealed 35b was now delayed until 2019. 35b should deliver 200+ meg downloads 500-600 meters, a crucial tool for DT, which is losing share to cable. Cable now covers about 70% of Germany and is expanding. DT now only offers 50-100 megabit DSL while cable is often 400 megabits, going to a gigabit. 

The problem is software; the hardware is shipping and supposedly will work. DT says 35b is not ready to turn on. Broadcom in 2015 said 35b was in "production" in the press release below. Alcatel in early 2016 said to expect complete systems very soon. "35g is very similar to 17a so there should be little delay."

Broadcom's problems are leading major telcos and vendors to have a plan B, using Sckipio DT itself is planning extensive deployments in 2019, mostly in apartment buildings.

Gigabit 100 Meters - Unless the Wires are Lousy
Speeds are fine, "Unless there's a line problem." I've been reporting for three years that ~10% of lines have problems. In the chart by Rami Verbin of Sckipio, he finds goes ~130 meters on good lines. Poor lines have about half the reach. 

His chart roughly matches the reports from Swisscom, Belgacom, and England for both & vectored DSL. The 10% with problems can cause the majority of the line-related complaints to support. The angry customers drive up cost.

Rami's solution to reach the gigabit is bonding, supported on the Sckipio chips. Verbin made some additional points:

  • 4 gigabits is possible by bonding two decent 2 gigabit lines.
  • Even in a service from remote cabinets, ~25% are close enough to get a full gigabit."
  • cDTA and iDTA are practical ways to deliver much higher upstream by switching some bandwidth from downstream to upstream only when needed.
  • 35B will probably be similar but Deutsche Telecom doesn't expect to deploy until 2019.

AT&T Wants Coax 2-5 Gigabit Very Soon.
AT&T faces intense competition from cable, talking about 10 gigabits in both directions. (Cable will only be 1 gig down, ~100 meg up, until ~2021.) AT&T wants something to brag about as well.

AT&T gained millions of lines of coax as part of the DirecTV deal. Alcatel and Huawei are leading the development of G.mgfast. That uses 424 MHz, full duplex, to achieve ~2.5 gigabits in both directions. The reach on telco twisted pair is only about 30 meters. On coax, those speeds can probably extend far enough to service most apartment buildings. Using 848 MHz, speeds can reach 5 gigabits. The ITU standards group has been aiming for 2019-2020 for G.mgfast, too slow for AT&T's marketers. David Titus wants a high-speed standard for coax "early in 2018." He believes that is "doable."

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