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
- Published: 27 February 2016 27 February 2016
Today's fronthaul CPRI usually requires 2.4Gb/s to 7.2Gb/s, too much for G.fast. 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 G.fast. 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 G.fast 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.
- Published: 21 February 2016 21 February 2016
XG-FAST, a potential future development of the technology, is in the early stages of lab testing, but has exceeded expectations in trials at Adastral Park, BT’s global research and development campus in Suffolk, and Alcatel-Lucent’s labs in Antwerp.
It delivered aggregate speeds of 5.6Gbps over 35 metres of BT cable, a record for full-duplex data transmission over a standard single BT line at this distance. The technology also performed well over longer distances, with aggregate speeds of 1.8Gbps over 100 metres; a significant result, as most UK homes are within this distance of their local distribution point, be that a pole or footway box. (below, full duplex excerpt from an article by Jochen Maes and team.)
At the start of the G.fast work, they investigated the possibility of sending data both upstream and down in the same frequency. It wasn't included then. There are trade-offs: complexity, reach, robustness.
- Published: 26 January 2016 26 January 2016
Telebyte is also ready with 35b vectored test equipment. You want to catch equipment problems in the lab because serious field trials cost millions. But how do you test the 300-page G.fast standard? Michael Breneisen's company chose to work closely with the Broadband Forum and their equipment is designed around the Forum's test suite. They've outfitted a lab at the University of New Hampshire which hosts the Forum's interoperability testing.
Breneisen tells me the most frequent problems in early G.fast equipment were in the stability of FEXT cancelation and noise protection. Once discovered, manufacturers corrected most of them. Looking forward, he believes the industry needs to be able to test sucessfully Interoperability between chipset vendors.
Field tests reveal even more. TNO's Rob van den Brink gave an outstanding presentation at last year's Ultra Broadband Forum. He offered surprising observations from DSL field results in the Netherlands. I always remain skeptical of company claims until we have results from 10,000 customers.
- Published: 17 November 2015 17 November 2015
playing an important role after the Intel takeover. Artusi built an interdependence between Lantiq and Sckipio, with complementary chip developments and reference designs. With the resources of $50B Intel, he can support his ally.With chips costing $10's of millions and more to develop, funding becomes just this side of impossible. Lantiq CEO Dan Artusi is
Lantiq had to give up independence and is now part of Intel. Alcatel and Dado Banatao put risk capital behind Ikanos. That wasn't enough and the VC's wound up selling to Qualcomm. Sckipio is essentially the only independent DSL chipmaker outside of China.
- Published: 17 November 2015 17 November 2015
Many claims, little data. Arun Hiremath suggests Ikanos has entered the promised land of G.fast chips ready to go in high volume. Their engineering is strong, harvesting the best of earlier companies Globespan, Virata, Conexant and the old Ikanos. CTO Debu Pal is a veteran of Bell Labs and DSL pioneer Amati and studied with the legendary Thomas Kailath at Stanford.
The data they provide for now is unfortunately limited. They have a modem/cpe chip and a single port distribution point chip.
- Published: 28 October 2015 28 October 2015
35b for Germany, bonding for AT&T/BT advertising. Vague claims of "up to 100% improvement" don't tell me what the result will be for most customers, which is what engineers reading this need to know. I doubt the 35b chips are delivering the 250 megabits down Broadcom salesmen promised customers for delivery about a year ago, but they haven't released data. On 35b, everyone in the industry is waiting to find out whether the tweaks to VDSL really will double downstream speeds. We need test results.
The desire for these chips is clear, if they deliver as hoped. Germany's DT and England's BT calculated the cost of all the field terminals in the original plans for G.fast and, the financial side of the companies balked. England's choice was to squeeze everything they can from existing terminals, increasing distances far beyond the ~100 meters in the original G.fast design. In their early testing, they are shooting for 330/50 to many homes with what I call G.halffast.