The next generation of G.fast chips will give network operators the ability to support gigabit speeds over twisted pair copper or coax wiring over distances of 100 meters or more – and chipmaker Sckipio expects to support the maximum possible bandwidth, said Michael Weissman, vice president of marketing for Sckipio, in an interview. Next-generation G.fast enhancements are in chips that have been in manufacturers’ hands since last year and are expected to be included in products that network operators will roll out in the second half of 2018, Weissman said.
The maximum G.fast speeds are made possible by expanding the portion of spectrum within a copper connection that can be used for G.fast to up to 212 MHz, Weissman explained. Previously the maximum limit was 106 MHz.
“The goal is to get a gigabit to more customers,” said Weissman.
By using broader spectrum and bonding multiple lines together, network operators can further boost G.fast bandwidth – an option that might be desired by business customers – or can extend the distance over which gigabit service can be delivered.
There are two versions of the next-generation G.fast standard, Weissman noted. The 212A standard is for twisted pair wiring and the 212C standard is for coax. Coax experiences less attenuation over distance in comparison with twisted pair – a reality that could give AT&T an edge as it makes plans to roll out G.fast in combination with DirecTV using coax wiring in multi-dwelling units (MDUs) outside its home turf. With coax, over distances of 300 meters, “you have around 500 to 600 Mbps more capacity,” Weissman said.
According to Weissman, the new G.fast standard calls for up to 2 Gbps of total aggregate capacity, but Sckipio uses what it calls cDTA technology to get up to 2 Gbps downstream and 2 Gbps upstream without bonding.
“With Sckipio’s bonding capabilities using the 212a profile, Sckipio’s boxes can achieve up to 4 Gbps in both directions,” Weissman said.
Sckipio also has made some enhancements involving G.fast scalability.
As Weissman explained, equipment makers must use vectoring to overcome G.fast cross talk challenges. “You’re trying to know [behavior] on every line, and every line needs to know about every other line,” explained Weissman. “As you increase the port size, it becomes more complicated.”
One solution is to use a separate vectoring engine, but that creates scale challenges. To prepare for future growth, for example, a network operator would have to invest in the engine even when only a few customers initially take service.
Distribution point units (DPUs) using Sckipio’s next-generation G.fast technology, however, will support cross-DPU vectoring. They will be able to interconnect with each other to support up to 96 G.fast ports using the 212A standard without a separate vectoring engine, Weissman said.
Operator G.fast Plans
Four of the five largest U.S. network operators have said they plan to deploy G.fast, Weissman noted.
One exception is Verizon. Several weeks ago, a Verizon executive said the company did not plan to use the technology but, unlike some other operators, would rely on fiber-to-the-premises equipment when bringing broadband to MDUs.
More recently, Verizon CEO Lowell McAdam hinted that the company might deploy fixed 5G outside its home turf to support broadband.