G.Fast Trends

Copper-to-Fiber MigrationCore/LegacyDSL/G.Fast/Vectoring
Challenges and Opportunities in the Quest for Cost-Effective Ultrafast Broadband —

G.fast is now gaining real momentum, with trials taking place around the world. The benefits have always been attractive, namely the ability to significantly boost the capabilities of Last Mile copper connections while maximizing existing assets. Now, the technical limitations that caused some initial delays are gradually being overcome.

In homes everywhere, the number of Internet-capable devices (phones, tablets, computers, game consoles, etc.) has increased dramatically. This places burden on existing infrastructure, creating slow speeds and bandwidth bottlenecks.

In addition, pressure from the FCC to improve download speeds to at least 100 Mbs and upload speeds to 50 Mbs by 2020 to improve service to education, healthcare, government, and other sectors, is sending providers scrambling to find affordable options to full FTTH, FTTB (building), FTTdp (distribution point), or FTTC (curb).

While providers used to push services to their customers, consumers are now demanding them at an increasingly fast pace. Some are turning to complete fiber solutions to offer gigabit broadband. Others are focused on maximizing their existing network to increase speed. Enter G.fast: fiber-like speeds over Last Mile copper.

G.fast Capabilities
While many believed copper would have reached its bandwidth limit a long time ago, G.fast is proving that not to be the case. Using higher frequencies to increase connection speeds on existing copper lines, G.fast delivers hundreds of megabits per second based on the initial G.fast standard, which operates at 106 MHz (the second amendment to the G.fast standard supports 212 MHz).*

G.fast capabilities when combined with line powering enables telecom operators to better use the embedded telecom grid, which has underutilized copper due to the reduced number of landlines in use.

This technology is also an attractive choice for operators because of its minimal disruption of the existing infrastructure. Equipping cabinets or existing infrastructure to handle G.fast helps reduce the time to engineer, obtain municipal permits and the resulting civil works, thereby helping reduce the cost and time needed to deliver high-speed broadband to customers.

Network Limitations
While the G.fast story is compelling, challenges exist, not the least of which is the requirement to drive the fiber deeper into the network to allow system operators to optimize the network data rate in balance with distance from the subscriber.

Operating at higher frequencies means losing effectiveness over longer distances. Offering customers speeds from 100 Mbs to 1 Gbps via G.fast means bringing active electronics much closer to customer premises, typically between 100 and 500 meters. From the G.fast terminal, the existing copper drops are used, helping reduce the need for new electronics at every customer location.

Also, many cable ducts are sized to suit the older generation of VDSL deployments. The next generations of VDSL equipment — plus the addition of ultrafast services via G.fast — will require support of both fiber cable and copper drops within the same cabinet. While replacing cabinets is an option, expanding capacity into existing cabinets and terminals may help minimize cost, time, and local disruption. By using high-performance connectivity within the expanded solution, network operators can be assured of an excellent result.

For the existing copper lines to transmit these desirable high speeds, signals need to travel over fiber placed deeper into the network. This requires additional splice closures and terminals to manage the connections.

Traditional copper cross-connect cabinets can also be retrofitted for fiber, enabling further fiber connectivity. Fiber Frames are an innovative approach to balance sustainability, aesthetics, and deployment speed, by using existing copper cross-connect cabinet infrastructure and converting them to high-density fiber distribution hubs.

MDU Upgrades
As network operators approach their trials and deployments of G.fast technology with a primary focus on brownfield broadband upgrades, site location decisions have been initially focused on MDU deployments. As G.fast technology continues to evolve for both the capacity and distance benefits, the focus is beginning to include multiple OSP terminal- and cabinet-based solutions. Existing indoor and outdoor building entrance terminals, garden terminals, cable terminals, pedestals, remote terminals, and cross-connect cabinets, become appropriate solutions to very quickly and economically add to the financial benefits to deploy G.fast within existing infrastructure. Connectivity and splicing components become of primary importance to deliver the speed and quality as expected.

In addition, adding capacity in existing infrastructure is a solution for network owners looking to quickly provide higher quality, reliable service. While utilizing existing copper distribution cables and drop wire, these services can be enhanced by embracing advancements in splitter-block technology, available in small form factors in very high density. These splitter blocks help increase the number of subscribers supported in each cabinet.

A single splitter block connects 3 pair of wires, taking the data from the network (1 pair) and creating the customer port connections for data (1 pair) and POTS(1 pair).

Connections are provided in the same space (or less) as existing traditional cross-connection blocks. These higher density splitter blocks also decrease the risk of cross-talk with so many high-frequency copper connections in such a small space. Advances in block protection and splitter designs by suppliers such as 3M mean that the environmental concerns surrounding the deployment of this type of connectivity within existing cross-connect cabinets are reduced.

Blocks and splitters are designed to be installed quickly and simply, without requiring special tools or extensive training. There is also easy access for testing and maintenance.

Looking to the Future
The second amendment to the G.fast specification specifies 212 MHz transmission speed, and has vendors and service providers the world over searching for additional solutions that can support not only G.fast at 212 MHz, but can also deal with more harsh environments.

Today, delivering high-quality services, generating revenue, and planning for a successful future, can be a delicate balancing act. By making use of existing infrastructure, G.fast has a major role to play in providing safe delivery of ultrafast broadband networks and services, helping operators meet demand quickly and cost-efficiently and giving customers the service and performance they insist upon.

Endnote
*For G.fast products testing, we based on the following standards for test limits: ITU-T G.9700, ITU-T G.9701, and ETSI TS 101 952-1 V1.1.1 (2009-06).

About Rob Mertz

Rob Mertz is a Marketing Manager with the 3M Communication Markets Division, based in Austin, Texas. He has more than 30 years of experience in the telecommunications industry. For more information, please email rrmertz@mmm.com or visit www.3M.com/Telecom.