Taking fiber deeper is future-proof and reduces ecological impact
Regulators, institutions and businesses all continue to expand green initiatives. Cable operators are no exception to this trend as they continue to look for ways that can help them reduce power consumption and evolve their networks in order to increase their return on investment and become more socially responsible.

For example, several years ago the industry launched a “Screen to Green” initiative that focused on educating consumers on the dangers of dumping TVs in landfills and on how to dispose of such equipment in an environmentally responsible way. Comcast Colorado also took a proactive role in Screen to Green by promoting a Recycling Rally in Denver via messages in bills, on-screen alerts and commercials co-produced with Discovery Communications’ Planet Green channel. In addition, Cox Enterprises launched its Cox Conserves initiative in 2007 that promoted responsible disposal of consumer electronics equipment.

Driving fiber deeperAs operators continue to take proactive steps to educate their customers on best practices, with respect to the use and disposal of consumer electronics equipment, they are also intensifying their search for efficiencies in energy consumption, operational costs and bandwidth utilization. But what is the most efficient way for operators to invest in their network that will not leave them high and dry down the road? The one solution that stands out is the cable industry’s first truly green architecture: Fiber Deep. It is a uniquely advantageous approach for cable operators because it delivers major efficiencies across all areas of concern, including net gains to the bottom line, customer satisfaction and corporate standing with the public and regulators.

It is now becoming clear that the case for rapid evolution of cable operators’ networks to a Fiber Deep architecture is more compelling than ever. There is no better way than Fiber Deep to cost-effectively meet operators’ goals of bandwidth efficiency, operations efficiency and energy efficiency.

Working smarter

Consumers are no longer satisfied with basic broadcast video and data services and are continuing to increasingly demand highdefinition television (HDTV), multi-screen services, video on-demand (VOD), higher speeds for data services and sophisticated voice offerings. There is no other way to successfully provide these services than cable operators increasing their network capacity.

By driving fiber deeper into the network, typically within a few hundred feet of the subscribers’ homes, the optical-to-electrical conversion of downstream signals occurs much closer to subscribers' homes, which eliminates the need to add RF amplifiers.

With the length of the coaxial cable runs shortened, that portion of the network becomes entirely passive. As this reduces the size of node service areas, it in turn results in an increase of the narrowcast bandwidth available to individual subscribers. For about the same cost as a traditional hybrid fiber coax (HFC) rebuild or greenfield construction, cable operators can deploy Fiber Deep and achieve significant bandwidth gains per home passed to support emerging services.

The gains are rather significant with up to a 500 percent increase in the downstream and a 1,000 percent increase in the upstream.

These increases in bandwidth can be utilized immediately in order to expand service offerings on the fly. In addition, with higher network availability, operators can provide improved network performance.


In addition to increasing bandwidth possibilities, Fiber Deep also cuts operation costs with regards to operators’ power supplies and maintenance costs, including troubleshooting and annual maintenance, and delivers major efficiencies across all areas of operators’ concern, such as CAPEX. Leveraging existing HFC infrastructures to significantly reduce the number of customers served by a single node, a Fiber Deep architecture cuts plant power consumption, reduces maintenance costs and lowers the amount of gas consumed in truck rolls—a further benefit driven from the embedded monitoring associated with digital return technology.

Extending the digital domainThe elimination of RF amplifiers also results in reduced energy consumption and leads to significant power savings.

This coupled with the lowered need for maintenances leads to overall cost savings. Recent research conducted by Aurora Networks actually demonstrates a net savings of over $615,000 in combined costs of maintenance and power consumption for Fiber Deep compared to HFC over the course of one year, for a 70,000 HHP serving area. This translates to a savings of approximately $620 per mile or over $8.75 per home passed.

In addition, as consumer demands evolve, operators will not be stuck with stranded investments. Rather, operators can add new modules to support a variety of innovative residential and commercial services.

It’s easy being green

Fiber Deep is one of the most cost-effective solutions toward addressing bandwidth needs and operations efficiencies.

However, bandwidth and operational efficiencies are just the tip of the opportunities’ iceberg to uncover in a Fiber Deep architecture. It also offers major benefits when it comes to reducing energy consumption.

From a green perspective, the benefits of Fiber Deep are extensive.

With this architecture, fiber is extended so that there is no longer a need for RF amplifiers in the coaxial plant. This results in cutting the number of active devices in the distribution network by 70 percent and in a 50 percent reduction in power consumption. Research shows that a Fiber Deep architecture results in an annual reduction in plant power consumption of about 25.8 kilowatt hours per household passed in comparison to power consumption over an average HFC network. In addition to increased network reliability, fewer truck rolls and maintenance visits required lead to significant reductions in fuel consumption and therefore generation of greenhouse emissions.

The green impact, in terms of power consumption, is undeniable, with a wattage variance of over 185,000 watts and a savings in kilowatt-hours per year of over 1,800,000. This adds up to a power cost savings of almost $235,000 in favor of Fiber Deep. Fiber Deep has major implications for the operator’s ability to demonstrate significant reductions in energy usage.

Making the Most of Fiber Deep

Benefits of Fiber Deep are now apparent, but what about new technologies that enable the operator to put their Fiber Deep architecture to best use? As it becomes increasingly expensive to break through bandwidth bottlenecks in the HFC network, operators are looking to implement distributed digital HFC architectures in addition to Fiber Deep. Digital HFC both preserves the existing infrastructure investment and leaves room for future innovation, by extending the digital headend domain out to the fiber optic node, thus moving toward a distributed digital HFC network.

With a distributed digital HFC architecture, the link from the headend to the node is transitioned from analog transmission, as today, to digital transmission. This architecture shifts the digital-RF interface from the headend to the node, enabling a bi-directional baseband signal between the headend and the node. Today this is achieved by placing the QAM modulation functionality in the node. However, going forward, other functionalities will undoubtedly be distributed. Numerous benefits are achieved, namely the advantages of digital transmission over analog from a performance and “set it and forget it” installation perspective. Schematically, the distributed architecture is shown in Figure 2.

Initially, it is anticipated that the nodemigration to all-IP QAM module would support the need for just new QAMs. However, over time, as more QAMs are required, it is expected that all transmission between the headend and the node would be migrated to baseband, as shown in Figure 3.

Key advantages to an operator adopting this approach include increased data capacity through elimination of the analog optical link bottleneck, improved robustness against transmission impairments and ingress, headend- quality RF at the node, service flexibility and simplified operations.

With a distributed digital HFC architecture, estimates predict more than 70 percent reduction in power consumption and more than 90 percent reduction in headend rack space required. Moreover, a digital HFC architecture enables operators to simplify the cost and complexity of their networks while maintaining their investment in the HFC network. This makes it easily one of the better-positioned solutions to save operators money, and simultaneously, solve the ever increasing bandwidth challenge.

There are many different solutions that operators evaluate when looking to increase their operational network efficiencies. By moving towards a Fiber Deep architecture, the industry can go above and beyond what is being asked today to set an example for others. Let us pave the way for advancements in technology while making the world we live in a better place. Building a network with a Fiber Deep architecture not only reduces power consumption, but it also requires fewer active components, which in turn greatly decreases overall costs of equipment installation and proactive network maintenance.

The cable industry can agree on the two most important elements of success of a green strategy: reducing environmental impact of the products and solutions while reducing costs to the operator. Fiber Deep is a proven future-proof architecture that achieves both. In the current economic environment, operators are looking at investments under a microscope, ensuring they all have a healthy and timely return. Fiber Deep not only allows operators to increase efficiencies within their networks, but also enables them to easily add next-generation services that consumers today crave.

And finally, the combination of Fiber Deep with a distributed digital HFC architecture far surpasses the benefits of any other architecture and leads to optimum results for cable operators. Together, they have emerged as the logical next step in the cable industry’s network evolution.

John Dahlquist is vice president, marketing, Aurora Networks