Why Fiber Optics Can't Solve Today's Broadband Shortage.

The vision of the fiber optic network carrying information at the speed of light to every business and residence in North America is still far from realization. Industry analysts estimate that fiber will reach only 40 percent of U.S. businesses within the next 10 years. In the meantime, Internet traffic is doubling every three months, adding to the last mile bottleneck. Although it seems counterintuitive that 19th century copper can solve the 21st century need for speed, recent developments may make copper the best way to provide speed and bandwidth--sooner rather than later.

Fiber technology is commonly deployed in backbone networks across North America, and Telco central offices are now fused by sophisticated switching equipment and high-speed fiber optics to create a more powerful Internet backbone. Despite these dramatic infrastructure improvements, however, Internet speed has continued to slow over the past two years. While the industry has looked to fiber optic technology to solve the local access bottleneck, only a fraction of North American businesses are currently served by fiber.

While fiber is the obvious choice to address this issue, many inhibitors stand in the way of realizing an all fiber network vision. Congested business districts, which have the greatest demand for broadband services, are the most difficult to serve. Long-term plans for trenching and deploying fiber are impacted by everything from rights of way to poor environmental conditions to labor shortages. In addition, the time and expense associated with the construction of fiber optic networks is immense. Extreme lag times between orders and delivery present even more obstacles to deployment. Fluctuations in fiber supply aside, installation time is often measured in years, not months.

Moreover, fiber rollouts are even less likely to occur in rural and suburban areas, where sparse populations provide little financial incentive for upgrades. LECs often concentrate broadband equipment upgrades in areas of higher population density where they can maximize return on their investment in new equipment. The FCC reports that as of June 30, 2000, rural populations were particularly underserved by broadband. While 96 percent of urban zip codes had at least one broadband service provider available to residents, only 40 percent of rural zip codes had access to broadband service in any form. And rural customers aren't alone in finding themselves stranded on the far side of the digital divide. Many suburban neighborhoods have large pockets of stranded customers who live too far away from a central office to get broadband service.

To upgrade rural customers within 18,000 feet of an RT, the National Exchange Carrier Association (NECA) estimates that telephone companies would need to spend over $20 billion on fiber-optic cable alone. In the meantime, customers are requesting DSL in record numbers, but carriers and service providers are turning them away. Nationwide, tens of millions of potential subscribers are beyond the reach of DSL service.

The Universal Service Mandate: Broadband For All

Both the Universal Service Principles of the Communications Act of 1934 and the Telecommunications Act of 1996 mandate that all Americans have equal access to telecommunications services, including broadband Internet access. Carriers and service providers are faced with the challenge of meeting the demand for universal broadband service quickly, reliably, and cost effectively. The federal government is stepping in to help carriers bridge the divide. For example, the Rural Utilities Service (RUS) is dedicated to implementing that mandate by providing funds for rural carriers to build or rebuild existing plants. Those funds come with a hitch, though: any funded plants have to be upgraded for broadband service.

An Ideal Solution: Leveraging The Existing Copper Infrastructure

In any location, whether it be the dense metro, suburban, or rural areas, upgrading physical resources is the key to providing universal broadband services to wide areas that are currently underserved. Despite a (painfully) gradual infrastructure shift away from copper to fiber, carriers are still looking for a means to provide broadband quickly. As a result, carriers are eager to leverage the value in the embedded copper infrastructure for delivering bandwidth.

For the last 15 years--with varying degrees of success--telecommunications service providers have been improving methods of transmitting more information on the ubiquitous copper lines that connect most businesses and homes to the Internet and other traditional telephony services. Although an entrenched asset, this infrastructure was not designed to handle the high-bandwidth needs of the digital age. Traditionally, broadband over copper has been associated with short-range, low-bandwidth technologies that are prone to unacceptable error rates and high noise levels.

More recently, emerging transport solutions may change copper's tarnished reputation. Some fairly radical advancements in signal processing are doing what seemed impossible: leveraging POTS-quality copper pairs to deliver anywhere from 10 to 100+ Mbps of symmetrical bandwidth with Bit Error Rates (BERs) on par with fiber-optic technology. New spatial signal management technology can transmit signals over multiple copper pairs stretching from the CO to a DSLAM in an RT cabinet or a Multi Tenant Unit (MTU). The net effect means that individual lines that perform at BERs of 10-4 or 10-6 are transformed into a fiber quality high-speed link with system performance of 10-10 or better. Those specs are typical of fiber-based solutions. Moreover these emerging technologies are quick to install, require no change to the physical connection between a CO and the RT or MTU, and cause no disruption to existing customer services.

As these new technologies for enhancing copper become available, carriers will be able to answer customer demand for high-bandwidth services with an emphasis on speed to market provisioning. Carriers can eliminate the enormous costs and lead times associated with trenching fiber to the curb. Most importantly, leveraging the existing infrastructure instead of constructing new facilities will improve customer retention by accelerating the time required to deploy high-demand services. If the carrier elects to construct fiber facilities to the RT or MTU in the future, the system can easily be redeployed to take advantage of the copper facilities in another area of the network.

Using this broadband delivery method will offer some important deployment advantages for carriers:

Carriers will be able to start generating revenue immediately on high-margin services with relatively low up-front capital costs.

Carriers will be able to guarantee a revenue stream before incurring the high capital costs of constructing fiber facilities.

If the business case justifies trenching fiber at some point, the system can easily be redeployed in a new location to continue pumping data over copper pairs.

Technicians familiar with existing copper technology will not require retraining.

The Promise Of The Information Age

By leveraging the embedded copper infrastructure to bring the power of the fiber backbone to the last mile, the promise of the information age is a lot closer than anyone thought. Today's Internet transmits information at an average of 40 Kbps. Imagine exponential accelerations in local access performance that produce data rates up to 100 times faster. One-step upgrades that transform the copper loop plant into a high quality, high bandwidth service platform will reliably bridge the bandwidth gap at prices that bring multimegabit services within the reach of the small to mid-sized enterprise customer. The ability to transform multiple copper pairs into a powerful DS3 backhaul to bring broadband to the final remote mile will further ensure that no one is stranded on the far side of the digital divide.

Gilad Rozen is vice president of R&D at Actelis Networks (Fremont, CA).

Statistical sources in this article include: Morgan Stanley Dean Witter: "Uncorking the Internet Bottlenecks" (June 5, 2000); and The National Exchange Carrier Association, "NECA Rural Broadband Cost Study: Summary of Results" (June, 2000).