Cable is a wired business. But what rides this industry’s cables are radio frequencies and light waves — in other words, types of electromagnetic energy that are wireless by nature. That combination makes cable more precisely a kind of "wired wireless" business and sets the stage for the ongoing adoption of technologies that wirelessly extend the cable plant. This is a technical adjustment, not a paradigm shift. Take microwave-based gear designed to transport the industry’s data services across waterways, railroad tracks, parking lots, freeways or whatever other obstacles stand between existing plant and potential customers. To an engineer who already knows the electromagnetic spectrum and the Data Over Cable Service Interface Specification (DOCSIS), such solutions are not far outside the box. Abetting this trend are vendors who seem to be hitting their stride. "Four years ago, much of this technology was bleeding edge. Engineering designs weren’t ready for three or four nines of availability," says Hunt Eggleston, president of Lawton AG, a telecommunications consulting firm. "Designs, chip sets, business practices at a number of these companies have improved." The story behind wireless line extensions is something other than the consumer demand for mobility (although the line is beginning to blur). It is partly a matter of cutting plant construction costs. Above all, it is a way for operators to offer data services to potential residential and business customers who otherwise lie beyond their reach. The big picture These potential markets cover a lot of territory, from individual subscribers to campus-wide enterprises. Their technical demands likewise range from the cable modem to T1- equivalents and higher. "We’re looking at plant extension for lots of things, primarily in our quest to serve multi-location opportunities," says Kristine Faulkner, vice president of product development and management for Cox Business Services. In particular: "Certain vertical areas, such as education, government, hospitality and health care." At the same time, Faulkner says Cox wants to capitalize on its existing data service with smaller customer opportunities. And wireless line extensions are a key to reaching a significant chunk of the small to medium business (SMB) market, according to Chris Martin, vice president of marketing for Arcwave. He says that 20 percent of SMBs in the United States that cable passes cannot be served using wired technology, yet 90 percent are within a mile of existing cable plant. Given its range of its target markets, Cox is likely to pick several solutions. Even within the vertical markets, Faulkner sees wireless fulfilling several possible roles: "As a permanent solution; as an interim solution, until possibly we can build to a campus or business park; and lastly as a nice redundancy option," she says. Mediacom’s FSO trial The city of Valdosta sits 20 miles north of the Florida line, off Interstate 75 in south central Georgia. It is the site of one of the four master headends that Director of Technical Operations Powell Bedgood oversees for Mediacom in that state. And it was here that Mediacom tested a cutting — if not bleeding — edge solution for the high-end enterprise market. The goal was to see whether it could provide a customer, the Valdosta Convention Center, with something more than cable modem service. To do so, Bedgood installed gear from Nortel Networks that uses free space optics (FSO), a license-free technology originally developed more than 30 years ago by the military and NASA. With a SmartBits simulator, Bedgood generated a constant, bidirectional stream of 100 Mbps traffic between one of Nortel’s light emitting diode (LED)-based FSO links on the side of a Mediacom office and another one at the convention center 300 meters away, across a four-lane boulevard. While a common perception of FSO has it working better in outer space than within the Earth’s variable atmospheric conditions, the results of this trial suggest that operators might want to add it to their commercial services toolkit. "The testing of the technology has been wonderful to date," Bedgood says. "We’re at seven nines, with very little packet loss." As it happens, the 45-day trial coincided with this summer’s considerable rainstorms, as well as occasional fog, which poses an even greater threat than rain to optical links. "And still no issues," Bedgood says. Certainly there were no conventional interference issues, given the RF immunity of optical links such as these in the 800-900 nm (infrared) space. Going forward, Mediacom plans to light up fiber between this particular office and a master headend 5 miles away, thereby connecting the FSO gear directly to the MSO’s cable modem termination system (CMTS) infrastructure. Would this be what Faulkner calls an "interim" solution, a prelude to dropping fiber off at the convention door? "Absolutely not," Bedgood says. "The cost to do that makes the business model not work." Extending DOCSIS Persuasive business models also underlie the deployment of the microwave-based extensions of the DOCSIS network. With less capacity but longer reach than FSO, these solutions operate largely in the Unlicensed National Information Infrastructure (UNII) bands of the 5 GHz spectrum. And being unlicensed helps. Eric Gallbreath, vice president of Rensselaer TV, a small, independent operator in northwest Indiana, considered a licensed approach several years ago. "The cost was just astronomical," he says. Considerations of cost and Federal Communications Commission interactions make operators skittish about licensed bands. Dave Blumberg, vice president and COO of Wireless-Bypass, which is now supplying Rensselaer with microwave transceivers, says his company met with a cold reception when they unveiled a licensed product at SCTE’s Cable-Tec Expo four years ago. Blumberg says that on the final day of that show in Las Vegas, one cable engineer, who said he was using an Alvarion radio to transmit Ethernet, was intrigued to learn that he could send the entire DOCSIS channel. But like others, he didn’t want to use licensed spectrum. "So we went and developed the 5.8 GHz unlicensed radio, and it took off like hotcakes," Blumberg says. This category does appear to be blooming. Blumberg says a retooled production process will help Wireless-Bypass achieve a more efficient cost structure and meet rising demand. According to the company, its gear is approved by two of the three largest U.S. MSOs. Competition comes from Arcwave, whose $8 million investment round this summer was led by Paul Allen’s Vulcan Capital; also participating was Comcast Interactive Capital. Arcwave’s Martin says they have about 10 deployments serving live customers and some 30 deployments involved in trails or certification activities. Arcwave uses both 5.8 GHz and 5.3 GHz for downstream and upstream traffic, respectively. And joining the fray is VCom (formerly WaveCom Electronics) with its own 5.8 GHz strand-mounted radio. VCom says it has other solutions designed to extend an operator’s DOCSIS network at different licensed and unlicensed frequencies including, but not limited to, 700 MHz, 2.5 GHz and 3.5 GHz. Five-mile link The case of Rensselaer TV sheds more light on both the business model and technical capabilities of wireless line extension technology. Serving some 4,500 subscribers in three northwestern Indiana communities, Rensselaer’s Gallbreath says the challenge he faced was delivering data service to several isolated subdivisions. "We’ve had cable out to these areas. But for us to do Internet, it was such a long cascade, especially on the return — 25 amps deep — it would kill us," he explains. Gallbreath says they considered fiber, but the annual recurring cost on 5 miles of pole easements of $3,000 was an initial disincentive. Add to that fiber and lashing, headend equipment and nodes, and the total project costs approached $100,000. "For 125 customers, I didn’t think that it was going to pan out," he says. Instead, Rensselaer deployed a point-to-point, bidirectional system from Wireless-Bypass. Costs were a fraction of fiber, and the project took a week rather than a year to complete. The solution entailed installing an integrated flat-panel antenna and hub on a pole in the targeted subdivision and a 3-foot parabolic dish halfway up the operator’s 400-foot tower in Rensselaer, five miles away. Instead of putting all the equipment on the tower, Gallbreath opted to link the parabolic antenna with (Times Microwave) LMR 900 cable and house the hub equipment below to cut down on maintenance costs. Operationally, the "wireless" traffic gets one downstream and one upstream port on Rensselaer’s Cisco uBR CMTS. But Gallbreath says the link is transparent. "Truthfully, we don’t even know it’s there anymore. It’s like regular plant," he says. The upshot was the opening of an otherwise closed market and a tremendously cleaner delivery of data than would have otherwise been possible. "Basically, you’ve knocked it down to a cascade of maybe five (amps) just in that neighborhood," Gallbreath says. "That would be the only noise." Next up is a 10-mile jump of coaxial from its system in Winamac to 175 subscribers in the Bruce Lake community. "We’re going to do exactly the same thing over there," Gallbreath says. And he also thinks this technology would be a good fit for a nearby college. Options and imperatives Wireless is part of cable’s ongoing shift toward new markets. At the CTAM Commercial Services Seminar in May, Jeff King, EVP Time Warner Cable and president of Road Runner, admitted that fiber is not always the best solution. "Go wireless the last mile," he said. Charter CEO Carl Vogel told attendees at Cable-Tec Expo in June that wireless plant extensions are an important way to reach enterprises. The task at the system level is now to assess market demands and technology options. Extending the DOCSIS network wirelessly, on a point-to-point or point-to-multipoint basis, is one promising alternative. "Cable modem service is what we deliver the most of, and this delivers cable modem service," says Peter Hicks, Charter’s manager of product development for commercial data. "I think it’s a natural fit." Not every MSO aims to meet the multi-location and high-capacity demands of large enterprise customers, as does Cox. Serving that market segment may entail another set of wireless tools, such as Nortel’s FSO gear. Wireless equipment that takes DOCSIS traffic and hands off Ethernet-based service to the enterprise is another option. How 802.11x (Wi-Fi) or 802.16 (Wi-MAX) technologies fit into this equation is a related and difficult question. Both play into the consumer demand for mobile data and voice solutions. Vendors are crowding into this space, and the line between enterprise and individual customers is blurring. As for pure-play line-extensions, the bottom line is a simple imperative. "Cable companies know they have to get involved in commercial services in order to continue to be profitable enterprises," Blumberg says. "So they’ve got to look at alternative access technologies." Jonathan Tombes is executive editor of Communications Technology. Email him at jtombes@accessintel.com. Bottom Line To reach and better serve residential and commercial customers, many operators are testing, trialing and deploying wireless line extension equipment, including those based on infrared and microwave transmission technologies. Deploying Wireless Line Extensions: Practical Advice "Do a path or spectrum analysis of what is available your area. There’s so much wireless being deployed these days, you don’t want to interfere with someone else. And with more and more people using (unlicensed spectrum), some people may not know what they’re doing when they put (a radio) up." Eric Gallbreath, Rennselaer TV "One of our challenges is just to be efficient at analyzing the suitability of wireless. There are challenging locations and line-of-sight issues. I want to hit a building that’s a mile away, and it’s popular development. Will there be a building in front of me in six months?" Peter Hicks, Charter Communications "The biggest interference potential will be self-interference. (Operators) put one up and want another one collocated, one street down. There is a terrible potential for interference. What you have to do is change the frequency." Dave Blumberg, Wireless-Bypass "Keep in mind that use of the unlicensed wireless spectrum does pose some potential risk regarding interfering with or being interfered by licensed over-the-air services. If this happens, the unlicensed user must take whatever steps are necessary to eliminate the interference—including shutting down the unlicensed link. Licensed spectrum users have priority." Ron Hranac, Communication Technology’s Senior Technology Editor

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