Broadband Communities

MAR-APR 2015

BROADBAND COMMUNITIES is the leading source of information on digital and broadband technologies for buildings and communities. Our editorial aims to accelerate the deployment of Fiber-To-The-Home and Fiber-To-The-Premises.

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MARCH/APRIL 2015 | | BROADBAND COMMUNITIES | 79 Joel Futterman, chief operating ofcer of iPhotonix, explains that RF return over fber ordinarily requires its own upstream wavelength (usually 1610 nm), which means that each ONT needs two optical transmitters – one for data and one for video return. Tis presents several challenges. First, it increases ONT cost and adds cost at the headend, where an optical splitter must separate out the second wavelength. Second, pushing two wavelengths through the optical splitter requires more power in the ONT. Finally, when two optical transmitters transmit simultaneously, they can cause a type of signal degradation called optical beat interference. Minimizing optical beat interference is tricky and adds still more cost. So instead of producing an RFoG ONT, iPhotonix developed a way to send RF return data in IP format over the GPON upstream wavelength of 1310 nm from existing set-top boxes. Futterman explains: "Our MSO customers with set-top boxes less than 15 years old now have to compete with broadband in places where DOCSIS isn't going to cut it. Tey want to introduce GPON in a way that is transparent to the cable TV ofering. … Tey can repurpose the fber they already had from cable to GPON and put new fber out to the customer premises, and no consideration needs to be made for the return path in their PON planning." HOW IT WORKS To support the two major types of customer-premises equipment in cable companies' installed bases, iPhotonix developed two RF return technologies. Tese are now integrated into iPhotonix ONTs and residential gateways. One, Transparent RF Return, works with SCTE-55-1 (Motorola/Arris) set- top boxes. Te Transparent Return software polls the 2-MHz-wide band in which RF return data might be found, captures any data, converts it to IP and sends it upstream. Te optical line terminal (OLT) in the hub recognizes the IP packets as belonging to a video service and forwards them to a modulator at the video headend. Te second technology, Packet- Aware RF Return, is designed to work with SCTE-55-2 (Cisco) set-top boxes. (Recently, iPhotonix developed Packet- Aware RF Return capability for the SCTE-55-1 standard as well.) In this case, the software in the ONT flters out noise and validates the package before sending it upstream to the video headend. Te data doesn't have to be modulated and demodulated again at the headend. "It's a much cleaner solution," Futterman explains. ONESOURCE COMMUNICATIONS In the last several years, a number of cable providers in the United States and Latin America – including a Mexican Tier 1 company – have begun installing iPhotonix ONTs with RF return. One of the earliest customers was OneSource Communications, a competitive local exchange carrier in Texas. In the late 1990s, OneSource built a dual network with copper and coax in every trench – the only way to ofer triple-play services at the time. However, in 2004, when Verizon launched its FiOS deployment right in OneSource's hometown of Keller, Texas, OneSource realized it would have to deploy fber to the home to stay competitive. Beginning in 2005, the company deployed FTTH for all new builds; it is now standardized on a GPON solution from ADTR AN. However, according to Kent Blackwell, vice president of operations, OneSource has not yet overbuilt its original copper/ coax network because the return on investment hasn't justifed it so far. Te infrastructure is still in good condition, the market share is still high, and the cost to overbuild is high. So the cable video headend – a Motorola (now Arris) product – is still in use. OneSource started its fber build with a Motorola BPON solution because nothing else could communicate with the Motorola video headend in 2005, before the RF return path was standardized. After the RFoG standard was specifed, the company had additional options and began transitioning to GPON. When it selected the ADTR AN GPON solution, ADTR AN suggested using ONTs from iPhotonix. (iPhotonix is an ADTR AN certifed partner.) Blackwell says, "Tey really impressed us because they were quick and nimble to solve customer-facing problems." He adds, "RFoG is kind of a bolt-on attachment, but the iPhotonx RF solution is more integrated into the data stream … for us, it means a more efcient handof between data and RF return. And we're able to continue using the same headend and set-top box equipment." Ultimately, Blackwell says, OneSource will have to transition to all- fber and all-IP networks, but that day is still far of: "It's a transition that we dream of doing someday, but it's hugely costly at the headend level, so it won't happen real fast." Whenever it does happen, the GPON ONTs will still be usable; the RF return is just a software feature that can be turned of, and the same ONTs will support IP video. "It gives us options for the future," he says. SUMMIT BROADBAND Summit Broadband is a competitive provider in Florida that was originally known as Orlando Telephone. After several changes of ownership, it is now the U.S. operating arm of Cable Bahamas and ofers triple-play services Sending RF return data over the same wavelength GPON uses for upstream data eliminates one optical transmitter – and a whole lot of difculty and expense.

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