CommScope RFoG Connects With PON, EuroDocsis

CommScope Inc. has tweaked its Radio Frequency Over Glass (RFoG) platform to make the cable-focused fiber-to-the-premises (FTTP) system more compatible with PON technologies and a better fit for systems that use the EuroDocsis profile.

CommScope's RFoG system, marketed under the BrightPath banner, already fits PON from an architectural standpoint. However, the ONU (optical network unit) electronics component of BrightPath that sits on the side of the house has historically used a 1310nm upstream, which conflicts with traditional PON systems, explains Carl Meyerhoefer, the director of marketing for CommScope's broadband products division. He says CommScope has fixed that by adding a 1610nm return path. (See CommScope Connects 'BrightPath' to PON and CommScope Sees BrightPath for Cable FTTP.)

But CommScope wasn’t comfortable releasing the 1610nm version, dubbed the R-ONU, until it was confident that the Society of Cable Telecommunications Engineers (SCTE) RFoG standard (which isn't final yet) had "reached a more solid point of definition" in terms of its compatibility with PON, Meyerhoefer says. However, that didn't stop Alloptic Inc. (now part of Communications Test Design Inc. (CTDI) ) from jumping ahead and creating a version that uses 1590nm. (See CTDI Acquires More Access Assets.)

CommScope is also trying to expand its RFoG reach with ONUs that conform with EuroDocsis specifications, with most of that work centered on upstream compatibility. North American Docsis typically uses an upstream band from 5MHz to 55MHz. EuroDocsis, which uses PAL (Phase Alternating Lines) signals, taps an upstream band in the 5MHz to 65MHz range. CommScope now claims to be supporting mid-split profiles that cable operators use on either side of the pond. CommScope will be showing off its new Euro-compatible handiwork at next month's ANGA Cable Show in Cologne, Germany.

"This [dual Docsis profile] gives us some flexibility on the product offering depending on what the customer requirements are," says Meyerhoefer.

It also gets BrightPath better aligned with PON and the capacities it brings to the cable table. On its own, RFoG lets cable operators extend fiber to homes and businesses while preserving their headends, back-office systems, and use of RF-capable cable modems, and set-tops. But RFoG doesn't offer much of a capacity boost, which is why some operators are starting to use PON overlays to juice things up for commercial services and other deployment scenarios that require big speed boosts.

CommScope was early to the RFoG party and has deployments with several Tier 2 MSOs, including Troy Cablevision, Bresnan Communications LLC , and Sunflower Broadband , along with some still-unnamed majors.

RFoG is typically viewed as the most cost-effective option in greenfields and in rural markets, and some MSOs plan to use RFoG in every new build. However, traditional hybrid fiber/coax (HFC) remains a better fit in most rural environments. (See Shaw Vetting FTTH for All New Builds and Costs Could Keep RFoG a Niche Player .)

The vendor hopes the next round of broadband stimulus funds will generate more deployment opportunities, but Meyerhoefer acknowledges that a down housing market hasn't helped.

"The [RFoG] market hasn't materialized as we expected it to," he concedes, but he still thinks RFoG offers a "good bridging technology" as MSOs deploy fiber deeper into their networks and start to pay consideration to PON.

Meyerhoefer says CommScope plans to expand BrightPath's optical portfolio in the coming months: "This is just step one. RFoG is not the end-all. CommScope will have more than just an RFoG play."

— Jeff Baumgartner, Site Editor, Light Reading Cable

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