Passive Fiber-Coax: One Option For Cable to Get a Gigabit-Plus to the Home

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Verizon has tested Gigabit-per-second links over FiOS. The city of Chattanooga, Tenn., already offers 1-Gbps to residential and business customers… and Google has stirred the pot with “Think Big With a Gig” (see Verizon Test Blasts 1-Gig Links To The Home, Bragging Rights: Chattanooga Does 1 Gig to the Home and Free Fiber Lunch!).

So how will cable get to a gig, especially given current upstream constraints?

Arris has examined the concept of a “passive fiber-coax” architecture as one possible solution for delivering gigabit-speed symmetrical data services to the home over existing coax plant.

A so-called “PFC” network would be based on a fiber-to-the-last-amplifier (FTTLA) network, overlaying Ethernet services to a node. (A passive network component, unlike an active one, requires no external power source.)

PFC would be a node-plus-zero network — in which there are no amplifiers between the last fiber-fed node and a subscriber’s premises — but it would differ from cable’s current HFC architecture in that it would transmit IP and Ethernet traffic rather than QAM-modulated traffic to subscribers.

One of the advantages of such a passive coax-fiber network is that it wouldn’t require upgrades to optical nodes or amplifiers to enable gigabit symmetrical services, said Mike Emmendorfer, Arris senior director of solution architecture and strategy office of the chief strategy officer. However, it would require new customer-premises equipment and may employ new media access control (MAC) layer technology, such as Ethernet over coax or a modified version of DOCSIS.

“It’s not that we endorse this over other approaches,” Emmendorfer said. “MSOs will have to look at their business needs and capital needs and evaluate their options.”

Don’t miss our report with more on this topic, Next-Generation Broadband: To a Gigabit — and Beyond, in the Oct. 18 issue of Multichannel News.

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