EPON-Over-Coax Starts Its Standards Journey

If a new Institute of Electrical and Electronics Engineers Inc. (IEEE) project bears fruit, cable operators might be able to delay costly fiber-to-the-home (FTTH) deployments, or even avoid them altogether.

The proposed physical-layer standard is called EPON-over-Coax (EPoC), and its goal is to provide symmetrical 10Gbit/s speeds over hybrid fiber/coax (HFC) networks. It's just getting started; the first EPoC Study Group meeting will get together on Jan. 24 in sunny Newport Beach, Calif.

Here's the slide deck (PDF) that was presented during an IEEE 802.3 call-for-interest meeting last November. The IEEE voted at that meeting to form the study group, a move that simply "gives us the right to study the problem," says Study Group Chairman Howard Frazier, who also serves as senior technical director at Broadcom Corp. (Nasdaq: BRCM), a chipmaker that has been championing EPoC. (See Broadcom Crafting PON-Speed HFC.)

EPoC will need to be compatible with or work around existing cable services, which tend to vary from operator to operator and from HFC plant to HFC plant.

"There's no way operators will do a forklift upgrade. We'll have to adapt to what they're deploying five years from now," Frazier says. That means EPoC will have to coexist with QAM-based video systems, Docsis 3.0 platforms, cell backhaul deployments and the next-gen Converged Cable Access Platform (CCAP), which some view as a possible bridge to EPoC. (See Comcast Gets Ready for CCAP and Cable Rethinks 'Modular' CCAP .)

Here's an example of how EPoC spectrum might live alongside cable's other services:



QAM's big goodbye?
EPoC could begin to steer cable away from its traditional QAM modulation schemes, and this part of the discussion is expected to be among the most hotly debated as engineers mull ways to modulate Ethernet on coax efficiently.

One idea that will get much attention is orthogonal frequency-division multiplexing (OFDM), a scheme popular in the wireless world that could help cable pump out more bits per hertz than they do today with QAM, says Shane Eleniak, vice president of advanced broadband solutions at CommScope Inc.

CommScope has a chip team (that came on board via the company's purchase of edge QAM maker LiquidxStream Systems Inc.) that's been eyeing the development of a mixed-mode QAM/OFDM Application-Specific Integrated Circuit (ASIC) or a more flexible Field Programmable Gate Array (FPGA) implementation, he notes. (See Why CommScope Bought LiquidxStream.)

Frazier acknowledges that OFDM is one scheme that the working group will likely consider, but he warns that nothing's been decided. "We're going to have a very interesting discussion," he says. "We'll have to duke it out and see what works best."

But the cable industry has definitely fallen in love with EPON. Following heavy adoption of EPON by service providers in Asia, domestic cable has grown partial to the technology in recent years, increasingly relying on it to deliver business services. Taking things a step further, CableLabs has also created a spec that grafts Docsis-style provisioning to EPON services. (See Docsis Gets Its EPON On.)

EPoC timetables
Based on the usual IEEE timetable, an EPoC standard would take about three years to complete. Frazier expects some pre-standard products to start coming out in late 2013 or early 2014. "There will be trials ... but I'm thinking that the deployment horizon will start two to three years out."

He sees initial adoption of EPoC happening in North America and also in China, where it's estimated more than 190 million users are connected to coax today, with 300 million expected to be passed by HFC by 2019, according to China's State Administration of Radio, Film, and Television (SARFT).

Here's who's supporting EPoC so far:

Table 1: EPoC Dudes

— Jeff Baumgartner, Site Editor, Light Reading Cable