Cable Tech

Another QAM-Tum Leap?

11:30 AM -- What do you call an edge QAM with 36 QAMs per port? A pretty good start, according to one analyst.

"This is just the beginning," says Infonetics Research Inc. directing analyst of broadband and video Jeff Heynen, in respect to QAM densities of the future.

Harmonic Inc. (Nasdaq: HLIT) and startup rival LiquidxStream Systems Inc. have set the bar at 36 QAMs per port, with Harmonic joining the party this week with the "HectoQAM," an edge device that's initially targeting capacity for video-on-demand (VoD) and switched digital video (SDV), but will later be used for Docsis 3.0 and cable IPTV applications. (See Harmonic Lays Claim to Edge QAM Density Crown .)

Although 36 QAMs per port is enough for now, Heynen sees 64 as a likely next target as vendors continue to push their chipset suppliers, a group that includes BroadLogic Network Technologies Inc. , Xilinx Inc. (Nasdaq: XLNX), and Altera Corp. (Nasdaq: ALTR). For its part, Harmonic says its HectoQAM architecture could easily ramp up to 100 or more. (See BroadLogic Chip Targets Altera, Xilinx and BroadLogic Unveils Dense QAM Chip.)

Cable's move to IP video and new architectures, such as Comcast Corp. (Nasdaq: CMCSA, CMCSK)'s Converged Multiservice Access Platform (CMAP), will eventually drive those density requirements higher, Heynen says, noting that MSOs will still need to add that capacity within their existing, and relatively limited, headend space. (See Comcast Proposes Its God Box and More MSOs Back Comcast's Big Box Project .)

But Heynen also worries that the push for higher port densities comes with some risk, because there will be a greater number of customers being served on each physical port. If the port goes down, more customers could lose service. But, given the real estate constraints that cable faces, MSOs may be willing to take that risk.

And don't expect a quick move to products that can handle more than 36 QAM channels per port. Heynen expects to see some prototypes show up next year, with trials following in 2012. The current bar-setting gear, he says, should be more than enough to handle cable's QAM capacity needs through 2011.

— Jeff Baumgartner, Site Editor, Light Reading Cable

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