Cable Tech

Channeling Docsis 3.0

5:40 PM -- What do you call a Docsis 3.0 modem that can bond eight downstream channels? Based on some of the items on Broadcom Corp. (Nasdaq: BRCM)'s drawing board, the answer very well may be: a good start.

Broadcom just saw several modem partners -- Cisco Systems Inc. (Nasdaq: CSCO), Thomson S.A. (NYSE: TMS; Euronext Paris: 18453), and Ubee Interactive -- obtain Docsis 3.0 and/or EuroDocsis 3.0 certification using a new chipset that bonds eight downstream channels and four upstream channels. On the downstream side, that's double the minimum specs, which call for at least a 4x4 configuration. Texas Instruments Inc. (NYSE: TXN), by the way, also has developed a new chipset that fuses together up to eight downstream channels, enough to create speed bursts in the neighborhood of 300 Mbit/s. (See Broadcom Breaks Docsis 3.0 Barrier and TI Flexes Docsis 3.0 Muscle .)

If capacity requirements call for it and there's enough free spectrum available, cable could be on a path to do even more. Although Broadcom isn't in the habit of pre-announcing products, the chipmaker will be building reference designs that can bond 12 or perhaps even 16 downstream channels, according to Jay Kirchoff, Broadcom's senior director of product marketing for cable modem gear. At roughly 40 Mbit/s per channel, that means a modem capable of speeds of 640 Mbit/s could be in the making.

"It's more than 'it could be done,'" Kirchoff says. "It will be done."

Great! When?

Probably not for a while. The eight-channel downstream Docsis 3.0 products, which not only will support regular high-speed Internet apps but IPTV services in specially outfitted set-tops and gateways, are likely to have a much longer lifetime than the first-generation 4x4 gear, which were certified less than a year ago and recently surpassed the 1 million unit shipment milestone. (See TI Ships 1M Docsis 3.0 Chips.)

Then again, there's already a wideband chip that can tune and demodulate up to 16 6-MHz downstream channels -- the BroadLogic Network Technologies Inc. BL12000 Wideband Receiver. Cisco initially used that chipset in a pre-Docsis 3.0 modem that's capable of bonding up to eight channels.

But that may be where BroadLogic's work in the cable modem market will start and stop. Docsis "is not a market we're chasing at this time," says BroadLogic VP of business development Al Johnson. Instead, BroadLogic is applying that chip toward digital-to-analog video conversion devices that are tailored for apartment buildings and other multi-dwelling units (MDUs) and capable of replicating up to 80 analog channels. (See Vecima Box Lets MDU Residents Keep Old TVs.)

— Jeff Baumgartner, Site Editor, Cable Digital News

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