For Motorola Inc. (NYSE: MOT), the upstream channel-bonding era for its flagship cable modem termination system (CMTS) will begin sometime in the second quarter of 2011.

That's the latest target for Moto to release upstream channel-bonding software for the BSR64000, a move that will take the company one step closer to having a CMTS that complies will all aspects of the CableLabs Docsis 3.0 specifications. (See Is Wideband's Upstream Ready to Go Mainstream? )

"We are in throes of completing our upstream channel-bonding development," says Mike Cookish, senior director of product management for Motorola's access networks solutions business.

Motorola's new software release will be tied into a new dedicated upstream CMTS blade that packs in 42 upstream ports, up from eight ports in the current-generation card. Moto's already shipping the new card, dubbed the RX48, for trials, and expects to have "hundreds" of units in MSO hands by the end of this year. (See Moto Hones Super-Dense CMTS Blade.)

"We expect a lot of demand for this [product] next year," notes Brian O'Neil, Motorola's senior marketing manager for the access networks solutions unit.

But instead of seeing MSOs go full-bore with D3 upstream channel bonding right away, the vendor says most will initially be using the new card in Docsis 2.0 mode and enabling S-CDMA, an advanced physical layer that allows operators to tap into typically noisy and unusable upstream channels in the lower portions of the spectrum. (See Moto Preaches Cable's Upstream Savior .)

So, instead of bonding multiple channels to create upstream pipes capable of 100Mbit/s bursts, S-CDMA should help operators use single-channel D2 scenarios to more easily pump out speeds in the range of 10Mbit/s to 30Mbit/s, and potentially higher, depending on the condition of the cable plant.

So far, Cox Communications Inc. is the only MSO to go public with its trials of Motorola's implementation of S-CDMA. O'Neil says as many as five other unannounced MSOs around the globe are using the technology to free up upstream channels below 20MHz. (See S-CDMA Gets a Sponsor and Moto: S-CDMA Starting to Spread.)

But Moto believes the addition of the upstream channel-bonding feature will help future-proof RX48 investments for when MSOs are ready to use all that D3 has to offer.

Cable has pretty much licked the downstream channel-bonding feature of D3, applying it to new wideband tiers that offer speeds in the neighborhood of 100Mbit/s. But the use of upstream channel bonding, considered an order of magnitude more complex, has largely been limited to small pockets of deployments and trials.(See Comcast's Target: 105-Meg D3 Downstream , Korean MSO Bonds With D3's Upstream , Comcast: Upstream Bonding Tests Yield 'Sustained' 75 Mbit/s , and Japan Cablenet Swims Upstream .)

Casa Systems Inc. remains the only CMTS vendor to achieve "full" CMTS qualification from CableLabs. (See CableLabs Cheers Casa Chassis.)

— Jeff Baumgartner, Site Editor, Light Reading Cable