Cable ops are lab-testing 'enhanced' DOCSIS 3.1, CommScope says

DOCSIS 4.0 is the future of the hybrid fiber/coax (HFC) network. But there's more proof that DOCSIS 3.1 still has a long life ahead of it.

Cable operators are starting to conduct lab tests of an upgraded, downstream-boosting form of DOCSIS 3.1 powered by a new release of software that CommScope has developed for the E6000, the company's chassis-based cable modem termination system (CMTS).

CommScope said it expects to reach field trials of DOCSIS 3.1 Enhanced, or DOCSIS 3.1E, later this year.

DOCSIS 3.1E, as CommScope refers to it, enables operators to increase downstream speeds by bonding together additional orthogonal frequency division multiplexing (OFDM) channels. That idea is being driven by the emergence of new DOCSIS 4.0 modems, upgraded DOCSIS 3.1 modems, and software upgrades for existing chassis-based CMTSs. Though this is all covered in the CableLabs DOCSIS 3.1 specs, the upgrades have been carrying multiple labels in industry circles, including DOCSIS 3.1+ and DOCSIS 3.1 "flex." Harmonic, pursuing the idea via its virtualized CMTS, has been marketing it as "BoostD 3.1."

More downstream capacity

CommScope said software release 13 would provide support for three OFDM channel blocks along with 32 single-channel QAMs (for backward compatibility with DOCSIS 3.0). That also sets the stage for future software releases that could eventually support service tiers of more than 8 Gbit/s in the downstream, the company noted.

Related:How Broadcom and MaxLinear will push the limits of DOCSIS 3.1

While today's DOCSIS 3.1 modems support the bonding of two OFDM channels, new models will support several more. MaxLinear's new Puma 8 modem chip, originally developed for DOCSIS 4.0, can bond up to five OFDM channels. A D3.1-focused iteration of the Puma 8 would bond up to five OFDM channels but would not house a programmable gain amplifier (PGA) that delivers the higher upstream splits supported by the fully-fledged DOCSIS 4.0 version.

Meanwhile, Broadcom, industry sources said, is working on an upgraded DOCSIS 3.1 chip, the BCM3392, that can bond four OFDM channels (up from the two OFDM channels supported by the current-gen BCM3390 chip). Importantly, Broadcom's new D3.1 chip, which hasn't been officially released, won't be encumbered by pricey joint development agreements (JDAs) that limit access to its new D4.0 silicon, industry sources said.

CommScope didn't reveal which operators are testing its new software – release 13 – for the E6000. However, industry sources indicate that enhanced/upgraded D3.1 technologies are gaining interest among tier 2 and 3 operators that are looking to extend the life and performance of their DOCSIS 3.1 networks prior to any future D4.0 upgrades.

Related:DOCSIS 4.0 modems might first run rampant on DOCSIS 3.1 networks

The expectation is that some operators, provided they have the bandwidth to spare, will eventually be able to deliver downstream speeds of 8 Gbit/s with DOCSIS 3.1E, possibly without a need to upgrade to a distributed access architecture (DAA) or move to a full DOCSIS 4.0 network.

Extending the life of the CMTS as the virtualized future approaches

Support for DOCSIS 3.1E, including DOCSIS 4.0 modems running in DOCSIS 3.1 mode, was one of several new features that CommScope is baking into software release 13 for the E6000.

The company said the new software release, when paired with "Gen 2" E6000s, also supports DAA remote PHY deployments, and Low Latency DOCSIS (LLD), a capability that Comcast is testing ahead of expected commercial deployments later this year. CommScope said the updated software also supports IPTV, enabling operators to transition from their legacy QAM-based video delivery architectures.

When taken together, the updated software could extend the life of CommScope's widely deployed E6000 chassis.

"In today's challenging business environment, with subdued subscriber growth and mounting competition, it's essential for MSOs to monetize their current network assets while maintaining competitive value proposition for consumers and getting the best return on investment from any field upgrades they deploy," Guy Sucharczuk, SVP and president of CommScope's Access Network Solutions (ANS) unit, said in a release.

Related:CommScope will ride one vCMTS in wake of Casa deal

He noted that the software release 13 upgrades and features will also be available in the company's new virtual CMTS platform.

Aided by its recent acquisition of Casa Systems' cable assets, CommScope is also looking to become a key player in the emerging vCMTS market, which is currently led by Harmonic. Vecima Networks, which also made a play for Casa's cable assets, has also developed a vCMTS.