The SCTE/ISBE and the Multimedia over Coax Alliance have issued a “standards operational practice” aimed at ensuring interoperability between MoCA 2.0 and DOCSIS 3.1, which can both live in frequencies above 1 GHz.
They said the work, under the label of SCTE 235 (Operational Practice for the Coexistence of DOCSIS 3.1 Signals and MoCA Signals in the Home Environment), addresses the need to prevent degradation of failure of signals due to shared spectrum above 1 GHz.
The issue arises as MSOs look to use RF spectrum above 1.2 GHz for downstream DOCSIS 3.1 capacity, creating shared frequency zones and setting up potential conflicts with MoCA and D3.1 in the 1125-1675 MHz range.
Cable operators and other types of MVPDs have used MoCA for whole-home DVRs and other in-home content distribution applications. DOCSIS 3.1 is a next-gen access spec for HFC networks that enables multi-gigabit speeds.
SCTE 235, they said, explains the need for sufficient isolation” and suggests proper location and required performance of filters to prevent MoCA signals from one residence to leak over to a nearby residence, and to prevent overload of DOCSIS receivers and MoCA receivers.
Among the key recommendations of SCTE 235 is the use of non-overlapping channels. They said the calculations are valid for DOCSIS 3.1 and for MoCA 1.1 and 2.0 single channel operation.
The operational practice is based on a technical study by MoCA in cooperation with CableLabs, and created by a Special Working Group on HFC Readiness for DOCSIS 3.1 within the Network Operations Subcommittee (NOS) of the ANSI-accredited SCTE/ISBE Standards Program. It was the result of a multi-year effort.
Per the SCTE 235 documentation (PDF), areas identified for further investigation include an analysis of MoCA 2.5 signals, recommendations for filters in “mid-split” systems (when the upstream ceiling is raised to 85 MHz), and the coexistence of DOCSIS 3.1 technology with other home networking technologies such as G.hn and HomePlug, among others.
“DOCSIS 3.1 and MoCA are important enabling technologies that support more powerful, flexible services,” Rob Thompson, director, network architecture for Comcast Cable, MoCA Board member, and chair of the Technical Work Group at MoCA, said in a statement. “SCTE 235 is designed to create home environments in which both technologies can perform as intended to meet customer demand.”
