CableLabs® Creating Advanced Modem Spec to Enable 30 Mbps in Upstream

CableLabs® will create a new version of the Data Over Cable Service Interface Specification (DOCSIS™) this year that will incorporate advanced physical layer modulation techniques. The next version of the specification, to be called DOCSIS 2.0, will significantly increase cable bandwidth for data transmissions without requiring any physical rebuilding of cable networks.

Since November 1998, CableLabs and its membership have worked with a number of manufacturers, including silicon vendors such as Broadcom Corporation, Conexant Systems, Pacific Broadband Communications, Terayon Corporation, and Texas Instruments, to advance this concept from the theoretical stage.

Specifically, DOCSIS 2.0 will include two modulation techniques: S-CDMA (synchronous code division multiple access) and A-TDMA (advanced frequency agile time division multiple access). DOCSIS 2.0 will have the following characteristics:

Full compatibility with DOCSIS 1.0 and DOCSIS 1.1 cable modems (CMs) and cable modem termination systems (CMTSs).
Additional channel capacity in the form of more digital bits of throughput capacity in the upstream path.
Increased protection against electronic impairments that occur in cable systems, allowing for a more robust operating environment.
Coexistence of S-CDMA and A-TDMA in the same physical channel as DOCSIS 1.0/1.1.
Further enhance and augment the international DOCSIS standard (ITU J-112), which has been adopted worldwide and provides international interoperability of data signals.

CableLabs will begin developing the DOCSIS 2.0 specification immediately, a process to be completed by year-end. Consistent with its open process, CableLabs will seek the involvement of any contributing vendor that wishes to participate in the development of the specification. CableLabs will run interoperability waves in its laboratories for vendors that have prototype implementations of DOCSIS 2.0 CMs or CMTSs. And, consistent with past practice in DOCSIS, suppliers will work with CableLabs to develop necessary automated test execution packages and equipment that will be used to perform interoperability, certification, and qualification of the products.

“DOCSIS 2.0 represents another successful collaboration between CableLabs, manufacturers, and developers. The net result of this effort will be to continue our progress in bringing the most advanced broadband technology into the homes of our cable customers,” said Joseph Collins, Chairman of the CableLabs Board of Directors.

“This advanced physical layer process will ensure that the cable industry will increase its market-leading position in the delivery of high-speed data services through the continued success of our DOCSIS program,” said Dr. Richard R. Green, President and CEO of CableLabs. “DOCSIS 2.0 will provide the cable operator with increased data throughput, as well as enhanced noise immunity, through a choice of advanced modulation protocols,” Green added.

Said Rouzbeh Yassini, CableLabs Executive Consultant, who is running the CableLabs cable modem initiative: “The cable industry requires this 2.0 version of the specification to be completed this year. We not only can accomplish this objective, but we also intend to have our modem project ready to accept any DOCSIS 2.0 devices for certification and qualification early in 2002.”

The current DOCSIS 1.0 technology provides about five megabits-per-second of throughput capacity upstream per 3.2 megahertz (MHz) cable channel over cable hybrid fiber/coax networks. The pending DOCSIS 1.1 technology, for which modems are currently undergoing certification testing, provides 10 Mbps upstream. DOCSIS 2.0 will provide up to 30 Mbps of upstream per 6 MHz.