Engineers at Cable Labs, a non-profit research and development consortium in Louisville, Colorado, are racing toward completion of the next generation of cable modem technology designed to significantly boost the speed of broadband service (high-speed internet) delivered to your home by your local cable company. They’re aiming for multi-gigabit per second download speeds on the Hybrid-Fiber Coax (HFC) network.
DOCSIS 3.1 has development roots in the U.S. space program
The technology is the next generation of an industry standard called Data Over Cable Service Interface Specifications (DOCSIS ®). DOCSIS 1.0 first appeared in 1997. DOCSIS 3.1 modems are expected to be under your desk by 2015 and the DOCSIS 3.1 network to be operational around 2016.
“We’ve put together 3.1 much faster than any other version of DOCSIS while enabling technology partners to begin their design and development as early as possible,” says Dan Rice, Vice President of Network Access at Cable Labs. “We want to be able to move fast and agile.”
The potential of DOCSIS 3.1 technology has the cable industry abuzz. Since 1996, it has spent more than $200 billion to upgrade its infrastructure to introduce residential broadband service to American households and lay down more than 600,000 miles of fiber optic cable.
What makes 3.1 such a quantum leap forward over past iterations of DOCSIS? The Connectivist popped the hood to find out. We discovered that like many products we take for granted in our homes today, DOCSIS 3.1 has development roots in the U.S. space program. In fact, DOCSIS employs some of the same technology that rides aboard NASA’s two Voyager space probes launched 36 years ago that are still in service.
“We can add as much as 50 percent more capacity in the upstream and downstream signal directions”
The technology, called Reed-Solomon Codes or RS codes, corrects for errors caused by electrical interference during data transmissions. That provides more stability and consistency at the receiving end. On space missions, where radio signals carrying images back to Earth can degrade because of the vast distances, RS Codes helped the Voyager probes beam back stunning color photos of Uranus and Neptune, more than two billion miles from Earth. In a cable system, RS Codes make for more robust and resilient signals despite the hundreds of miles the data must travel to reach you.
DOCSIS 3.1 makes the jump to light speed with a few distinct innovations. First, it increases the number of bits per second per hertz with an advanced signal modulation scheme (called 4096 QAM and OFDM). This is similar to the one found in the latest Wi-Fi and LTE networks.
Simplified, it allows for more capacity for speed and data, which is more efficient to create than the current technique of “channel bonding.” Channel bonding combines many channels into single streams of data. It’s akin to what would happen if you could hold multiple garden hoses together in one hand—you’d get more water volume in the same amount of space.
When the advanced modulation is combined with new state-of-the-art correction codes, known as Low Density Parity Check (LDPC), you have a leaner system that is able to operate near the theoretical limits. (Similar LDPC codes have been adopted by NASA in the IRIS solar observatory mission launched this past June.)
“We can add as much as 50 percent more capacity in the upstream and downstream signal directions,” notes Mark Palazzo, Vice President/General Manager of the Cable Access Business Unit for Cisco Systems.
On top of the increased capacity, the new standard will be “backwards-compatible with the large installed base of earlier DOCSIS gear,” says Palazzo.
Indeed backwards-compatibility is another big plus for 3.1. The upgrade to DOCSIS 3.1 will use a phased approach with the cable operators first offering their customers DOCSIS 3.1 capable modems operating in DOCSIS 3.0 mode. This will enable customers to be ready for the warp speeds of 3.1 – without needing to change equipment – after cable operators add 3.1 technology to their data centers.
When it comes to broadband offers, the promise of speed may be the sexiest girl in the room. But Rice suggests that bandwidth is the real trophy. We are streaming more and more video, uploading tons of photos, and practically living on our mobile devices.
“Who knows what interesting innovations are going to result out of people being able to do new things with higher speeds and greater capacity?” says Rice.