New Modulation Scheme Said To Be 'Breakthrough' In Network Performance
A startup plans to demonstrate next month a new digital modulation scheme that promises to dramatically boost bandwidth, capacity, and range, with less power and less distortion, on both wireless and wired networks.
MagnaCom, a privately held company based in Israel, now has more than 70 global patent applications, and 15 issued patents in the U.S., for what it calls and has trademarked Wave Modulation (or WAM), which is designed to replace the long-dominant quadrature amplitude modulation (QAM) used in almost every wired or wireless product recently on cellular, microwave radio, Wi-Fi, satellite and cable TV, and optical fiber networks. The company revealed today that it plans to demonstrate WAM at the Consumer Electronics Show, Jan. 7-10, in Las Vegas.
The vendor, which has released few specifics about WAM, promises extravagant benefits: up to 10 decibels of additional gain compared to the most advanced QAM schemes today; up to 50 percent less power; up to 400 percent more distance; up to 50 percent spectrum savings. WAM tolerates noise or interference better, has lower costs, is 100 percent backward compatible with existing QAM-based systems; and can simply be swapped in for QAM technology without additional changes to other components, the company says.
Modulation is a way of conveying data by changing some aspect of a carrier signal (sometimes called a carrier wave). A very imperfect analogy is covering a lamp with your hand to change the light beam into a series of long and short pulses, conveying information based on Morse code.
QAM, which is both an analog and a digital modulation scheme, "conveys two analog message signals, or two digital bit streams, by changing the amplitudes of two carrier waves," as the Wikipedia entry explains. It's used in Wi-Fi, microwave backhaul, optical fiber systems, digital cable television and many other communications systems. Without going into the technical details, you can make QAM more efficient or denser. For example, nearly all Wi-Fi radios today use 64-QAM. But 802.11ac radios can use 256-QAM. In practical terms, that change boosts the data rate by about 33 percent.
But there are tradeoffs. The denser the QAM scheme, the more vulnerable it is to electronic "noise." And amplifying a denser QAM signal requires bigger, more powerful amplifiers: when they run at higher power, which is another drawback, they also introduce more distortion.
MagnaCom claims that WAM modulation delivers vastly greater performance and efficiencies than current QAM technology, while minimizing if not eliminating the drawbacks. But so far, it's not saying how WAM actually does that.
"It could be a breakthrough, but the company has not revealed all that's needed to assure the world of that," says Will Straus, president of Forward Concepts, a market research firm that focuses on digital signal processing, cell phone chips, wireless communications and related markets. "Even if the technology proves in, it will take many years to displace QAM that's already in all digital communications. That's why only bounded applications - where WAM can be [installed] at both ends - will be the initial market."
"There are some huge claims here," says Earl Lum, founder of EJL Wireless, a market research firm that focuses on microwave backhaul, cellular base station, and related markets. "They're not going into exactly how they're doing this, so it's really tough to say that this technology is really working."
Lum, who originally worked as an RF design engineer before switching to wireless industry equities research on Wall Street, elaborated on two of those claims: WAM's greater distance and its improved spectral efficiency.
"Usually as you go higher in modulation, the distance shrinks: it's inversely proportional," he explains. "So the 400 percent increase in distance is significant. If they can compensate and still get high spectral efficiency and keep the distance long, that's what everyone is trying to have."
The spectrum savings of up to 50 percent is important, too. "You might be able to double the amount of channels compared to what you have now," Lum says. "If you can cram more channels into that same spectrum, you don't have to buy more [spectrum] licenses. That's significant in terms of how many bits-per-hertz you can realize. But, again, they haven't specified how they do this."
According to MagnaCom, WAM uses some kind of spectral compression to improve spectral efficiency. WAM can simply be substituted for existing QAM technology in any product design. Some of WAM's features should result in simpler transmitter designs that are less expensive and use less power.