High-Def Is in the Air

New technologies wirelessly transmit high-definition video.

Big bandwidth: This SiBeam chipset, which is about the size of a deck of cards, enables high-definition video to wirelessly move between televisions and other electronic devices. The gold square on the right side of the chipset is an array of antennas that shape the data signal into a directed beam. The radio circuitry is below the antenna array and is not visible. The black chip in the center encodes the signal and controls the antenna and radio. Credit: SiBeam

A trip across the showroom floor at last week's Consumer Electronics Show (CES) in Las Vegas pointed to a home entertainment trend: bulky cabinets that hold boxy televisions, stereos, and media players are out, and flat-panel displays on walls are in. But as good as those skinny displays look, they still pose the aesthetic and logistical challenge of what to do with the wires connected to them. Now, a handful of companies are racing to outfit televisions, media players, video cameras, and gaming systems with wireless chips that can cut some of those cords.

At CES, SiBeam demonstrated its wireless chipset, which could stream high-definition video and audio from a media player to a television. With SiBeam's technology, it would be possible to hang a television on a wall and place the media player in the same room, but far away and out of sight, without wiring the two together. In the demonstration, the company sent data from the media player to the television at a rate of two gigabits per second, fast enough for standard high-definition video, which is known as 1080i. But the company's first commercial chips--available in Panasonic displays in early 2009--will be better. They will transmit data at four gigabits per second, fast enough to stream the highest-quality high-definition video, 1080p.

Wireless data-transfer technologies are already familiar to most people. But Wi-Fi and Bluetooth, the most common, weren't designed to send and receive as much data as is needed to make a wireless entertainment center possible, explains John Marshall, vice president of sales and marketing at SiBeam and president of Wireless HD, a collection of companies developing technology guidelines for the consumer electronics industry to follow.

Unlike Wi-Fi, which operates in the 2.4-gigahertz range of the electromagnetic spectrum, Wireless HD works in the 60-gigahertz range, a previously unused region that has a significant amount of bandwidth to spare. As a consequence, Wireless HD can transmit over a broad swath of spectrum, between 59 and 66 gigahertz, greatly expanding its data capacity. But transmission in the 60-gigahertz range also poses significant technical challenges.

For one thing, objects, such as walls or people, readily absorb signals at this frequency, says Jeff Gilbert, chief technology officer at SiBeam. This means that if a signal were simply sent from a media player to a display, and someone walked in front of the player, the picture quality would degrade. SiBeam got around this problem by building a radio that uses beam steering, says Gilbert. Unlike Wi-Fi signals, which send data in all directions, SiBeam's chips create a beam of information and send it directly between two devices--essentially creating a wireless wire. But the chips' antenna arrays can also route the signal along multiple paths. To ensure that the link between devices is never broken, explains Gilbert, the radio's software is ready to switch to an alternate path almost instantly. "In less than a millisecond, it can switch directions," he says.

SiBeam's beam-steering technology can bounce signals off of surfaces to maintain a wireless link between devices. If the beam is interrupted by an object or a person, the SiBeam chip automatically and instantly reroutes it.
Credit: SiBeam

Another challenge for SiBeam was to make the chip cost effective. Historically, transmitting data at 60 gigahertz has required radios made of a semiconductor called gallium arsenide, which has advantageous electrical properties but is expensive to mass-produce. While it would be cheaper to build the radios out of silicon, the circuit designs used in gallium arsenide radios didn't translate well to silicon. So SiBeam turned to Bob Brodersen, an electrical engineer at the University of California, Berkeley, who is also the chairman of the company's board. Brodersen's team had developed the circuitry to make 60-gigahertz radios out of silicon and has advised the company on the technology. SiBeam is now ramping up mass production of these radios in standard silicon-manufacturing facilities.

SiBeam's 60-gigahertz chip has progressed faster than many industry watchers expected. "It's an esoteric part of the spectrum," says Brian O'Rourke, senior analyst at In-Stat, a technology research firm. "I thought it'd take them longer to get the solution." One of the features of SiBeam's technology, O'Rourke notes, is that it works only within a single room. As 60-gigahertz signals pass through walls, they degrade, which means that their data rate would drop enough that picture quality would suffer.

SiBeam isn't alone in its quest to bring wireless high-definition content to homes, however. Another company, called Pulse-Link, demonstrated its chips at CES as well, and it expects to have products to consumers by the end of this year. Like SiBeam's chip, Pulse-Link's increases bandwidth by operating over a range of frequencies, from 3.5 to 4.7 gigahertz--frequencies that have a longer transmission range than 60-gigahertz signals. This means that Pulse-Link's technology could be used to wirelessly network an entire home, says John Santoff, the company's founder and chief technology officer. But signals in the 3.5-to-4.7-gigahertz range don't have the bandwidth of those in the 59-to-66-gigahertz range, so Pulse-Link's data rates will never match SiBeam's. However, Santoff says, his company's chips can handle a little more than a gigabit of data per second. In addition, Pulse-Link has developed software that shrinks the file size of high-definition video when it's sent through the air and decompresses it when it arrives at the television. The company's chips work with wired media too, Santoff says. In other words, a chip in a media box could receive a signal from an Internet coaxial cable and transmit it wirelessly to a television.

While the first wireless-HD products are expected to be available later this year, experts who are tracking them don't expect them to overtake home entertainment centers anytime soon. "My big question is, how bad do consumers want to get rid of cables?" says O'Rourke. When wireless-HD first hits the market, he says, it's going to be expensive. Initially, he says, manufacturers, such as Panasonic, will put it in high-end products where there is less cost sensitivity. And depending on consumer response, the technology may or may not then find its way into mid- and low-range products within the next few years.

Still, the technologists are optimistic. "Ideally, people want to go wireless," says Pulse-Link's Santoff. "Who likes that rat's nest of wires behind the home entertainment center? We want to plug this stuff in and have it intelligently and wirelessly connect. That's where the industry is going."

http://www.technologyreview.com/Infotech/20086/?a=f