You Tell Us: Gigabit Wireless on the Cheap

2 min read

Ensuring that the motion of a hyperkinetic kung-fu master taking on hordes of henchmen does not appear blurred or jerky on, say, a 60-inch plasma screen requires gigabit-per-second data-transfer rates between the high-definition video player and the TV. Up to this point, the only products that did this wirelessly were those containing pricey and clunky transceivers that transmitted signals on millimeter-wave frequencies between 57 and 66 gigahertz.

SiBeam Inc., a Sunnyvale, Calif.�based fabricationless semiconductor company, aims to dramatically cut the price of these US $1000-plus components, putting wireless A/V connectivity within the reach of the average consumer. With OmniLink60, SiBeam has achieved 4 Gb/s data rates between devices within 10 meters of each other on the same 60-GHz band with commodity-priced CMOS components instead of exotic semiconductors like indium phosphide and gallium arsenide. A SiBeam spokesperson says that this breakthrough will make these transponders so cheap that they’ll be a negligible addition to the bill of materials for TVs and other home electronics equipped with them.

The company has compounded this breakthrough with adaptive beam�forming algorithms and highly steerable microarray antennas that allow transceivers connected to a TV and, say, a PlayStation 3 video-game console to communicate even if there is no direct line of sight between them. And if someone walks into the beam’s path, the OmniLink technology adjusts the antennas, instantly finding a new path, even if it means bouncing the beam off a wall or the ceiling.

Cool as SiBeam’s technology is, its insistence that the OmniLink60 will transmit uncompressed signals may be shortsighted. Doug Bartow, a marketing manager at Analog Devices Inc., in Norwood, Mass., one of the device makers working with SiBeam to produce commercial versions of its prototype transceivers, says that SiBeam’s claim ignores what he calls the rate-range tradeoff. Bartow notes that because the transmission range of a wireless signal decreases as the data rate goes up, SiBeam’s 4-plus-Gb/s scheme can be no more than a ”same-room technology,” when the ultimate ambition of home networking is to have complete flexibility as to where you put your home electronics. He also notes that high data rates require more complex signal modulation schemes that make components more expensive than they have to be. At present, with video signals being transmitted in 1080i (shorthand for a video mode with 1080 lines of vertical resolution that are interlaced), the data-transfer rate of SiBeam’s chips is more than sufficient for delivering every packet making up a digital signal. But as TV and video-screen makers make sets capable of displaying 1080p video (where the p stands for progressive image scanning) to exploit its smoother scanning and crisper images, twice as much information will need to be transferred to produce each frame. Bartow says that sending uncompressed data over the wireless link will not only be well nigh impossible in a few years, when the industry shifts from today’s 8-bit video technologies to 12-bit schemes, but is unnecessary even today. He notes that copies of feature films sent to cinemas with digital projectors are compressed. ”And if the movies, for which picture quality is paramount, are compressed, I can’t imagine what advantage an uncompressed signal would offer the home viewer.”

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