You Tell Us: Gigabit Wireless on the Cheap
By Willie D Jones
First Published January 2008
Image: Sibeam
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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.”