New technology promises to increase the speed of wireless networks by a factor of 20, but the emerging standard is being delayed by squabbling vendors.
A major upgrade has arrived for Wi-Fi that massively boosts speed and range while all but doing away with interference problems. The technology is called MIMO, and is already making its way into homes and small businesses.
The technology, which uses multiple antennas to achieve dramatic performance gains, is already available. Chipmaker Airgo, for one, is currently working on its fourth-generation products with Cisco's Linksys subsidiary; Belkin and Buffalo all use Airgo's technology. Samsung is also planning to use Airgo's chips in its laptops.
Many experts believe that MIMO is the future of the wireless LAN. "The first wave, 802.11b, 11a and 11g, improved modulation," explains Leif-Olaf Wallin, an analyst with research firm Gartner. "The next step is to make the antenna smarter."
But while MIMO has the potential to become move Wi-Fi forward it is not yet standardised, with several different, incompatible implementations of it being shipped by rival chipmakers including Intel, which is used to getting its own way. The issues facing MIMO are very similar to the situation with the 802.11g standard in the last few months before the standard was finalised, with vendors shipping gear promised to be compatible with approved kit. But this time around, instead of being a few months off, the standard in question--802.11n--is about two years away, and a draft hasn't even been agreed on yet.
The standards issue surrounding MIMO has led some industry analysts to issue a warning to enterprises and even the general public to steer clear of the technology for the time being. But so far, consumers and small businesses, at least, don't seem to be listening. Blistering performance gains are one reason--Wi-Fi gear with MIMO added on can make networks run at four times the speed of standard 802.11a/g networks, and 20 times that of older 802.11b networks.
But despite the standards problems, a lot of companies are choosing to invest in proprietary MIMO WLANs for the very simple reason that the technology is available now. "People have a tendency to buy whatever's the latest thing," says Gartner analyst Ken Dulaney.
Manufacturers say large enterprises are also getting on board. Airgo is targeting big business and promising to reveal an enterprise-grade licensee this year. The company says larger companies are "very open" to the technology, now that a number of competing chipmakers have jumped aboard the MIMO bandwagon. Trapeze Networks says it will begin selling MIMO Wi-Fi products to enterprises for specialised applications such as wireless videoconferencing.
How it works
MIMO's main benefits are
all to do with using its multiple antennas--which can be internal or external--to process signals.
One of these techniques, used by most MIMO chips, is the ability to resolve multiple signal paths, known more technically as multipath signals. These are the echoes and fragments of signals that arrive after the main line-of-sight signal, such as the reflections off of buildings in a built-up environment. Traditional 802.11 gear sees these signals as distortion, but MIMO is able to use them to reinforce the main signal. That means clearer signals, longer-range signals or a bit of both.
A related feature, pioneered by Airgo, is spatial division multiplexing (SDM), which transmits multiple independent data streams within a single channel of bandwidth. This can increase throughput as the number of data streams is increased. Multipath processing can work with a conventional transmitter at the other end, but spatial multiplexing requires an antenna pair at each end of the transmission for each data stream--in other words, it won't give any benefits unless MIMO hardware is in use on both ends of the signal.
MIMO antennas each need dedicated processing hardware, which means manufacturing costs are unavoidably higher than current standard Wi-Fi kit.
Routers from Linksys and Belkin are currently using Airgo's True MIMO technology, with multipath and spatial multiplexing. The RangeMax Wireless Router from Netgear uses BeamFlex from Ruckus Wireless, formerly known as Video54. This MIMO variant has seven antennas and uses a technique called beamforming instead of spatial multiplexing.
Beamforming transmits multiple identical data streams, instead of independent streams, but the results are similar. D-Link's Super-G with MIMO wireless router uses a four-antenna
Play video
There are currently no comments for this post.