Faster, Farther Wi-Fi
A faster and more far-reaching wireless Internet is coming within a year or so thanks to new Wi-Fi standards approved by members of the IEEE (Institute of Electrical and Electronics Engineers). These standards will provide a framework for the next generation of wireless routers and chipsets in laptops, mobile phones, and any other wireless consumer electronic devices.
The new IEEE 802.11n standards will be exceedingly fast, transmitting at least 100 megabits of information per second, and possibly more, depending on the equipment used. That’s roughly four times the current 802.11g rate of 24 megabits per second. Moreover, equipment that incorporates the new standards could extend the range of a wireless signal by 50 percent, says Bill McFarland, chief technology officer at Atheros, a wireless chip maker.
At first look, these standards may seem like a formality; but they represent a fundamental shift in the way information is transmitted over airwaves. Consequently, manufacturers, as well as other wireless experts, are excited about the prospects for 802.11n. “I don’t think this is incremental,” says Babak Daneshrad, an electrical engineer at UCLA. “I think this is a major step…a paradigm shift.”
The technology that puts 802.11n in a league of its own, MIMO (“multiple input, multiple output”), is necessary to meet the data transfer rates and extended range dictated by the standards. MIMO routers use multiple antennas and radio systems to simultaneously receive and transmit information. The “simultaneous” part is crucial. Although some routers have multiple antennas, before MIMO, they could be used only one at a time, explains McFarland.
With MIMO, multiple, intertwined wireless signals are received, then sent through “signal processing” algorithms that untangle the data. Because MIMO equipment can handle many more data streams than traditional wireless gear, there’s built-in redundancy, which augments not only the data transfer rate, but also network reliability and range.
The more antennas on a router, according to McFarland, the faster the data can be moved around. Theoretically, rates of 600 megabits per second could be achieved, but “the true throughput level is usually significantly less” because, as well as transmitting data, resources also direct the flow of data packets.
With 802.11n, the high-speed transfer will be noticeable only within the traditional range of wireless routers. Once outside that range, the transfer rate will drop to about 801.11g speeds. This will occur because of a resource trade-off in wireless networks, explains UCLA’s Daneshrad. Using pizza dough as an analogy, he notes how one starts with a certain amount of dough, then can either keep the crust thick or stretch it out to cover a larger area. Similarly, “you can use multiple antennas to blast [data] at the closest distance,” he says, “or you can fall back on the [data transfer] rate and give yourself range extension.”
Most broadband Internet connections piped into a home through DSL, for instance, can transfer data at a maximum rate of only two megabits per second. Therefore, depending on the set-up, these faster routers won’t necessarily make Internet connections feel much faster (although you will be able to connect further away from your router).
However, one of the more exciting implications of the increased speed afforded by MIMO is shuttling data faster throughout a local network – such as the digital home. “There’s going to be a lot of media that you have on your own machines that you’ll want to move around within your home,” McFarland says.
In fact, the 802.11n standards were crafted with this sort of media application in mind, says McFarland. “Sony, Toshiba, and Sharp wanted to make sure there were features to carry video through an entire home,” he explains. One of the features, called “beam forming,” focuses energy in a particular direction and zips data to a particular device. For instance, your living room PC could stream music on one direct beam to a sound system with more reliability and speed than sending the signal in all directions.
The wireless handheld industry, too, was interested in shaping the 802.11n standards, so that phones using voice-over-Internet protocol (VOIP) are more reliable. “VOIP has some unique characteristics,” says McFarland, such as requiring a steady stream of small packets of data, which needed to be considered in the new standards. The approved standards “introduced capabilities so that those transmissions could be handled efficiency,” McFarland says.
The 802.11n standard still needs to pass through several IEEE members’ committees, a process McFarland expects will be completed around early 2007. But the preliminary set of rules isn’t expected to change much; in fact, manufacturers such as Airgo, Broadcom, and Atheros have already introduced equipment that complies with the standard. Telecommunication research group Dell ‘Oro predicts that by 2009, 90 percent of all consumer wireless equipment will be 802.11n compliant.
It’s been about three years since the 802.11g standards arrived – giving rise to cafés full of laptop owners sipping lattes while checking their e-mail. And these next Wi-Fi standards are likely to revolutionize the way we use wireless devices once again.
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