Magazine

Wi-Fi: Revolution Turns into Confusion


Wi-Fi wireless networking, both at home and in offices, has gotten off to a much faster start than most high-tech innovations. A big reason is that the technology, also known as 802.11b wireless Ethernet, has been spared the standards wars that have plagued the industry. It even has a trade group, the Wireless Ethernet Compatibility Alliance (WECA), dedicated to ensuring that all equipment bearing the Wi-Fi logo will be able to work together.

This happy situation was too good to last. Successful as it is, Wi-Fi has some serious disadvantages. With a theoretical top speed of 11 megabits per second and a practical maximum of about half that, it is too slow to carry high-quality video. And it shares the 2.4 gigahertz band with cordless phones, microwave ovens, and Bluetooth short-range wireless. As Wi-Fi networks proliferate, especially in apartments and multi-tenant office buildings, interference problems will become serious.

The industry has come up with two solutions. One, called 802.11a, operates in an empty, higher frequency band and offers a theoretical top speed of 54 megabits. A proposed standard called 802.11g offers the same faster speed but stays at the crowded frequency.

Right now, 802.11a looks like the winner, if only because hardware is shipping now from an assortment of companies, while the "g" standard is still a work in progress. I tried a Skyline access point ($390) and PC Card ($160) from Proxim (PROX) (www.proxim.com). Despite a complex set-up procedure that reminded me of Wi-Fi systems when they were introduced three years ago, the Proxim gear worked well and, under ideal conditions, transmitted data at about six times the speed of Wi-Fi.

In theory, the 802.11a has a shorter range than Wi-Fi. But Netgear has done considerable testing of 802.11a, and CEO Patrick Lo says the company has found that while speed degrades as you move away from an access point, 802.11a was significantly faster than Wi-Fi at all distances. That's consistent with what I found in my informal testing.

The big question for businesses and consumers is how smooth the transition to faster wireless will be. So far, the signs are good. Atheros Communications is shipping samples of combination 802.11a/Wi-Fi radios. Existing networks will use either these combo radios or a mix of "a" and Wi-Fi access points so that users will be able to connect no matter which flavor of 802.11 their laptops or other devices use. Hardware for 802.11a currently carries a premium of about 50% over the older gear, and combos will be more expensive yet. These prices are expected to plunge dramatically as production builds, though dual-mode radios will always cost at least a bit more.

The advent of 802.11g will be the wild card that could disrupt this orderly transition. "G" offers a couple of advantages. It can use the same radio as Wi-Fi, so it is potentially cheaper; in fact, the draft 802.11g specification requires that systems support both the old and new standards. And, in theory, it should offer longer range, providing better coverage in homes and requiring fewer access points in offices or schools.

There's one huge drawback to 802.11g, however. It shares a band with Wi-Fi and other devices. As wireless networks proliferate, interference will get worse and worse. This boosts the chances that 802.11a, which allows for at least five times as many independent networks operating within range of each other, will become the new standard.

The danger here is that confusion spurred by this proliferation of numbers and letters will stall the growth of a useful technology. WECA is drafting a standard called Wi-Fi 5 (for the 5 GHz frequency the new systems use) to handle issues of compatibility between "a" and "b" but has not yet decided what to do about "g." For now, consumers can buy Wi-Fi systems with confidence they will work with whatever comes along. But if you are worried about compatibility, it might be a good idea to avoid the temptation to go with a faster 802.11a system until the dust settles. By Stephen H. Wildstrom


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