Wi-Fi Takes New Turn With "Wireless-G"
IEEE ratifies the 802.11g standard, offering three to five times the speed of 802.11b
Photo: Bill Cardoni
A shopper at a Best Buy store in Wilkes-Barre, Pa., looks over a Linksys office router with built-in IEEE 802.11g capabilities. The product, dubbed ”Wireless G,” was released in anticipation of the standard’s finalization.
On 12 June, the IEEE Standards Association’s Standards Board formally ratified IEEE 802.11g, an amendment to the wildly popular local-area networking standard known as Wi-Fi. But details of the standard were largely settled last year, enough so that by last January, manufacturers like Linksys Group Inc. and D-Link Systems Inc., both in Irvine, Calif., jumped the gun and shipped to retail stores their home and small-office routers incorporating the standard [see photo, above]. Consumers, in turn, have for some months faced the choice of which 802.11 flavor is best.
Anyone walking the aisles of a computer store finds shelves stocked with a bewildering assortment of local networking products, labeled with an alphanumeric soup worthy of a government bureaucracy. IEEE 802.11g is an extension of 802.11b and competes with 802.11a, with which it shares many features. So one obvious question some consumers are asking themselves is whether, given that a has yet to take off in a big way, it will now be superseded by g. Does a still have a real mission?
In fact, at an 802.11 conference held in Boston in June, industry analysts and executives were unanimous that within a year or so, virtually all access points will be dual-mode, accommodating both 802.11a and 802.11g. And since the 802.11g standard is backward compatible with b, the so-called access ”hotspots” will bill themselves as ”trimode.” That being the case, consumer devices will be able to use either a or g with impunity, or even remain with b, the version originally dubbed Wi-Fi. The a and g variants specify a bandwidth of 54 MHz, while the b specifies 11 MHz.
Picking through the soup
The general IEEE designation for networking standards is ”802” (IEEE 802.3, for example, is the standard for Ethernet). The ”11” family of standards governs wireless local-area networking, a category that exploded two years ago as companies and tech-savvy homeowners discovered that for a few hundred dollars they could set up Internet access points without wires in conference and living rooms.
The first in the ”11” family to market were a and b. But the first to take off was IEEE 802.11b, which uses an unlicensed portion of the radio spectrum, 2.4 GHz, that is inexpensive to implement. It specifies a networking protocol and an air interface—that is, a way for routers and servers to send out a signal and for devices like laptops and PDAs to find that signal.
The IEEE 802.11a standard also uses an unlicensed, though different, portion of the spectrum, 5 GHz, but a products are more expensive to manufacture. ”802.11b was a relatively simple hardware upgrade from existing 2.4-GHz [wireless] products, which had been on the market for a couple of years,” says Jim Geier, whose company, Wireless-Nets Ltd. (Yellow Springs, Ohio), provides consulting services to chipset and wireless manufacturers. ”It was taking manufacturers much longer to finalize circuits that would operate in the bands that 802.11a uses.”
IEEE 802.11a now stands at a crossroads: it offers high data rates, as high as 802.11g does, and more channels—and therefore many more opportunities to avoid interference with other users. Nonetheless, it is incompatible with 11b, presenting the wireless industry with something of a dilemma.
Will it be a or g, Mesdames, Messieurs?
The choice between a and g seems, in fact, to be a near-perfect balancing of equally tasty apples and oranges [see table, at http://www.spectrum.ieee.org/WEBONLY/resource/aug03/80211gtab.html]. They have about the same data rate: nominally 54 Mb/s, but in practice 20-30 Mb/s within the local networking loop. But 802.11g is inherently compatible with b, which millions of laptop and palmtop owners are already using.
Yet g’s compatibility with b may be unimportant in the long run because, as many analysts see the situation, most potential providers and consumers haven’t committed themselves to anything yet. ”Only 1 percent of all U.S. households use 802.11b,” points out Julie Ask, a senior analyst at Jupiter Research (Darien, Conn.). So she wonders why consumers would care about compatibility with b.
The same logic applies to network providers. ”There are almost two million potential 802.11 public hotspots, only 0.1 percent of which are actually deployed,” observes Joel Short, chief technical officer of Nomadix Inc. (Westlake Village, Calif.), which creates public-access wireless hotspots in places like train stations and retail stores.
So it would be a mistake to undersell IEEE 802.11a, which has one notable advantage that could carry weight in the years ahead. It operates in unlicensed frequencies in the 5-GHz range, nearly virgin territory in the radio spectrum. On the other hand, 802.11b and 802.11g use an 83.5-MHz band located between 2.4 and 2.4835 GHz, an unlicensed band already employed by a wide variety of home applications—from cordless telephones to microwave ovens to garage-door openers. In practice, only three channels can be used simultaneously.
The 5-GHz bands are not only less crowded, they’re much larger: the 5.15- to 5.35-GHz and the 5.725- to 5.825-GHz bands allow for at least eight simultaneous channels. In addition, a transfer is under way in the United States of another 255-MHz band at 5.47-5.725 GHz, which will become unlicensed and available for applications such as 802.11a, a use that’s already allowed in Europe.
In the final analysis, however, cost—not power usage, range, or data rates—probably will be the determining factor. ”Wireless consumers are primarily price-driven,” says Jupiter Research’s Ask. That might give a decisive edge to Wireless-G, at least at the retail level.