Introduction

The wireless networking world seems to have lost interest in 802.11a wireless LAN products. Although its advantages of operating in a quieter frequency band, significantly faster maximum data rate, and more non-interfering channels than 802.11b were attractive, its range problems and cost premium caused many prospective buyers to look, but not buy.

One of the best kept secrets of the WLAN world, however, seems to be the significantly improved performance of Atheros' second generation 802.11a designs.

In The Beginning...

When it first started shipping in Spring 2002, 802.11a equipment was poised for big things, since it seemed to hit all the right buttons for Enterprise buyers, at least. First, it really did have about five times the best-case throughput of 802.11b products, although the typical equipment clocked at about 24-25Mbps vs. the advertised 54Mbps raw data rate. And second, all products operated on eight non-interfering channels in the 5GHz band, with some products offering five additional "high-band" channels. This not only moved WLAN activity to a less crowded and more interference-free part of the radio spectrum to improve reliability, but greatly simplified multiple Access Point installations.

Figure 3: SMC 2755W and 2735W 802.11a throughput
(click on the image for a full-sized view)

A Step Sideways

It didn't take long for WLAN equipment vendors to realize that 11a-only products weren't going to kill off the still-growing 11b WLAN market. So about 6 months later, dual-band products started to appear. Atheros has some work to do, however, to help consumers identify gear that contains its 2nd generation 11a technology.

Table 1 (supplied by Atheros) lists APs and routers with 2nd Gen 11a radios, but it's by no means a complete one.

The following rules of thumb may help in finding second generation 11a products:

• Dual-band, dual-mode (a/b) client adapters are all based on 2nd generation Atheros chipsets
• Same goes for integrated a/b mini-PCI cards in notebooks
• Most a/b APs and routers are not second-generation. The exception is NETGEAR's WAB102.
• Single mode 802.11a products are virtually all first-generation

Although it probably won't be the dominant wireless standard, I'm more positive about 802.11a's future than I was a few months ago. Atheros' second generation technology really makes a difference and, in my mind, makes 802.11a a viable alternative for WLAN building—even in home and small office settings.

The improved performance and availability of dual-band, tri-mode products should also help corporate purchasers overcome performance and interoperability fears (once 802.11g is finalized, of course). They'll now be able to standardize on a single client type, build their network with whatever AP type fits their needs, and be able to use 11a's non-interfering channels and 5GHz operating band to escape from tricky 2.4GHz installation problems.

It remains to be seen, however, whether Atheros will continue to be the dominant 802.11a solution provider, and whether the competition has equivalent, or better 11a stuff. The second chance that 11a is getting with tri-mode products will be quickly killed if tri-mode products with inferior 11a performance get shipped by any of the major equipment suppliers. So let's hope WLAN gear manufacturers choose their 11a radio components carefully.

It's also an open question whether Atheros cranks up their marketing machine and starts getting their 2nd gen message across. It's not Atheros' style to be flashy or loud, but in present WLAN product market, they'll need more than whitepapers to be heard over the noise that Broadcom and its partners are making over 11g.