The FCC has added 255 megahertz of bandwidth, divided into 11 channels, to the 5 GHz 802.11a ISM band.

The new rules went into effect Jan. 20, and allow the use of 5.47 to
5.725 GHz—11 channels in the 802.11a version of Wi-Fi—with a couple of
key signal usage modifiers. The rule also changes the requirements for
the next-down stretch of spectrum, 5.25 to 5.35 GHz to conform to those

Both bands must now use dynamic frequency selection (DFS) to avoid
in-use spectrum, and transmit power control (TPC), which throttles
power to the minimum necessary for given communication. Older equipment
using 5.25 to 5.35 GHz is exempt, although one might expect
manufacturers to push out firmware upgrades. These requirements are
part of 802.11h, which extended 802.11a for legal European operation.

Interest in 802.11a has grown over the last year as both vendors and buyers have recognized the benefits of the virtually untapped band for voice over WLAN. I've heard from two medical device vendors who are developing radios that will support 802.11a. Sure 802.11b is the no-brainer for wireless medical devices today, but today's WLAN infrastructure will be obsolete and discontinued long before today's medical device is half way through its life cycle. No one really knows what the wireless environment will be like in 4 or 5 years - an option to use 802.11a could end up a real godsend.