802.11a

Because the physical layer of this specification involves the 5-GHz band,
it is becoming the common replacement for the widely distributed
802.11b. It uses eight available radio channels. In some foreign counties,
however, it is possible to use 12 channels. 802.11a allows for a high
throughput of 54 Mbps per channel. The greatest user throughput is
about half this value, because throughput is shared among all users who
are currently transmitting data on a given radio channel. The data rate
proportionally decreases as the distance between the user and the radio
access point increases.

In the majority of implementations, the data throughput will be
greater than 11 Mbps. Furthermore, with more radio channels you
achieve increased protection from any hacker interference from a rogue
access point.

802.11 products have become increasingly available in the latter half
of 2002 with more and more vendors offering products compliant with both 802.11a and 802.11b. Prices have decreased significantly as
802.11a is quickly becoming the standard for WLANs.