802.11h

Thiscompeting standard is trying to satisfy European power regulations
for transmission in the 5-GHz band. These products must have transmission
power control (TPC) as well as dynamic frequency selection
(DFS).

TPC restricts the transmission power to the least amount necessary
to reach the user who is farthest away. DFS then chooses the radio
channel at the access point to reduce interference with other networked
systems functioning in the same radio portion of the spectrum.
Its competition with 802.11 increases its European acceptability for 5-
GHz WLAN products. The actual acceptance of products that use 5 GHz
with TPC and DFS won’t officially take place until the latter half of
2003 and perhaps even as late as early 2004.