http://lwn.net/Articles/296400/

Linux 2.6.27 kernel upwards a new wireless regulatory infrastructure has been added. The main motiviation behind this was to centralize regulatory code as each driver was implementing their own regulatory solution, and to replace the initial centralized code we have where:

* only 3 regulatory domains are supported: US, JP and EU
* regulatory domains can only be changed through a module parameter
* all rules are built statically in the kernel

We now have support for regulatory domains for many countries
and regulatory domains are now queried through a userspace agent
(CRDA) through udev allowing distributions to update regulatory rules
without updating the kernel. Updates on regulatory rules can
now be left as an independent effort.

if dmesg shows this:
cfg80211: Using static regulatory domain info
cfg80211: Regulatory domain: US

You can set your own regulatory domain in /etc/modprobe.d/options by adding the following string:

options lbm_cw_cfg80211 ieee80211_regdom=EU

you can replace JP with EU or US depending on your area.

NOTE: ascfg80211 module has recently been renamed to lbm_cw_cfg80211