# iwconfig wlan0 sens -90 Error for wireless request "Set Sensitivity" (8B08) : SET failed on device wlan0 ; Operation not supported. # iwconfig wlan0 sens -70 Error for wireless request "Set Sensitivity" (8B08) : SET failed on device wlan0 ; Operation not supported. # iwconfig wlan0 sens -60 Error for wireless request "Set Sensitivity" (8B08) : SET failed on device wlan0 ; Operation not supported. # lsmod | grep rt2 rt2800pci 6723 0 rt2800lib 28134 1 rt2800pci rt2x00pci 4001 1 rt2800pci rt2x00lib 25300 3 rt2800pci,rt2800lib,rt2x00pci On some other driver, as reported by a user on the fedora users mailing list, it does work: http://lists.fedoraproject.org/pipermail/users/2011-February/392324.html
mac80211-based drivers simply do not support setting that parameter. These drivers are simple and do not roam on their own. Instead they rely on a userland component (e.g. wpa_supplicant) to do the roaming.
*** Bug 29042 has been marked as a duplicate of this bug. ***