Have installed Fedora 15 on my new notebook, Thinkpad E420. After powering on first time, I found that wireless network is not working. In the system messages, it seems that it is blocked by rfkill signal though I tried to turn on wireless lan adaptor.
After hours of investigation, I have found that "acer_wmi" kernel module which I think I don't require is loaded and sending blocking signal. "modprobe -r acer_wmi" command removes acer_wmi module and it works. To apply "modeprobe -r acer_wmi" command permanently, I plased the command in rc.local startup script.
Now wireless network works fine. It's great.