I’m currently running Ubuntu 15.04 on my Dell E6510 laptop, and when the device is connected to the wifi, the led constantly blinks, it’s annoying, well it is to me any way. I had the same problem with this and Fedora, but it’s an easy solution.
edit the file /etc/modprobe.d/iwlwifi.conf
add the following line
options iwlwifi led_mode=1
save the file and reboot and your led should no longer blink, well it might and it might not 😀