Comment 25 for bug 219057

Be aware that adding things that you don't understand can have unwanted results... For exemple, "power_save=0" prevents your wifi card to enter power saving mode, and could reduce your battery autonomy...

In my case (on Linux Mint 17.3), simply adding the "bt_coex_active=0" parameter in /etc/modprobe.d/iwlwifi.conf fixed the problem. See http://superuser.com/questions/924559/wifi-connection-troubles-solved-why-does-my-fix-work for more information on this parameter.