If another device seems to be working just fine, and yours won't, it usually is a hardware problem or coverage problem...
although, it possibly could be the software drivers for your devices. but you mention a "mobile" and iPad, what is the "mobile" device? it would sure help if we knew what you have.
you say 'roommate', so is this a college dorm? I highly suspicion what you are experiencing is a "coverage issue".
what happens if you go sit in the same area of the room that the roommate's device works okay in?
will yours stay connected then?
download WiFi360 and use it to sniff out the signals available, and how strong they are.... if the signal strength is pretty low, down below -90 dBm it is going to be tough to stay connected all the time. Just having thing change in the environment around you can cause it to disconnect... like if you are sitting and the roommate gets up and walks around, then poof! your WiFi drops.
my laptop is a piece of crap, it will not stay hooked up with foreign WiFi signals at all.... so I know the feeling.
* WiFi Overview 360 Pro - Android Apps on Google Play