Lately my WiFi connection has been quite slow, and sometimes I lose my internet connection altogether (but the computer does not actually disconnect from the WiFi network). This only affects my laptop and only when it's running Ubuntu, so I think it must be a problem with Ubuntu. I haven't changed anything recently; this is on 12.10 64-bit. What could it be?

Update: It's doing this now. The connection isn't completely dead, it's just staying under 5 kB/s. Still frustrating though. It also seems to affect all users.