Comment 13 for bug 361461

I just saw the "disassociation by local choice (reason 3)" on Karmic & Jaunty USB based systems which previously worked fine. I'm using the b43 Broadcom open driver and the opensource Broadcom firmware. I think this is a hardware problem, since iwlist scan will show the two available aps with strengths around -75db and quality of both in 30s where one shoud be qual = 78/100, strength= -59db and other is 2/100, -89 Db. The laptop having problems has been failing, and this looks like the latest failure symptom. Your probems may be as simple as a bad antenna connection.
Good Luck