I have this problem with my new note 4. I don't know if it's a bug, it's a not good compatibility with my Neatgear DG834v5 (it's a little old but it's a very good router and it's quite common). I tried everything and uff, now I only wait lollipop in order to find if the problem is software.
In the meantime I live with this bug and try something (for instance, now I'm trying to block the client.google url but I'm quite sure it won't work)
update: as I wrote, I can confirm that this solution doesn't work, I blocked the client.google but the wifi drops randomly.
Last edited by Legatus Onoris; 31st January 2015 at 05:25 PM.