I finally solved the problem on my Samsung 5 Ultra Series with Win8-64 and the advanced 6235 which always would loose connection to the Internet (not to the router) and tell me (after running problem-solution) that I was missing gateway. Ive been running crazy for almost two weeks now and my laptop was almost on its way back to amazon.
1) I deinstalled the WiFi-driver and let Windows reinstall it after booting again, (now Version 15.7.0.3)
2) Deactivated the Ethernet Controller (!!!)
3) Rebootet again... and voila!
No Drop outs ever since (its been 3 entire days).
So it seems like the two devices badly interfere with each other.
Hope this helps some people facing the same problem.
Cheers!