Originally Posted by Eric618
1. Go to your (stock) phone dialer
2. Dial *#0011#
3. Select "WiFi"
4. Turn off "Wifi Power Save Mode".
5. Exit this menu, turn off your Wifi and turn it back on. If you already entered all your wifi credentials, forget your network info (remove it) and re-enter it again.
Unlike the S3 however, this "fix" does not survive a power-down. When you reboot your phone it will be ON again.