If none of those work then :
--At home, reboot the router by unplugging the power, waiting 10 seconds, and plugging it back in, then waiting another 20-30 seconds for the connection to reestablish.
--On your phone, go to Settings/Wireless & Networks/Wifi, select your home network, and tap "Forget network." Then reconnect.
--Try going into the router's settings (read the manual for this) and turning off security temporarily.
--If you have Bluetooth on, see what happens if you turn it off. Bluetooth has been known to interfere with wifi signal sometimes.