What steps have you taken to troubleshoot the problem?
Did you reboot your router at home - unplug if from power for about 30 seconds and then plug it in again?
Did you try Forgetting the Network and try to Rejoin? Settings>WiFi>Tap the blue arrow next to your network name>Forget this Network. Restart the iPad and then go back to Settings>WiFi>Tap your network name, enter your password and the tap Join.
Did you try Resetting Network Settings? Settings>General>Reset>Reset Network Settings and start all over again?