I've personally had incidences of wifi from one device just no agreeing with my wifi router. This could just be one of those instances.
Do you have encryption enabled? Could your phone have an old password stored on it?
Does your home network share the same network name as an other network you may have connect to at any point?
In your wifi set-up, if your phone detects you home network, see if you can click on it and get it to forget the password.
If you do not have a password set, turn on encryption and set a password, at least that way when the router starts up and asks you for a password you'll know that it has saved it's settings properly.
One more thing, make sure you encrypt your home wifi even if you have mac filtering enabled, it's pretty easy to spoof a mac address and has part of the TCP/IP packet your computer actually broadcasts your mac address so using it to secure your wifi is not the best option if privacy if your concern (other than preventing others from using it).