Q: WiFi disconnects sporadically, automatically reconnects when I unlock my iPhone 4

For the past week or so my Macbook has been dropping its wifi signal at home, even with full signal strength and no other devices showing connectivity problems.  Trying to reconnect manually, it won't recognise my router, but strangely if I unlock my iPhone 4s, it will quickly re-establish the connection by itself... any ideas on why this would be?