iPad WiFi Disconnect or Dropping connection

We are using the router coming with Verizon FIOS and experiencing same issue as some of iPad users. WiFi drops from time to time.I have to rejoin network by retype password. After reading blogs and discussion related to this issue. it seams it is related to iPad and router. Not every router gets this issue. So I tried to connect a Buffalo router to Verizon router and set iPad to use this Buffalo router. It is working! I don't get disconnect any more.