iPhone 6 - bad static when using in home despite strong cellular signal

My iPhone 6 sound has static when using the phone in my home. It is especially bad in my home office, where the sound cuts out so much that I can't hear the other person. The farther I move away from my home office the better, but it's never as good as when using it away from my home. I'm wondering if my wireless router, which is located in my office, is causing this interference and if so, what to do about it. BTW, the cellular signal is great in my home, so that's not the issue. (Good thing I still have a land line!)