The question is whether the conflict is being caused by radio interference, or a network problem. The network problem would be, for example, the receiver and the iPhone requesting the same local IP address.
Do the devices play nicely if you put some distance between them? That would rule out the IP address conflict. If it's a radio interference problem, then unfortunately I haven't heard of it before (nor do I know how to fix it). There's no practical way to connect the receiver with an ethernet cable? Don't be afraid to drill through walls--it's liberating.