I have just noticed that this is happening to me as well.
I have a TP LINK wireless N adapter and I couldn't understand why it kept dropping but now I get it. When ever I'm charging my iphone or I get a call near the PC it drops the wireless signal. Weird
Anytime I am in a game like Battlefield 3 I lag out and get disconnected when a call or text comes in on my iphone 5 (had the same prob with my 4s). Left 4 Dead 2 lags hard when a call or text comes in or if my phone is using data. Youtube videos are stopped dead in there tracks when a call comes in...
Both my router and cable modem are in close proximity to me in my office, moving the phone out of the office or turning it off fixes the problem. My computer is hard wired to the wireless router.
I should note that this will make anyone on the network lag or completely stop their internet connection.
Why is this happening to me. I have read many threads on how data on my phone shouldn't interfere with a wireless router unless it could be interfering with the modem itself. I wonder what its doing to my brain