I had an issue tonight. I visited a mall this evening for a few minutes; not sure if I hit a dead spot but when I came out I noticed when I left that I had no signal on my phone. I kept expecting it to fix itself but, after driving a couple of miles, I still had no signal. I finally turned on Airplane mode, and then back off, and afterward immediately had a signal. For reference, I have a Verizon iPhone and currently have it on T-Mobile, so it is not an issue with the Intel radio.
I wasn't happy and don't recall seeing it before, though can't definitively say it was from 10.1.1 -- though I've been in the mall previously with my 7 Plus (Apple Store is there) and not had this issue.