Connect to https://www.grc.com/x/ne.dll?rh1dkyd2 (with a web browser) when you're on wifi and see if any ports are open (or even visible). then turn off wifi, turn on mobile data and do the same thing. Then you'll know. (You can "close" any open ports by installing a firewall. (Just for kicks I just checked my Note 3. It's not there, as far as incoming ports are concerned, with either connection. You'll probably find the same thing with your phone. IOW, there are no open ports.)