I didn't go to Zhanjiang. How to receive the short message from Zhanjiang CDC?

Your mobile phone may be connected to a local base station, at which time you may receive a short message from a foreign CDC.

At present, mobile phone positioning mainly depends on the base station of the mobile phone. When traveling, the mobile phone will constantly search for base station signals and choose the base station with the strongest signal to keep connected, so that you can communicate. So in your personal activities, you haven't been there, but the mobile phone base station has been connected, resulting in.