Can an Android phone detect 3G/4G signals + ID from nearby phones?

Question

I have an idea for an app, and I need to know how many cellphones are in my vicinity. I don't care about communicating with them, or what they have installed. Just knowing that they are there is enough, and a nice perk would be to know their unique ID they use to call the cell tower.

Any way to program one of the radios on an Android device to do this?

Answer 1

Your phone has a transmitter and a receiver that are strong enough to send and receive signals to and from a network base station, provided that the phone is near enough to the base station. Of course, this transmitter and receiver could in theory pick up signals from other phones, if they were transmitted on the right frequency, and with a coding that your phone could understand. But the phone's software doesn't do this.

There is no software in any standard commercially available GSM/UMTS/LTE phone that tries to find transmissions in these network technologies, from other phones.

You could try Bluetooth to find devices with Bluetooth switched on, which might be phones, in the vicinity.