I can imagine that there are electronic elements that can convert the text of an SMS (or the speech of a mobile phone) into a signal and that this signal can also be decoded. However, how does this signal find its way to the right mobile phone? Does the signal simultaneously travel in all directions as a ‘wave’ that expands in all directions simultaneously (spherical) and is it then received by a mobile phone mast for further transmission? But how does the signal ‘know’ from that point which path to follow? And do text messages travel around us all the time (by us?) without being decodable by our mobile phone (at least if they’re not intended for us)?
Answer
Best,
It’s all technically much more complicated than what I’ll tell you, but this explanation will give you an idea of ​​the process.
As you rightly pointed out, the GSM waves propagate towards the GSM mast. This mast and the GSM speak a language (we call this a protocol) that allows you to determine the telephone number of your GSM correspondent. The masts are interconnected with a computer network such as the internet. Connected to it is a ‘phone book’ computer that knows where each cell phone was last set up, or where it is when it gets up. The message is then sent to the mast that the receiver’s GSM sees as soon as it is set up. Then radiation is used again from the mast to the receiving GSM to transmit this message via the same protocol. That’s how it ends up on the cell phone.
And yes, in this process you can see GSM messages that are not intended for him, but the GSM is polite and only reads his own mail.
I hope this simple explanation gives you an idea of ​​this complicated process.
Answered by
yves rolain
high-frequency electronics electromagnetics
Avenue de la Plein 2 1050 Ixelles
http://www.vub.ac.be/
.