Today we will look at how the mobile phone network works. As I said before, the detailed workings of mobile phones are a bit huge. So I’ll try to go deeper slowly. I hope you will benefit from my support in this series.
We have the following two types of mobile operators in our country-
- GSM (Global System for Mobile Communication)
- CDMA (Code Division Multiple Access)
These two technologies have advantages / disadvantages which I am not going to discuss now. We see lots of mobile towers around us. But have you ever wondered why BTV or Bangladesh Betar don’t need so many towers? But BTV can be seen all over the country, radio can be heard.
This is because, firstly, in the case of BTV / Radio, only one Frequency / Frequency from each Station is sending a signal in the air and everyone is watching / listening to the same thing. But in the case of mobile, what would happen if everyone was exchanged at the same frequency ??? Like the RJs on FM Radio, everyone could hear.
There was a lot of noise though which was like everyone shouting together. And to overcome this problem, first of all, many frequencies are used and the most important thing is to use these frequencies repeatedly. You will get some ideas from the image below. This means that the frequency at which your message is being sent is being used again at a later BTS except for the BTS around your tower or BTS.
Let’s take a look at the architecture of the mobile phone network at the beginning:-
If I look a little easier than this, the architecture will look like the following:
Any mobile phone network consists mainly of the following four parts:
- Radio Access Network (RAN)
- Switching Network or Core Network
- Intelligent Network (IN)
- Transmission Network
Radio Access Network (RAN)
When we call someone, it goes directly to the nearest BTS / tower from our mobile phone through the air. These towers or BTSs are controlled by BSC (Base Station Controller). One BSC can control about 150-200 BTS. And these BTS and BSC together form the largest network of the entire mobile network – Radio Access Network (RAN).
Switching Network or Core Network
Those who are familiar with the former T&T (now BTCL) Exchange (Telephone Exchange) know that when calling T&T, an operator would first pick up the call and ask you for the extension number. And he would give the connection to your desired extension number. That means he would do the switching.
Now think about it, if the amount of calls that are made from mobile to mobile every day had to be exchanged with the operator, then how many crores of operators would it take ???
The Mobile Switching Center (MSC) does the work of this exchange on mobile phone networks.
Intelligent Network (IN)
Now come to Intelligent Network (IN). We have two types of connections available
Pre-paid users have a balance / money on their mobile, whether he is a legitimate user, whether he is registered for the service he wants to use, it is reserved for IN. You are allowed to call with all these inquiries before your call is connected.
Transmitting means sending something from one place to another. Mobile phones work with our Voice or Data (SMS / Internet / Multimedia Data). Transmission Network acts as a medium to convey this word (Voice) or Data (SMS / Internet / Multimedia Data) to the person you are calling.
This transmission network uses Micro Wave Link (Micro Wave Antenna as seen in the tower of the mobile) or Optical Fiber.