How a Call is made in Mobile Communication?

Mobile Phones Nowadays are one of the basic necessities in everyone's lifestyle. If not before, then after the outset of this Covid Pandemic, Certainly Everything has become Online. and Mobile Phones became part of our lives. If we consider the basic necessity of a mobile phone, it is an electronic device that is used to transmit and receive radio frequencies. In other words, its basic requirement is to make a call to other people.

Have you ever wondered?

1. 
   What is the background process that takes place to connect with the dialled number?
2. Why there is no disturbance during a call while we are even travelling?
3. How a call is taking Place, within seconds after dialling?
4. How do cell Phone Towers Work?

Let us Try to Understand this.....

Theories Involved

Now to Understand How Mobile communication works we need to understand three theories. The mobile communication system is Mainly Dependent upon these Concepts.

• Cellular Concept.
• Mobile Phone System.
• Hand Off Procedure.

Cellular Concept:

A vast region of land is divided into small Hexagonal Regions Called Cells depending upon terrain and reception characteristics. There will be a Signal Tower in every cell to provide Frequency(signal) to every Mobile user in its cell region.

This signal tower provides signal for every mobile in its Hexagonal cell region. In other words, a specific signal tower gives signal to the only mobiles in its cell region. it cannot give signal to a phone which is in another Hexagonal cell region.

A Curious Question that can arise at this point, is that, Why cell shape is only Hexagonal? why it is not Circle?

The idea behind keeping cells Hexagonal is to cover the whole region of space. If it is a circle, No Tower would be available to cover the region in between them, and hence, Mobiles in that region can never get Signals. So, Shapes other than Hexagon are not taken as Cell Shape.

Mobile Phone System:

Every Mobile has an Antenna. This Antenna converts Sound into Radio signals and Radio signals to Sound. Whenever a person is speaking in a call, His voice is converted into radio signals and is transmitted to the opposite person, whose mobile antenna again converts these Radio signals into Normal sound and vice-versa.

Now let us try to understand the Hectic Backend Process of building a connection for a call. i.e, How these radio signals are getting transmitted from one Mobile to another.

A group of towers are Controlled by a station called Base Station Controller(BSC). Every tower is controlled and connected with some BSC. And these Base Station Controllers are under the control of another higher station called Mobile Switching Centre(MSC). Every Station has a transceiver that receives and transmits Radio Waves.

Whenever a user dials a number, information of a number is transmitted in form of a Radio signal to the Tower which is responsible for the cell, in which the user is present. Then from the Tower, Radio signals are transmitted to Base Station Controller (BSC). Then from there to its Mobile Switching Centre (MSC).

Then the signal is transmitted to the MSC which controls the tower that is transmitting the signal to the dialled user's Mobile. In this way, a call is connected.

In most cases, Whole this process is completed within seconds and your call is connected. Thanks to the Speed of Radio Signals. They travel with a speed at par with Light speed.

Reason For Getting Network Error.

A Point to be noted here is that one MSC is provided with thousands of channels. when a call is Dialled Radio signals Carrying this call Detail occupies a channel in MSC. for each call one channel is occupied in MSC. If all the channels are filled with other calls in MSC then the call cannot be connected till some channel becomes free.

Let's say a call is going from Area1 to Area2. The Radio signal transferred from a channel from Area1 MSC must occupy a channel in Area2 MSC. If radio signals are able to occupy channels in both Area's MSCs then call will be connected. In the other case, If the call is unable to occupy channels, then we get Error messages like "Call cannot be connected", "Network Error".

MSCs Also store every call information and the call recording. If it is an International call, based on the key number before the Mobile Number, MSCs transmit the Radion signals to the Respective country's regional MSC's Based on Mobile Number and connects the call Following the same procedure.

Hand Off Procedure

While we are travelling, as we move away from the Signal Tower and reach the end of a Hexagonal cell, signals start decreasing. at the Border of two Hexagonal cells, both towers give your Mobile phone the least possible signal. And after you enter the second cell completely, the second tower starts to give you a signal and Eventually, the signal starts Increasing.

when you are in the first Hexagonal cell first Tower would be giving you a signal. and when you move to the second cell, the second tower would be giving you a signal. In this way, the call keeps connected and we feel no Trouble in conversing through the call.

In this way Mobile Communication works.

I Hope You Have Learnt something from this Blog.

Keep Learning.

Take Care.