How does a Tower Crane Work

How does your Mobile Phone Work

Mobile phones are a part of most of our lives. But I am sure that such questions will always come to your mind. How to make a mobile phone call, And why are there different generations of mobile communications?

How Mobile communication works:

Let's talk about the technology behind mobile communication.

When you talk on your phone your voice goes into your phone's microphone. The microphone converts your sound into digital signals with the help of MEMS sensor and IC. In digital signals your voice is in the form of zero and one. An antenna inside the phone receives zero and one and transmits them in the form of electromagnetic waves.

 Electromagnetic waves transmit wave properties, such as amplitude, frequency, phase or combinations, to zero and one. For example, in the case of frequency, zero and one are transmitted. So, if you can find a way to transmit these electromagnetic waves to your friend's phone, you will be able to make a call.

However, electromagnetic waves are unable to travel long distances. They lose their power due to the presence of electrical appliances and some environmental factors.

 In fact, even if there were no such problem the electromagnetic waves would not continue forever because of the curved structure of the earth. To overcome these problems cell towers were introduced using the concept of cellular technology.

 What is cellular technology:

In cellular technology, a geographic area is divided into hexagonal cells in which each cell has its own tower and frequency slot. Typically, these cell towers are connected by wires, or especially by optical fiber cables. These optical fiber cables are laid underground or under the sea to provide national or international connectivity.

 How electromagnetic wave Travels:

The electromagnetic wave generated by your phone travel to the tower in your cell and the tower converts these high frequencies into light pulse. These light pulses are transported to the base-based transceiver box at the base of the tower for further signal processing. After processing, your voice signal is routed to the destination tower.

 When the light pulse is received, the destination tower propagates it outward in the form of electromagnetic waves and your friend's phone then receives the signal. This signal goes through a reverse process so your friend hears your voice.

 Therefore, it is true that mobile communications are not completely wireless they also use a wired medium. However, there was a major problem that we deliberately did not answer. Mobile communication is only successful when your tower transmits signals to your friends' towers.

How will your tower know which cell tower area your friend is in?

The cell tower is aided by something called a mobile switching center. MSC is the focal point of cell tower groups.

What is MSC:

When you buy a SIM card, all the subscription information is registered in a specific MSC. This MSC will be your home MSC. Home MSC stores your information such as service plans, your current location, and your activity status.

If you go beyond the limits of your home MSC, the new MSC, which serves you instead of home MSC, is known as Foreign MSC or External MSC.As soon as you enter the range of an external MSC it connects to your home MSC.

 In short, your home MSC always knows which MSC area you are in. MSC uses a few techniques to understand which cell location of the subscriber is in MSE. One way is to update the subscriber's location after a certain period of time. When the phone crosses the default number of towers, the location is updated again. The last of these is when the phone is turned on.

Let's try to understand all these methods with an example:

Suppose Emma wants to call John. When Emma dials John's number, Call request reached Emma's home MSC. Upon receipt of John's number, the application will be forwarded to John's Home MSC. Now, John's MSC is testing his current MSC. If John is at his home MSC, call requests will be sent immediately to the current cell location.it checks if John is busy on another call, or his cell phone is off. If all goes well, John's phone rings, and the call will be connected.

However, if John is not in his home MSC, John’s Home MSC can easily send a call request to an external MSC. External MSC will follow the procedure described earlier. To find John's phone, and then set up the call.

 Frequency Spectrum:

Now, let's talk about why the frequency spectrum is so important in mobile phone communication. In digital communication, to transfer zero and one each subscriber is assigned a frequency range. However, the frequency spectrum available for cellular communication is quite limited and there are billions of users.

This problem is solved with the help of two technologies

•   frequency slot distribution
•  multiple access techniques.

 In the first technique, different frequency slots are carefully allocated for different cell towers.

In multiple access techniques, this frequency slot is efficiently distributed among all active users in the cell area.

 Why are different Generations of Mobile:

 Now, the big question is why are there different generations of mobile phone technologies?

First Generation of Mobile:

1G actually allowed users, for the first time, to carry a phone without a cable.

 1G faced two major problems

 The first problem was that the wireless transmission was in analog format.Analog signals that are easily converted by external sources. Therefore, it provided poor sound quality and poor security.

 The second problem was that it used frequency division multiple access techniques which inefficiently used the available spectrum. These factors paved the way for the second generation of mobile communications.

 Second Generation of Mobile:

2G using digital multi-access technologies, namely TDMA, or CDMA technology. The second generation also introduced a revolutionary data service, SMS, and Internet browsing.

3^rd  Generation of Mobile:

3G technology was focused on speeding up more data transfers. It uses a WCD multiple access technique with increasing bandwidth. To achieve this, 3G speeds of two Mbps allowed data transfer for use such as GPS, videos and voice calls.3G was a big step in transforming the basic phone into a smartphone.

 4^th   Generation of Mobile:

Then came 4G, which gained speeds of 20 to 100 Mbps. It was suitable for high resolution movies and television. This rapid OFD was made possible by multiple access technologies, and MIMO technology. MIMO uses multiple transmitter receiver antennas inside both mobile phones and towers.

 5^th Generation of Mobile:

The next generation of mobile communications, 5G, will be introduced soon,using improved MIMO technology and millimetre waves.It will provide smooth connectivity to support the Internet of Things,Such as driverless cars and smart homes.