How does your mobile phone work communications ?
for most of us a mobile phone is a part of our lives but i'm sure your curious minds have always been struck by such questions as how a mobile phone makes a call and why there are different generations of mobile communications let's explore the technology behind mobile communications when you speak on your phone your voice is picked up by your phone's microphone the microphone turns your voice into a digital signal with the help of a mems sensor and ic the digital signal contains your voice in the form of zeros and ones
an antenna inside the phone receives these zeros and ones and transmits them in the form of electromagnetic waves electromagnetic waves transmit the zeros and ones by altering the wave characteristics such as the amplitude frequency phase or combinations of these for example in the case of frequency 0 and 1 are transmitted by using low and high frequencies respectively so if you could find a way to transmit these electromagnetic waves to your friend's phone you would be able to establish a call however electromagnetic waves are
incapable of traveling long distances they lose their strength due to the presence of physical objects electrical equipment and some environmental factors in fact if there were no such issues even then electromagnetic waves would not carry on forever due to the earth's curved structure to overcome these issues cell towers were introduced using the concept of cellular technology in cellular technology a geographic area is divided into hexagonal cells with each cell having its own tower and frequency slot generally these cell
towers are connected through wires or more specifically optical fiber cables these optical fiber cables are laid under the ground or the ocean to provide national or international connectivity the electromagnetic waves produced by your phone are picked up by the tower in your cell and convert them into high frequency light pulses these light pulses are carried to the base transceiver box located at the base of the tower for further signal processing after processing your voice signal is routed towards the destination tower
upon receiving the pulses the destination tower radiates it outwards in the form of electromagnetic waves and your friend's phone then receives the signal this signal undergoes a reverse process and your friend hears your voice so it's true that mobile communications are not entirely wireless they do use a wired medium too this is how mobile communications are carried out however there is a big issue that we intentionally left unanswered mobile communication is only successful when your tower transfers the signal to
your friend's tower but how does your tower know in which cell tower area your friend is located well for this process the cell tower gets help from something called a mobile switching center the mfc is the central point of a group of cell towers before moving further let's explain more information about the msc when you purchase a sim card all the subscription information is registered in a specified msc this msc will be your home msc the home msc stores information such as service plans your current location and
your activity status if you move outside the range of your home msc the new msc which serves you instead is known as a foreign msc as you enter a foreign msc region it communicates with your home msc in short your home msc always knows which msc area you are in to understand in which cell location a subscriber is within the msc area the msc uses a few techniques one way is to update the subscriber location after a certain period when the phone crosses a predefined number of towers the location update is again done
the last one of these is when the phone is turned on let's try to understand all of these procedures with an example suppose emma wants to call john when emma dials john's number the call request arrives at emma's home msc upon receiving john's number the request will be forwarded to john's home msc now john's msc checks for his current mse if john is in his home mse the call request will be immediately sent to his current cell location and it checks whether john is engaged on another call
or if his mobile is switched off if everything is positive john's phone rings and the call will be connected however if john is not in his home msc john's home msc simply forwards the call request to the foreign msc the foreign msc will follow the previously explained procedure to locate john's phone and will then establish the call now let's discuss why the frequency spectrum is quite important in mobile phone communications to transfer zeros and ones in digital communication each subscriber is allocated a frequency
range however the frequency spectrum available for cellular communications is quite limited and there are billions of subscribers this issue is solved with the help of two technologies one frequency slot distribution and two multiple access technique in the first technique different frequency slots are carefully allocated to different cell towers in the multiple access technique this frequency slot is efficiently distributed amongst all the active users in the cell area now the big question why are there different generations of mobile phone
technologies 1g originally allowed users for the first time to carry a phone without a cable attached to it but 1g suffered from two major problems the first problem was that the wireless transmission was in an analog format analog signals are easily altered by external sources so it provided poor voice quality and poor security the second problem was that it used the frequency division multiple access technique which used the available spectrum in an inefficient way these factors paved the way for the second generation of mobile
communications 2g used digital multiple access technologies namely tdma or cdma technology the second generation also introduced a revolutionary data service sms and internet browsing 3g technology was focused on giving a higher data transfer speed it used a wcd multiple access technique along with an increase in bandwidth to achieve this the 3g speed of 2 mbps allowed the transfer of data for uses such as gps videos voice calls etc 3g was a huge step in the transformation of the basic phone to a smartphone next came 4g which achieved speeds of 20
to 100 mbps this was suitable for high resolution movies and television this higher speed was made possible due to the ofd multiple access technology and mimo technology mimo uses multiple transmitter receiver antennas inside both the mobile phone and the towers the next generation of mobile communication 5g to be rolled out soon will use enhanced mimo technology and millimeter waves it will provide seamless connectivity to support the internet of things such as driverless cars and smart homes would you like to learn how a touch
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