THE GROWTH OF TELECOM NETWORKS IN INDIA.
Everyone from the millennial era and early Gen Z must have quite a memory when our home used to have those clumsy landline phones, ever wondered how they worked?
I’ll try to explain this to you briefly.
Let us suppose there is Mahesh, based in Bangalore, who wants to make a call to his friend Yug in Mumbai. So when he dials Yug’s number, this message travels through the wires in the form of an electromagnetic wave to the nearest cell tower which is then directed to the area’s switching centre and it is then received by the nearest switching centre to Yug through the cables held underground or underwater then directed to the nearest cell tower to Yug and finally his landline rings. This way of communication through the circuits is known as circuit switching.
There are two types of cable which support the transfer of message like this:
These are PSTN(Public Switched Telephone Network) and ISDN (Integrated Service Digital Network).
Both these networks pre-date to the 2G era and have been in use for over a century. The network you’ll use among the two depends on your telecom provider.
In the 21st century came the evolution of mobile phones, which made the phone calls wireless.
It also made the transfer of data or text possible, therefore, to do so another type of switching was used known as packet switching, in which the mode of transfer remained quite the same except, instead of switching centre, routers (named routers because it’s sole purpose was to find the fastest route between two points and transfer the message) were used.
After the emergence of phones, only the message transfer from people’s house to the switching centre was made wireless.
This wireless technology that was built over the circuit switching network was called the Global System for Mobile Communications (GSM) or CDMA(Code Division Multiple Access).
Therefore, the voice communication wasn't wireless completely as wires were still required to transfer messages between two switching centres.
The first version of data (your internet) was in the form of GPRS (General Packet Radio Service), which made the mode of communication fastest in terms of packet switching.
Therefore GSM for voice communication and GPRS for the data together came to be known as 2.5G.
You may still witness the symbol of ‘E’ is visible in your phone when your data strength is low, which stands for EDGE (Enhanced Data Rates for GSM) and which was the second evolution in terms of data and together with GSM was known as 2.75G.
The third evolution in data was ‘3G’ which was in the form of or led by UMTS(Universal Mobile Telecommunication Service), although the voice network still remained the same.
The symbol ‘H’ and ‘H+’ in your data bar stands for ‘HSPA’ (High-Speed Packet Access) and ‘HSPA+’ respectively.
‘HSPA’ was the fourth evolution and was known as 3.5G together with GSM. It was soon replaced by ‘HSPA+’ and was named as 3.75G.
In 2016, came the ‘4G’ era in which data was the core purpose and voice was considered secondary. So they created another mode of transfer called LTE(long term evolution).
The beauty of 4G is that both voice and data are transmitted in the form of a packet network and which is why it is called VoLTE ( Voice over LTE).
This minimizes the expense of installing circuits over long ranges since there’s no need for sending voice and text in two different ways.
Another advantage of 4G is that it makes it possible for a large number of users to make calls at the same time which was not supported by GSM due to circuit switching.
A quick flashback if you all remember during the 2G/3G phase while on call the data used to stop working that was because both data and voice travel differently and cannot operate simultaneously but this doesn't happen in VoLTE as both are transmitted in the form of packets and use one mode of transfer.
Many telecom providers are still using circuit and packet switching but Jio is the only network provider in India who fully provides network as VoLTE.
