What's 5G? Vol.3. Let us explain about the flow and features of 4G
The 4th generation (4th Generation, hereinafter abbreviated as 4G) started service around 2012. The evolution in 4G was the inclusion of voice digital signals in IP networks. Up to 3G, voice was separated at the base station and connected to the voice network, but from 4G, the IP network was used in the same way as web and mail data. In the medium term of 3G, the expansion of HSPA increased the demand for mobile Internet connection and data communication of e-mail, still images, and videos, and this tendency became remarkable due to the spread of smartphones. Of course, 4G also had improvements that made it possible to communicate with a larger amount of data, but it was difficult for users to feel the benefits of accommodating voice IP networks, and people were exclusively interested in communicating with a large amount of data. In particular, with the advent of flat-rate video distribution services, users can now enjoy the results of the evolution.
Until the first half of 3G, data communication was a method of paying for the data used in full pay-as-you-go billing,
but from the middle of 3G it became a rate plan that sets the amount for data communication up to a certain capacity,
and this trend has increased with the introduction of 4G.
I have the impression that up to 3G, various functions have been added to mobile phones, but with 4G, voice is also absorbed by the IP network, and it can be said that it has established itself as an indispensable tool (information terminal) for daily life. In fact, up to 3G, the name "mobile phone" has been used quite often, but I think the name "sma-fo" (abbreviation of smartphone in Japan) or "smartphone" has taken root in Japan. I think this is a big contribution by iPhone and Steve Jobs in heaven. Outside of Japan, it is called a cellphone (probably an abbreviation for cellar phone) or a mobile phone, but it is also often called simply a cell or a mobile. Sooner or later, we may forget that it was derived from the telephone.