The D-Network was the first mobile phone technology that was no longer based on analogue technology but on digital technology.This made it possible for the first time to build mobile phones so small that you could actually put them in your pocket (OK, you needed big bags :-)) and so cheap that a much larger circle of people could afford one.
In 1991, the D-Network was introduced in Germany.Only frequencies in the 900 MHz band were usedand the protocol was GSM (G lobal System for Mobile Communications).This was also the first uniform mobile phone system in the world. D.H. you could even take your phone abroad!
Data transmission was possible but with 9.6 kBits/s or under optimal reception conditions even 14.4 kBits/s slow, if you compare it with today.But mobile phones weren’t “smart” for a good 15 years, so nobody cared.
Oh yes: SMS were free!Since the devices had to constantly exchange packets with the network and SMSen only filled unused space in these packages, no one saw any point in asking for money for it. That only changed when a smart person in one of the mobile phone companies saw the number of messages sent and the thought of what you could take when you asked for money to sabre. Since then, SMSen cost money 🙂 (or 🙁 ?).
Let’s move on to LTE (Long Term Evolution): Also a mobile phone technology but quite different from GSM.While GSM was primarily a technology for telephone calls and data transmission was only a side idea, LTE is initially all about data transmission – so much so that no telephone calls could be made via LTE at the beginning. VoLTE (Voive over LTE) was retrofitted later. Unlike the D-network, LTE operates in many different frequency bands from 700 MHz to 2600 MHz. Bandwidths are higher and more efficient modulation methods and other improvements mean that the maximum download data rate is up to 1200 Mbps. This is about 80000 times faster than in the D network. However, the probability in D-Network was much higher that you could always use the full data rate.
So the difference:
Other frequencies (and more frequencies), other modulation methods, larger bandwidths end up leading to much higher data rates for data transmission.Of course, every single point in the changes means a much higher effort in the mobile phone, but this is more than absorbed by constantly better chip technologies.
More details are available as always on Wikipedia:
PS.: Thanks to Andre Koppel, we now know that the C network was already automatically mediated.