Mobile Phone Technology

The original mobile phone network was analogue which had many problems, most seriously the security of the phone call, people could easily listen in. In 1991 there was a swap into a digital network, this is 2G. 2G allowed for greater network capacity and being a digital network it allowed the operators to add some security to the network. The emphasis was still on the phone network, on phone services, with the only devices connected to the 2G network, initially, being mobile phones.

As well as phone services, a simple SMS messaging service was introduced. SMS uses the spare capacity on the network control channel to send messages. Originally SMS messages were used by network technicians to communicate. SMS provided phone customers a simple messaging system, something we had not seen before.

Data was also supported but initially as a dial-up connection on the phone system; reflecting the contemporary way the Internet was delivere to households. The user could have a phone call or send data but not both. Speeds were measured in Kbps rather than the Mbps. The Internet was available but very slow, used a special technology [WAP rather than HTML] but it was the internet on the phone.

Later, as data became more important, enhancements were made to 2G. Most notably GPRS where a separate packet switched always-on network for data was introduced. Later enhancements to this network included Edge technology. By this time 2G was a respectible network but too slow for the modern user

In the UK there were four 2G networks (Vodafone, O2, Orange and T-Mobile). These operators, or their equivalent, still maintain a 2G network today. This provides a back up phone system when 4G calling is not available in areas of difficult coverage. 2G is also currently used for a number of IoT applications most notably the communications associated with smart meters; but also alarms, health sensors, weather recording, parking machines and traffic lights.