We live in a digital world nowadays so it may not seem very relevant to think about the analogue world, but if you are interested in the history of mobile communications then it would be worth knowing when mobile networks became digital.
In simple terms, the first generation of mobile networks (1G) used analogue technologies and was analogue. The digital era started from the second generation (2G) onwards which means that 2G, 3G, 4G and 5G networks are digital.
Analogue networks refer to the first generation (1G) of mobile networks which were introduced in the early 1980s. 1G networks employed various analogue standards to launch mobile services in different parts of the world. The technology standard Advanced Mobile Phone System (AMPS) was used in the United States to provide 1G services while in the United Kingdom, 1G was achieved through Total Access Communications System (TACS). The Nordic countries utilised another technology standard for 1G called Nordisk MobilTelefoni (NMT, English name: Nordic Mobile Telephone) and Germany used Funktelefonnetz-C (C-Netz, English name: Radio Telephone Network C) to enable 1G services. The first generation of mobile networks relied on an access technique called Frequency Division Multiple Access (FDMA) for the air interface to connect mobile phones to the mobile network. 1G networks offered low capacity, and the communication was not very secure. 1G handsets were hefty in size and offered a talk time of around 30 minutes only. The first generation mobile networks are now obsolete, and they have been replaced by 2G, 3G, 4G and 5G.
Analogue networks were followed by digital networks in the early 1990s which marked the beginning of the type of mobile networks we see today. 2G networks were the first to use digital technology standards to offer highly secure mobile services in different parts of the world. The most widely used technology standard is GSM which uses a combination of FDMA and TDMA techniques for multiple access to provide highly secure voice and short-message-service (SMS) to the customers. D-AMPS, also sometimes referred to as ‘TDMA’, is the digital version of AMPS which provided the 2G upgrade path to mobile operators who used AMPS for 1G. Another prominent 2G standard is IS-95 (proprietary name: cdmaOne) which uses Code Division Multiple Access (CDMA) for its air interface. The 2G GSM networks use a switching method called circuit-switched in which a dedicated circuit is made available for the entire duration of a call or session even when the users are not speaking or exchanging any data. All mobile networks today including 2G, 3G, 4G and 5G use digital technology.