Cellular telephony in telecommunications is a type of mobile telephony characterised by access to a telephone network via a cellular network and intended for the end user. Moreover, access to the telephone network is private (as opposed to public telephony), i.e. owned by the end user or reserved for them by the owner of the access or by the person who manages it, and is realised by means of radio waves and terrestrial transceivers (i.e. located on the earth's surface) that give rise to radio base stations, each of which covers a portion of territory known as a coverage cell.
By using radio waves for access to the telephone network, it is able to serve entire geographical areas on a continuous basis, and is therefore in contrast to fixed telephony that is only able to serve fixed geographical points (a constraint that is partly overcome by the use of cordless telephones). These two different types of telephone service are not, however, in substantial competition with each other, but can be seen as entirely complementary in serving the user.
Already since the 2nd generation systems in cellular systems, in addition to the classic telephony service, a data transport service and subsequent connection to the Internet has been added for the user.
Cellular telephony technologies
Since its appearance, the mobile phone has used several main (and some 'intermediate') operating systems, called generations, based on different communication technologies and standards:
- 0G: analogue mobile radio networks in the 450 MHz band. At this stage, interoperability between networks and devices was almost non-existent and many states developed networks and devices independently (one of the leaders being the Italian company Italtel). Several networks in northern Europe were based on NMT (Nordisk MobilTelefoni) from which Italtel probably drew inspiration to develop the RTMS (Radio Telephone Mobile System) network in Italy, which became operational in Milan and Rome in September 1985. At first, the telephones were of the vehicular type, i.e. intended for fixed installation in vehicles, but as technology progressed, the size and weight of the devices gradually decreased, and it became possible to market transportable telephones that looked like small cases that allowed the telephone to be carried). At this stage in the development of mobile telephony, territorial coverage was still based on macrocells (more effective, however, than those of the embryonic 160 MHz system of the 1970s) and was still rather limited - coverage of the entire country was not achieved until 1989.
- 1G (Generation I): analogue TACS (Total Access Communication System) and ETACS (ExtendedTACS, Extended TACS with the addition of new frequencies) standards used mainly in Europe, AMPS (Advanced Mobile Phone System) used mainly in America, and NMT (Nordisk MobilTelephones) used mainly in northern Europe - Analogue mobile phones.
- 2G (2nd generation): GSM standard (Groupe Spécial Mobile, later Global System for Mobile communications), CDMA IS-95 and D-AMPS IS-136 - First digital mobile phones.
- 2.5G: GPRS (General Packet Radio Service) standard - Digital mobile phones with packet-switched data transmission (evolution of GSM).
- 2.75G: EDGE standard (Enhanced Data rates for GSM Evolution) - Faster version of the GPRS standard for data transfer over the GSM cellular network.
- 3G (3rd generation): UMTS (Universal Mobile Telephone System) standard, Wideband CDMA (W-CDMA), CDMA 2000 - 3GPP (3rd Generation Partnership Project) mobile phones.
- 3.5G: new HSDPA (High Speed Downlink Packet Access) and HSPA+ technology
- 4G (4th generation): VSF-Spread OFDM (Variable-Spreading-Factor Spread Orthogonal Frequency Division Multiplexing) and LTE standards
- 5G (5th generation): mobile phone networks superior to 4G/IMT-Advanced technology.