Making calls or transferring data by mobile phone requires a mobile phone network. These networks consist of radio cells, each with their own base station (= transceivers which both transmit and receive signals) that provides them with a signal. The size of the cells and the number of base stations depends on the number of subscribers and the required data transfer rate. As the number of subscribers and the data transfer rate rise, a more tightly-knit mobile phone network, i.e. more base stations, will be required.
As with all electromagnetic waves, radio waves used for mobile communications propagate at the speed of light. The sender transforms a speech or data signal into a high-frequency signal that is sent as a radio wave from an antenna. The receiver then picks up the incoming radio wave with its antenna, amplifies it and transforms it back into the output signal.
Modern mobile communications use electromagnetic fields to exchange information between mobile phones and base stations, that is, to transmit speech and data. Mobile communications use certain frequency ranges to transmit this type of information.
People want to be able to use their mobile phones anywhere. Now that mobile devices such as smartphones, tablet PCs and tablets offer more than just making calls, it has become quite usual to surf the internet, make video calls and download photos, music and videos.
Applications for video calls, internet surfing, social networks or downloads require greater power from the networks. In order to increase capacity, networks need to develop and expand.
Mobile networks have a complex technical infrastructure, which is the design and responsibility of the mobile network operators. In Germany, four operators provide their own GSM and UMTS networks in addition to the new LTE networks under construction.
GSM and UMTS provide the standards for the technology used in more than 232 countries. Over five billion people worldwide use one of these two standards. In contrast to these networks, which employ different standards in America, Europe and Asia, the new LTE standard, introduced in 2010, is the first mobile technology that is globally standardized.
Cell sites and base stations
The key to modern mobile telephony is its sophisticated technology. It guarantees both high transmission quality and constant coverage, made possible because of the cellular structure of the networks. They consist of many interconnected cell sites; each one served by a transceiver which both transmits and receives signals. This is what we know as a mobile phone base station.
Mobile phone base stations
Because calls are always made between the phone and the closest base station of the network operator, mobile phones can be used anywhere.
Each base station provides the radio cell with a signal. At the same time, it registers those mobile phones from its network that are operating within the area. This data enables each mobile phone to be located automatically anywhere in the world within seconds, so connections are fast.
The physics of mobile telephony is based on high-frequency electromagnetic radio waves. These are the medium of transportation, carrying information at the speed of light from the mobile phone to the closest base station. Speech and data are digitised, broken into small units and transformed into radio waves before they can be transmitted.
The mobile phone base station receives radio signals from a mobile phone and transmits them via a cable or radio connection to a distant switching centre operated by the network. From there, calls are forwarded to the receiver and connections are made.