María Belén Gómez
How the mobile network works
The mobile network
Many people use a mobile phone, be it a modern smartphone or an old 'mobile phone', but few people wonder how it actually works. Part of the answer to this question lies in the name of the object in question: mobile phone.
Certainly the object can be defined as a telephone, as it is useful for carrying our voice at a distance ('telephone' is in fact composed of the Greek words tèle, meaning 'far, at a distance' and phonè, meaning 'sound, voice'), but why is the term 'mobile' added to this word?
It's easy to say, the term refers to the type of technology that allows our mobile terminal to function: it is only by dividing the territory into "cells", often partially overlapping, that it is possible to provide the mobile communication service that we all use.
For mobile communication to work properly, our terminal must be connected to the network and this connection must not be disturbed or interrupted by the fact that we are on the move.
The best solution found to ensure that these two characteristics are always (or almost) met is to implement a network of anten
nas organised according to a "cell" scheme, not very dissimilar to the typical structure, albeit only in two dimensions, of a beehive.
Why is it called a 'cellular network'?
A typical cellular network is made up of a pattern of contiguous cells, each containing a radio antenna capable of connecting to mobile terminals and keeping the connection active, at least within a certain distance.
It is intuitive to understand that signal strength and quality degrades proportionally to the distance from the antenna. Practically every mobile phone on the market has a function (the famous "notches") that continually updates us on how strong our connection is with the reference antenna.
As a general rule, every mobile terminal connects to the antenna which is closest to it as the crow flies. In this case, the mobile terminal is said to be in one of the cells presided over by that antenna. In reality, each cell can have varying dimensions and shapes, even very different from the hexagon. In fact, each cell, i.e. the portion of space subtended by a certain antenna, is characterised by the fact that there is no other antenna closer than the reference one.
So when we move towards the edge separating two contiguous cells, what happens is that we move towards an area in which at least two different antennas are equidistant from us. Once we have crossed the border and passed into the adjacent cell, the new antenna presiding over the new cell will connect to our mobile terminal, applying the general rule expressed above. Generally speaking, being connected by a new antenna implies being disconnected from the old antenna, although in some cases, depending on the network technology and the type of mobile terminal in use, this may not even happen, thus allowing us to take advantage of redundancy in the connection to the benefit of communication stability and navigation speed.
However, there are other cases in which the rule of connecting to the nearest antenna is broken and therefore our terminal will find itself connected to a different antenna from the nearest one. Some examples may be the fact that a certain antenna is congested due to the presence of too many mobile terminals within the cell it covers (typical case: large gatherings of people such as concerts, events, etc.) or the presence of natural or architectural obstacles that prevent or in any case deteriorate the connection with the nearest antenna, making it preferable to connect with an antenna that is further away but with a clearer line of sight.