María Belén Gómez
Cell phone network. How does it work?
We often wonder how is it that we have gone from having thousands of workers connecting telephone networks to a single object capable of communicating from anywhere in the world. Mobile telephony has been one of the great developments of the last twenty years. Therefore, it is worth wondering how it works, and what makes our voice reach the other side of the world?
What makes a cell phone connect to the network?
Although it may seem strange, mobile telephony is not an immediate connection between devices, but in between, there is different equipment necessary for the communication to be fluid and stable.
In the past, this was done with the use of fiber optic networks that transmitted the communication, but in today's mobile telephony, communication is sent by repetitive waves, and they flow through unique frequencies that reach the receiving antennas of each telephone company. From there, each company is responsible for distributing the waves according to the available antennas and the distance between them and the cell phone.
Mobile telephony and the hexagon rule
The hexagonal geometric figure is the best description of how the distribution of mobile telephony antennas is physically organized so that all areas are completely covered with signals. Each operator creates its hexagonal cells, which are composed of small hexagons that are joined in a staggered manner so that the company provides the best service to users.
In turn, these cells are composed of a base antenna, which allows the reception and transmission of voice. The channels are counted by quantity and it is through these that calls from the same operator can be made simultaneously from different mobile devices. What distinguishes one channel from another and ensures that there is no interference, is the frequency under which mobile telephony is adjusted.
Another instrument used to ensure a stable and smooth connection is the switch. This automated operations center is responsible for establishing communication between a base antenna and a receiving antenna.
What happens on a call?
When initiating a call from a cell phone, the transmitter connects its frequency to the nearest antenna of its service operator. When the operator receives the electromagnetic signal, it automatically connects to the "switching center", which is fully digitalized and automated, so it looks for the closest base antenna in its hexagon in the receiving cell phone to make the call. Finally, the voice is transmitted by electromagnetic signals from one antenna to the other.
In order to make each cell phone unique and to be able to connect easily to the antennas of each hexagon, operators create databases called VLR or Visitor location register which details the base location of each cell phone. And it is integrated into a larger base such as the HLR or base location register, which is composed of different informative data of both the user and the mobile that is being used.
Now, we all know that mobile telephony allows us to be connected and go from one place to another. This is thanks to the fact that each hexagon has a base antenna that already has programmed all the necessary information so that in the middle of a moving call the voice is not cut off. What happens is that the information is imperceptibly transferred from one antenna to another to maintain fluidity, this is known as "transfer or handover".