Today, all machines need to communicate with each other. The fact that they are heavier than other technologies is the reason why the Internet has become so fundamental in our everyday lives. This would never have been possible, however, without wireless communication, that is, devices capable of connecting to each other using electromagnetic waves in the air.
Following on from a previous article on DSL and its scientific bases, I now want to review the fundamentals of another technology: radio. As with a DSL, the ability to transmit data in any radio communications system – from the very first Marconi experiments to 5G networks – is bound by Shannon’s equation, based on the channel’s bandwidth and signal-to-noise ratio. In radio, we also have another interesting equation that can tell us the received signal strength when the transmitter power and frequency, antenna characteristics and distance to the receiver are known.
The nature of electromagnetic waves is such that anyone in a wireless network can receive the data sent over the air. With high-gain antennas, it is possible to listen in on the data that passes through an office from outside the building. That is why, right from the outset, a great deal of importance has been attached to wireless network security.
Nowadays, all offices, hotels, parks, hospitals and above all private domiciles, have Wi-Fi connectivity for laptops, tablets and smartphones. Likewise, we must consider the new lines of intelligent domestic equipment, also connected and remotely managed via Wi-Fi. There is, however, a question we all ask ourselves: how safe are wireless networks?