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?
Nowadays, all companies provide their customers with Wi-Fi in some form or another. We find it in shopping malls, airports, restaurants, offices and even on transport. It is fair to say that Wi-Fi has become a commodity.
Each time we download an application, browse the Internet, read an email or watch something on YouTube on our smartphones, we’re using some type of wireless technology. For mobile networks this means 3G or 4G LTE. However, when it comes to our home or work environment, we’re probably using Wi-Fi.
From 802.11a, endorsed in the 90s (reaching speeds of up to 54 Mbps over 5 GHz radio waves) to the current range of 802.11ac routers (up to 1.3 Gbps over a 5 GHz band and 450 Mbps over 2.4 GHz), many things have changed. (more…)