How Wifi Works
Published:
Curious about wifi 6 after Cphile video
My understanding of how wifi works
Wi-Fi is a type of radio wave signal that is used to transmit and receive data. In order to establish a connection, Wi-Fi routers constantly send out beacon packets at certain frequencies, which consumes power even when the router is not in use. To reduce power consumption and increase the range of the signal, beacon packets are typically sent out over a period of time, allowing them to effectively reach large distances. When you view the Wi-Fi signal settings on your device, you are seeing a list of all the beacon packets that your device has received.
It is interesting to note that two routers cannot transmit packets at the same frequency at the same time, as this can cause destructive interference. To prevent this, routers have a “listen first, then transmit” policy, in which they check if any nearby routers are transmitting on the same frequency before transmitting themselves. This can affect the speed of both routers.
Most Wi-Fi routers in 2022 operate on the 2.4 GHz band, which is made up of several channels, or sub-frequency ranges, over which the router can choose to transmit its data. When there are many Wi-Fi devices in the area, the chances of a frequency match increase, which can reduce the speed of all the devices. Dual-band routers, which became available with Wi-Fi 5, can transmit on both the 2.4 GHz and 5 GHz bands, which can help to reduce interference. The latest version of Wi-Fi, called Wi-Fi 6 (802.11ax), has even higher efficiency and faster theoretical download speeds. It also enables a technology called Multi-User Multi-Input-Multi-Output (MU-MIMO), which allows multiple users to connect to the router simultaneously and allows the router to transmit beacon packets at multiple frequencies.
An interesting fact is that a slow Wi-Fi signal that is far away can affect your connection more harshly than a fast Wi-Fi signal that is close by. This is because the signal has to travel further, which can result in more interference and a weaker connection. According to a Cisco paper on best practices for Wi-Fi in an office setting, it is recommended to use a combination of the 5 GHz band (which is less crowded) and the 2.4 GHz band (which is more crowded) to maximize the speed and reliability of the Wi-Fi connection.