As the saying goes “home is where the Wi-Fi connects automatically”. As much focus as smartphone makers put on advertising the next-gen cellular connectivity of their phones, many of us spend most of the day connected to the Internet over Wi-Fi.
Wi-Fi is certainly not the first method of transferring data between nearby devices wirelessly. Early PDAs used infrared, which allowed them to sync calendar appointments and email inboxes, for example. Infrared is directional, however, so to connect your PDA and PC you needed to aim at the IR adapter and keep still for several seconds. The easiest way to do this was to have both the device and the adapter stationary on a desk. Technically, you didn’t plug in any wires, but there was little difference in mobility.
PDAs were among the first pocketable devices to gain Wi-Fi connectivity, though they didn’t always come with that feature out of the factory – CF and SD cards were used as modular add-ons that could enable Wi-Fi, GSM, Bluetooth and other functionality.
Unsurprisingly, the first mobile devices to have Wi-Fi on board were Windows Mobile PDAs. Wi-Fi connected you to the Internet (and corporate intranets) and could sync emails, calendars and so on, mostly business related tasks.
Bluetooth is another early local wireless connectivity option. However, it was slower than Wi-Fi (which mattered more to laptops than PDAs but still) and had lower range (at least with the commonly available adapters).
Wi-Fi is limited by law to 100mW transmit power and the rule of thumb is that you can get up to 100m range in ideal conditions (i.e. outdoors with clear line of sight). Interesting note – in 2007 researcher Ermanno Pietrosemoli managed to transmit 3MB of data at a speed of 3Mbps between the mountain peaks of El Aguila and Platillon in Venezuela, which are separated by 382km/238mi. Some long-range Wi-Fi connections are in use today to connect remote locations in the mountains, but these are the exceptions to the rule.
A 382km connection between the mountain-tops of El Águila and Platillon, was established in 2007
Before we continue, we should cover the naming of Wi-Fi. First, “Wi-Fi” stands for “Wireless Fidelity” (similar to Hi-Fi) and was coined by a brand-consulting firm, which was hired to come up with something that was “a little catchier than ‘IEEE 802.11b Direct Sequence’”. The technology is part of the IEEE 802.11 family and different versions append a letter, e.g. 802.11b.
But that’s not very catchy, is it? So in 2018 the Wi-Fi Alliance changed things to a simpler and more user-friendly naming scheme – Wi-Fi 802.11n became Wi-Fi 4 and versions after that adopted subsequent numbers. Check out the table below. Note that 802.11g and earlier were retroactively renamed since “Wi-Fi 4” doesn’t make much sense without them.
|Generation||IEEE Standard||Adopted||Maximum Linkrate (Mbit/s)||Radio Frequency (GHz)|
|Wi-Fi 1||802.11b||1999||1 to 11||2.4|
|Wi-Fi 2||802.11a||1999||6 to 54||5|
|Wi-Fi 3||802.11g||2003||6 to 54||2.4|
|Wi-Fi 4||802.11n||2008||72 to 600||2.4/5|
|Wi-Fi 5||802.11ac||2014||433 to 6,933||5|
|Wi-Fi 6||802.11ax||2019||574 to 9,608||2.4/5|
|Wi-Fi 7||802.11be||2024||1,376 to 46,120||2.4/5/6|
Let’s look at some of the major evolutions of Wi-Fi. Early versions operate in the 2.4GHz band, the so-called ISM radio band (ISM stands for Industrial, Scientific and Medical as those were the initial uses for the band). Since regulations in this band are pretty loose, there are many devices that operate there. Including microwave ovens, which are at least part of the reason why 2.4GHz is the wild west of wireless. Early on, when a microwave started blasting 1000W at your lunch, Wi-Fi and Bluetooth connections briefly turned unreliable. Modern devices are a lot more resilient (and modern ovens are better insulated).
Wi-Fi 4 (802.11n) is probably the biggest improvement to Wi-Fi since its inception. Most Wi-Fi before 2008 operated in 2.4GHz, though 5GHz was supported from the beginning – Wi-Fi 1 (802.11b) worked in 2.4GHz, Wi-Fi 2 (802.11a) in 5GHz. Both standards are from 1999, though 2.4GHz was the most commonly used band. However, as noted above, it became very, very crowded and connectivity suffered from it.
Wi-Fi 4 reintroduced support for the 5GHz band. It was less crowded and could fit larger channels. Initially, channels in the 2.4GHz band were only 5MHz wide, later support was added for 20MHz channels. That created an issue, though, only four 20Mhz channels can fit in the 2.4GHz band without overlapping (i.e. without interfering with each other).
This is why you should space out your Wi-Fi channels – the best channels to pick are 1, 6 and 11 (there are channels 12 and 13, but they are not available everywhere). For comparison, the 5GHz band has enough room for at least 23 non-overlapping 20MHz channels.
Anyway, Wi-Fi 4 added support for pairing two 20MHz channels to double the speed. Then came Wi-Fi with added support for 80MHz channels and the ability to combine two such channels for a total of 160MHz. That only worked in 5GHz, of course, as 160MHz is more than the total bandwidth allotted for Wi-Fi in the 2.4GHz band.
Wi-Fi 4 also introduced support for Multiple Input, Multiple Output, aka MIMO. This enabled devices (both transmitters and receivers) to have multiple antennas, which had two major benefits – it increased range and speed.
These days even the 5GHz band is pretty crowded so Wi-Fi 6 moved upstairs and opened up the 6GHz band. This tech is called Wi-Fi 6E and in the US (it varies a bit by country) it has access to a whopping 1,200MHz of bandwidth. There is plenty of room here, 6E fits seven 160MHz channels, though range is limited compared to lower frequencies. This is a blessing and a curse – it helps ease congestion, but low range means you may need more access points or to build out a mesh network.
There is a lot of cool tech that we haven’t covered here. For example, Wi-Fi 6 introduced Target Wake Time, which reduces power usage by making sure that the mobile device is awake only when it should transmit or receive data and can immediately go back to sleep after.
There is also the topic of security, from the woeful WEP to the WPA standards that replaced it. The handy WPS feature also had its issues (WPS allows users to connect a new device to the network just by pressing a button on the access point and the device).
We haven’t covered WiGig either, a 60GHz standard, which we have seen in some mobile devices as a way to transmit high resolution, low latency video to a display without using wires. But this post is already getting pretty long, so we’ll leave that for another time.
The most interesting thing on the horizon is Wi-Fi 7. Chip makers like Qualcomm and MediaTek are already preparing for it and we may see the first devices as early as this year. The Snapdragon 8 Gen 2 and some phones powered by it claim to support Wi-Fi 7, though the standard it still in the draft stages and is expected to be completed in 2024. This has happened before, the first Wi-Fi 4 devices also launched based on a draft specifications of the standard. Wi-Fi 7 will bring support for 320MHz bandwidth and speeds of up to 30Gbps.
Do your phone and access point at home support the latest Wi-Fi version? And is that something that you care about or are you happy with using an older version?