As the saying goes, “home is where Wi-Fi automatically connects”. As much as the emphasis smartphone makers put on advertising their phones’ next-gen cellular connectivity, many of us spend most of our day connected to the internet via Wi-Fi.

Wi-Fi is certainly not the first method of transferring data wirelessly between nearby devices. Early PDAs used infrared, which allowed them to synchronize calendar appointments and e-mail inboxes, for example. Infrared is directional, however, to connect your PDA and PC, you had to aim the IR adapter and hold 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 handheld devices to benefit from Wi-Fi connectivity, although they were not always equipped with this feature from the factory – CF and SD cards were used as add-ons that can enable Wi-Fi, GSM, Bluetooth and other features.

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, etc., 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 less range (at least with commonly available adapters).

Wi-Fi is limited by law to a transmit power of 100mW and the general rule is that you can get a range of up to 100m under ideal conditions (i.e. outdoors with a 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, separated by 382 km/238 mi. Some long-range Wi-Fi connections are used today to connect remote sites in the mountains, but these are the exceptions to the rule.

A 382 km connection between the peaks of El Águila and Platillon was established in 2007

Before we continue, we should cover the naming of Wi-Fi. First of all, “Wi-Fi” stands for “Wireless Fidelity” (similar to Hi-Fi) and was coined by a brand consulting company, which has was hired to come up with something that was “a bit catchier than ‘IEEE 802.11b Direct Sequence’”. The technology is part of the IEEE 802.11 family and different versions add a letter, for example 802.11b.

But it’s not very catchy, is it? So in 2018, the Wi-Fi Alliance changed things to a simpler, more user-friendly naming scheme – Wi-Fi 802.11n became Wi-Fi 4, and later versions adopted subsequent numbers. See the table below. Note that 802.11g and earlier have been renamed retroactively because “Wi-Fi 4” doesn’t make much sense without them.

Let’s look at some of the major evolutions of Wi-Fi. The early versions operated in the 2.4 Ghz Band, the so-called ISM radio band (ISM stands for Industrial, Scientific and Medical as these were the initial uses of the band). Since the regulations in this band are quite loose, many devices operate there. Including microwave ovens, which are at least part of the reason why 2.4 GHz is the Wild West of wireless. At first, when a microwave started emitting 1000W during your lunch, the Wi-Fi and Bluetooth connections briefly became unreliable. Modern appliances are much stronger (and modern ovens are better insulated).

Wi-Fi 4 (802.11n) is probably the biggest improvement to Wi-Fi since its inception. Most pre-2008 Wi-Fi ran at 2.4 GHz, although 5 GHz was supported early on – Wi-Fi 1 (802.11b) ran at 2.4 GHz, Wi-Fi 2 (802.11a ) at 5GHz. Both standards date back to 1999, although 2.4 GHz is the most commonly used band. However, as noted above, it got very, very crowded and connectivity suffered.

Wi-Fi 4 reintroduced support for the 5 GHz band. It was less crowded and could accommodate larger channels. Initially the 2.4 GHz band channels were only 5 MHz wide, later support was added for 20 MHz channels. This created a problem, however, only four 20 MHz channels can fit in the 2.4 GHz band without overlapping (i.e. without interfering with each other).

That’s why you need to space out your Wi-Fi channels – the best channels to choose are 1, 6, and 11 (there are channels 12 and 13, but they’re not available everywhere). For comparison, the 5 GHz band has enough room for at least 23 non-overlapping 20 MHz channels.

Anyway, Wi-Fi 4 added support for pairing two 20 MHz channels to double the speed. Then came Wi-Fi with additional support for 80 MHz channels and the ability to combine two of those channels for a total of 160 MHz. It only worked in 5 GHz, of course, because 160 MHz is more than the total bandwidth allocated to Wi-Fi in the 2.4 GHz band.

Wi-Fi 4 also introduced support for Multiple Input, Multiple Output, aka MIMO. This allowed devices (transmitters and receivers) to have multiple antennas, which had two major benefits: increased range and speed.

These days, even the 5 GHz band is pretty crowded, so Wi-Fi 6 moved upstairs and opened up the 6 GHz band. This technology is called Wi-Fi 6E and in the US (it varies a bit by country) it has access to a whopping 1200 MHz bandwidth. There’s plenty of room here, 6E is suitable for seven 160 MHz channels, although range is limited compared to lower frequencies. It’s a blessing and a curse – it helps reduce congestion, but poor range means you may need more access points or build a mesh network.

There are a lot of interesting technologies that we haven’t covered here. For example, Wi-Fi 6 introduced Target Wake Time, which reduces power consumption by ensuring the mobile device is only awake when it needs to transmit or receive data and can immediately go back to sleep afterwards. .

There is also the theme of security, from the dismal WEP to the WPA standards that have replaced it. The handy WPS feature also had its issues (WPS allows users to connect a new device to the network with just the press of a button on both the access point and the device).

We also haven’t covered WiGig, a 60GHz standard that we’ve 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 quite long, so we’ll leave that for another time.

The most exciting thing on the horizon is Wi-Fi 7. Chipmakers like Qualcomm and MediaTek are already gearing up for it, and we could 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, although the standard is still in draft stages and is expected to be completed in 2024. This has happened before, with the first devices Wi-Fi 4 also launched based on a draft specification of the standard. Wi-Fi 7 will support 320 MHz bandwidth and speeds of up to 30 Gbps.

Does your phone and home hotspot support the latest version of Wi-Fi? And is it something you care about or are you happy with using an older version?