WiFi has been around for a long time now and as such it has been subject to years and years of improvement. In fact, the immediate precursor to the first official WiFi standard known as WaveLAN was invented by NCR and AT&T in 1991. It was intended for use with cashier systems.
The WiFi standard became officially known as 802.11 and is now under the custodianship of the WiFi Alliance. Any local area network that is wireless is technically WiFi, although a device must conform to the standards set out by the Alliance in order to talk to another device wirelessly.
The same protocols that allow all devices on the internet to speak to each other, as well as the devices on your ethernet-wired home network, all work over WiFi as well.
In total there are currently sixteen 802.11 standards spanning from the first one in the 1990s to to ones that have been proposed for the future. Don’t worry, I’m not going to discuss every single one, just the important ones and the ones that are relevant today.
Original Recipe: 802.11
Also known as “802.11 legacy” this is the original version of WiFi. Released in 1997, it is obsolete today. The specifications for the legacy standard was either 1Mbps or 2Mbps. Achingly slow today, but at the time it must have seemed like a blazing connection speed. Although this early WiFi standard operated over different physical signals such as infrared, the basic technology was already in place. Most importantly, it supported the 2.4Ghz radio frequency that falls into the industrial, scientific, and medical radio bands.
Higher Power: 802.11a-1999
This is different from the 802.11a that devices support today, and to differentiate the year 1999 is often tacked on to the standard. This was the first implementation of the 5.8 Ghz frequency, which gave it advantages in terms of avoiding interference compared to the relatively crowded 2.4Ghz range, but it also meant that objects such as walls would block the signals much more readily. The speed one could achieve on this standard was much, much faster than plain 802.11, at up to 54Mbps.
Big Success: 802.11b
This is probably the first truly practical and successful WiFi standard and it is still relevant today. Most modern WiFi chips are still backwards compatible with 802.11b. The adoption rate of 802.11b was fast and wide. It was much faster than 802.11 at a maximum of 11Mbps and much cheaper to produce and therefore buy. Pretty soon people were using 802.11b WiFi all over the place.
One of the issues with this standard was how susceptible it was to interference. Radio controlled planes, Bluetooth, and more readily available equipment could all mess with this WiFi. Still, it was the point where WiFi entered the big time.
The “g” revision combined the technology of 802.11a and 802.11b. Using the 2.4Ghz band, but making use of the high-speed data modulation from 802.11a it could achieve 54Mbps as a theoretical maximum while being backwards compatible with 802.11b. Interference is still an issue with this standard and if the network is mixed between b and g devices it will operate at the older standard’s speed.
The 802.11n standard was when WiFi came into its own not just as a popular technology but as a fast and reliable one. The biggest change that this standard brought about is the use of multiple antennas. Previous standards used one single antenna to send and receive data. 802.11n can operate on both the 2.4Ghz and 5.8Ghz bands. However, the standard makes 5.8Ghz optional, so not all equipment marked as 802.11n will have the hardware to work on the second band. This is why some are marked as “dual-band”. There is also quite a lot of variability among “n” equipment when it comes to maximum speed. Cheaper gear may max out at 54Mbps while high-end gear have a theoretical maximum of 600Mbps. The most popular is probably the 300Mbps mark, which for the most part is good enough for the typical household. However, the rise of high bandwidth cloud and video application may put a strain on even a 600 Mbps home network. Today 802.11n is still massively popular.
The New Hotness:802.11ac
This is the latest home WiFi standard and provided the first ever gigabit-class wireless networking solution that is not specialized for industrial or enterprise use. They made a lot of changes with this standard and incorporated the best elements of previous standards into the technology.
Compared to the “n” standard this has wider channels. 802.11n has a 40Mhz channel width. The ac standard uses either 80 or 160 megahertz. More data streams, more modulation and lots of antennas. With 802.11ac you’ll find both 2.4Ghz and 5Ghz bands. While lots of devices have the ability to combine both into one stream, the 2.4Ghz band which is what “n” devices can communicate with and is limited to 600Mbps, although cheaper ac gear may only support up to 300Mbps.
At the moment the fastest combined bandwidth available on ac devices amount to 2.1Gbps – a massive improvement over previous generations. Since the bulk of that bandwidth is in the 5Ghz band, the issue of radio interference is now lower than ever. We also have new technology such as beamforming, which help the high frequency band penetrate walls and approach the range of the 2.4Ghz band.
While 802.11ac is now slowly becoming the norm and supplanting 802.11n, the WiFi alliance is already looking towards the future. The 802.11ax standard is still super-early in the development stages, but is predicted to be much, much faster than 802.11ac. How much faster? Well, we won’t know until the standard is officially ratified, but early predictions are for as much as 10Gbps. While today that seems like more bandwidth than anyone could possible need, the rise of 4K and 8K video and huge software files may make short work of even a 10Gbps stream.