Networking Standard (802.11 alphabets)
Let’s talk wifi history! Hey, where’d you go? This won’t delve deep, but just go over the generational improvements of wifi. The first generation of wifi was 802.11a, then 802.11b, and you can probably guess the third… 802.11g. What happened to c through f? The Wifi standard is designed by committee, so those standards did exist, but didn’t reach agreement to make it into a full standard and to the market.
2019 Update: With the introduction of 802.11ax, the wifi standards have been renamed to the simpler Wifi 6, wifi 5, wifi 4, etc.
It begins with A and B (802.11a and 802.11b) (AKA Wifi 1 and Wifi 2 as of 2019)
802.11a and 802.11b were created at the same time as competing standards against each other, 802.11a used the 5 GHz band, and 802.11b used the 2.4 GHz band. The 5 GHz frequency of ‘A’ provided an interference free environment and was faster with enhanced modulation, but B won out because the lower 2.4 GHz frequency can connect through larger obstacles, and the dumber modulation of B made the radios cheaper to manufacture compared to A. Why 2.4 GHz and not 2.3 or 1.7? It’s one of the few unlicensed bands available, the rest are either reserved or bought and paid for. Unfortunately, all of our modern wireless devices are running off the scraps of spectrum left available from when they were all allocated a considerable time ago and the parts that get freed up go to the highest bidder, which is the telcos more often than not. 802.11b had a top speed of 11 Mbps, but real world rates were closer about 8 Mbps max.
old d-link wifi router, in a retirement home now, if you listen closely you can hear it muse about old days of needing to be rebooted all the time.
802.11g (AKA Wifi 3 as of 2019)
802.11g was next, radio costs had come down so the advanced modulation of A was folded to the existing B standard in to help the speeds up to 54 Mbps (theoretical). 802.11g was made to be backwards compatible with the previous 802.11b equipment, so a new G router will work to your existing B notebook, just at B speeds. G devices will start talking to each other on the B standard, and take moments to ask the other side if it speaks G, where it could switch to the faster G if both sides agree. Getting the faster G speeds often meant replacing all network equipment to 802.11g devices to avoid the backward compatibility fall back to B speeds. Some needed encryption security was added was added to 802.11g as well.
802.11n (AKA Wifi 4 as of 2019)
802.11n was then finalized around 2010, and as of 2015, this is the one that you are most likely to find in the wild. 802.11n supported using more than one spatial stream through MIMO (multiple in multiple out), where a device could transmit and receive on up to four streams to help the throughput, which at best is usually 2 streams in and 2 streams out, also called 2×2 (previous 802.11a/b/g was SISO – single in single out, or 1×1). 802.11n also added the option of using the 5 GHz band, which is larger and less noisy, but to save costs, many devices don’t have a 5 GHz radio and work on 2.4 GHz alone. If your router or networking device supports 5 GHz, it is often referred to as dual band, even though they don’t actually use both bands at the same time (you either connect to the 2.4 GHz wifi or to the 5 GHz wifi). Because of the MIMO ability, most wifi routers started sporting more than one antenna. If both your router and your wireless device connecting to the router support the 2×2 MIMO communication, then top speeds around 144 Mbps are theoretically possible, but a strong connection on the 5 GHz band is often required to get this rate. You might see routers advertising 450 Mbps, but this is with illegitimate oversized channels that have a very limited application.
802.11ac – replace all equipment again? (AKA Wifi 5 as of 2019)
Wifi 5 had two tricks up its sleeve, it supports more streams with the MIMO communication, up to 8 compared to 802.11n’s possible 4 (2×2). Beamforming was also standardized. Beamforming helps the radios intelligently direct the signal to the destination (spatial selectivity), instead of throwing it 360 degrees and hoping the other side gets it, it manipulates the phase and amplitude of the radio wave to adjust for the expected interference in the path to the connected device. The 802.11ac standard was introduced in waves, and only in ‘wave 2’ is beamforming mandatory. Most of the newest smart phones have 802.11ac support, but often with only 1 antenna, so it will only use 1 stream (SISO) instead of the possible 8, which is a theoretical max of 78 Mbps to tablets and phones, and faster on laptops supporting MIMO depending on their network adapter. Here’s the big downside to the AC additions, it’s only on the 5 GHz band! The 2.4 GHz band isn’t large enough to support it, but 5 GHz with a bunch of antennas means more expensive equipment (home routers selling for $200-300) and the smaller 5 GHz wavelength is less forgiving for obstacles in the path. The lack of frequencies, particularly lower ones, is a major handcuff that wifi can’t seem to slough off.
These spider like routers can also scare bugs and small animals away
Wifi 6! (802.11ax)
Wifi 6 was standardized in 2019. As of this writing in May of 2019, there are only two (expensive) routers and 1 model of smart phone that support wifi 6. The comparative strength of the new standard is that it allows for multiple users to use the wifi at a time (OFDMA technology), in both the download and upload direction. Better battery utilization for small devices like cell phones, and support for WPA3 encryption.
- Will a fancy Wifi 6 or 802.11ac (Wifi 5) router help my signal or speeds to my older wifi devices?
With the additional antennas, a newer Wifi 6 and 5 routers generally will help the signal and throughput slightly to older devices. Keep in mind that the advances of Wifi 5 and 6 are on the 5 GHz band, so it has limited penetration through walls and floors. The tradeoff here is that the equipment to run more advanced wifi is more expensive, so a top tier Wifi 5 router (ac) might be upwards of $300, and in May of 2019 there are only 2 Wifi 6 routers on the market, and both around the $500 dollar range. Routers typically don’t have the lifespan to warrant spending top dollar on them. The price of these devices does generally go down over the years. For best coverage, a Mesh system of wifi 6 routers would be ideal.
- Why doesn’t wifi use the 900 MHz band to get through walls and floors?
900 MHz will blast through walls and floors compared to 2.4 GHz, but only a small chunk of the band is available, and it tends to be very noisy. Early cordless phones used this band, and it worked almost too well, where you could pick-up the cordless phone and catch your neighbour’s cordless phone conversation from a couple of hundred feet away. 900 MHz is much more impressive for its range and penetration, but it’s such a tiny frequency range that there is no room for multiple networks to co-exist. This problem also rears its ugly head in the next ‘MCSnet Network’ section concerning 900 MHz. The 700 MHz band was recently freed from the old analogue TV bands that went digital, and they were bought by the telecoms for billions of dollars. There has been some encouraging work to use the TV whitespace for local wifi-like connections, which could improve connectivity by orders of magnitude.