Now I am sure this is not a question that is on the mind of the average man in the street, but for IT professionals that have an ageing Wi-Fi infrastructure that is struggling to keep up with the ever increasing demand for Wi-Fi coverage and capacity, it certainly is.
Certified Wi-Fi 5 (802.11ac Wave 2) devices first appeared in 2016 and in 2019 Wi-Fi 6 (802.11ax) devices were released – these increase peak bandwidth by 25% and more importantly significantly improve the overall air-time utilisation, the net result is a 4 fold increase in real-world capacity.
High-end Wi-Fi 6 Access Points can provide eight 5 GHz spatial streams with a channel width of up to 80 MHz, this will provide a maximum throughput of 4.8 Gbs – assuming a 60% real-world throughput this gives us 2.8 Gbs to play with. Now this is a lot of Wi-Fi capacity that is capable of supporting 560 concurrent Netflix HD (5 Mbs) clients and 112 Ultra HD (25 Mbs) clients, now of course this is an extreme example and in the real-world average per client bandwidth is likely to be much lower.
The key to this level of capacity is wide channels and a large number of streams, but there are a couple of caveats:
- Even though a single stream is capable of a real-world throughput of 360 Mbs if the average client is only using 1 Mbs there is a lot of wasted bandwidth as older clients can only transmit one at a time
- In order to take full advantage of eight streams you need devices that support MU-MIMO (Multi-User Multiple-Input and Multiple-Output) – each stream is allocated to a different client (e.g. eight single stream clients or four dual stream clients)
In order to take full advantage of all this available capacity we need technologies that will enable multiple clients to transmit at the same time, we have had MU-MIMO for many years, but previous generations only supported 4 simultaneous clients and it only worked for downloads – Wi-Fi 6 increases the client count to a maximum of 8 and it also supports both uploads and downloads.
The most important improvement in Wi-Fi 6 is OFDMA (Orthogonal Frequency Division Multiple Access), which solves the biggest Wi-Fi challenge – how do I chop-up a big fat pipe such that each client can get their own appropriately sized share (so that airtime utilisation can be significantly increased)? Depending on the age of your Wi-Fi clients you may find a reasonable proportion support MU-MIMO, but only Wi-Fi 6 clients support OFDMA.
So back to the question – if you need to refresh your wireless network should you deploy Wi-Fi 5 or 6 APs?
This comes down to two things:
- Cost – if they are comparable then Wi-Fi 6 is a no brainier as it is clearly far superior
- Client support – if you know that over the next year or so you will have a significant proportion of WiFi 6 clients then Wi-Fi 6 is the way to go, otherwise Wi-Fi 5 may still make sense
Of course delivering great Wi-Fi involves much more than just supporting the latest standards – vendors also need to provide the best signal possible to every client and high-levels of automation to deliver the best user experience whilst minimising management overhead.
Our partner Ruckus has put together an excellent paper that discusses the challenges of delivering great Wi-Fi that you can download here.