Tech Talk with Wireless Nick - 802.11ax The Future Begins
The networking industry is full of buzzwords and hype; A.I., M.L., SDWAN, and virtual everything. This is even more evident in the world of wireless networking; claims of speeds up to 1 Gbps, wired-like connectivity, mobility first, future-proofing, and so on.
The new 802.11ax amendment (not yet standard), or WiFi6 as it is now being called, is slated to be ratified later in 2019. This is creating a significant amount hype in some circles and not so much in others as end-user computing devices will probably not have chipsets to support 802.11ax until the end of 2019. Looking forward, more full adoption will probably not happen until 2020 or even as late as 2021.
What is 802.11ax?
802.11ax will build on the features that the 802.11ac, or WiFi5, standard gave us as well as adding some cool new features to help with the ever-growing demand on wireless networks. From a desire for mobility-first networks to cellular offloading that is wanted (and sometimes needed) from the carriers,11ax has it’s work cut out for it.
802.11ac gave us some significant improvements with additional channel widths in the 5GHz space to allow for 80MHz channels in Wave 1 and 160MHz channels in Wave 2. This gives increased bandwidth availability to user devices if those devices had the chipset to support it. The drawback is now with 80MHz and 160 channels is that we take the available 5GHz channels from a total of 24 down to 5 or 1 available, non-overlapping channels, depending on the usage of DFS channels. This makes it much harder to channel plan in an enterprise or LPV style of deployment, so I still recommended using 20 MHz channels, or perhaps 40MHz if done properly. However, when this style of deployment is done the 1.3Gbps that is touted by the marketing folks cannot be met even when using 3×3 spatial streams. 802.11ax can achieve throughput speeds of up to 4.8Gbps according to the data sheets and marketing put out so far. But how can we get to those speeds?
As with 802.11ac, to reach the speeds marketing is telling us that we need two things, multiple bonded channels and clients that can support it. Let’s look at these one at a time.
802.11ac Wave 2 began to support 160MHz channels as well as Multi-User Multiple Input/Multiple Output to support multiple streams of data. This implementation yielded multi-user downlinks from the AP to the client. However, uplink traffic from the client to the AP is a single client at a time, by contrast. 802.11ax looks to improve this by allowing MU-MIMO APs to talk bi-directionally to up to 8 devices simultaneously and to become almost ‘switch-like’ (I know more buzzwords, sorry). The new standard will also allow capable clients to take full advantage of MU-MIMO and to use dual-streams to an AP which would potentially double the bandwidth to that client.
The best analogy I have seen of this so far is with 802.11ac there is an eight-lane road, that funnels down to one-lane creating a bottle neck and allowing only a single car through at a time. This is how MU-MIMO worked previously with legacy uplink/downlink mechanisms. Now with 802.11ax that one-lane road is extended to a full eight-lanes, eliminating the bottle neck and allowing traffic to flow freely.
More to come on this subject soon.