In 2019 and 2020, I’ve seen first Wi-Fi 6 (802.11ax) capable devices coming to the market, mostly smartphones. On notebooks, the standard still hasn’t made a real impact, even the current Lenovo Thinkpad X390 still comes with a Wi-Fi 5 (802.11ac) modem. Also, on the Access Point side, first products have become available but the impact so far is still small. Nevertheless, now is the time to have a look at the spec and here are a number of resources that give a good technical overview of what’s new:
For a super brief first look, the ‘802.11ax For Dummies’ book by Aerohive, available as a PDF for free is a good read! For more details, have a look at Aruba’s 802.11ax whitepaper. And for the details, there is the current draft 4 of the standard, but that’s unfortunately not available for free. A pity, I wished they were as open as 3GPP. Shame on them!
And here’s the elevator pitch of what’s new in Wi-Fi 6:
For home networks, 1024-QAM modulation is probably the most interesting feature, boosting speeds when very close to the access point by 25%. Most other features of Wi-Fi 6 are specifically tailored for environment with lots of devices such as offices, stadiums, airports etc. For such environments, Wi-Fi 6 introduces OFDMA (Orthogonal Frequency Division Multiple Access). Unlike previous generations where all devices could decide on their own when to transmit and receive and take the complete bandwidth of the channel using OFDM modulation, Wi-Fi 6 introduces centralized control and assigns chunks of the channel to different devices. In the downlink direction, this is only used when the Access Point has packets of more than one device waiting to be sent over the air. Otherwise, single-user transmission, i.e. plain OFDM is used, just as before. Uplink OFDMA has also been specified with random access and centralized assignments in a similar way as in cellular networks. However, it seems that this is a functionality that will only come in a second wave. There are lots of other mandatory and optional features in Wi-Fi 6, but since this is just an elevator-pitch, I think the ones I have mentioned here are the most important ones to look forward to from a high level point of view.