The Evolution of Wi-Fi 6: Part 5

Avatar_NewDog Ruckus Networks March 4, 2019


In part four of this series, we explored a range of Wi-Fi 6 (802.11ax) features, including target wake time (TWT), 1024-QAM and Long OFDM Signal. In this blog post, we’ll take a closer look at the benefits of Wi-Fi 6 (802.11ax) for new and legacy devices, as well as the expected feature set arriving in Wi-Fi 6 (802.11ax) Wave 1 and Wave 2.


Wi-Fi 6


Wi-Fi 6: Current and legacy devices


Although there are relatively few Wi-Fi 6 devices (802.11ax) on the market today (90% of the devices of are still Wi-Fi 5), it is important to note that the industry faced a similar situation when Wi-Fi 5 (802.11ac) was first introduced. From our perspective, there are several reasons to begin moving to Wi-Fi 6 (802.11ax) as soon as possible.

Firstly, a Wi-Fi 6 access point (AP) can serve new Wi-Fi 6 (802.11ax) devices, along with legacy Wi-Fi 5 (802.11ac) and Wi-Fi 4 (802.11n) devices. Secondly, a number of manufacturers are already selling Wi-Fi 6 (802.11ax) clients. Thirdly, Wi-Fi 6 (802.11ac) and legacy clients can co-exist just like Wi-Fi 5 (802.11ac) and Wi-Fi 4 (802.11n). Last, but certainly not least, both Wi-Fi 6 (802.11ax) and non-Wi-Fi 6 clients benefit from Wi-Fi 6 technologies.

For example, Wi-Fi 6 clients are more efficient, thereby freeing up more spectrum for Wi-Fi 5 (802.11ac) devices. This is perhaps analogous to a carpool lane, in which the first two lanes are for Wi-Fi 6 (802.11ax) devices. More specifically, let’s say 50% of the devices are Wi-Fi 5 (802.11ac) and 50% are Wi-Fi 6 (802.11ax). We put all the Wi-Fi 6 (802.11ax) devices in the carpool lane, allowing them to operate more efficiently. Concurrently, the remaining Wi-Fi 5 (802.11ac) clients benefit because we took half the cars from all the lanes – which frees up contention for the Wi-Fi 5 (802.11ac) devices.


This provides higher throughput and performance for networks, with beacon intervals occurring every 100 milliseconds. So, how does this work? Well, the AP ‘says’ that it will use its first 40 milliseconds of the beacon interval for Wi-Fi 6 (802.11ax) devices – while deterministically ‘telling’ all legacy devices to remain silent for the first 40 milliseconds (these are the two carpool lanes). The AP subsequently implements scheduled access for Wi-Fi 5 (802.11ac) devices, which get served, go to sleep and vacate the medium, all without ‘speaking’ for the remaining 60% of the time. Put simply, wireless access is improved for all types of devices, with Wi-Fi 6 clients using the fast lanes, while Wi-Fi 5 (802.11ac) devices have less clients to contend with. Put succinctly, more efficiency equals more airtime.


Wi-Fi 6: Release 1 and Release 2


As we discussed earlier in this series, Wi-Fi 6 (802.11ax) features a range of new technologies to optimize spectrum efficiency including OFDMA, MU-MIMO, Long OFDM signal, 1024-QAM, BSS Coloring and Target Wake Time (TWT). Like its Wi-Fi 5 predecessor, Wi-Fi 6 will be rolled out in two releases, although the exact feature split isn’t yet finalized. Nevertheless, Wave 1 is expected to feature DL and UL OFDMA, DL MU-MIMO and Target Wake Time (TWT). Meanwhile, release 2 is likely to feature UL MU-MIMO, spatial reuse using BSS Coloring, along with support for 160 Mhz and 6 GHz. Moreover, the FCC is still working on finalizing the release of the 6 GHz unlicensed spectrum, which will open 1.2 GHz of unlicensed space.


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