WN Podcast 010 – 802.11ax with David Coleman

Welcome to our new WiFi Ninjas Podcast episode.

In this episode we feel very privileged to have a true WiFi Legend on as our guest – David Colemen from Aerohive discuss all things 802.11ax.

A bit about David:

  • CWNE number 4
  • Director of Technical Education and Marketing
  • Primary company liaison to the Wi-Fi Alliance
  • Senior technical evangelist for Aerohive
  • Published WLAN author

What is 802.11ax or Wi-Fi 6?

  • The next generation of the Wi-Fi standard is Wi-Fi 6, also known as 802.11ax, the latest step in a journey of nonstop innovation. The standard builds on the strengths of 802.11ac while adding efficiency, flexibility, and scalability that allows new and existing networks increased speed and capacity with next-generation applications.
  • The Institute of Electrical and Electronics Engineers (IEEE) proposed the 802.11ax Wi-Fi 6 standard so it can couple the freedom and high speed of Gigabit Ethernet wireless with the reliability and predictability found in licensed radio.

Is Wi-Fi 6 different from 802.11ax?

  • No, they are the same. The Wi-Fi Alliance started a campaign to coin the term “Wi-Fi 6” when referring to the IEEE 802.11ax standard. It indicates that it is the sixth generation of Wi-Fi. The premise was to simplify the marketing message to help 802.11ax be better positioned relative to the Third Generation Partnership Project (3GPP) standards used in cellular (such as 5G). Wi-Fi 6 will also be the name of the Wi-Fi Alliance certification for 802.11ax inter-operability.

What are the benefits of 802.11ax or Wi-Fi 6?

  • Wi-Fi 6 allows enterprises and service providers to support new and emerging applications on the same wireless LAN (WLAN) infrastructure while delivering a higher grade of service to older applications. This scenario sets the stage for new business models and increased Wi-Fi adoption.  The main benefit will be all about better more efficient use of the existing frequency space.

High Level overview of what’s new/ improved in 802.11ax:

  • OFDMA – Better use of the frequency space.
  • BSS Colour/ Spatial reuse operation – mitigate CCI.
  • Uplink and Downlink MU-MIMO.
  • 1024-QAM Higher Data Rates.
  • Target Wake Time (TWT).

OFMA – The secret sauce of 802.11ax!

  • OFDMA the AP is in charge.
  • Rules of contention still apply, however the AP controls the medium during a TXOP for both downlink and uplink.
  • Can also work with 40Mhz and 80Mhz channels.
  • Sub channel utilisation – resource units.
  • OFDMA can use a narrower portion of the frame so that means we can send to 4 stations at the same time.
  • AC and previous we would have to go to 1 station at a time.
  • Huge efficiency gains when our clients also support 802.11ax.

What is MU-MIMO?

  • The term multi-user (MU) simply means that transmissions between an AP and multiple clients can occur at the same time dependent on the supported technology.

Technology Dimensions:

  • Denser modulation using 1024 Quadrature Amplitude Modulation (QAM), enabling a more than 35 percent speed burst.
  • Orthogonal Frequency Division Multiple Access (OFDMA)-based scheduling to reduce overhead and latency.
  • Robust high-efficiency signalling for better operation at a significantly lower Received Signal Strength Indication (RSSI).
  • Better scheduling and longer device battery life with Target Wake Time (TWT).

1024-QAM in 802.11ax:

  • Higher modulation rates require better signal quality or (SNR).
  • 1024 QAM will require an even better signal than 256-QAM from 802.11ac.
  • Greater sensitivity required – will have to be closer to the AP and good SNR to be able to de-modulate the info.

802.11ax / Wi-Fi 6 Benefits:

  • Wi-Fi 6 will build on the success of 802.11ac. It will let access points support more clients in dense environments and will provide a better experience for typical wireless LAN networks. It will also provide a more predictable performance for advanced applications such as 4K or 8K video, high-density high-definition collaboration apps, all-wireless offices, and the Internet of Things (IoT). Wi-Fi 6 will drive Wi-Fi toward the future as the growth of wireless continues.

Is there any benefit for legacy clients? Yes and no!

  • 802.11ax APs will not improve the performance or efficiency of any legacy Wi-Fi clients (802.11a/b/g/n/ac).
  • However, as we see more 802.11ax clients mixed into the client population, the efficiency improvements gained by 802.11ax clients will free up the valuable airtime for those older clients and therefore an overall efficiency of the system.

 802.11ax / Wi-Fi 6 APs:

  • There are some Wi-Fi 6 access points already on the market, targeted for early adopters and customers who are eager to test the new standard. The access points that are released early will be pre-standard APs because the standard will not yet have been ratified. This means key features that are part of Wi-Fi 6 may not be supported on some of these initial, pre-standard access points. However, when available, some of these access points will be able to become certified through software updates and Wi-Fi 6 features will be supported. This approach is similar to the introduction of prior generations such 802.11ac and 802.11n.