Why OFDMA is the Secret Sauce for Wi-Fi 6

At the Wireless LAN Professionals Conference, David Coleman (Senior Technical Evangelist) spoke about Wi-Fi 6, and why OFDMA is the most important aspect of the new standard. Watch the video below to learn more about Wi-Fi 6 (802.11ax), how it works, and why it’s important.

Key Takeaways

What is Multi-User (MU) in Wi-Fi 6?

Transmissions between an access point and multiple clients can occur at the same time depending on the supported technology. MU can be very confusing when discussing Wi-Fi 6. MU capabilities exist for both MU-OFDMA and MU-MIMO. OFMDA is the key technology for 802.11ax / Wi-Fi 6. OFDMA is a multi-user version of the OFDM digital modulation scheme we’ve already been using in Wi-Fi.

What about 40 Mhz and 80 Mhz channels?

For most environments, 20 Mhz will be ideal channel width. In 802.11ax, 20 Mhz can be subdivided into as many as nine channels to help with capacity. 40 Mhz can work, but proper design will have to be considered. 80 Mhz isn’t likely to be useable in most enterprise deployments.

The AP is in Charge for Multi-User Communication

With ODFMA, the access point is in charge. The rules of medium contention still apply, though. The access point has to compete for its transmit opportunity (TXOP). Once it has it, the AP can control up to nine 802.11ax client stations for downlink or uplink transmission.

What are Buffer Status Reports?

Clients deliver Buffer Status Reports (BSRs) to assist the access point in allocating multi-user resources. Clients can explicitly delivery BSRs to the access point in response to a BSRP trigger frame. Clients can also implicitly delivery BSRs in the QoS Control Field or BSR control field of any frame transmitted to the AP.

Over the past few months, we’ve posted a number of technical blogs related to 802.11ax. Here are links to a few of them. If you are ready to move ahead with a Wi-Fi 6 deployment (learn why you should), contact us to learn your next steps.


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