OFDMA Is the Only Part of Wi-Fi 6 That Matters (For Most Enterprises)

The new Wi-Fi 6 (802.11ax) standard offers several new technologies, but only one that really matters (for most enterprises): OFDMA.

Have you heard about Wi-Fi 6?  (Or, at least, 802.11ax?)  If you work in or around networking or Wi-Fi, you probably have.  Your humble author has read about it in blogs, tweeted about it, streamed about it on Twitch and watched commercials about it on college football telecasts.

It was the last thing -- the TV commercials -- that gave yours truly a double-take.  "Is Wi-Fi 6 that big?", I murmured to myself while taking in CDW's commercial for Cisco's Wi-Fi 6 gear.  Commercials on national sports broadcasts aren't cheap, so someone must be asking about it.  (Or at least think there's money in it.)

The standard (technically an "amendment", not a full-blown IEEE standard) Wi-Fi 6 is based upon is 802.11ax, and according to the latest 802.11 Working Group timeline, 802.11ax won't be finished for several months.  Clearly that has not stopped enterprise wireless LAN vendors and integrators from hawking Wi-Fi 6 upgrades, and understandably so.  While the final stamp of approval for 802.11ax has yet to arrive, the nuts and bolts of the technology have been known for quite some time.

New technologies for Wi-Fi 6/802.11ax are:

• 1024-QAM, which allows for higher per-frame data rates (assuming signal-to-noise ratio [SNR] is high enough to make higher rates work).

• BSS Coloring, which allows co-located APs to share a channel.  (Which may or may not be a good thing.)

• Target Wake Time (TWT), which allows dozing client Wi-Fi radios to sleep through Beacon frames (thus reducing post-Beacon channel congestion and possibly improving client battery life).

• Longer Guard Intervals (GI), which should reduce overhead for long distance, point-to-point "microwave" links.

• Uplink MU-MIMO antenna & radio technology, which allows multiple client devices to send network traffic to an AP simultaneously, over the same channel.

• OFDMA, a technology from the cellular world, which allows APs to create multiple narrower channels from one wider channel, and allows APs to control channel access.

Sussed out, three of these technologies are providing marginal improvements.  1024-QAM creates a 20% data rate boost compared to Wi-Fi 5/802.11ac's top modulation, 256-QAM.  The channel sharing created by BSS Coloring may make for "smarter" channel sharing, but it doesn't change the laws of physics; sharing is still sharing.  TWT could aid battery life, but that's more of a user want than a network need.

One technology, Longer GIs, doesn't apply to most enterprise Wi-Fi activity.  Although improving microwave link overhead should be useful where long distance, outdoor wireless links are needed.

Then there's Uplink MU-MIMO, which will be great... if it works.  Downlink MU-MIMO has been a part of Wi-Fi standards for a half-decade, and has yet to deliver wide scale performance benefits (outside of vendor test labs, that is).

Which leaves us with one: OFDMA.

OFDMA should be a big deal for enterprise Wi-Fi.  It allows for wide channels to be divided up into narrower channels for client devices' network communication.  Narrow channels are important, because they offer more reliable mobility and greater application stability compared to wider channels, especially in dense user environments.

For enterprise network engineers considering whether to upgrade to Wi-Fi 6, OFDMA offers the one compelling reason to do so. (From a technological perspective, that is.  There can be all sorts of financial and political reasons to procure and deploy new Wi-Fi gear.)  The flexibility of 802.11ax APs to offer super fast, wide channel speeds when locations are sparsely populated, then dynamically change to mobility or density optimized narrow channels when needed is something that Wi-Fi 5 simply does not offer.

Stay tuned to Sniff Wi-Fi, because I'll be writing more about Wi-Fi 6 in the near future; which devices support it, details on OFDMA, how to analyze its effects, and more.

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Twitter: @benmiller

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