Linksys WRT 1900AC. Curvier, and with four antennae.


Wireless standards tend to get proposed, drafted, and finally accepted at what seems like a glacial pace. It’s been roughly 17 years since we began to see the first 802.11b wireless routers and laptops. In the intervening time, we’ve only seen three more mainstream standards take hold since then: 802.11g, 802.11n, and now 802.11ac. (I’m leaving out some lesser-used ones like 802.11a for the purposes of this story.)

Now a new standard looms over the horizon. And if you thought that your new 802.11ac router’s maximum speed of 1,300Mbps was already fast, think again. With 802.11ac fully certified and out the door, the Wi-Fi Alliance is looking at its successor, 802.11ax — and it looks pretty enticing. While you may have a hard time getting more than 400Mbps to your smartphone via 802.11ac, 802.11ax should deliver real-world speeds above 2Gbps. And in a lab-based trial of technology similar to 802.11ax, Huawei hit a max speed of 10.53Gbps, or around 1.4 gigabytes of data transfer per second. Clearly, 802.11ax is going to be fast. But what is it exactly?

What is 802.11ax WiFi?


The easiest way to think of 802.11ax is to start with 802.11ac — which allows for up to four different spatial streams (MIMO) — and then to massively increase the spectral efficiency (and thus max throughput) of each stream. Like its predecessor, 802.11ax operates in the 5GHz band, where there’s a lot more space for wide (80MHz and 160MHz) channels.

With 802.11ax, you get four MIMO (multiple-input-multiple-output) spatial streams, with each stream multiplexed with OFDA (orthogonal frequency division access). There is some confusion here as to whether the Wi-Fi Alliance and Huawei (which leads the 802.11ax working group) mean OFDA, or OFDMA. OFDMA (multiple access) is a well-known technique (and is the reason LTE is excellent for what it is). Either way, OFDM, OFDA, and OFDMA refer to methods of frequency-division multiplexing — each channel is separated into dozens, or even hundreds, of smaller subchannels, each with a slightly different frequency. By then turning these signals through right-angles (orthogonal), they can be stacked closer together and still be easily demultiplexed.

According to Huawei, the use of OFDA increases spectral efficiency by 10 times, which essentially translates into 10 times the max theoretical bandwidth, but 4x is seeming like more of a real-world possibility.