What’s next for Wi-Fi? A second wave of 802.11ac devices, and then: 802.11ax

Now that blazing-fast routers based on the IEEE 802.11ac standard are finally entering the mainstream, intrepid engineers are busily cooking up all-new hardware that will make that gear’s performance seem quaint by comparison.

That’s not to say 802.11ac is about to fall by the wayside—after all, the IEEE didn’t officially ratify the standard until December 2013. It’s just that the chipsets capable of delivering all the features and performance in that standard are still in development.

You see, most of the first wave of 802.11ac routers were based on draft versions of the 802.11ac standard. While some newer routers, such as Netgear’s six-antenna Nighthawk X6, are implementing cool tricks to squeeze more performance from that technology, a second wave of 802.11ac routers will hit the beach in early 2015.

“Wave 2 802.11ac routers will deliver maximum physical link rates in the range of 7- to 10Gbps.”

These devices support a number of optional features in that standard that will deliver even higher wireless performance. At the same time, new and complementary wireless technologies designed for specialized applications will also appear.

But there’s no point in trying to cheat obsolescence by putting off your next router purchase: The industry is already hard at work developing the successor to 802.11ac. Let’s dive into what’s next for Wi-Fi.

The two-party system

The IEEE (Institute of Electrical and Electronics Engineers) defines Wi-Fi standards such as 802.11ac and the older 802.11n. The Wi-Fi Alliance (an association of companies that build wireless-networking devices) certifies that the hardware based on those standards will work together.

Wi-Fi Alliance certification is not a requirement (manufacturers must pay for the designation), but it can be reassuring to consumers, especially in the early days. That’s because the IEEE can take several years to finalize its standards (it started working on 802.11ac in 2008 and finished in late 2013). Manufacturers often don’t want to wait, so they’ll bring new products to market as soon as the ink dries on an early draft. Buffalo shipped the first 802.11ac router in 2012, but the Wi-Fi Alliance didn’t launch its first 802.11ac certification program until mid 2013.

SU-MIMO (single-user multiple input/multiple output) technology was one of the hallmarks of the older 802.11n standard. It allowed multiple spatial streams to be transmitted to a single client. This technology was carried over to the 802.11ac standard, which added a more-powerful modulation technique (among other things) to deliver a maximum physical link rate of 433Mbps per spatial stream.

IEEE logo

Since it can support up to three such streams simultaneously, a Wave 1 802.11ac router can send and receive data at a maximum physical link rate of 1.3Gbps. Compare that to 802.11n routers, which provide up to three spatial streams with maximum physical link rates of just 150Mbps each (for aggregate throughput of just 450Mbps).

Wave 2 802.11ac routers will arrive sometime in 2015. These devices will also operate on the less-crowded 5GHz frequency band, but they’ll take advantage of several optional elements of the 802.11ac standard: First, they’ll support a feature called MU-MIMO (multi-user multiple input/multiple output), which allows them to transmit multiple spatial streams to multiple clients simultaneously.

Qualcomm multi-user MIMO Qualcomm

This Qualcomm illustration compares single-user MIMO to multi-user MIMO with beamforming. (Qualcomm’s Vive product line supports MU-MIMO.)

Second, they’ll bond multiple channels on the 5GHz frequency band to create a single channel that provides 160MHz of bandwidth (Wave 1 802.11ac routers can also bond 5GHz channels, but the bonded channel is only 80MHz wide). Third, where 802.11n and Wave 1 802.11ac routers support a maximum of three spatial streams, Wave 2 802.11ac routers will potentially support up to eight spatial streams.

Using some combination of wider channels or additional spatial streams (there isn’t enough available bandwidth to do both), improved beamforming, and other techniques, Wave 2 802.11ac routers will deliver maximum physical link rates in the range of 7- to 10Gbps. Quantenna Communications announced its first Wave 2 802.11ac chipset last April.

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