What is 802.11ac, the Future 5G Wi-Fi Standard?

Wi-Fi, the wireless connection we rely on when our data plan is running short or when we simply cannot touch the boundaries of LTE coverage, is going to receive a huge upgrade in the near future. Known as IEEE 802.11ac within specialized circles, this upcoming edition of the well-known standard will increase transfer speeds to unseen levels and vouch for steady connections, even in brutal environments.

Through the use of several interesting techniques, 5G Wi-Fi (as marketers like to call it) should theoretically increase the maximum throughput up to nearly 1 Gbps for a single transfer stream and accomplish even more when multiple links are aggregated. Imagine these insane speeds bringing high-quality content directly on a smartphone from a local Starbucks shop, without any charge from carriers. But how are all of these accomplished?

How Does Wi-Fi 802.11ac Work?

There are a couple of interesting new concepts brought by 802.11ac, in addition to existing standards (a/b/g/n). Perhaps the most important of all is the mandatory increase of the channel bandwidth, from up to 40 MHz in Wi-Fi/n, to a minimum of 80 MHz in the fifth generation. Optionally, users can also enjoy streams running on 160 MHz channels, depending on the coverage quality and a range of additional factors, which will be discussed later on.

What needs to be remembered at this point is that a larger channel permits more data to travel at the same time, pretty much how a bigger train would carry more passengers when compared with a smaller train. In our case, we are talking about up to four times more “passengers”.
Secondly, the concept of MIMO, the same one used by LTE Advanced, has been upgraded to accommodate greater speeds. In MIMO, a single device can have multiple antennas which can be used at the same time for the same transfer stream. Until the moment, 802.11n took advantage of maximum four streams, while the future 5G Wi-Fi can accommodate up to eight.

Moreover, MIMO has been easily transformed into MU-MIMO, which is a fancy term for multi-user access over the same medium. In plain English, this means that with only one access point, several stations can transmit or receive independent data streams at the same time, even with multiple antennas to gather data.
This technique is then combined with beamforming and null steering, two other principles which improve coverage and increase signal strength, while decreasing noise for other users in the same area.
As showed in the figure below, our access point transmits data to a station situated at “User 1” through the help of a blue-colored beam of bizarre shape. This process is known as beaming, and provides signal for a moving user, as long as is within a predefined area. A rather important observation is that this beam is stronger near the targeted user, and almost zero near other users – a technique called as null steering.

Another important factor is a new modulation scheme, which has migrated from the classic 64-QAM used in 802.11/n to the best-effort 256-QAM. Basically, this means that on the same medium, the upcoming Wi-Fi standard can theoretically transmit up to four times more bits, without affecting connection stability. We say theoretically, because five out of six bits transmitted using this new modulation will be used for the desired information, while the last will be saved for signaling (establishing and maintaining a proper link).

5 GHz – a faster frequency

The 5 GHz spectrum was first deployed in the early stage of Wi-Fi, more precisely by 802.11a. Used predominant in the States, its popularity rapidly faded due to its shorter coverage, sensibility to common obstacles (walls, leafs, trees, windows, etc.) and increased noise weakness. Not long after its release, this spectrum was replaced by the 2.4 GHz frequency, which proved a better candidate for crowded environments, even though it was slower and could have been disrupted by sources that function in the same interval (such as microwave ovens).
When 802.11/n came out, it gave users the possibility of tweaking their machines into functioning with both frequencies, depending on the environment. When there was a good reception, the trend was to use 5 GHz to accommodate greater speeds and when the signal proved to be weak, jumping to 2.4 GHz should have done the trick. Thanks to the fifth generation of Wi-Fi, this is not needed any more.
By combining all those features presented above, any 802.11ac equipment will solely rely on the 5GHz spectrum to deliver information, without having to worry so much about harming factors. Walls and other protective elements will be successfully penetrated thanks to beaming and whenever the reception proves to be bad, changing to a more robust coding scheme, such as 32-QAM, will prevent the connection from failing while providing decent transfer speeds.

Taking in consideration that 5GHz is a less-crowded spectrum, with most legacy devices running on 2.4 GHz, including conventional house-hold items, interface will be kept at a minimum. Moreover, there are only three orthogonal transmission channels in the 2.4GHz band, which can ensure a distortion-free communication between two devices. This means that in theory, if we have four users online in the same area, at least one of them is going to disrupt another. The downside fades in 5 GHz, where a total of 21 channels vouch for independence.

The End-user Impact

From an array of possible scenarios, we’ve found that 5G Wi-Fi will mostly increase transfer speeds for bigger devices, such as conventional computers, laptops and TVs. This is the category which can aggregate multiple antennas for a singular information stream, dividing the stream into multiple links and re-assembling everything at the destination (a proper MIMO implementation). In the best-case scenario, one constructed with a high-end access point that has 8 antennas and high end station with 4 antennas, the maximum theoretical speed will be 3.39 Gbit/s.
Moving the discussion towards the mobile segment, tablets will probably accommodate up to 2 antennas, and the maximum speed resulting from this configuration should be around 1.69 Gbit/s. When it comes to smartphones, only one antenna will be implemented, a presumption which will result into speeds up to 867 Mbit/s.
Another interesting aspect is that power-consumption has been optimized and several credited voices say that future chips should consume six-times less juice than existing versions, which may prove to be a fantastic benefit for mobile devices. Moreover, backwards compatibility with older standards such as 802.11 a/b/g/n will be guaranteed, at least in the first period.

When will 5G Wi-Fi be Available?

Actually, it sort of is already. The 802.11 ac standard has been completed and a full-state worldwide release is expected this year. Manufacturers are waiting to standardize products and the rift should hit sometime this summer. Even more, we can see signs of this upcoming tide in existing products.
For example, the first 802.11 ac chipset for retail routers was released in late 2011, while the first Broadcom-enabled router was launched in April last year, by Netgear. Most importantly, the first product to ever see true clients surfaced last summer, when Asus unveiled the ROG G75VX gaming notebook.
When it comes to smartphones, Android especially, HTC made the breakthrough this March with their famous One. Shortly after that, Samsung followed the queue with the Galaxy S5 and we are certain that even more will arrive in the following months. On the other camp, Apple has been known of working hard to integrate 802.11 ac technologies into several products this year, including AirPort base stations, Time Capsule, Apple TV and why not, the next iPhone.