Is the future of the new WIFI standard 802.11ad reliable?

Now there is a new WIFI standard that can increase the transmission speed to a higher level, that is 802.11ad. Compared with the current 802.11ac, the speed of the new standard reaches 4.6Gbps. It is much faster than the current standard Gigabit Ethernet and home broadband access.

Those who know about WIF know that there is a gap between theoretical speed and actual application speed. But we should also firmly believe that it is easy to wirelessly transmit 4K and HRR movies on 802.11ad, because the maximum speed of the highest quality triple-layer UHD Blu-ray is only 128Mbps.

The new standard even makes wireless virtual reality headsets possible.

From the current situation, 802.11ad will be first used in home routers. And now there are indeed many related products on the market. But with new technologies and new products come higher prices. So the question is, is it worth paying so much for 802.11ad?

How 802.11ad works

Like previous standards, 802.11ad is also promoted by the Wi-Fi Alliance. However, the difference from previous standards is that the technology behind ad does not come from IEEE, but from the WiGig Alliance, which was launched in 2009. It joined the IEEE drafting stage in 2011, and finally merged with the Wi-Fi Alliance in 2003. Understanding these reasons is very useful for consumers to further analyze the new standard. But until now, we have not said why the 802.11ad standard is more complicated. Let's talk about it in detail.

The key is that the new standard uses a completely different frequency band than the previous standard. That is, the 60Ghz band (between 57Ghz and 66Ghz bands) replaces the previously used 2.4Ghz or 5Ghz bands. The specific choice depends on the country you are in. The huge bandwidth makes it possible to transmit a variety of data, but there are also some limitations.

Wi-Fi spectrum diagram of a traditional home

Based on our knowledge system, we can clearly know that the first problem that the new generation of WIFI standards will face is the increase in frequency, the shortening of wavelength, and the resulting rate absorption. In a vacuum, this is no problem, but if it is placed in the real world with wooden floors and brick walls, it will be a serious problem because high-frequency waves will have difficulty passing through these obstacles. This is why those long waves (that is, low frequencies) can propagate so far, and this is also the reason why short-wave signals such as visible light can be absorbed by most materials.

If this comes to WIFI, its frequency is in the microwave band of 300Mhz to 300Ghz, and the wavelength is between 1 mm and 1 meter.

Back to the traditional 802.11 a/b/g in the 2.4G band, the signal can easily pass through people, doors and walls because it has strong enough penetration in this band. But when it comes to 802.11n/ac in the 5Ghz band, the available range is directly reduced, which is why many routers support both 2.4G and 5G bands. But if you are in a small space, the availability of 5G is very high.

With 802.11ad, the signal is so weak that it cannot pass through a thin wall, and even a wooden door will have a significant impact on the signal penetration. In this case, if you are in the same room with the router, you will get a very good network experience, but once you leave the room, I'm sorry, you can't play. This is why 802.11ad has not yet replaced the existing WIFI standards, and this is also why current routers need to support both 2.4G and 5G.

Of course, 820.11ad will also support previous standards.

Replacement of wired

One of the future directions for 802.11ad is to replace wired technology, which is the original intention of WiGig.

In the future, we will see 802.11ad support injected into TVs, set-top boxes, smartphones and other products. On NAS and portable hard drives, this wireless transmission plays a more important role. From a certain perspective, 802.11ad may even replace the DisplayPort on your monitor in the future.

At present, in a living room, you can use this wireless technology to arrange all the devices in your room. In addition, in some PC and work environments, you can also use this wireless technology to arrange devices.

Is 802.11ad really as powerful as it is hyped to be?

It seems that it will take some time for 802.11ad to be officially popularized. So the question is, is it really as powerful as advertised? For the purpose of testing, we compared the following three existing ad routers on the market and obtained the following results.

From the test results above, we can see that the download speed of *** can reach 868Mbps or 108.5MB/s. It is still far from the theoretical 4600Mbps. However, compared with the current standards, the speed has really improved a lot.

Since the coverage of ad is not wide enough, we need to automatically switch to the traditional WIFI band when we are at a long distance. This requires the router to provide "intelligent connection" to achieve seamless connection.

What comes after 802.11ad?

If 802.11ad is not the final choice for Wi-Fi, then how will it develop in the future?

From the current situation, in the next two or three years, in addition to 802.11ac and 802.11ad, other standards will emerge, such as 802.11ax, which adds support for 1024QAM (this thing has now been added to some ac routers) and OFDMA in the 2.4G and 5G frequency bands, so that a higher throughput can be obtained, and the speed can reach 10Gbit/s. However, these tests are all completed in the laboratory, and the standards have not yet been determined. I believe that by 2019, 802.11ax will not be available.

There is also 802.11ay, which is an extension of 802.11ad. This standard adds MU-MIMO, which can increase the throughput to 20-40Gbit/s, and according to the introduction, the coverage of this standard can be extended to 300-500 meters. Relevant people said that this standard may arrive in 2017, so we can see the second generation of 60Ghz routing next year.

As for using other higher frequencies, I think the inherent disadvantages make this idea impractical. But there are some studies now showing that some standards similar to WiFi can be used to increase WiFi speed by using other frequencies. For example, visible light communication such as "LIFI" works a bit like optical fiber. Especially the property that visible light can only travel in one direction.

But coverage is still an issue worth exploring. Energy consumption is another reason.

At the same time, in order to obtain enough certified frequency bands, the new WIFI standard must use more low-frequency intervals. The most representative one is 802.11ah, which uses 1Ghz bandwidth. It can cover a range of up to 1 km, but the data transmission rate will be very low, only 150Kbps. Many people regard ah as a standard for the Internet of Things.

Similarly, 802.11af is called white space Wi-Fi or Super WIFI, and the frequency they use is between 54MHz and 790MHz. Its transmission distance is very long, but as far as we can see, it has little impact in home applications because its frequency band overlaps with the frequency band of TV communication, and it also requires GPS location confirmation.

So for now, 802.11ad is the most suitable home WIFI technology, but it will take a long time before it becomes truly popular.