Wi-Fi 6E interview questions

Petr Koudelka, Senior Sales Engineer at Zyxel, follows the latest trends in network technologies and designs network architecture for businesses and organisations.

What do you think are the key benefits of the Wi-Fi 6E standard?

Opening the license-exempt 6 GHz band is as revolutionary a step as the release of the 5 GHz band for general use a few years ago. While the 6 GHz band remains less than 50% available in Europe compared to the US, it provides a significant additional frequency space for data transmission. The 2.4 GHz band has become congested by the high number of networks and the 5 GHz band is starting to experience the same problem, but the 6 GHz band is still vacant. We can enjoy this situation for some time. As the 6 GHz band can coexist with the 5 GHz one, more space will remain available for simultaneous data transmissions without mutual interference.

To put it simply, it is like adding ten highway lanes to the existing four ones. Even though you need to buy a new car to use those new ten lanes, the boost is so massive in terms of the capacity needed now and in the future that the investment is definitely worth it. The other benefits of Wi-Fi 6E are largely technical.

Transmission in the 6 GHz band has a significantly shorter reach – what is the required increase in the density of access points compared to the previous Wi-Fi 5 and Wi-Fi 6 standards?

To better understand the analogy with the new 6 GHz band, we need to go back to the 2.4 GHz and 5 GHz bands. As the 2.4 GHz frequency range is very small, one can say that the signal always behaves the same in that band. Attenuation, obstructions and other physical phenomena play the biggest role here, even though, of the three frequency bands used for Wi-Fi, this band is least susceptible to them. Attenuation, based on logarithmic rather than linear calculations, is an important criterion. So, removing 3 dB halves the attenuation while adding 3 dB doubles the attenuation.

In simple terms, transmission quality in the 2.4 GHz band is X at a distance of 1 meter from the transmitter while transmission quality in the 5 GHz band is X-7 dB at the same spot, i.e. about one quarter. And since -6 dB is half of half, the 6 GHz band provides even one dB less at the same spot, which is X-8 dB.

The spectrum available in the 5 GHz band is approximately six times larger than in the 2.4 GHz band, as a result of which its behaviour and frequency attenuation at the beginning and end of the spectrum cannot be completely overlooked. Even so, we are talking about a small number – just less than 1 dB. The frequency width of the European 6 GHz band is similar to that of the 5 GHz band, which means that the attenuation will also differ by about 1 dB between the lowest and highest frequencies.

Let’s now compare the 5 GHz and 6 GHz bands. These two frequencies are similar in behaviour and they are far from the 2.4 GHz frequency, which behaves in a completely different manner. The difference between the first and last channel of both the 5 GHz and 6 GHz frequencies is about 1 dB, making the difference between the highest channel of the 5 GHz band and the lowest channel of the 6 GHz band negligible. If we choose the channels at the opposite ends of the two bands, the difference in attenuation can be up to 2 dB. An ordinary interior door results in an attenuation of about 3 dB, so we can see that there is a difference here, but not a major one.

A problem may occur if someone designs a network at the very limit of technical usability and does not allow for any margin. However, if a network is designed with capacity and good signal overlaps in mind, you will not notice any difference when switching from 5 GHz to 6 GHz. For example, switching to 6 GHz may pose a problem in places like large warehouses where the signal in the 5 GHz band is at the very limit of usability. But offices and households are unlikely to see their Wi-Fi coverage degrade.

Adopting a new standard of wireless networks involves upgrading not just network equipment but also end devices. Are their manufacturers ready for Wi-Fi 6E?

Major manufacturers of wireless cards for network equipment already supply products supporting the 6 GHz band, but it is all about the price. Even a small increase in the price of cheaper products such as mobile phones, tablets or laptops will delay the launch of the latest technologies. But if you purchase a higher-end product, it is safe to assume it will already support the new frequency. For example, the selling price of the Intel AX200 and Intel AX210 network adapters is CZK 357 and CZK 473 respectively, which is a 32% difference or just CZK 116 in absolute figures. But with millions of units, the difference gets really big.

Can you compare the benefits of deploying Wi-Fi 6E and 5G networks in an industrial environment? Which technology is better suited for which purposes?

While each of these technologies specialises in something slightly different, their features overlap to some degree. Where these two technologies differ fundamentally is the purpose of their deployment. In particular, Wi-Fi 6E focuses on a smaller signal range but a huge data rate of the local network. This is essential where a local gigabit network is no longer sufficient, requiring an upgrade to multi-gigabit speeds to stream 8K videos from a storage device, to transfer massive amounts of data, etc.

A 5G network provides a lower data rate, generally 500 Mbps to 1 Gbps or even less, depending on the operator. On the other hand, its signal has an extensive reach, covering a large area around the transmitter, as well as a huge capacity for connected clients, although this is because IoT devices such as sensors are not expected to generate much data traffic.

Most businesses and organisations have not yet migrated to the previous Wi-Fi 6 standard. Would you advise them to wait and upgrade straight to Wi-Fi 6E?

Electronics manufacturers will start using new chips in their products as chipmakers will gradually phase out older technologies. The lifecycle of wireless products is several years, with the launch of the new Wi-Fi 7 standard being currently scheduled for late 2024. Wi-Fi 7 access points and clients will not hit the shelves until much later.

Making the 6 GHz band available is a huge step to achieve a higher data rate, distribute the traffic generated by connected clients and connect more clients. So, if you are considering the deployment of a new Wi-Fi network right now, Wi-Fi 6E access points are definitely worth the investment. If we are talking about a small network in places such as a pension where speed and other benefits are not that important, the lifecycle of existing access points will surely be even longer than in a large hotel with conference rooms or in other locations where the wireless network is required to handle massive data traffic.

What do you think the next development of Wi-Fi technologies will be? Is it possible to continue increasing the throughput of wireless networks, or is the development focusing on something else?

The limited transmission speed of metallic networks plays a role here: instead of simply replacing access points we must also address the transmission capacity problem by upgrading to multi-gigabit switches. The Wi-Fi 6 standard ushers in a major technological shift in terms of both speed and transmission technology, making both of the original 2.4 and 5 GHz bands faster. Dividing the band into sub-channels has increased the capacity for connected and served clients. First and foremost, the new standards have brought more efficiency and better transmission options.

Higher speed can be achieved simply by two ways – more frequency bandwidth and better modulation. However, both ways have their pitfalls. The Wi-Fi 7 is to support a frequency range of up to 320 MHz, which is the entire “European” 5 or 6 GHz band today, i.e. one transmitter without onsite interference. Placing another transmitter into the 320 MHz channel is not possible without interference. Better modulation requires an interference-free signal of very high quality, which means a very small distance between the client and the access point. This results in a lower performance of the access point and a shorter distance from the client. These are major limitations, so I think that the opening of the 6 GHz band for wireless transmissions will be the most significant move that will affect the development of Wi-Fi for quite a long time.