Wi-Fi 6 is here. Is it time to make a move?
If we were to cite the most influential wireless technologies of the past two years, 5G would undoubtedly come out on top. However, other wireless technologies are not loafing around as 5G gallops ahead. In fact, they are each advancing in their respective directions, in the hope of securing a place amongst increasingly heated competition while constantly seeking opportunities for increasing their market share.
The Wi-Fi Alliance announced in September 2019, which formally authorized the use of Wi-Fi CERTIFIED 6™, means that application of Wi-Fi 6 has already begun. This refocuses attention on Wi-Fi, an old friend who has been quietly by our side but hardly top-of-mind.
Constantly increasing speed
If we look back at the history of Wi-Fi development, the original idea behind Wi-Fi was not to create the gold standard of data transmission in wireless LAN, but simply to develop a wireless technology to solve the problem of tedious wiring between cash registers in stores. However, the value of this technology was quickly realized, and it soon became the international standard IEEE 802.11. Coupled with the rise of PCs and support from computer manufacturers, Wi-Fi eventually became the only option for large throughput wireless data transmission in LAN.
Even though Wi-Fi offers the convenience of wirelessness, its data transmission rates have always been compared to the rapidly developing wired Ethernet technology. After all, achieving higher speed has always been a core task in the development of Wi-Fi technology. As it turns out, Wi-Fi has not let us down.
As a wireless LAN technology that operates at the 2.4 GHz UHF or 5 GHz SHF ISM radio frequency bands, the Wi-Fi standard has been through five iterations of upgrades.
- The first Wi-Fi standard was established in 1999 (802.11b). It operated at 2.4 GHz, and could attain data transmission rates of up to 11 Mbps, which laid the foundation for commercial application of Wi-Fi.
- Second generation, faster Wi-Fi was announced during the same period (802.11a). The highest transmission rate that could be attained was 54 Mbps. However, it operated at 5 GHz and was not compatible with 802.11b, so it was only used in certain specialized fields.
- Third generation Wi-Fi was introduced in 2003 (802.11g). It attained a transmission rate of 54 Mbps at 2.4 GHz. It had backward compatibility and brought Wi-Fi performance to another level.
- Fourth generation Wi-Fi was released in 2009 (802.11n). It was able to operate at both 2.4 GHz and 5 GHz. When using a double-wide channel (40 MHz) and four antennas, it could attain a data transmission rate of up to 600 Mbps.
- Fifth generation Wi-Fi was released in 2016 (802.11ac wave2). It expanded on 802.11n and optimized the 5 GHz band. In the 2.4 GHz band, it was backward compatible with the previous generation and could attain a data transmission rate of up to 1.73 Gbps.
Figure 1, Development and comparison of Wi-Fi standards (Source: NXP)
Wi-Fi 6 is the sixth-generation standard, released by the Wi-Fi Alliance. From a technical perspective, Wi-Fi 6 is 37% faster than 802.11ac when transmitting data to a single user. Furthermore, its throughput is expected to increase four-fold through the combination of various new technologies, achieving a data transmission rate of a phenomenal 10 Gbps. It is fair to say that this will bring the Wi-Fi user experience to unprecedented new heights.
More than just higher speed
If you thought Wi-Fi 6 is simply Wi-fi 5 with more speed, think again. In fact, the Wi-Fi Alliance crammed Wi-Fi 6 with a swag of new technologies – those in the know will be truly amazed. Here is a summary of its key technologies:
Wi-Fi 6 uses OFDMA (Orthogonal Frequency Division Multiple Access) technology for uploading and downloading. It allows up to 30 users to share a channel to reduce latency, increase capacity, and improve efficiency. This makes Wi-Fi 6 much more stable than a cellular network. Previous Wi-Fi standards adopted a "best effort" approach, and users sometimes could not connect even when the Wi-Fi signal was strong, which greatly affected the user experience. OFDMA technology provides better network stability and reliability, and also creates more diverse application scenarios for Wi-Fi 6.
Though MU-MIMO is not a new technology introduced by Wi-Fi 6, it significantly optimizes the previous generation standard – implementing MU-MIMO in Wi-Fi 5 Wave 2, which only supports four download connections and one upload connection. Now Wi-Fi 6 can support multiple users with up to 8 upload and download connections.
In terms of modulation method, Wi-Fi 6 uses 1024-QAM to increase the amount of data transmitted in every effective load. By comparison, Wi-Fi 5 uses 256-QAM and Wi-Fi 4 uses 64-QAM, increasing the amount of data in each data packet to further increase throughput. Each OFDM symbol in 1024-QAM uses 10 bits, an increase of 25% compared to the 8 bits in 256-QAM. This increases the theoretical data transmission rate of an 80 MHz channel by 39% to 600 Mbps.
- Dynamic fragmentation
Compared with the static fragmentation used by Wi-Fi 5, the dynamic fragmentation used by Wi-Fi 6 allows different size fragments of data packets, and better utilizes network resources.
- Target Wake Time (TWT)
Previous Wi-Fi generations used a regular schedule to save power, waking up equipment at fixed times for transmission before going back to sleep. However, equipment was sometimes woken up when there was no data to transmit, thus wasting power. The new Target Wake Time (TWT) function in Wi-Fi 6 decides the wake time based on requirements negotiated between terminals and network, thus minimizing power consumption and even reaching BLE levels. This will transform the way people see Wi-Fi, which has been regarded as a high consumer of power.
Figure 2, Overview of Wi-Fi 6 key technologies (Image source: Wi-Fi Alliance)
In addition to increasing the peak rate on a single piece of equipment, Wi-Fi 6 aims to gain a critical edge in at least two other areas. Firstly, it aims to cover and connect to a larger number of different types of products. Secondly, it aims for higher throughput and reliability with denser connections. For all of these reasons and more, Wi-Fi 6 promises to be a major innovation for indoor wireless networks.
New fields of application
There are weighty commercial considerations behind any new version that is released. Given the improvements in Wi-Fi 6, Wi-Fi can be expected to open up new commercial application scenarios due to its ability to support more users, faster speed and higher reliability. Wi-Fi could even be applied in some low power consumption scenarios that seemed "atypical" in the past, and provide a new application experience.
In terms of the relationship between Wi-Fi 6 and the 5G network, despite overlapping markets, Wi-Fi 6 highlights its complementarity. In fact, Wi-Fi 6 and 5G each have their own strengths. The high frequencies used by the 5G network have less interference outdoors, but easily attenuate indoors and have higher network deployment and maintenance costs. On the other hand, Wi-Fi 6 is more suitable for indoors, areas with dense signals, and local area networks. It also has lower deployment and maintenance costs. Hence, some people are considering using Wi-Fi 6 routers as a small indoor base station for 5G, allowing users to continue using 5G services when indoor cellular signals are limited. Mobile phones can then switch between the two types of wireless communications.
Another trend that is expected to follow the introduction of Wi-Fi 6 is the use of the 6 GHz frequency band, which means higher speeds and more reliable connections. Some predict that a hybrid Wi-Fi network structure will appear in the future – a LAN with two networks, with the backbone using the 6 GHz frequency band with little interference and fast speeds, and the ability to use 2.4 GHz + 5 GHz for connections between terminal equipment in homes.
These are early days for Wi-Fi 6 and its commercial potential has only just been glimpsed. Much more will be revealed in 2020. Chances are that new products will be introduced at breakneck speed, and a series of mergers and acquisitions will shake up the industry. At this stage, all of the players are actively jostling for their market positions. With so much going on, shouldn't you also start thinking about making a move?