Tech Corner
By Kerstin Naser, Corporate Product Manager Wireless at Rutronik
The latest Wi-Fi standards fit for current and future requirements
The latest Wi-Fi standard, Wi-Fi 6, and its extension, Wi-Fi 6E, promise high data transmission speeds, higher capacity and low latency, even in environments with many network subscribers. These advantages open up numerous new application options and areas of use, but also give rise to new requirements.
The much-cited refrigerator that automatically orders food has not caught on, but many other smart home devices have, such as washing machines that inform their owners via smartphone that the laundry is done. This is made possible by Wi-Fi, one of the best-known and most widespread wireless technologies. More and more devices offer a Wi-Fi interface, and not just in the smart home sector. Wi-Fi is also increasingly finding its way into industrial environments through applications such as mobile robots, crane systems, automated guided vehicles or even safety and security systems and the networking of sensors in production lines. Virtual reality and gaming applications, as well as wallboxes, also use this wireless technology.
The new application areas also place new requirements on the technology; and despite the increasing number of subscribers in the Wi-Fi network, users expect a stable network connection. That is why the Wi-Fi Alliance is constantly further developing the standards. Since the first IEEE 802.11 protocol appeared back in 1997, data throughput has improved significantly with each new Wi-Fi standard.
This time, however, the Wi-Fi Alliance has not only optimized the technology, but also the naming: Wi-Fi 6 and Wi-Fi 6E (E = enhanced/extended) replace the cumbersome title IEEE 802.11ax. The predecessor standards have also been given new names: IEEE 802.11ac is now called Wi-Fi 5 and IEEE 802.11n is now Wi-Fi 4.
Figure 1. Countries where Wi-Fi 6E is supported. (as of April 2022)
Technically speaking, Wi-Fi 6 and Wi-Fi 6E offer a whole range of enhancements:
OFDMA (orthogonal frequency division multiple access): OFDMA is an extension of the OFDM method used in Wi-Fi 5 technology. While only one data packet can be transmitted to a single terminal within a given time window when using OFDM, OFDMA enables the transmission of multiple sets of data for various terminals in the same data packet. This increases data rate efficiency and reduces network latency significantly.
1024-QAM (quadrature amplitude modulation): Compared to Wi-Fi 5, which uses the 256-QAM modulation method, 1024-QAM allows a 25 percent higher data throughput with Wi-Fi 6. With 1024-QAM, a total of 10 bits can be transmitted; with 256-QAM, it is only 8 bits. This is particularly advantageous in environments characterized by a high density of WLAN terminals, for example in railroad stations or at large events.
MU-MIMO (multi-user – multiple input, multiple output): By breaking up the available bandwidth into separate spatial streams, communication via multiple antennas between an access point and multiple devices is possible simultaneously, both downlink and uplink. With Wi-Fi 5, this only worked for downlink. As a result, Wi-Fi 6 further reduces network latency and provides greater stability.
TWT (target wake time): TWT “wakes up” network subscribers to transmit data only at specific times. The rest of the time, the devices “sleep” and thus require less energy. This also avoids interference in the network communication, since sleeping subscribers do not transmit data and do not block the communication streams—a decisive plus point, especially in industrial automation with many sensor applications.
Figure 2. Wi-Fi is a market with billions of devices and an economic value currently estimated at $3.3 trillion.
BSS (basic service set) coloring: Each BSS, consisting of an access point and the clients’, is assigned a “color” (i.e., a number) as soon as another BSS is in its vicinity. Signals from another network can therefore be detected and ignored. This allows more efficient use of the streams and better transmission quality.
Security standard WPA3 (Wi-Fi Protected Access 3): Compared to its predecessor standard WPA2, WPA3 provides significant enhancements in the area of authentication and encryption, as well as in the configuration of WLAN devices. Moreover, it ensures greater security at public hotspots. The WPA3 standard is mandatory for Wi-Fi 6 certified products.
Wi-Fi 6E offers even more advantages
Wi-Fi 6E offers more than just the aforesaid advantages: extension to the 6 GHz band, for instance. Wi-Fi 6E is also based on the IEEE 802.11ax Wi-Fi standard, thus supporting all the technologies mentioned, just like Wi-Fi 6. However, only the now heavily congested original 2.4 GHz and 5 GHz bands are defined for Wi-Fi 6. In contrast, the 6 GHz band is also available with Wi-Fi 6E. Further 80 MHz and up to seven additional 160 MHz spatial streams for data transmission allow even higher data throughput with wider spatial streams. The 2.4 GHz and 5 GHz bands, which devices with older Wi-Fi standards use for transmission, are relieved, which in turn leads to lower latency. This makes Wi-Fi 6E an ideal solution for gaming, streaming and virtual reality applications.
However, Wi-Fi use of the 6 GHz band has not yet been opened up in some countries. The USA started in 2020; Figure 1 shows which other countries have since followed its lead.
Switching over requires new hardware
Anyone who is now considering switching to Wi-Fi 6 or Wi-Fi 6E should keep in mind that devices with older Wi-Fi standards cannot simply be upgraded to Wi-Fi 6/6E through a software update. This means that all routers and devices that need to use the latest standard must be equipped with new hardware. Wi-Fi 6/6E devices, on the other hand, are backwards compatible with older Wi-Fi standards.
Established standard
Products are, therefore, available and numerous device suppliers are already applying them. According to the Wi-Fi Alliance, 2.3 billion and 350 million of the total 29 billion Wi-Fi devices shipped in 2022 will be equipped with Wi-Fi 6 and Wi-Fi 6E respectively (see Figure 2). Thanks to their advantages, the overall share of the new standards will certainly increase significantly.