How far can Wi-Fi 6 go?

Wi-Fi is an indispensable part of modern people's lives. In October 2018, the Wi-Fi Alliance renamed the Wi-Fi standard based on the naming method of communication technology to better promote Wi-Fi technology. 802.11ax was named Wi-Fi 6, 802.11ac was named Wi-Fi 5, and so on. So far, the 802.11a naming format, which has been used since 1999, has officially withdrawn from the stage of history.

As a new generation of Wi-Fi wireless LAN transmission technology, Wi-Fi 6 has many advantages over Wi-Fi 5, including high speed, high number of connections, low latency, low power consumption, and security.

When Wi-Fi 4 was upgraded to Wi-Fi 5, in addition to improving the QAM modulation method and Wi-Fi bandwidth, a new 5Ghz Wi-Fi frequency band was also opened up. Because the 2.4Ghz frequency band is too crowded, it is difficult to run 256QAM and 80Mhz Wi-Fi 5. If Wi-Fi is compared to a highway, then compared to Wi-Fi 4, Wi-Fi 5 not only has faster "cars", but also more "lanes", and the two-lane road has been transformed into a high-speed expressway. The 5Ghz Wi-Fi channel can accommodate faster Wi-Fi transmission.

Limitations of Wi-Fi 6

However, the upgrade of Wi-Fi 6 simply uses the 5Ghz Wi-Fi channel of Wi-Fi 5, which only brings faster "cars" but no more "lanes".

Although 5Ghz has more channels than 2.4Ghz, the congestion of 5Ghz is still very considerable in 2020. After all, a few years ago, the only device we needed to access Wi-Fi might be a mobile phone or a computer. Now, we have all kinds of smart devices, such as smart doorbells, smart TVs, smart light bulbs, and so on.

That is to say, even in the era of Wi-Fi 5, 5Ghz is almost reaching its upper limit. The acceleration method of Wi-Fi 6 still relies on increasing QAM and channel bandwidth, both of which can only be effective when there is less Wi-Fi interference.

The dilemma of Wi-Fi 6 is that 160Mhz Wi-Fi is difficult to implement. Under a fixed total Wi-Fi bandwidth, the higher the Wi-Fi transmission bandwidth, the fewer available channels there are, and the greater the mutual interference. Without widening the "lane" and opening up new Wi-Fi channels, Wi-Fi 6's 160Mhz high-speed Wi-Fi will be difficult to apply.

Wi-Fi 6E = Wi-Fi 6 + 6 GHz

WiFi 6E is an enhanced version of WiFi 6 (E stands for Extended). The main difference between WiFi 6E and WiFi 6 is that the 6GHz band (5925-7125 MHz, a total of 1.2 GHz bandwidth) is added to the original frequency band.

In other words, the introduction of Wi-Fi 6E is to solve the spectrum problem. Wi-Fi 6E allows operation on the 6 GHz band.

Wi-Fi 6E's 160Mhz Wi-Fi channels increase from 2 in 5Ghz to 7. As the Wi-Fi Alliance says, Wi-Fi 6E allows for "14 additional 80 MHz bands and 7 additional 160 MHz bands." This is very good news for the currently crowded 2.4GHz and 5GHz. These channels will not overlap with each other, helping to reduce congestion, especially in areas where a large number of networks are running.

6GHz is a relatively idle frequency band. WiFi 6E can provide 7 consecutive 160MHz frequency bands at a time, which is very suitable for high-performance applications. This means that using a system that supports WiFi 6E, the traditional 2.4GHz and 5GHz frequency bands can be allocated to devices with low performance requirements, and the clean and complete 6GHz frequency band can be allocated to high-performance devices, so that different devices can get what they need.

In addition, the two 160Mhz channels of 5Ghz are restricted by DFS (to avoid interference with radar, etc.). In some areas and with some firmware, DFS channels cannot be opened, while all 160Mhz channels of 6Ghz WIFI are not affected by DFS.

Not only that, WiFi 6E is also important because it can leverage the implementation of important applications. WiFi 6 is mainly an improvement in data throughput compared to the previous generation of Wi-Fi, while WiFi 6E's improvement over WiFi 6 is in two dimensions: data throughput and latency. The improvement in communication latency will be the key to WiFi 6E leveraging new applications, such as the next generation of multimedia applications and industrial applications leveraged by edge computing. These new applications that require high data throughput and low latency are the strengths of WiFi 6E.

Previously, manufacturers such as Broadcom and Intel have begun testing WiFi 6E. According to the test results of WiFi 6E released by Broadcom, its peak throughput rate can reach 2Gbps and the delay is only 2ms. Its high throughput and low latency are very suitable for high-performance applications.

In April this year, at the Federal Communications Commission's monthly meeting, the FCC voted to approve a proposal to open the 6GHz frequency band, releasing up to 1200MHz of frequency band resources at one time, from 5.925GHz to 7.125GHz, for unlicensed use (indoor devices are limited to low-power routers, smart hardware, etc., and outdoor devices are limited to the same power level in the 850MHz frequency band).

Wi-Fi 6 = Obsolete?

Wi-Fi 6E is so useful, can previous Wi-Fi 6 devices be directly eliminated?

In May this year, Qualcomm launched the first batch of new routers and mobile Wi-Fi 6E series platforms, which can work simultaneously in the three frequency bands of 2.4/5/6GHz. Wi-Fi 6E devices will be backward compatible with Wi-Fi 6 and previous Wi-Fi standards. As for whether the Wi-Fi 6 devices launched by various manufacturers in the past can support Wi-Fi 6E through software upgrades, it is still unknown.

However, 5Ghz and 6Ghz signals are physically fundamentally different. Unless the current Wi-Fi 6 chips and antenna modules have 6Ghz reserved, it is impossible to achieve Wi-Fi 6E through upgrading.

For those who have already bought a new Wi-Fi 6 router as early as last year, this may not be too good news, but there is no need to worry too much. After all, it will take some time for Wi-Fi 6E to be launched, and it is still too early. At present, Wi-Fi 6 has just become mainstream, and there are very few devices on the market that support Wi-Fi 6E. Most Wi-Fi 6E devices will not be available until after 2021.

Looking Ahead to Wi-Fi 7

Wi-Fi 6 has just become popular in the market, but research on Wi-Fi 7 is already underway.

Wi-Fi 7, or 802.11be, is now named IEEE 802.11 EHT, where EHT stands for Extremely High Throughput (compared to 802.11ax, which is HEW, High Efficiency WLAN). The Wi-Fi 7 working group was actually established in May 2018, and the project was established in early 2019.

The Wi-Fi Alliance has already begun researching the Wi-Fi 7 (802.11be) standard draft. According to the plan, the Draft 1.0 standard will be released in May 2021, Draft 2.0 in March 2022, Draft 3.0 in November 2022, and the final Draft 4.0 standard will be formulated in November 2023, and then officially promoted in 2024.

Although Wi-Fi 7 is still in the early stages of development and is still a long way from becoming the final standard, some of the details revealed so far have already shown significant improvements over existing Wi-Fi capabilities.

Wi-Fi 7 supports 16 data streams and introduces CMU-MIMO. Wi-Fi 6 supports up to 8 data streams, and Wi-Fi 7 will exaggerately double this number. The "C" stands for "Coordinated", which means that the 16 data streams can be provided by multiple access points simultaneously instead of one access point.

Wi-Fi 7 also upgrades the signal modulation method to 4096QAM to have a larger data capacity. Wireless technology will of course involve the modulation method of the signal. In 802.11 ax, the standard uses 1024-QAM modulation, and Wi-Fi 7 is expected to continue to upgrade the modulation method and directly use 4096-QAM to further expand the transmission data capacity and lay a solid foundation for the highest 30Gbps.

The first Wi-Fi 7 chipsets are expected to be tested in 2021, but it will take longer for manufacturers to explore, perfect features, and design products around the new standard. Overall, the technology is not likely to be widely available until at least 2024.