New breakthrough! WiFi 7 is coming soon…

On February 15 , Qualcomm's official website clearly stated: Our innovative Wi-Fi 7 solution sets the standard for the next generation of Wi-Fi, giving WiFi 7 extremely high expectations.

This is not the first time that WiFi 7 has appeared. In January 2022, MediaTek debuted WiFi 7 and became the first company in the industry to successfully complete the WiFi 7 technology demonstration. However, WiFi 7 has not yet been launched. The latest WiFi standard on the market is WiFi 6E. However, it seems that WiFi 6E has not yet been fully popularized. Is WiFi 7 a King card or a pie?

What are WiFi and WiFi 7?

Before talking about WiFi, we have to mention an actress, Hedy Lamarr, who is also an inventor. In 1941, she borrowed the principle of synchronous piano playing by musician George Antheil and invented the "frequency hopping technology" FHSS (Frequency-Hopping Spread Spectrum), laying some foundation for future technologies such as CDMA, Bluetooth, and Wi-Fi.

In 1985, the FCC issued an ISM license and opened three frequency bands, including 2.4GHz, allowing nodes to communicate using spread-spectrum technology. After the ISM band was opened, the earliest wireless local area network WaveLAN was born in 1988. It is also considered to be the prototype of WiFi design. From then on, the development of WiFi gradually kicked off.

In 1993, the concept of hotspot access was proposed. That is, through the wireless network protocol, a small base station is built, and then the base station and the ISP network are directly connected. The hotspot concept has also become one of the key points for the final implementation of WiFi.

In 1997, the Institute of Electrical and Electronics Engineers (IEEE) of the United States issued the first generation of wireless LAN standard - IEEE 802.11 protocol, which stipulated that wireless LAN should operate in the 2.4GHz band, which was defined as a spread spectrum band by the Global Radio Regulation Organization. WiFi technology began to evolve and iterate based on 802.11.

In 1999, the Wireless Ethernet Compatibility Alliance (WECA) was formed to promote the development of the IEEE 802.11b specification. In October 2002, it was renamed the Wi-Fi Alliance.

After the release of IEEE 802.11, the Wi-Fi Alliance changed the naming convention to WiFi+number. In 2009, the release of 802.11n, also known as WiFi 4, was an important turning point for the industry. WiFi 4 increased the transmission rate from 54 Mbit/s to a maximum of 600 Mbit/s, introduced MIMO technology, and supported both 2.4Ghz and 5Ghz dual-bands.

In 2013, WiFi 5 (802.11ac) technology was officially passed, introducing MU-MIMO technology, which only works in the 5G frequency band and can reach speeds of up to 6.9Gbps.

In 2019, WiFi6 (802.11ax) introduced OFDMA technology, with speeds reaching 14Gbps.

Source: Zhihu-NETGEAR

In May 2019, the IEEE 802.11be Task Group (TGbe) was established to develop 802.11be (Wi-Fi 7). WiFi 7 is the seventh generation of WiFi wireless network. Compared with WiFi 6, WiFi 7 will introduce CMU-MIMO technology to support up to 16 data streams. Wi-Fi 7 can handle at least 30 Gbps, possibly up to 40Gbps. In addition to supporting the traditional 2.4GHz and 5GHz frequency bands, WiFi 7 will also support the 6GHz frequency band, and the three frequency bands can work simultaneously.

Image source: Qualcomm official website

What new breakthroughs does Qualcomm’s WiFi 7 have?

As can be seen from the WiFi 7 draft released in 2021, WiFi 7 has made great breakthroughs compared to WiFi 6. WiFi 6 uses unlicensed 2.4 GHz and 5 GHz bands, which are subject to restrictions and congestion. Although Wi-Fi 6E greatly expands the use of wide channel spectrum, multiple 160MHz channels can be used in any area where 6GHz spectrum has been allocated.

To achieve a maximum throughput of 30 Gbps, Wi-Fi 7 will support the 6 GHz frequency band and expand new bandwidth modes, including continuous 240 MHz, non-contiguous 160 + 80 MHz, continuous 320 MHz, and non-contiguous 160 + 160 MHz.

Wi-Fi 7's multi-connectivity feature provides clients with multiple options for using these channels, and the most effective way is to take advantage of the higher capacity, higher peak speeds, and lower congestion of the high frequency bands. In Qualcomm's WiFi 7 solution, terminal connections can switch alternately between frequency bands. In this solution, the terminal uses the first available frequency band for each transmission, and once the previous transmission is completed, it can select any frequency band for the next transmission. This approach can avoid connection link congestion and reduce latency.

Alternating multiple links, where devices alternate between available frequency bands to reduce latency

Currently, some areas can support three 320MHz continuous spectrum channels, some areas support one, and some areas do not support it at all. For the 5GHz band, there are no continuous 320MHz channels, so only areas that support 6GHz can support this continuous mode. High-band multi-connection concurrency can provide a wider effective channel by aggregating two available channels. That is, by combining two 160MHz channels in the high band, a 320MHz effective channel is created.

In China, the use of high-band multi-connection concurrent technology enables an effective channel of 240MHz, which means that even when 6GHz spectrum is not allocated, the advantages of Wi-Fi 7 ultra-high throughput can be taken advantage of. It can operate simultaneously on each band, so it is even better at avoiding congestion to reduce latency.

High-band Simultaneous Multi-Link, where high-bands are aggregated to provide the highest throughput and lowest latency

In some scenarios, users will occupy a portion of the bandwidth in an idle continuous channel (such as 20MHz or 40MHz), which usually prevents the AP access point from using the spectrum. In this case, Qualcomm's Wi-Fi 7 technology brings an innovative solution called "Preamble Puncturing", which allows devices to operate simultaneously on multiple frequency bands to avoid congestion and reduce latency. Supporting AP access points makes it possible to use the continuous channel while not being affected by the above interference. Although the amount of puncturing reduces the overall bandwidth, it can still achieve a wider channel than other methods.

Preamble puncture allows wider channels

The highest order modulation supported by Wi-Fi 6 is 1024-QAM, which allows each modulation symbol to carry up to 10 bits. Wi-Fi 7 introduces 4096-QAM so that each modulation symbol can carry 12 bits. Using the same encoding, 4096-QAM in Wi-Fi 7 can achieve a 20% rate increase compared to 1024-QAM in Wi-Fi 6. It can better enable 8K video playback and extended reality (XR) applications.

There are two major changes that differentiate WiFi 7 from WiFi 6. The first is a major upgrade to WiFi upload links. WiFi 7 will feature Uplink Multi-User Multiple Input Multiple Output (UL MU-MIMO) technology. This new technology creates multiple paths between the router and WiFi-connected devices. Connecting multiple paths to a device will significantly increase the amount of data that can be transferred in a short period of time. WiFi 6 allowed eight paths to transmit simultaneously, and WiFi 7 increases that to 16 paths.

WiFi 7 will also bring another improvement labeled Coordinated Multi-User MIMO (CMU-MIMO). CMU-MIMO will allow home devices to connect to multiple WiFi routers at the same time. This coordination should result in faster connections, lower latency, and the ability to provide high bandwidth to every corner of a home equipped with multiple WiFi access points. This is the most complex challenge in the WiFi 7 specification.

Source: Huawei Encyclopedia

Why do we need WiFi 7?

WiFi is now an integral part of our daily lives. It is also mentioned in "29% CAGR, China's Wi-Fi IoT is taking off" that China's Wi-Fi IoT market will continue to grow at a CAGR of 29%, from 252 million connections in 2021 to 916.6 million in 2026. This shows that the demand for WiFi is huge, and the number of indoor IoT connections will continue to increase in the future. Enterprises and users will have even greater requirements for low latency and fast transmission speeds.

WiFi 7 has already written a track of technological innovation. The new features it introduces will significantly increase data transmission rates and provide lower latency. WiFi 7 technology will be the core network for industries such as video/voice conferencing, cloud gaming, smart home, industrial IoT, metaverse, and telemedicine. Before commercial use in 2024, the results it will show are very exciting.

However, the key to determine the fate of WiFi 7 is the promulgation of the 6GHz spectrum policy. Modern high-speed Wi-Fi devices have increasingly higher performance requirements for WiFi transmission. Currently, some emerging industrial applications cannot provide the best service quality in the congested 2.4 GHz and 5 GHz bands. WiFi 7 will support high-band multi-link mode, which requires the use of the 6GHz carrier band. The allocation of the 6GHz spectrum will be an important message that affects the WiFi industry.