Ⅰ Introduction

With the evolution of the Wi-Fi standard, WFA chose to rename Wi-Fi with a numeric serial number in order to facilitate Wi-Fi users and device manufacturers to easily understand the Wi-Fi models that their devices are connected to or supported. On the other hand, the next-generation naming method is also chosen to better highlight the major advances in Wi-Fi technology. It provides a large number of new features, including increased throughput and faster speeds, and support for more concurrent connections.

On September 16, 2019, the Wi-Fi Alliance announced the launch of the Wi-Fi 6 certification program, which aims to enable devices using the next-generation 802.11ax Wi-Fi wireless communication technology to meet established standards. In 2020, Qualcomm released a brand-new WiFi6E solution, which increased the key frequency band of WiFi6 by 6GHz, and the throughput and download rate can reach as high as several gigabits, realizing the experience of the wireless network at the same speed as a wired network.

Ⅱ Features

Wi-Fi 6 mainly uses OFDMA, MU-MIMO, and other technologies. MU-MIMO (Multi-User Multiple Input Multiple Output) technologies allow the router to communicate with multiple devices at the same time instead of sequentially. MU-MIMO allows the router to communicate with four devices at a time, and Wi-Fi 6 will allow communication with up to 8 devices. Wi-Fi 6 also uses other technologies, such as OFDMA (Orthogonal Frequency Division Multiple Access) and transmit beamforming, both of which improve efficiency and network capacity respectively. The maximum rate of Wi-Fi 6 can reach 9.6Gbps. New technology in Wi-Fi 6 allows the device to plan communication with the router, reducing the time required to keep the antenna powered on to transmit and search for signals, which means reducing battery consumption and improving battery life.

In order for Wi-Fi 6 devices to be certified by the Wi-Fi Alliance, they must use WPA3, so once the certification program is launched, most Wi-Fi 6 devices will have stronger security.

The most important improvement of Wi-Fi 6 is to reduce congestion and allow more devices to connect to the network. Wi-Fi 6 uses a technology called MU-MIMO (Multi-User Multiple Input Multiple Output) to achieve this, which allows the router to communicate with multiple devices at the same time instead of sequentially. MU-MIMO allows the router to communicate with four devices at a time, and Wi-Fi 6 will allow communication with up to 8 devices. Wi-Fi 6 also uses other technologies, such as OFDMA (Orthogonal Frequency Division Multiple Access) and transmit beamforming, both of which improve efficiency and network capacity respectively.

Ⅲ Differences from previous generations of Wi-Fi

Compared with previous generations of WiFi technology, the main features of the new generation of WiFi 6 are:

1.Faster

Compared with the previous generation of 802.11ac WiFi 5, the maximum transmission rate of WiFi 6 has been increased from 3.5Gbps to 9.6Gbps, and the theoretical speed has increased by nearly 3 times.

In terms of frequency bands, WiFi 5 only involves 5GHz, while WiFi 6 covers 2.4/5GHz, which completely covers low-speed and high-speed devices.

In terms of modulation mode, WiFi 6 supports 1024-QAM, which is higher than WiFi 5's 256-QAM, and higher data capacity means higher data transmission speed.

2.Lower latency

WiFi 6 is not only an increase in upload and download rates, but also greatly improves network congestion, allowing more devices to connect to the wireless network, and have a consistent high-speed connection experience.

The WiFi 5 standard supports MU-MIMO (Multi-User Multiple Input Multiple Output) technologies, and only supports downlink, which can only be experienced when downloading content. WiFi 6 supports both uplink and downlink MU-MIMO, which means that both mobile devices and wireless routers can experience MU-MIMO when uploading and downloading data, which further improves wireless network bandwidth utilization.

The maximum number of spatial data streams supported by WiFi 6 has been increased from 4 to 8 in WiFi 5, which means that it can support up to 8×8 MU-MIMO, which is one of the important reasons for the significant increase in the rate of WiFi 6.

WiFi 6 adopts OFDMA (Orthogonal Frequency Division Multiple Access) technologies, which is an evolved version of the OFDM technology adopted by WiFi 5. It combines OFDM and FDMA technology. After using OFDM to parent the channel, the transmission technology of uploading and transmitting data allows different users to share the same channel, allowing more devices to access, with shorter response time and lower delay.

In addition, WiFi 6 uses the Long DFDM Symbol transmission mechanism to increase the transmission time of each signal carrier from 3.2μs of WiFi 5 to 12.8μs, reducing the packet loss rate and retransmission rate, and making the transmission more stable.

Effective coverage of Wi-Fi during long-distance or multi-obstacle transmission

3.More capacity

WiFi 6 introduces the BSS Coloring mechanism to mark each device connected to the network, and at the same time add corresponding tags to its data. When transmitting data, there is a corresponding address, and it is directly transmitted to the place without confusion.

Shading mechanism display

Multi-user MU-MIMO technology allows multiple terminals in the computer network to share channels at the same time, allowing multiple mobile phones/computers to surf the Internet at the same time. Combined with OFDMA technology, each channel under the WiFi 6 network can carry out high-efficiency data transmission.

4.Safer 

If a WiFi 6 (wireless router) device needs to be certified by the WiFi Alliance, it must use the WPA 3 security protocol, which is more secure.

At the beginning of 2018, the WiFi Alliance released a new generation of WiFi encryption protocol WPA 3. It is an upgraded version of the widely used WPA 2 protocol. The security is further improved and can better prevent brute force attacks and brute force cracking.

5.More power saving

WiFi 6 introduces the TARget Wake Time (TWT) technology, which allows the device to actively plan the communication time between the device and the wireless router, reducing the use of wireless network antennas and signal search time, which can reduce power consumption to a certain extent and increase the battery life of the device.

Ⅳ Wi-Fi 6 core technology

The difference between Wi-Fi 6 and previous generations of wireless technologies is the introduction or upgrade of two major technologies, MU-MIMO (Multi-User Multiple-Input Multiple-Output) and OFDMA (Orthogonal Frequency Division Multiple Access) technologies.

1.MU-MIMO

Nowadays, there are more and more devices that need to be connected to Wi-Fi in each family. In the same Wi-Fi network, watching a high-definition movie on the TV is likely to make the mobile phone that is watching the live broadcast freeze. When eating in a restaurant, the Wi-Fi signal is clearly full, but the internet speed is unbearably slow. Why is this?

The reason is simple: According to the 802.11ac standard, an AP (router, hotspot) can only communicate with one terminal at a time. At the same time, if a large number of devices are connected to the same Wi-Fi network, the network will slow down and become stuck.

The introduction of MU-MIMO technology can change the operating mode of Wi-Fi networks, improve the utilization of network resources, significantly increase the total network throughput and capacity, and greatly increase the terminal's Internet speed.

MU-MIMO means that in a wireless communication system, a base station serves multiple mobile terminals at the same time, and the base stations make full use of the airspace resources of the antenna to communicate with multiple users at the same time.

WiFi 5 uses MU-MIMO technology in the downlink, WiFi 6 continues the MU-MIMO (multi-user multiple input multiple output system) brought by WiFi 5, but WiFi 6 supports the full version of MU-MIMO technology, which supports uplink and downlink. It can support 8 terminal devices to transmit more data in uplink/downlink at the same time, which is twice that of WiFi 5.

WiFi 6 allows the router to use multiple antennas to communicate with multiple terminal devices at the same time, achieving "multiple purposes". Compared with the previous design where only a single antenna and a single device can communicate at the same time, MU-MIMO is more capable of increasing the network speed and connecting more devices.

2.OFDMA

WiFi 5 uses OFDM (Orthogonal Frequency Division Multiplexing) technology, while WiFi 6 borrows OFDMA used in cellular networks. Multiple terminals can transmit in parallel at the same time without waiting in line and competing with each other, thereby improving efficiency and reducing latency. For example, it turns out that only one carrier can transmit a data packet in a time period. After using OFDMA, it is equivalent to multiple carriers that can transmit multiple data packets at the same time in a time period.

OFDM and OFDMA

Although OFDMA and MU-MIMO are both technologies that allow multiple devices to transmit at the same time, they are completely different. OFDMA can help in high-density environments with low throughput or small packet applications (such as IoT sensors), while MU-MIMO can help achieve high-throughput applications. OFDMA technology is a supplement to MU-MIMO.

Comparison of OFDM technology and OFDMA technology

OFDMA and MU-MIMO are the core technologies of WiFi 6. By providing multiple concurrent technologies in frequency space and physical space, respectively, they have greatly improved network performance and speed, and fully optimized user experience.

Ⅴ Wi-Fi 6 Applications

1. Carry 4K/8K/VR and other large broadband videos

Wi-Fi 6 technology supports the coexistence of 2.4G and 5G frequency bands. The 5G frequency band supports 160MHz bandwidth and an access rate of up to 9.6Gbps. The 5G frequency band has relatively less interference and is more suitable for transmitting video services. At the same time, it adopts BSS coloring technology, MIMO technology, dynamic CCA, and other technologies to reduce interference, reduce packet loss rate, and bring a better video experience.

2. Carrying low-latency services such as online games

Online game services are strongly interactive services, and higher requirements are put forward in terms of broadband and delay. For VR games, the best access method is Wi-Fi wireless mode. Wi-Fi 6 channel slicing technology provides games. The dedicated channel reduces the delay and meets the low-latency transmission quality requirements of game services, especially cloud VR game services.

3. Intelligent interconnection of smart homes

Smart home interconnection is an important factor in business scenarios such as smart home and smart security. The current home interconnection technology has different limitations. Wi-Fi 6 technology will bring the opportunity of technological unification for smart home interconnection and will connect high-density and large-number connections. Optimized integration of input and low power consumption, while being compatible with various mobile terminals commonly used by users, providing good interoperability.

4. Industry Application

As a new generation of high-speed, multi-user, and high-efficiency Wi-Fi technology, Wi-Fi 6 has a wide range of application prospects in industries such as industrial parks, office buildings, shopping malls, hospitals, airports, and factories.