Let's first understand the key technologies of Wi-Fi 6.
1 OFDMA
Wi-Fi 5 uses OFDM technology, while Wi-Fi 6 uses OFDMA technology. What is the difference between the two?
If you compare data transmission to freight, OFDM technology only sends a car to one user at a time, even if it is a small piece of cargo that is empty in the carriage, it must be sent once. The goods of the previous user are sent out, and then the goods of the next user are sent. Obviously the efficiency is very low.
And OFDMA is like express logistics in our real life. The courier fills the truck with the goods of multiple users and then pulls it to the community for distribution. Every time the vehicle is fully loaded, of course the efficiency is greatly improved.
Specifically, under the OFDM (Orthogonal Frequency Division Multiplexing) technology, each user (terminal device) occupies the entire wireless channel in each time period when uploading or downloading data. The terminal equipment takes turns occupying the entire wireless channel in a time-division manner.
On the other hand, OFDMA (Orthogonal Frequency Division Multiple Access) divides the wireless channel into multiple sub-channels (sub-carriers) in the frequency domain to form a time-frequency resource block. User data is carried on each resource block instead of occupying the entire channel. In this way, multiple users can transmit at the same time in each time period, that is, they can communicate with multiple terminals at a time without waiting in line, which improves efficiency and reduces waiting time delay in queue.
2 MU-MIMO
A road with many vehicles makes the road very congested. MU-MIMO technology is equivalent to adding multiple layers (multiple) roads, thereby greatly improving traffic efficiency.
Although MIMO technology has been used as early as the Wi-Fi 4 era (802.11n), until the previous generation Wi-Fi 5 (802.11ac) only allowed the router to communicate with four terminal devices at a time, and only supported downlink MU-MIMO . Wi-Fi 6 supports simultaneous communication with up to 8 terminal devices, which is equivalent to extending the original 4 one-way roads to 8 two-way roads, which doubles the traffic efficiency.
3 1024QAM
QAM, Quadrature Amplitude Modulation, is the process of converting data signals into radio waves for transmission. The higher the QAM level, the more data contained in the wireless signal transmitted each time.
Wi-Fi 5 supports 256QAM (8bits/symbol), while Wi-Fi 6 supports 1024 QAM (10bits/symbol), which is an increase of 25%, which means that each car can carry more goods, and the data transmission rate has also increased by 25 %.
4 BSS Coloring
In the past, in order to avoid conflicts during data transmission, Wi-Fi checks whether there is data transmission on the wireless channel every time before transmitting data. If there is, avoid data transmission when the channel is clear. This causes the need for data transmission when busy. It takes a lot of time to stop and wait.
BSS Coloring was born to solve this situation. By adding 6bits of BSS Color to the data header, data can be transmitted on the same channel without mutual interference.
5 TWT
TWT, Target wake time, target wake time. Wi-Fi 6 uses TWT technology, which can define different wake-up times for each terminal, that is, only the terminal device enters the working state after receiving its own "wake-up" message, and the rest of the time is in the sleep state, which can save Power consumption, extend battery life.
From the above key technologies, Wi-Fi 6 mainly has the following advantages:
1) Thanks to the 160MHz large bandwidth, 1024QAM, OFDMA, MU-MIMO and other key technologies, the Wi-Fi 6 rate has been greatly increased, and the theoretical maximum speed is close to 10Gbps.
2) Multiple terminals can transmit in parallel at the same time without queuing and competing with each other, thereby improving efficiency, reducing time delay, and improving connection density.
After Wi-Fi 6 has improved its performance in terms of bandwidth, delay, and connection density, it has enhanced its scene adaptability, which means it can be applied to a variety of future business scenarios.
It mainly includes applications such as VR/AR, park office, smart manufacturing, smart city, smart education, and AI assistance.