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’s the difference?
If we compare data transmission to freight transport, OFDM technology sends one vehicle for one user at a time. Even for a small item, the vehicle is empty, but it still makes a trip. Once the previous user’s goods are delivered, the next user’s goods are sent. This is clearly very inefficient.
OFDMA, on the other hand, is like our real-life express logistics where the courier fills the truck with goods from multiple users and then delivers them to the community. Each vehicle is fully loaded, which greatly improves efficiency.
Specifically, under OFDM (Orthogonal Frequency Division Multiplexing) technology, each user (terminal device) occupies the entire wireless channel during data upload or download, taking turns to occupy the entire channel in a time-sharing manner.
In contrast, OFDMA (Orthogonal Frequency Division Multiple Access) divides the wireless channel into multiple sub-channels (sub-carriers) in the frequency domain, forming multiple time-frequency resource blocks. User data is carried on each resource block instead of occupying the entire channel, allowing multiple users to transmit simultaneously within each time period, enabling communication with multiple terminals at once without waiting in line, thus improving efficiency and reducing queuing delays.
2 MU-MIMO
Imagine a road with heavy traffic, MU-MIMO technology is like adding multiple layers (multiple roads) to significantly improve traffic efficiency.
Although MIMO technology has been used since the Wi-Fi 4 era (802.11n), it was only in the previous generation Wi-Fi 5 (802.11ac) that routers could communicate with four terminal devices at a time, and only supported downlink MU-MIMO. Wi-Fi 6 supports communication with up to 8 terminal devices simultaneously, which is equivalent to expanding the original 4 one-way roads to 8 two-way roads, greatly enhancing traffic efficiency.
3 1024QAM
QAM, or Quadrature Amplitude Modulation, is the process of converting data signals into radio waves for transmission. The higher the QAM level, the more data each transmission of the wireless signal contains.
Wi-Fi 5 supports 256 QAM (8 bits/symbol), while Wi-Fi 6 supports 1024 QAM (10 bits/symbol), increasing by 25%. This is like each vehicle being able to carry more goods, thus increasing the data transmission rate by 25%.
4 BSS Coloring
In the past, to avoid conflicts during data transmission, Wi-Fi would check if there was data being transmitted on the wireless channel before sending data. If there was, it would wait until the channel was clear before transmitting, which caused constant waiting during busy times and wasted a lot of time.
BSS Coloring was created to solve this situation. It adds a 6-bit BSS Color to the data header, allowing data to be transmitted on the same channel without interfering with each other.
5 TWT
TWT, or Target Wake Time, is a feature of Wi-Fi 6 that allows for defining different wake times for each terminal. This means that terminal devices only enter active mode upon receiving their own “wake” signal, remaining in sleep mode the rest of the time, thus saving power and extending battery life.
From the above key technologies, Wi-Fi 6 mainly has the following advantages:
1) Thanks to key technologies such as 160MHz wide bandwidth, 1024 QAM, OFDMA, and MU-MIMO, the speed of Wi-Fi 6 has significantly improved, with a theoretical maximum speed approaching 10Gbps.
2) Multiple terminals can transmit in parallel without having to wait in line or compete with each other, thus improving efficiency, reducing latency, and enhancing connection density.
With improvements in bandwidth, latency, and connection density, Wi-Fi 6 enhances its adaptability to various future business scenarios.
Mainly including applications such as VR/AR, campus office, smart manufacturing, smart city, smart education, and AI assistance.
Source:5G Communication
Reviewed by: Zhao Lixin
