Wi-Fi 6 is here! Wireless veteran explains the next generation of Wi-Fi

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Why is it called Wi-Fi 6?

Each new Wi-Fi version brings new features and its acronym, like 802.11.ax, the Wi-Fi Alliance calls it Wi-Fi 6, which stands for the sixth generation of Wi-Fi. Wi-Fi 6 is the next generation of Wi-Fi in the journey of next-generation wireless technology innovation.

What can we expect from Wi-Fi 6?

Based on the advantages of Wi-Fi 5 (11ac), this standard further enhances the efficiency of spatial reuse through enhanced coding and scheduling methods, allowing each AP to communicate with more devices at the same time, allowing for a higher density of device deployment, lower latency, longer coverage, and higher speed. At the same time, its improvement in low power consumption can extend battery life, which is particularly friendly to battery-powered IoT devices.

We will soon feel the experience revolution brought by Wi-Fi 6 in conference venues with tens of thousands of people, high-density offices, wireless production, smart teaching, smart media, and digital scenarios of cities and enterprises.

Wi-Fi 6 adds efficiency, flexibility, and scalability. This performance increase enables increased speed and capacity for the next generation of advanced applications, such as seamless mobile roaming, 4K or 8K video, high-definition collaboration applications, fully wireless offices, and the Internet of Things, even in high-density environments.

How does Wi-Fi 6 improve the experience?

We will use the example of traffic as an example because there is no other analogy that is more appropriate. Roads are like frequency bands for Wi-Fi, which are limited and fixed. Vehicles on the road are like messages for Wi-Fi, which can be large or small and have different transmission rates.

1. 1024QAM

QAM (Quadrature Amplitude Modulation): It is a two-dimensional dot matrix modulation method, which converts the data signal "01" into radio waves.

Wi-Fi 6 supports 1024QAM, which is 2 to the 10th power bit, a 25% improvement over Wi-Fi 5's 256QAM (2 to the 8th power 8 bits). This is equivalent to optimizing the road, bringing the lanes on the road as close together as possible and increasing the number of lanes without causing traffic congestion.

2. 256QAM

3. 1024QAM

4. OFDMA

OFDMA (Orthogonal Frequency Division Multiple Access): Orthogonal frequency division multiple access divides the wireless channel into multiple sub-channels (subcarriers) to form frequency resource blocks. User data is carried on each resource block instead of occupying the entire channel, so that multiple users can transmit in parallel at the same time in each time period.

Compared with the OFDM solution of Wi-Fi 5, which dispatches trucks based on orders, regardless of the size of the goods, one truck is dispatched for each order, even for a small piece of goods, which often results in empty carriages, low efficiency, and waste of resources. The OFDMA solution aggregates multiple orders and tries to load trucks fully, greatly improving transportation efficiency.

5. OFDM

6. OFDMA

7. MU-MIMO

MU-MIMO (Multi-User Multiple-Input Multiple-Output): Multi-user multiple input and multiple output, which allows the router to communicate with multiple devices at the same time instead of communicating one by one.

Wi-Fi 5's MU-MIMO allows the router to communicate with four devices at a time and only supports downlink MU-MIMO. Wi-Fi 6 will allow communication with up to 8 devices at the same time and support both uplink and downlink MU-MIMO.

Using a traffic analogy, it is like expanding from 4 one-way lanes to 8 two-way lanes. Multiple devices no longer have to wait in line like many vehicles to exit from one exit. Instead of queuing up one by one, multiple devices can exit/enter from different roads simultaneously and efficiently.

8. Comparison between OFDMA and MU-MIMO

Both of them solve the uplink and downlink of multiple users and improve the wireless access density, but in fact there are still big differences between the two. Although both are parallel transmission solutions, they are neither iterative nor competitive, but complementary. Their technical principles are different, and their applicable scenarios are also different. The specific use needs to be determined according to the application type of the service.

9. BSS-Color

BSS (Basic Service Set)

A 6-bit identifier is added to distinguish the BSSs of the same channel of different APs. The 6-bit is added to the message header. In this way, when an AP receives a message that is not its own, it does not need to decapsulate the entire packet before discarding it as before. It can discard the message as long as the physical guide code is decapsulated to avoid conflicts. This orderly and deterministic use of channel resources greatly improves the overall system performance in dense environments.

Using a traffic analogy, it is equivalent to dividing vehicles in the same lane into independent and non-interfering three-dimensional lanes in space according to different transmission purposes, effectively performing spatial reuse.

10. TWT

TWT (Target Wakeup Time): Target wakeup time

Allows the AP to plan communications with devices and negotiate when and how long to wake up to send/receive data. Terminals can be grouped into different TWT cycles, 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 performance, while also reducing the number of devices competing for wireless resources at the same time after waking up.

In the future, smart water meters, smoke detectors, access control in smart building scenarios, machine tools, AGVs, in-and-out scanning devices, and other types of smart devices in smart factory scenarios can all be connected to Wi-Fi. Thanks to TWT, each device can establish a "wake-up protocol" separately. The terminal device will only enter the working state after receiving its own "wake-up" information, and will be in a dormant state for the rest of the time, which can save up to 7 times the battery power consumption.

At the same time, this makes it possible for some IoT devices that require high-bandwidth communication, such as smart office equipment. TWT can save up to 7 times of battery power.

But the technology won’t help all devices, for example laptops need constant internet access and are therefore unlikely to benefit too much from this feature (perhaps more when going to sleep). The technology is more beneficial for small, low-power devices that occasionally need to update their state.

Therefore, TWT technology demonstrates Wi-Fi 6's determination to embrace the Internet of Things.

What capabilities does Wi-Fi 6 test Wi-Fi vendors?

In summary, Wi-Fi 6 provides many technologies that can effectively improve the efficiency of the entire Wi-Fi network. However, each technology has a lot of room for free play, such as the application of OFDMA technology, how to plan the most suitable subcarrier size; when multiple users transmit at the same time, how to implement corresponding power control for multiple users to ensure that the signals of users in close proximity do not overwhelm users in distant locations, etc.

For Wi-Fi 6 to achieve the best user experience, it is imperative that AI technology be introduced to adjust strategies in real time based on changes in the environment and application types of access terminals. This will be a stage for major manufacturers to demonstrate their strength.

Ruijie Networks Wi-Fi 6+AI, stay tuned for the next article to learn more.