Wi-Fi 6 is here: These 12 questions will clarify it for you

5G is here, and WiFi 6 is here too.

Everyone has learned a lot about 5G, whether in WeChat or in the media. But many people are still unclear about WiFi 6. Today, we will answer all your questions about WiFi 6 at once.

1. What is WiFi 6?

In technical terms, WiFi 6 is 802.11AX. On October 4, 2018, the WiFi Alliance announced that the next-generation WiFi technology 802.11AX will be renamed WiFi 6. The name of 802.11AX has changed, and the names of previous generations of WiFi must also change accordingly:

802.11ac becomes WiFi 5;

802.11n Becomes WiFi 4

Here are the early WiFi years and the new WiFi names:

802.11b — Wifi 1 (1999)

802.11a — Wifi 2 (1999)

802.11g — Wifi 3 (2003)

802.11n — Wi-Fi 4 (2009)

802.11ac — Wi-Fi 5 (2014)

In my opinion, the previous WiFi naming was complicated and cumbersome, and more importantly, ordinary consumers did not quite understand it.

After changing to numbers, the WiFi names are simple, unified, and easy to recognize by users. When ordinary people buy routers, they only need to compare the "numbers behind WiFi", which is very intuitive and simple.

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2. How fast is WiFi 6? How much faster is it compared to WiFi 5?

For a single spatial stream on an 80Ghz channel, the theoretical speed for WiFi 5 is 866MB/s and for WiFi 6 it is 1201MB/s.

In real life, WiFi performance will vary, depending on the range of the wireless access point and device, obstructions, other signals in the air, and the quality of the radio.

3. If I upgrade my AP to WiFi 6, will the original 802.11ac/802.11n/802.11a/b/g devices still work properly? Is WiFi 6 backward compatible?

WiFi 6 is backwards compatible. That said, don’t expect to see performance gains simply by upgrading your AP—client devices also need to be WiFi 6.

4. How to achieve backward compatibility in 802.11ax?

Devices with 802.11ax radios can communicate with other 802.11ax radios using OFDM or OFDMA.

Devices with 802.11ax radios can communicate with older radios using OFDM or HR-DSSS.

When only 802.11ax OFDMA sessions occur, the RTS/CTS (Request to Send/Clear to Send) mechanism is used to defer legacy transmissions.

To add:

OFDM, orthogonal frequency division multiplexing, is a type of multi-carrier modulation. It uses frequency division multiplexing to achieve parallel transmission of high-speed serial data. It has good resistance to multipath fading and can support multi-user access.

OFDMA, or 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, enabling simultaneous parallel transmission for multiple users in each time period.

5. What problems can WiFi 6 solve?

Traditionally, WiFi performance has been unpredictable under load. 802.11ax is more deterministic, both in terms of latency and throughput. The main focus behind 802.11ax is not speed. The standard addresses network congestion and capacity issues that arise when "large numbers of devices" are connected to the network.

Compared with WiFi 5, WiFi 6 has a 4-fold increase in network bandwidth, a 4-fold increase in the number of concurrent users, and a network latency reduction from an average of 30ms to 20ms. A wireless access point (AP) can handle up to 12 WiFi streams simultaneously.

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6. How does WiFi 6 solve the efficiency problem?

In previous WiFi protocols, the wireless access point (AP) could only "talk" to one device at a time. However, WiFi 6 enables the wireless access point (AP) to send and receive data from multiple devices at the same time.

Traditionally, in 802.11, there is the concept of DCF (Distributed Coordination Function). This means that if you are a radio that is about to transmit data, you need to first see if anyone else is using the channel.

This means that even if you are on WiFi 5, you still need to "wait your turn" and fight for channel access with other older 802.11a/b/g devices.

In other words, at any given point in time - for a channel, only one frame can be on that channel within a range of signal strengths. Therefore, different devices have to seek each other out to see if the others are "talking" before they can "talk".

Another interesting feature is the concept of "TWT". TWT stands for Target Wake Time, which allows the AP to plan communications with devices, negotiate when and how long to wake up to send/receive data, and group terminals into different TWT cycles, reducing the time required to keep the antenna powered on to transmit and search for signals.

This means reducing battery consumption and improving battery life, while also reducing the number of devices competing for wireless resources at the same time after waking up.

Based on TWT technology, all smart devices connected to WiFi in the future can establish a "wake-up protocol" for each device. The terminal device will only enter the working state after receiving its own "wake-up" information, and will be in sleep state for the rest of the time.

This makes it possible for some IoT devices that require high-bandwidth communications, such as smart office equipment, to use TWT, which can save 7 times the battery power.

7. My WiFi works great. Do I really need to upgrade to WiFi 6?

That's up to you. The problem that WiFi 6 solves is "dense deployment scenarios". Places where there is a lot of CCI - Common Channel Interference. Many client devices trying to access WiFi at the same time.

In many public wireless access points, such as airports and stadiums, these are scenarios where WiFi 6 can play its own strengths. Its own characteristics can better use the wireless medium.

As a reminder, there is little benefit in upgrading your AP if your clients don’t support the latest protocol. 802.11ax offers enhancements to the PHY and MAC layers, which should improve operation in limited frequency bandwidths — but that’s only if the clients can use it, too.

You'll still get the benefits of MU-MIMO, but it may not be enough to justify the cost of the upgrade.

That said, if you’re deciding between 802.11ac and 802.11ax, it’s recommended that you go with the latest technology to future-proof your choice.

8. I thought 2.4Ghz was “dead”. Does 802.11ax add support for the 2.4Ghz spectrum?

WiFi 6 is dual-band, while its predecessor was only 5Ghz spectrum. Some vendors tried to implement WiFi 5 on 2.4Ghz, but the standard only approved 5Ghz wireless.

I think 2.4Ghz is driven by economics, and both old and newer models support the cheaper 2.4Ghz. Although 2.4Ghz is more susceptible to interference, it does provide better reception. That is, it can be "received" at a greater distance.

Even “2.4Ghz-only” devices will benefit, thanks to new enhancements in WiFi 6, like BSS shading.

9. Is 802.11ax the official standard?

No, the IEEE plans to ratify the protocol standard somewhere in the third quarter of 2019. That said, networking vendors such as Cisco, Asus, and Netgear have already begun to bring 802.11ax products to the market.

10.Is WiFi 6 full-duplex communication?

I'm afraid not, with OFDMA you just divide the 20Mhz channel into 2Mhz sub-channels. It's still half-duplex, think of it as a half-duplex switch with shared bandwidth.

While many big names supported opening up the 6Ghz band for use in unlicensed WiFi spectrum, that has not happened. We are still operating devices on both 2.4Ghz and 5Ghz.

11. When will 802.11ax devices be available on the market?

Broadcom manufactures over 70% of the world's device chips. We expect WiFi 6 devices to become popular in the second quarter of 2020.

There has already been talk of some phones from Samsung and LG coming out with 802.11ax compatibility.

12. What is BSS shading technology?

BSS (Basic Service Set) adds a 6-bit identifier to distinguish the BSSs of the same channel of different APs. The 6-bit is used in the message header. 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 it as long as it decapsulates the physical guide code to avoid conflicts. This makes the use of channel resources more orderly and more certain, thereby greatly improving the overall performance of the system in dense environments.