802.11ax emerges, what does it bring to wireless?

In 2017, Broadcom, Qualcomm, Marvell and other manufacturers launched 802.11ax chips, and downstream wireless manufacturers also released experimental APs or wireless routers that support the 802.11ax protocol. If nothing unexpected happens, 802.11ax will be commercialized in 2018.

In fact, like the impetus for the launch of 5G, WLAN is also moving towards high bandwidth, large connections, and low latency. 802.11ax now plays the role of promoting the evolution of WLAN. Since the launch of the 802.11 protocol family, it has gone through the development process from b, a/g, n to ac, and the data transmission rate has been continuously improved, from the earliest 2Mbps to 11Mbps, 54Mbps, 450Mbps, and then to 802.11ac wave1 Theoretical transmission rate of 1.3Gbps, 802.11ac wave2 80MHz bandwidth The rate is increased to 1.73Gbps.

There is no doubt that 802.11ax is a newcomer in WiFi technology and the next generation version of the currently popular 802.11ac. Although the technical standards are being formulated, in the wireless field, products are mostly developed first.

What are the characteristics of 802.11ax and what will it bring to wireless?

Many people think that 802.11ax will speed up wireless communication. Indeed, 802.11ax brings higher transmission rates. It introduces a higher-order modulation and coding scheme, 1024QAM. Compared with the 256QAM standard in 802.11ac, the coding and modulation efficiency is higher. The association rate of each 80M bandwidth spatial stream is increased from 433Mbps to 600Mbps, and the theoretical maximum association rate (160M bandwidth, 8 spatial streams) is increased from 6.9Gbps ​​to about 9.6Gbps.

However, "fast" is not the core of 802.11ax. The core of 802.11ax is OFDMA (Orthogonal Frequency Division Multiple Access), which is derived from LTE technology and allows terminals to have a more stable and reliable multi-user concurrent transmission mode that does not rely on MU-MIMO. Unlike the orthogonal frequency division multiplexing (OFDM) modulation method used in 802.11a/g/n/ac technology, in a high-density access environment, a single channel can only be used by a single user at the same time. The OFDMA mechanism can provide smaller (but exclusive) sub-channels for multiple users at the same time, thereby improving the average transmission rate of each user.

To put it in simpler terms, the core of 802.11ax is to have stronger concurrency capabilities. Its design scenario initially focuses on dense environments. In other words, its initial design concept is somewhat different from traditional 802.11. The purpose is to increase data throughput in crowded network spaces. Because 802.11ac and previous protocols can provide significantly lower actual data throughput in environments with very dense users.

The 802.11ax standard will be able to improve Wi-Fi performance in multi-user environments (such as exhibitions, high-speed rail stations, and stadiums) by improving spectrum efficiency, better managing crosstalk, and enhancing the PHY underlying protocol (media access control data communication) to maintain high throughput even in densely populated environments.

In addition, 802.11ax also introduces more networking features in the LTE field, such as spatial reuse (SR) technology. In the past, APs had poor coordination and there was "noise" between them. The networking features of 802.11ax have greatly improved the anti-interference performance.

In addition, 802.11ax also has good protocol compatibility. It supports both 2.4G/5G Hz frequency bands, and the preamble frame structure remains almost unchanged. It is forward compatible with 802.11a/b/g/n/ac. There is no need to worry about the massive amount of existing Wi-Fi terminals being eliminated in the 802.11ax era.

Why is it necessary to upgrade to 802.11ax?

Some people may ask, the 802.11ac I am using now is already very fast, why is it necessary to upgrade to 802.11ax? Indeed, the answer to this question should be combined with the scenario. If in a traditional enterprise office environment, 802.11ac is sufficient to meet the needs, in addition to purchasing new APs, then you can upgrade to 802.11ax when the equipment is updated. However, in high-density scenarios such as exhibitions, high-speed rail stations, and stadiums, 802.11ac will indeed face bottlenecks, which is a problem that 802.11ax focuses on improving. As mentioned above, OFDMA technology is designed to solve high-density concurrency, so such scenarios should pay more attention to 802.11ax.

In addition, driven by application scenarios, the deployment of 802.11ax may be faster. For example, AR/VR, 4K video, etc. These applications require higher network throughput. Their maturity and development are bound to have a significant impact on the implementation of 802.11ax.

When will the 802.11ax industry chain mature and become commercially available?

Having said that, although the upstream is actively promoting 802.11ax, its commercial use also has another important factor. That is, terminal devices, including laptops, mobile phones, etc. Therefore, this requires the maturity and evolution of the entire industry chain. From the current information, the terminal popularization that everyone is more worried about is only a matter of time. The first batch of terminals is expected to be launched in the second half of 2018. Some industry insiders have predicted that at least 30% of terminals will support 802.11ax in 2019.

However, "to get rich, you must first build roads", and wireless upgrades and evolutions are very necessary. With the widespread use of Wi-Fi, there are more and more high-concurrency and short messages in current scenarios. Traditional Wi-Fi protocols have no advantages in handling high concurrency and a large number of short messages. 802.11ax's improvements and optimizations for these scenarios will support better application experience.

In summary, the maturity and commercialization of 802.11ax is similar to that of 5G. Although they are aimed at different application scenarios, they do overlap in some areas. In terms of technology, although the two are not giving in to each other, they are also converging to a certain extent.