Wi-Fi 6 (802.11ax) Analysis: Protocol Introduction
The IEEE 802.11 protocol has experienced its 20th anniversary since its initial setting. The latest 802.11 protocol is the 802.11ax protocol. Today, I would like to share with you the overview and research progress of the protocol. let’s start.
Introduction to 802.11ax
802.11ax is a further extension of the wireless LAN protocol itself after 802.11ac, and can be regarded as a direct version after ac. The Wi-Fi Alliance calls it Wi-Fi 6, also known as High Efficiency WLAN (HEW). By the way, HN8546X6 is WIFI6 ONT, if you are interested, please click the link for more details.
Its initial naming code is HEW (High Efficiency WLAN), which started in 2013. Currently in November this year (2016), the protocol should have launched Draft 1.0.
802.11ax usage scenarios focus on Dense User Environments, which are different from previous protocols.
The evolution of 802.11a/b/g/n/ac generally focuses on the single-AP network to improve the throughput of the physical layer to improve the overall rate of the network. The initial design scenario of 802.11ax focuses on dense environments. In other words, its initial design ideas will be different from traditional 802.11. Moreover, the design of 802.11ax does not add a larger bandwidth than the current 160M bandwidth of 802.11ac (in fact, it is also impossible to find a channel with a larger bandwidth under the 2.4G and 5G spectrum resources). Therefore, the efficiency of the HEW named by the protocol also hopes to use the current frequency band resources more effectively, thereby providing a higher actual network rate.
Features of 802.11ax
1. Protocol compatibility:
802.11ax requires compatibility with the previous 802.11a/b/h/n/ac, which also proves that it is the second protocol that can work in both 2.4G and 5G frequency bands (802.11ac only works in the 5G band). Therefore, in its data frame structure and MAC access protocol, it needs to be compatible with the design, so that the traditional protocol is compatible.
2. Better energy efficiency to increase the battery life of mobile devices.
3. Higher transmission rate and coverage: In 802.11ax, the higher rate is reflected in the improvement of the PHY layer and the MAC layer. The specific improvements include the following:
- Provides higher order code combinations (MCS10 and MCS11). The main one is the introduction of QAM-1024. In 802.11ac, the highest order is 256QAM.
- At the same bandwidth, 802.11ax uses a FFT with more points (ie, 4 times the size of the original FFT). The more FFT points, the more sub-carriers and the smaller the sub-carrier bandwidth (the bandwidth is reduced from 312.5kHz to 78.125kHz. The corresponding symbol time is also increased by 4 times), which can cover farther scope. (The coverage is related to the coherence bandwidth. As long as the bandwidth of the channel is smaller than the coherence bandwidth, then it is flat fading, and the signal will not be affected by multipath. So the smaller the channel bandwidth, the longer the range can be covered)
- Introduce uplink MU-MIMO. In 802.11ac, the protocol only specifies downlink MU-MIMO. Uplink is still independently transmitted by a single node, while in 802.11ax, both uplink and downlink need to support MU-MIMO.
- Introduce OFDMA technology. The use of OFDMA in LTE is referenced in the design of 802.11ax, which allows multiple users to access the channel at the same time through different subcarrier resources to improve channel utilization. However, because 802.11 is a distributed access scenario, OFDMA in 802.11ax is actually less complex than in LTE.
802.11ax (Wi-Fi 6) adds many new features for high-density deployment scenarios. 802.11ax improves Wi-Fi networks by introducing new technologies that greatly increase transmission capacity, provide better coverage, and reduce congestion. Provide users with a better experience.
I hope today’s introduction will be helpful to you, thank you for reading.