We'll start with a quick review of how Wi-Fi has changed over the years. In f act, the earliest generation of 802.11 standard can be traced back to 199 7, when the wireless speed is very low, only 2Mbps, it is an original standard of the first generation . With the introduction of 802.11b in 1999, the physical layer speed was increased to 11Mbps and there were very few commercial applications. At that time, Wi-Fi was still far away from people's lives In 2003, the third generation of the standard, 802.11a/ g. Laptop began to configure wireless network card and home wireless router appeared in large quantity . Wi-fi comes into ordinary family. For Wi-fi 4, in 2007 we saw the second peak of growth in Wi-Fi, with the advent of the 802.11n standard. In 2012, the fifth generation comes that is 802.11AC.While 802.11AC Wave2, the new standard which is the second phase of 802.11AC appear in 2015. For WiFi 6, it's the sixth gen...