https://blog.wongcw.com/2019/02/25/5g%e5%9f%ba%e5%b8%b6ppt%e5%a4%a7%e6%88%b0%e8%8f%af%e7%82%ba%e5%b7%b4%e9%be%8dvs-%e9%ab%98%e9%80%9a%e9%a9%8d%e9%be%8d%e8%aa%b0%e6%98%af%e7%9c%9f%e9%be%8d%ef%bc%9f/