https://blog.wongcw.com/2018/12/19/3gpp%e5%ae%a3%e5%b8%835g%e6%a8%99%e6%ba%96%e5%87%8d%e7%b5%90%e6%8e%a8%e9%81%b2%e4%b8%89%e5%80%8b%e6%9c%88%e5%b0%87%e5%b0%8d%e7%94%a2%e6%a5%ad%e6%9c%89%e4%bd%95%e5%bd%b1%e9%9f%bf%ef%bc%9f/