https://blog.wongcw.com/2022/01/01/%e6%84%9b%e7%ab%8b%e4%bf%a1%ef%bc%9a2g-3g%e5%82%b3%e7%b5%b1%e6%8a%80%e8%a1%93%e9%80%80%e6%9c%8d%e9%80%80%e7%b6%b2%e5%b7%b2%e5%8b%a2%e4%b8%8d%e5%8f%af%e6%93%8b/