https://blog.wongcw.com/2020/09/23/gsma%e5%b0%87mwc-2021%e5%b1%95%e6%9c%83%e5%b7%b4%e5%a1%9e%e7%be%85%e9%82%a3%e7%ab%99%e6%94%b9%e6%9c%9f%e8%87%b36%e6%9c%88%e5%ba%95%e8%88%87%e4%b8%8a%e6%b5%b7%e7%ab%99%e5%b0%8d%e8%aa%bf/