bubble signal

例句：

1. 1.The bubble signal is a good way to communicate with people who are far away.
   气泡信号是一种与远方的人进行沟通的好方法。
2. 2.The bubble signal was used to transmit messages over long distances.
   气泡信号被用来在长距离上传输信息。
3. 3. The bubble signal helped us to establish communication with the other team.
   气泡信号帮助我们与另一个团队建立了通信。