为了实现地铁移动通信信号的覆盖，建立了专用无线通信系统。

In order to realize subway mobile communication signal coverage, specialized radio communication system was established.

youdao

为了实现地铁移动通信信号的覆盖，建立了专用无线通信系统。

In order to realize subway mobile communication signal coverage, specialized radio communication system was established.

youdao