What's with the cell phone broadcast? How to use it? Can I use mobile Unicom?

community broadcasting is a short message service. It sends short messages to all mobile phone users in a certain area. For example, when you enter the airport, your mobile phone automatically receives a short message. Welcome to the airport. This is the service, and there is no charge. But I haven't met anyone who has opened a community radio. If you often cross provinces, you will receive welcome messages from one province to another.