With Cell Broadcast it is possible to send a text message to a large number of subscribers
* in near real-time,
* with location specific information,
* including visitors from other countries,
* in their desired language,
* without suffering from network congestion.
Near real-time means that millions of citizens can be reached witin a few minutes;
Location specific information means cell-site granularity, which is a few hundred meters in a densely populated area to 30 km in a rural area;
Including visitors from other countries means that everyone who roams on a network is able to receive the warning messages;
In their desired language means that messages can be broadcast in more than one language;
Without suffering from network congestion means that in cases where the network is congested (and networks do get congested when an emergency occurs) and voice calls and SMS are no longer possible, CB will still be available.
This makes CB perfectly suitable for public warning purposes. In fact, it is the only viable solution today.
NTT Docomo in Japan offers the Area Mail Disaster Service. The technology for this service is based on an extended version of CB and is currently being standardized in 3GPP.
The US is extending the Emergency Alert System (EAS) with a Commercial Mobile Alerts Service, which shall provide a public warning service in the mobile network. In April 2008, the FCC announced that rules have been adopted for delivery of commercial mobile alerts to the public during emergencies. The full text is in the First Report and Order. The Report and Order does not prescribe which technology shall be used, but Einstein Wireless in Wisconsin demonstrates that it works with CB today.