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DRM Emergency Warning Functionality Saves Lives

In times of disaster, it’s mandatory to reach the entire population

The author is senior business development manager for Digital Radio and Streaming Applications at Fraunhofer IIS.

ERLANGEN, Germany — When disasters are about to strike, getting the message to everyone affected as quickly as possible is of the utmost importance. Technical solutions need to be able to meet specific requirements for this and ensure, reliability, even when the local infrastructure is down. In addition, everybody in a disaster area needs to be reachable, even people with impairments or visitors who don’t speak the local language.

Digital Radio Mondiale can round off the established set of national tools for early warning dissemination. Radio receivers have long been a core component of warning systems worldwide. Receivers can be battery-, solar- or wind-up powered, and transmission infrastructure is both easily secured against power losses and can reach the affected area from outside. Radio transmissions are often the last way to maintain contact with people in heavily hit areas, when local power, cell and TV towers are gone.


DRM’s support for Emergency Warning Functionality allows digital radio sets to automatically switch from the current service to the emergency program when needed, and even automatically switch on the emergency program even when on standby. In addition, the volume is increased and the emergency state is visually indicated (e.g. through a flashing screen or LED). In an emergency, a DRM digital radio set can wake up its user and provide the required information. The same is true for cars and mobile phones: Alerts and information will reach you even if the car radio is off or when your mobile phone is disconnected from the internet.

The emergency program via DRM can consist of the audio announcement (e.g., a quickly repeated headline in a single language), but can also be accompanied by text information based on the standardized Journaline service component, a core DRM element. The structured text feature allows users to look up relevant information on the device’s screen much quicker and in more detail than what would be available over audio channels.

This enhanced information can include locations and descriptions of shelters sorted by region, contact details of public authorities, or general advice for before, during and after the event. The information can be dynamically updated and enhanced at any time as the situation evolves. In addition, Journaline is designed to reach the hearing impaired, as well as travellers who don’t speak the local language through its multilingual support. The system also carries an exact description of the affected area to limit unwanted receiver switching.

On a technical level, implementing EWF functionality into any DRM receiver is not complicated, because EWF is a combination of standard functionalities that need to be supported by any DRM receiver. It combines DRM’s alarm announcement and alternative frequency signaling and switching (AFS) with audio decoding and Journaline presentation.

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There is very little manufacturers need to do for the receiver to be EWF compliant. Mainly, they just need to ensure the receiver is equipped with an automatic volume increase and visual alarm indication. To ensure that the automatic receiver wake-up functionality will be available on the widest possible set of DRM receivers in a country, regulators are encouraged to mandate this element in addition to general DRM EWF support as part of a policy for the receiver and automotive industry.

On the transmission side, all modern DRM encoder and multiplexer solutions today support EWF natively. To issue alarm signaling (typically triggered by a national authority) and to provide core information in audio and textual form to the DRM multiplexers for immediate playout, many countries rely on the commonly deployed Common Alerting Protocol (CAP) protocol, or its enhanced derivatives such as the Modular Warning System (MoWaS) standard in Germany.