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Emergency Warning Functionality on DRM Digital Radio for Saving Lives

Six-hundred-and-seventeen (617) lakh people in the world were impacted by disasters in 2018. Extreme weather conditions accounted for majority of people affected by these disasters. Unfortunately, India is also being affected by disasters a number of times. But extreme weather conditions often come with a pre-warning phase. The questions is – Are we getting the most out of this time window to warn the public and save lives?

When disasters are about to strike, getting the message to everyone affected as quickly as possible and with all relevant information is of the utmost importance.

  • A typical early warning system should meet the following requirements:
  • Send notification to maximum number of people in the affected areas as promptly as possible;
  • Must cover large areas with very high reliability;
  • Must work when common information services and local services fail;
  • Make warnings available on devices that people use on daily basis;
  • Reach devices that are still operational, if electricity fails (i.e. radio sets and other devices with independent energy source);
  • Be as un-intrusive as possible for daily use;
  • Must be available and continuously on-air for the duration of the emergency;
  • Control of emergency notification and immediate access by authorities; and
  • Make emergency message available to widest possible audience, including the visually or hearing impaired.

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 do not speak the local language.

Unfortunately, internet, telephones, and electricity are generally the first causalities in disasters. Radio receivers have long been a core component of warning systems worldwide. Radio receivers can be battery, solar or wind-up powered; transmission infrastructure is both easily secured against power losses and can reach the affected area from outside. Thus 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.

Radio is being used world over to provide emergency warnings but in the conventional analogue radios, the emergency program replaces the normal program, and radio listeners in the entire coverage area of the transmitter get only emergency program even if disaster is in a limited area. In disasters, it is of utmost importance that my radio receiver should automatically get tuned to the emergency program so that even if I am listening to a radio station, which is not broadcasting emergency program, still my receiver should get tuned to the emergency program automatically. Also, volume of my radio receiver should get increased, and if the receiver is in standby made it should get automatically switched on. But in analogue radios, there is no such provision to provide alert signaling and as such they cannot get automatically tuned to the emergency programs. Also analogue radios provide only audio programs and do not have any provision to provide text, which is very important to provide information in the local languages.

Emergency Warning Functionality (EWF) in the DRM digital radio standard, adopted by All India Radio (AIR), overcomes all the shortcomings of the analogue radio and has all the tools required for early warning dissemination.

When the alarm signal is triggered by the authorities, all running DRM receivers pick up the alarm signal from the currently tuned DRM service and switch to the emergency broadcast; all DRM receivers present the audio content of the emergency broadcast; all DRM receivers with a text screen, in addition, present text headlines (DRM text messages) plus detailed, multilingual information, and instructions (Journaline) for instant and interactive look-up by user, and turned-off receivers may switch on automatically. 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 its standardized Journaline service component, a core DRM element. The structured text feature allows users to look up relevant information on the digital radio’s screen much quickly 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 by the disaster management authority at any time as the situation evolves. In addition, Journaline is designed to reach the hearing impaired, as well as travelers who do not 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 into any DRM receiver is not complicated, because EWF is a combination of standard functionalities that need to be supported by any DRM digital radio receiver. It combines DRM’s alarm announcement and alternative frequency signaling and switching (AFS) with audio decoding and Journaline presentation.

There is very little manufacturers need to do for the digital 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), or its enhanced derivatives such as the Modular Warning System (MoWaS) standard in Germany.

Thirty-five high-power transmitters of AIR are already broadcasting programs simultaneously in analogue as well as in DRM digital. These DRM transmitters of AIR would cover over 50 percent population of the country on operation in pure DRM digital mode. Over 15 lakh cars on the Indian roads have line-fit DRM digital radios. This number is increasing day by day. Most of the automotive manufacturers in India are either already rolling out cars with DRM reception facility or have plans to incorporate the same. A number of Indian and foreign companies are also working to produce standalone DRM digital radios. An Indian firm has also developed a DRM Wi-Fi hot spot, which will enable a listener to receive DRM digital radio signals on any Wi-Fi enabled device – be it mobile phone, laptop, I-pad, desk top computer, or TV.

For using DRM digital radio network for disaster management in emergencies, the following four major steps are required:

  • Government decision to utilize DRM for dissemination of EWF;
  • Identification of coordinating agency;
  • Choice of language(s) and additional information to be provided; and
  • Firm communication to the receiver industry for full incorporation of EWF features.

AIR has already tested the EWF successfully, in coordination with National Disaster Management Authority (NDMA), on both the DRM transmitters installed in Delhi using CAP protocol. Decision by the Indian government to use DRM digital radios for providing emergency warning signals would go in a big way to provide timely information to disaster-affected people to save their valuable lives.

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