Emergency announcements with DAB
If a disaster occurs, the mobile phone networks are quickly overloaded or no longer available. The public must therefore be informed via an independent infrastructure. DAB offers a robust and well-established transmission network and simple (battery-powered) DAB receivers are sufficient for reception. In addition, DAB broadcasts are unencrypted and freely available and can reach the entire population. DAB is therefore very well suited for transmitting emergency warning information.
By default, DAB offers native functions for emergency announcements. Thus, the EWF Emergency Warning Functionality - a combination of different services such as Alarm Announcement, Service Linking, Programme Associated Data (PAD) and Non-PAD - enables the provision of multimedia and multilingual information.
AVT has supplemented the existing concept and implemented it in all AVT multiplexers. The so-called EWB – Emergency Warning Break-In offers, in addition to the EWF functions, a simultaneous replacement of all audio programmes by the emergency announcement. This is also supported by information texts and warning pictures via the PAD channel (Dynamic Label, SlideShow).
The big advantage: the EWB procedure is also compatible with all old DAB receivers and thus ensures that listeners are warned. Modern receivers are also switched on automatically with EWB and can display helpful information via other data services.
EWB is already used in 17 regions in Poland and allows nationwide emergency announcements there.
For the technical implementation, a standard AVT DAB+ audio encoder is required. This can be used, for example, by the emergency services where the encoder is installed to activate the emergency announcement by simply pressing a button. The Audio Encoder enables the live announcement, the insertion of the emergency PAD and generates the control commands to the AVT DAB Ensemble Multiplexer. The multiplexer replaces all audio programmes with the provided emergency content seamlessly and without delay. Provisioned PADs are available on all audio services.The new MAGIC DABMUX plus Ensemble Multiplexer supports this function natively. But existing DAB headends can also be extended cost-effectively by a low-cost EWB repeater based on the MAGIC DABMUX Go.