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Suggestions to Improve EAS, Advanced Alerting

The A/331 standard doesn’t address all of the problems with the current system

The author is CEO and chief technology officer for Kybernetix.

The Advanced Television Systems Committee has developed standard A/331, called Advanced Emergency Alerting.

A/331 does not meet the system latency for Earthquake Early Warning System alerts of 3 seconds or less, and could be improved in the U.S. implementation.
Credit: iStockphoto/Petrovich9

The XML format can vary by country and is flexible. Options include CAP or the EDXL protocols alongside encryption, but a minimum of a PC level processor is required (e.g., 486).

The A/331 protocol is carried on the highest power level of the Layered Division Multiplex modulation, which is QPSK, giving it the greatest range and a receive capability by small antennae in smartphones. That received QPSK data is usable for TV on smartphones. The lower levels of the protocol use IP or related standards, which is broadcast in South Korea TV.

A/331 does not meet the system latency for Earthquake Early Warning System alerts of three seconds or less, and could be improved in the U.S. implementation. The possibilities for smartphones to receive alerts include WEA, AEA, social media and alerting vendors, among other sources.

To avoid alert fatigue, developing definitions and software is imperative. One goal could be having a maximum of two alerts for life endangering messages and one for others, and several manufacturers are working on this, including Verance.

WEA is using single-level cellular broadcast including Femto (10 m), Pico (200 m), micro (1 km) up to macrocells (up to 10 km). While macrocells are expected to have generator backup, Femto and Pico cells most likely do not. During an extended power outage, the macro cell service restricts the number of supported calls. For cell broadcast alerting, the loss of power would mean the loss of alert area polygon selection. With macrocells, the selectivity should be implemented in the handset based on relative location and transmitted the polygon data.

During Hurricane Sandy, which primarily affected the New Jersey, New York and Connecticut area, only one New Jersey broadcaster went off the air; residents could easily tune to another station. Likewise, during Hurricane Katrina, a few broadcasters in New Orleans went off the air (one was a Spanish-language radio station).

Having multilingual capabilities for EAS is important when communicating emergencies. While Text-To Speech is useful, there are situations in which the pronunciation or meaning is mistaken due to numerous languages. The inclusion of the International Phonetic Alphabet as part of the ASCII text and part of other worldwide alphabets would be beneficial and simplify processing.

A/331 does not add any improvements for the implementation of EAS to legacy broadcasting radio and TV, nor for cable, fiber (e.g. FiOS), DBS (e.g. DirecTV or DISH Network) or SDARS (SiriusXM). An improved EAS is needed and a proposal has been made that addresses most limitations of the present system, especially radio.


A Kybernetix proposal discussed with FEMA addresses a majority of those limitations, and the implementations vary between HD Radio (or other digital radio) and other TV systems.

Certain specifications and operations are implemented in the receiver, which is primarily using software on a suitable processor including the following: an 8-bit microcontroller for less cost, less power consumption and less electromagnetic interference generation, which is important for radios that have the antennae within the radio.

Because of varying CAP profiles and language or location/jurisdiction systems, the implementation of AEA would vary by country; the improved EAS is without these limitations. A country code would define the jurisdiction ID system. A coding system provides for varying languages where a maximum of six per country is suggested for practical international and technical implementation; two being local languages, and the others multinational.

A Digital Daisy Mesh is important for redundancy. This consists of two (or more) regional primary stations with monitoring receivers at other broadcasters that can function as system quality control monitors reporting to the State Emergency Communications Committee. With the large coverage area typical of TV broadcast and considerable bandwidth for multiple languages and data transmission, these would make the best primary stations. Currently, radio stations function as the primaries with the existing EAS. The analog modem tones are the data transmission and contain only the message header and tail; HD Radio data transmission capabilities are not utilized. Analog modem tones could not add area selection polygons or the message text.

Though ATSC 3.0 would use AEA, translating to an improved EAS would be simple, as defined for CAP. The transmission of the EDXLs and other file formats are possible without disturbing the public.

A worldwide standard is preferable for consumer electronics manufacturers. CAP is in process of becoming an ITU standard X.1303. Kybernetix considers this in the definition development for an improved EAS standard.

The least cost to consumers always is desirable, and approximately two cents for about 1 MB of additional memory is expected to be the requirement; a discrete 1 MB USB flash memory costs around 50 cents. With suitable encoder/decoders installed, the cost of an upgrade to the system for a radio station should be limited to a software upgrades plus digital broadcast receivers with a data output for the Digital Daisy Mesh.


One major problem for EAS is the ability to selectively deliver an alert within a broadcast coverage area. With HD Radio, everyone in the affected area would be force-tuned to the analog signal, except those listeners allowed to opt out of the message; they would be able to continue with the HD signal. If the alert is for everyone, then all signals are switched to alert. Not all radio transmitters support a –15 dBr or higher injection level of HD data carrier because of intermodulation becoming excessive.

Another problem is how to rapidly deliver EEW messages. There are check-sums built in. The first data transmission is not delayed, and if validated, and the receiver is selected, this would start a playback of the warning tones and the word “EARTHQUAKE” from receiver memory. Subsequent reception of the audio (having the HD delay) provides further alerting and information as previously described. This process means that the alert audio allows for analog degradation and single language selection normally, thus accommodating radio stations not set up for Digital Daisy Mesh.

Current EAS event codes do not provide a prioritization scheme in terms of timeouts or immediate override. Permitting a timeout scheme would enable interaction between the encoder/decoder and the automation system. When data regarding the duration of the alert is provided, a trigger to the playout of alternative content (e.g. PSAs) of identical duration on receivers without the alert becomes possible.

Improvements have been made, but more are needed. None so far have addressed issues that require permitting changes to the present definition of EAS. The use of a selectivity mechanism is not permitted, nor is the proposed latency reduction for an EEW.

Other limitations exist: 1) The ability to selectively deliver alerts to first responders using a temporary additional HD Radio stream on selected broadcasters via agreement; and 2) The ability to use AEA as a source for a Digital Daisy Mesh, for which requires testing and debugging prior to deployment is recommended.

If all these changes are made, the improved EAS would be a valuable system. For more information, go to

Frank W. Bell holds two patents, has worked in telecom and consumer electronics and has participated in engineering the launch of 21 TV signals. He also worked in facility recovery after 9/11.

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