Estonia's EE-Alarm system operates using a location-based SMS solution (Location-Based SMS, or LB-SMS). Text messages are sent to SIM card-equipped devices located in the danger zone, as determined through geolocation. How quickly people receive the message largely depends on the transmission capacity of mobile network operators. A recent drill revealed that many people waited more than 30 minutes to receive the alert.

In contrast, much of Europe — and countries frequently faced with disasters, such as Japan — use a significantly faster system that does not rely on sending SMS messages. This is known as cell broadcast system (CBS) technology. It enables simultaneous transmission of short messages to all mobile phones within a designated geographic area.

Unlike SMS, CBS does not require messages to be sent individually to each number. Instead, messages are broadcast at once to all devices connected to specific mobile towers. The alerts reach phones within seconds. Notably, CBS can even override silent mode, forcing phones to emit loud alerts.

Among Estonia's neighbors, Lithuania already uses the CBS system and Latvia plans to adopt it soon. Estonia's continued reliance on the much slower LB-SMS method makes it something of an outlier in Europe. Sweden and Iceland, which have also been using SMS-based alerts, are planning transitions to CBS. In several countries, including France and Norway, both systems are used in parallel. For now, Estonia is not considering CBS. The reasons are largely historical — but not exclusively so.

CBS not justified in threat assessment

Kadi Luht-Kallas, an adviser at the Ministry of the Interior, explained that in 2018, the European Union adopted a directive requiring all member states to implement a mobile-based public alert system by the summer of 2022. Broadly speaking, there were two available solutions: the faster CBS and the slower LB-SMS.

"Initially, several member states wanted to go with a mobile app instead. However, according to the EU's electronic communications regulator, mobile apps would not be downloaded widely enough to be considered a viable alternative to CBS or LB-SMS," Luht-Kallas said.

After thorough analysis, Estonia decided in 2020 to develop the LB-SMS solution. According to Luht-Kallas, the analysis concluded that CBS is best suited for sudden natural disasters, such as earthquakes or flash floods. At the time, Estonia was not seen as facing events that would require such immediate alerting.

"At the time the decision was made in favor of LB-SMS, our threat assessment did not include such events. We're talking about 2020 — so the decision was made several years before the full-scale war in Ukraine began. The system, of course, was completed once the war was already underway," the adviser noted.

Margus Rohtla, a 3GPP mobile network expert at Tallinn University of Technology, recalled that when Estonia began developing its emergency alert system, all potential technical solutions were examined and their pros and cons evaluated. The needs and requirements of the Rescue Board and other ministries were also taken into account. Specific performance criteria were established, including how many users had to receive the message and how quickly.

Among other considerations, the following factors had to be taken into account:

1. The ability to alert the entire population within seconds. While LB-SMS can meet this requirement on a regional level, it does not ensure it nationwide.
2. Emergency alerts must reach everyone, regardless of phone model — including older button-operated mobile phones that do not support apps.
3. The service should not be possible for users to disable.
4. It should be simple to use.
5. It must allow for alerts to be delivered in the user's native language.
6. It should be possible to determine how many people received the alert.
7. The Rescue Board also wanted the ability to estimate how many people were in the danger zone. This information would help plan logistics in case evacuation was necessary.
8. The system should ideally support the ability to alert Estonian citizens abroad—providing advance notice of potential threats at their destination so they can consider postponing or avoiding travel to that area.

"Taking all those criteria into account, LB-SMS was the only technical solution that met them all — except for the first one: the ability to alert the entire population within seconds. That's something LB-SMS simply can't do — we're talking hours," Rohtla explained. He added that threats requiring the attention of the entire population are typically known in advance, which means LB-SMS can still be effectively used.

To illustrate, Rohtla offered a rough calculation: "Very broadly speaking, the population can be divided among three mobile operators, or about 500,000 users per operator. If an operator can send 50 SMS messages per second, it would take about 2.8 hours to notify the entire population," he said.

At the same time, Rohtla emphasized that the capacity of LB-SMS could be increased if operators agreed to allocate more signaling resources in their radio networks and expand the throughput of their SMS centers. "With LB-SMS, you can also filter out M2M users — such as gate remotes, IoT sensors and similar devices — to conserve radio network resources," he added. CBS, by contrast, sends messages to all devices currently active in the affected cell.

According to Luht-Kallas, following the outbreak of war in Ukraine, Estonia has begun looking into additional solutions to complement EE-Alarm — ones that would allow for fast, CBS-like mass dissemination in case of military threats.

Estonia's solution also has a few advantages

Kadi Luht-Kallas noted that beyond the threat assessment, several other factors influenced Estonia's decision to opt for the LB-SMS solution over CBS, making it the more practical choice. "This primarily concerns our population. We have a large vulnerable demographic, particularly among the elderly. Reaching them via CBS is problematic. Cell broadcast isn't SMS — it uses a completely different standard and usually comes with a sound and visual alert. It appears on the screen automatically, but then disappears. Finding it again later can be quite difficult," the adviser explained.

In other words, while CBS messages do remain stored on the phone, they are likely to be rediscovered only by younger users — elderly people often cannot locate them again. "Cell broadcast is indeed very fast, but it's less user-friendly than SMS, since most older people know how to read a text message," Luht-Kallas added.

Another argument in favor of LB-SMS for Estonia was that authorities wanted the ability to gauge how many people in a danger zone might need assistance. With the SMS system, it's possible to see how many devices received the alert.

Margus Rohtla, however, noted that many other countries followed a different logic in their decision-making. "CBS has the advantage of complying well with GDPR requirements because the messages are sent anonymously — we don't know who received them. That was a key factor for many countries," the expert said.

In Estonia, the data protection issue was addressed by ensuring that user information stays with the mobile operators, and messages are sent through the operators' SMS centers. "That approach has largely resolved the GDPR aspect," Rohtla explained.

Estonia not rushing to switch to CBS

Echoing Margus Rohtla, Kadi Luht-Kallas noted that the throughput capacity of LB-SMS could be significantly increased if needed. "In drills, we used a message delivery speed that operators can reasonably maintain in day-to-day operations. But if we provided them with additional support, the speed of message delivery could be greatly improved and the number of messages sent could increase severalfold," Luht-Kallas explained.

"Since we don't foresee such incidents occurring in the coming months, there's no reason to invest extra funds at this time. However, if the situation changes, the system can be made many times faster," she added.

She also pointed to the considerable additional costs involved — an issue that cannot be overlooked. "In the case of CBS, there's the added expense of licensing fees for every transmitter. Historically, each mobile operator in Estonia has built its own network. That means we would have to ensure licenses are in place for all three networks and for every transmitter."

In contrast, Lithuania — which uses CBS — has a state-owned mobile network that is leased to private companies. "They have one network. We would have to fund three," the adviser noted.

--

Follow ERR News on Facebook and Twitter and never miss an update!