RESCAT, the Catalan invisible network that never fails
321 base stations and 41,000 terminals that keep emergency services connected when mobile networks fail, amid the European debate on the transition to 5G
BarcelonaWhen firefighters combat a forest fire in Les Gavarres or the Mossos carry out an operation in a motorway tunnel, they don't use their mobile phones, but radios connected to RESCAT, the Emergency and Security Radio Network of Catalonia: owned by the Generalitat, operated and maintained by Cellnex Telecom, and designed not to fail even when the power goes out.
RESCAT's origin dates back to the 1990s, when Catalan security forces operated with incompatible networks. In 1994, the Mossos launched NEXUS (TETRAPOL); in 1998, firefighters and other services adopted ÀGORA, already based on the TETRA (Terrestrial Trunked Radio) standard. The two networks merged in January 2009 into a single one: RESCAT, the first integrated autonomous TETRA network in Spain. In 2010, the Generalitat bought ÀGORA's infrastructure from Abertis. TETRA is not a technology known to the public, but it is omnipresent in environments where a failed communication can cost lives: a group call is established in less than a second and reaches all terminals on a channel simultaneously.
The backbone of RESCAT is a network of 321 base stations, complemented by 150 coverage repeaters. Most antennas are installed at Cellnex's mobile telephony sites, but own infrastructure is also utilized: rooftops of Mossos police stations, Generalitat buildings, and forest watchtowers. This combination allows for 97% territorial coverage for radios installed in vehicles. The network operates in the 400 MHz band, which offers good propagation for the geographically complex Catalan territory.
RESCAT connects more than 60,000 users from 250 bodies: 12,000 Mossos d'Esquadra, 11,400 local police officers, 4,400 firefighters, 2,400 Civil Protection professionals, 1,900 Emergency Medical Service personnel, and 1,500 rural agents, in addition to dozens of smaller organizations. To access this network, an approved terminal is required: robust, waterproof, with an average price of 500 to 600 euros. A consumer can buy one identical to what a Mossos officer uses, but they won't be able to hear anything: transmissions are end-to-end encrypted. The annual activity is impressive: over 600,000 voice hours, 60 million group calls, and 10 million GPS position updates.
Autonomous TETRA networks (Galicia, Navarra, Madrid, Andalusia, Valencian Community, Balearic Islands, Murcia), municipal, railway, and nuclear networks coexist in the state. The largest is the state-level SIRDEE, which Telefónica manages for the National Police and the Civil Guard. It has about 150,000 users on TETRAPOL technology, and in Catalan territory, it operates independently but in parallel to RESCAT.
The resilience of these networks compared to commercial ones was demonstrated on April 28, 2025, the day of the general power outage. Commercial mobile telephony sites ran out of battery in three hours or less; 112 was inaccessible in many communities. In contrast, TETRA networks held up: all RESCAT antennas incorporate UPS and diesel generators as a contractual requirement. It wasn't the first test: in August 2017, the terrorist attack on Barcelona's Rambla caused a peak of 14.7 voice hours on RESCAT in a single hour, yet communications were maintained without interruption, while conventional mobile networks collapsed.
TETRA has an expiration date
The reliability of TETRA networks is their main asset. But they have an insurmountable ceiling: a maximum data speed of 28.8 kbps, which makes it impossible to transmit real-time video. Today, a fire commander must be able to receive the thermal image from the drone flying over a fire; a pursuing police officer needs to send a license plate to the coordination center in fractions of a second. TETRA does not allow this; therefore, throughout Europe, there is a debate about how to transition to broadband technologies.
The debate is polarized between building new dedicated 4G or 5G networks under state control –expensive, but sovereign– or utilizing commercial 5G networks with prioritized private segments, which is naturally the option preferred by operators. The April 28 outage revealed the problem with this second path: 5G networks stopped working at the same time as 4G because they shared electrical infrastructure. For this reason, the Spanish government has already imposed an autonomy requirement on telcos, and Telefónica and Cellnex announced during the past MWC that they would deploy high-capacity batteries at 2,000 mobile sites.
The technical framework for the transition is MCX (Mission Critical Services, a 3GPP standard since 2016). France is ahead with the RRF program (Réseau Radio du Futur), operational since June 2025 with a budget of 900 million euros. The United Kingdom is experiencing delays with its ESN, with costs of 11.2 billion pounds. South Korea completed its total migration in 2023. The European Commission is promoting EUCCS with a horizon of the year 2030. Whichever option is adopted, the transition will be long: new technologies operate in the 700-800 MHz frequencies, compared to the current 400 MHz, and at higher frequencies, more antennas are needed to cover the same territory. With Catalonia's orography, moving from the current 321 stations to the new technology would mean deploying between 600 and 1,000 sites. It is estimated that the coexistence of TETRA and the new networks will last at least a decade.
CECAT: the brain of Catalan emergencies
The nerve center of all this infrastructure is CECAT, the Operational Coordination Center of Catalonia, which operates 24 hours a day from two sites that function as one: the Barcelona room, on Passeig de Sant Joan/Diputació –which I visited a few days ago with a group of international press– and the Reus room, which guarantees continuity if the first one were affected. Each room operates in twelve-hour shifts with four operators, two team leaders, and on-call press staff. What makes CECAT a coordination center is the simultaneous physical presence of representatives from all involved organizations: Civil Protection (4 positions), Mossos (2), Firefighters (2), SEM (2), Barcelona City Council (2), Meteorological Service (1), Catalan Water Agency (1), Provincial Council (1), Rural Agents (1), Red Cross (1), State Highways (1), Generalitat Highways (1), and Catalan Traffic Service (1). When there is a serious emergency, all technicians are in the same room, making joint decisions in real-time. They communicate via RESCAT with the personnel on the ground, and from there, information is provided to the media and ES-Alert warnings are sent to the public's mobile phones... provided that the telcos do their job.
