Enhancing the ASTRID Network – Brussels attacks

On Tuesday 22 March 2016, the ASTRID network processed an unprecedented amount of radio communications from all of the emergency and security services that were mobilised in Brussels. ASTRID immediately convened a meeting with the ASTRID User Advisory Committee, which represents all emergency and security services, in order to make an initial analysis. ASTRID has since conducted a thorough technical analysis of the communications on the day of the attacks, while the Committee conducted a study from an operational perspective and immediately made recommendations to the relevant users. These unprecedented terror attacks have brought a new reality to our country. ASTRID wants to bring all stakeholders involved in security together to see how everyone can prepare even better for potential new emergency situations. 

On the day of the attacks, some of the ASTRID base stations in Brussels became saturated due to: 

  • The exceptional nature of the emergency, which involved violent attacks that were carried out successively at different locations, within a few hours and within a limited radius.
  • Emergency and security services from across the country were mobilised to provide assistance in Brussels, which required additional network capacity in Brussels.
  • The saturation of the commercial mobile phone networks. This resulted in an increased number of individual calls on ASTRID that would normally take place over the mobile phone network. 

Some facts about 22/03:

  • More than 4,300 active radio users in Brussels, instead of 2,500 as is the case on a typical day
  • Up to 600 active talk groups (each group has an average of 34 radio users) instead of the 200 or so on a typical day.
  • 26,000 successful group communications
  • 8,400 unsuccessful (or interrupted) group communications
  • 1,000 individual communications

The ASTRID radio network is built around the concept of “talk groups”: The dynamic creation of groups of people who need to communicate with each other according to their duties. These groups are either predetermined or can be tailored by the emergency and security services in the event of an incident.

Despite an overall heavy load, not a single ASTRID system experienced a technical breakdown: The radio network and the paging system as well as the control rooms (emergency centres 100/112-101) never faltered. Shortly after the attacks, seven ASTRID base stations (five in Brussels and two in Flemish Brabant), including the base station near the Maalbeek metro station, reached their maximum capacity (saturation), preventing a part of the communications from proceeding trouble-free at times, in particular between 10:00 and 12:00.

Following the attacks, ASTRID immediately convened its Crisis Management Team and took a number of measures: Consultations with the Federal Crisis Centre and the main users of the network, putting the main suppliers of its infrastructure on standby and deploying the mobile ASTRID base station to temporarily boost radio capacity. At the request of the user organisations, ASTRID also logged 210 additional radios onto the network on the day of the attacks.

Supplemental to the technical aspects, use is also an important factor. Therefore, on 25 March, ASTRID requested the User Advisory Committee to conduct an operational analysis as well. The use of the radios has an impact on network capacity. Especially in crisis situations, compliance with communication procedures and plans can prevent network saturation.

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