While mobile broadband communication systems operate on the basis of the infrastructure provided by teleoperators and mobile service operators, communication systems used in crisis situations are independent of them, adding a particular value to selected users. Critical communications is often defined as the ability to provide means of communication in situations where conventional networks fail to work. This happens often during mass events, when a large number of mobile users simultaneously try to use a given network, which, as a consequence, is not able to handle increased traffic and is overloaded.
Another example are areas affected by natural disasters or events that threaten public safety which lead to overloading of mobile networks, depriving emergency services of means of communication.