There are many earthquakes in Japan and it is hardly possible to predict when and where earthquake happens, therefore the approach to increase installed capacity in all the areas that costs considerable much is impossible. In order to produce communication in congestion conditions in the earthquake, it is not only efficient from installed capacity aspect but also vital from service aspect to perform "access control interval application"
that description below explains.
There is an area where access control is performed. In order to allow all the users in the area to setup calls, broadcasting access class numbers are changed at an interval of some seconds. For example, in an interval UEs with access class 0 can perform setup and UEs with access classes 1-9 cannot do setup, in another interval UEs with access class 1 can do setup and UEs with access classes 0, 2-9 cannot do setup.
Due to access control interval application, the communication between the unauthorised users in the disaster areas is possible. The communication helps users in the emergency situation. Following are use cases.
A mother calls to her child to know where he/she is in the disaster areas.
A mother sends a message to her child to know where he/she is in the disaster areas.