The Emergency Call Server (ECS) is an important and innovative element in the general CAUTION architecture, as it provides to the operator an online option to apply different resource management techniques to certain cells, immediately and effectively. This is extremely useful in emergency situations (i.e. accidents, earthquakes, and catastrophes), where the automatic mechanism (RMU) cannot recognize or solve the congestion problem immediately. In emergency situations, the RMU, and more specifically, its module, TLSR, may experience difficulties in recognizing the real traffic congestion scenario immediately. Moreover, the SS module may not face up the problem effectively. The main reason is that, in these cases, the increase of the congestion is rapid. In fact, the TLSR cannot predict exactly the duration of the emergency congestion event. It also cannot estimate the total increase of the congestion.
ECS mainly operates as a backup to the automated system. When some severe problems are presented and prevent the properly working of the RMU, then the ECS can take action dominantly and face up the problems immediately. The ECS operator can apply all the resource management techniques, which the automated system can apply too. The operator can select the desired BSC and BTS, where he wants to apply a specific technique, as well as he can set the parameters of any technique at an appropriate form, and after that to send in XML form the command that will be executed.
In addition, ECS is capable of sending emergency messages using the CBCH (Cell Broadcast Channel). These messages will be sent to the subscribers of the problematic cells in order to inform and advise them for the problem and its confrontation. Furthermore, it can send optionally SMS or EMS to the subscribers who are in danger, and to advise them properly. When someone is in danger and cannot make an emergency call, the ECS perceives this problem and makes an operator initiated call to him.
The status of this element in the CAUTION system is dominant. Its decisions and commands override all the actions performed by the RMU. In contrast to the automated processes of the RMU, ECS is fully dependable on the operator�s demand and is manually operated, because of its purpose and importance in an emergency situation. ECS is a distributed element, since it exists behind every ITMU module. It is operated manually, as mentioned above, with the help of a �user friendly� Graphical User Interface (GUI). When the congestion comes to the desirable level, the operator can release the selected technique. Moreover, the element is capable of retrieving extra information from ITMU when is needed with appropriate queries. It also monitors the network via ITMU, and the results from the techniques application.
All the above key features declare that ECS is a very powerful and innovative emergency handling tool, which can contribute to effective confrontation of emergency situations, higher network performance, better customer satisfaction and higher revenues for the cellular network operator.
Remarkable dissemination activities related to ECS have been carried out. The element has been presented in several conferences and workshops and the dissemination activities are planned to be continued by further publications and presentations to companies.
Currently, ECS is a prototype, successfully tested "in action". To drive it towards a commercial product (integrated in the CAUTION platform), more testing would be required and the prototype should be further enhanced. Maintainability, modularity, extensibility and flexibility have guided the design choices of ECS so that it is quite easy to extend it and add new features to it.
ECS could be used after the project in future research activities and projects to meet the evolving requirements of next generation networks, or as an integrated part of the commercial CAUTION platform.