Researches On Simulation Of Equivalent Bandwidth Access Control Algorithm In Emergency Rescue Scenario

In case of an emergency, such as the fire and crime incidents happened in public places like railway station or shopping malls, the sharp increase of the phone calls in short time may lead to the decrease of the success ratio of call access and the system performance seriously. How to guarantee the quality of services (QoS), improve the success access ratio and ensure the high-priority users can access so that the rescue activities can be fulfilled smoothly in the first instance are the focus of our researches.Starting from the guarantee of QoS, the thesis analyses the call admission strategies of wireless multimedia communication network. Based on the classical equivalent bandwidth admission control algorithm, the admission control strategy that can support multiple services is put forward for emergency scenario. In CDMA2000system, multiple services are divided into various priorities according to the service characteristics. Voice service is assigned the highest priority due to its sensitivity to time delay. The priorities of other services involving streaming media, interaction and background services are ranked from high to low. According to the various priorities, QoS requirements and equivalent bandwidth of different services, we can control the admission of new users.To ensure the special users can communicate smoothly in emergency, the user classification admission control strategy is proposed on the basis of equivalent bandwidth algorithm. With attribute-based trust negotiation, for the case of insufficient bandwidth resources, to ensure the admission of users with special role, our scheme enables the high priority users access the system first while low priority users can only access after higher priority users release the resources.By using JAVA the JAVA multi-thread technology, two emergency access control strategies are proposed and simulated in the thesis, the performance results of which are compared with those of the traditional equivalent bandwidth algorithm in normal and emergency case. The comparison shows that the proposed access control strategies improve the system performance effectively.