Research Of Network Selection And Admission Control Strategy In Heterogeneous Environment

With the development of wireless networks,more and more network technologies integrate in heterogeneous wireless networks and utilize the limited wireless bandwidth resources.Meanwhile,the type of network service and the number of Internet users are increasing,the users' requirements for speeds of data transmission and bandwidth are growing.People improve the utilization of wireless resources by radio resource management,while ensuring that users enjoy a high quality of the communication service.As a key technology in heterogeneous wireless networks,network selection and admission control strategy have great significance and practical value.1.Proposed a network selection algorithm based on load balancing,which adjusts the network preference and user preference dynamically.First,according to the users' speed of movement and RSS(Received Signal Strength)preprocessing initial candidate networks.Then,setting different weight value of different business types by extension theory with fuzzy analytic hierarchy process(EFAHP),this can reduce the arbitrariness and subjectivity of experts' score in analytic hierarchy process.After that,calculating the total performance function values of candidate networks by dynamical adjust the network preference and user preference.Last,select the network with maximum total value.Through the simulation analysis,the proposed algorithm can realize the load balance much better than others,particularly when the neworks' load is heavy.2.Proposed a admission control strategy based on channel allocation.Analyzing dynamic channel allocation models is the first step,on this basis,proposed a dynamic channel allocation model with the function of channel-borrowing.The proposed model in channel allocation considerate two types of business:real-time and non real-time,different business types have different priorities.Then make the rules of bandwidth allocation and channel-borrowing to do admission control,using the Morkov state transition diagrams to describe the process of model state transition.Finally,through the simulation contrast,the proposed channel allocation model can guarantee the service quality of real-time business better than other models.Besides,the proposed admission control strategy can increase the throughput of system and the quality of service.