Design And Estimate Of Cluster Evolution Based Mobility Model

Mobile Ad Hoc Network(MANET)is a collection of wireless mobile devices forming a multi-hop and self-organized wireless network without using any existing infrastructure,and it has the advantages of fast networking,strong anti-destruction.Node mobility is the main characteristic of MANET,which can lead to the change of whole network topology so as to influence the performance of the protocol.Therefore,Mobility Model(MM)is used to describe the movement of node in the network as an important part of MANET simulation.The reality of MM can heavily affect the authenticity and reliability of the evaluation of network protocols.Mobile devices are generally carried by humans in the real scene,so the movement of nodes in a network has the mobility features of human movement.Traditional classic mobility model rarely consider the moving characteristic of human mobility features;Because of the limitation of the data set,the Mobility Model based on trace analysis does not take into account the cluster evolution caused by the human movement.By the analysis of taxi GPS data set with Cluster Evolution characteristics,we propose a Cluster Evolution based Mobility Model(CEMM).In this paper,the main work includes the following four aspects:(1)Analyzing the cluster evolution characteristics of taxi GPS data sets and classical human movement model SMOOTH,including cluster size distribution,cluster division and polymerization,the number of cluster node dynamic change and cluster survival time.Analysis result shows that smooth models do not have cluster evolution characteristics.(2)According to the cluster evolution characteristics of taxi GPS data set,we proposed the CEMM.The design idea and the modeling process of the Mobility Model was introduced in detail,the simulation area is divided into the grid to simulate cluster,the cluster grid and not-cluster grid are classed according to the number of grid nodes,and the specific method that node selects the grid for moving targets is also given.(3)The CEMM and its mobility model simulation evaluation function is achieved by Java language,and NS-2 scene file required for network simulator is generated,which lay a foundation for the performance evaluation of the network protocol.(4)CEMM put forward in this paper is evaluated in terms of authenticity,which is verified to be consistent with the data set of taxi in the aspect of cluster evolution.The topological structure characteristics and parameters affecting performance of routing protocols of the CEMM,smooth,RWP and were compared,which provides a reference for network simulation to choose the appropriate mobility model.