Research On Opportunistic Networks Simulation And Validation Based On OMNeT++

With the rapid development of Internet of Things(IoT),the number of devices has increased by hundreds of millions.It is urgent to achieve effective communication of massive devices.By virtue of its inherent mobility,opportunistic networks using the"store carry forward" mode to solve the problem of communication between IoT mobile devices caused by the lack of a complete communication link,has the very big development space in disaster relief,health monitoring and warning broadcasting scenarios.Network simulation is one of the most useful ways to evaluate the performance of opportunistic networks.The authenticity and effectiveness of opportunistic networks have attracted more and more researchers' attention.The correct and perfect opportunistic network model can truly reflect the characteristics and message transmission process of the network.On this basis,the communication protocols and algorithms designed and simulated are more practical and valuable,and it is also easy to find and process the communication problems in the real environments.Therefore,the authenticity of the model is an important criterion for evaluating the opportunistic network simulation.Due to the highly mobility of nodes in the opportunistic network,simulating the connection status of the network correctly is the key point to determine the authenticity of the model.Contact times between nodes is regarded as an important performance metric to evaluate the connectivity of the network.Through the combination of experiment and simulation,the trace-based mobility model and Unit Disk Graph(UDG)connectivity model in opportunistic networks to simulate the connection status of real environments in OMNeT++ has been validated,the authenticity and validity of simulation contact times extracted from mobility traces is the conclusion.On this basis,the existing Opportunistic Protocol Simulator(OPS)opportunistic network simulator is optimized.When the simulation scale and frequency reach a tremendous scale,the optimized simulator will save a lot of simulation time and show obvious advantages.The main work and contribution of the thesis are as follows:(1)Collected the real GPS location and Bluetooth Low Energy(BLE)beacon of volunteers,and deploying Android applications on the users' smart phones,according to the design of indoor and outdoor different experimental scenarios,we carried out many field experiments.(2)Designed the trace-based mobility model and UDG connectivity model in OMNeT++,and built a simple opportunistic network including the mobility and connectivity model to run the simulation,mobility traces was collected for simulation models to determine contact times;(3)Verified the authenticity of connection status of mobile nodes in opportunistic network simulations,to demonstrate the effectiveness of the trace-based mobility model and UDG connectivity model implemented in OMNeT++ and the reliability and authenticity of the contact times obtained by simulation;(4)Optimized the network structure of OPS opportunistic network simulator by removing mobility model,directly inputing contact time traces in link layer to simplify the network structure.When the number of mobile nodes and simulation times reach a certain scale,the optimized simulator will save plenty of simulation time and show the good performance.