Research On Cooperative Offloading And Cell Handover Methods Based On Mobile Edge Computing In Ultra Dense Networks

In Ultra Dense Network(UDN),small base stations with computing functions are prone to overload due to limited computing capabilities.On the other hand,UDN deploys a large number of small base stations to expand the system capacity and also leads to the densification of the network.Frequent and unnecessary cell handovers will generate additional network energy consumption.The two major network resource management problems mentioned above restrict the development of UDN.In Mobile Edge Computing(MEC),the problem of server overload is often handled in a negative way.The server either refuses to provide services to the user or sets a long waiting time for task execution,which causes a very poor experience for the user.The thesis researches the way that many service stations in the network cooperate with each other to complete the overload task of the small cell server,and proposes a combination of penalty function and two-step quasi-Newton to optimize the solution.Analyze and calculate the total delay and total energy consumption to complete the task of the entire network,and design the utility function according to user needs.Through the simulation results,we can see that the studied offloading optimization algorithm performs better than traditional methods.Signal overlap causes the resident time of the user device in the current service cell to be shorter and the switching probability to be increased greatly in UDN.However,a large number of frequent small base station switching will bring more uncertainty to the offloading and caching scheme of the network system.In this thesis,a smooth transition method is studied.The Hidden Markov Model(HMM)is used to predict the user service base station according to the change of the RSRP.In order to avoid unnecessary cell switching,the fixed buffer parameter is extended to an adaptive transition band when determining the service base station.Through the simulation results,we can see that the transition zone discrimination smooth handover method based on the HMM can reduce the number of handovers and save network resources while ensuring the quality of user service.