Research On Several Algorithms Of Mobility Management Of 5G Networks

5G mobile communication is booming.The emergence of heterogeneous networks and ultradense networking has effectively increased the original system capacity.At the same time,the introduction of distributed caches has also reduced backhaul network traffic and reduced system pressure.The emergence of these technologies has improved the user experience and brought huge challenges to mobility management algorithms.For ultra-dense networks,the probability of pingpong handover for mobile terminals is greatly increased;when the distributed cache technology appears,the traditional best target cell,that is,the cell with the strongest signal strength,will not necessarily be the best service cell.Therefore,this thesis studies the ultra-dense networking scenarios in 5G networks,mobility management algorithms based on content caching scenarios,and heterogeneous network scenarios.At the same time,an SDN-based management platform is built to effectively manage and control ultra-dense networks.The main tasks of this thesis are as follows:(1)In view of the impact of ultra dense network and the introduction of distributed cache,this thesis proposes a content aware mobility management algorithm for ultra dense network.Firstly,the interruption between the user and the service cell and the candidate cell set of the user's next switching access are predicted by the mobile prediction algorithm.Then,the cell with the least delay in the candidate cells is selected as the target service cell and triggered in advance.If none of the candidate cells has the content required by the user and there are cells with empty storage,the required content is migrated to the candidate cells with empty storage,and the cell with the least delay is selected as the target service cell and triggered in advance;if neither of the above conditions exists,the cell access that can obtain the required content from the content server as soon as possible is selected.Simulation results show that compared with the traditional algorithm,this algorithm effectively reduces the user's delay.(2)In order to realize that small cells can control mobile terminals in specific scenarios,mobile terminals need to be able to switch from macro base stations to small cells deterministically.In response to this problem,this thesis proposes a mobility management algorithm based on SDN.Firstly,SDN controller and intelligent change based on terminal service state are introduced to reduce the switching delay,which effectively reduces the signaling interaction between terminal and base station,and reduces the delay of the whole system.At the same time,the compensation coefficient of switching signal strength and the dynamic change of switching offset are added.The simulation results show that the algorithm can improve the handover success rate and the performance and user experience of the whole system.(3)Complete the design,compilation,operation and result analysis of LTE small base station ultra dense network management and control system based on SDN controller.Through the SDN controller and the designed handover algorithm,the real-time supervision and control of the LTE small cells ultra dense network is realized.The results show that the designed SDN controller and handover algorithm can control the ultra dense network in real time and efficiently,and achieve load balance between each cell.