Research On Handover Technology For Cooperation Of Multiple Terminals

In recent years,with the continuous increase of mobile terminal equipment and the continuous development of terminal technologies,Cooperation of Multiple Terminals has emerged at the historic moment,bringing great opportunities to mobile communications.On this basis,the communication network mobility management framework is also facing a new challenge.The communication mode of the mobile terminal will no longer be limited to the user connecting to the fixed base station through a single mode,but truly expanding into a diversified service collection.Among them,device-to-device(D2D)communication and UE-to-Network Relay have received extensive attention as important communication modes in Cooperation of Multiple Terminals.In a Cooperation of Multiple Terminals scenario,the terminal can dynamically select a mode from a plurality of serviced collections according to its own service requirements.Therefore,this thesis studies the Cooperation of Multiple Terminals handover technology,improves the energy efficiency of the network system and improves the user service satisfaction by determining the distribution state of the mode selection in the region and enhancing the path switch process.The main work of this thesis is as follows:For the communication mode selection of Cooperation of Multiple Terminals,based on the characteristics of D2D short-range communication,on the one hand,it can reduce the communication delay and reduce the transmission power consumption.On the other hand,due to the geographical limitation,compared with tradtional cellular communication,it brings larger handover probability and results in unnecessary singaling overhead.Based on the above two points,this thesis proposes a dynamic mode selection algorithm with the goal of maximizing the communication energy efficiency of network systems.Firstly,the network model is modeled by random geometry.Based on the continuous movement state of the terminal in the network region,the closed-form solution of the cross-layer handover probability and the D2D handover probability is derived by applying mathematics.Then,according to the switched closed-form result and the transmission power consumption in two communication modes,the selection based on the Stackelberg Game master-slave form is used to select the state distribution of the mode selection through the ESS stability strategy,and finally the overall network revenue is optimized.The dynamic mode selection algorithm proposed in this thesis can improve the energy efficiency of network system and reduce the transmission power consumption of users.At the same time,considering the continuous movement state of the terminal in the network area.The established network model has reference value for the revenue analysis of the network system in continuous time.For the UE-to-Network Relay technology,the 3GPP standard has no differential path switch selection for Remote UE.This thesis proposes a path switch enhancement strategy,including path switch trigger conditions,path switch measurement configuration,and path switch decision making and switching process settings.First,the priority of the Remote UE is switched to the Relay UE by setting the path switch trigger corndition,thereby reducing the transmission power consumption during communication;using the Relay UE dual-link feature as the handover decision condition,and enhancing the stability of the Remote UE connection to the Sidelink,and the handover probability is reduced;Optimizing the handover performance of the network system by setting a weighting factor dynamically adjusted according to the terminal service type in the path switch decision algorithm;finally,the non-3GPP participation handover procedure is defined and set.The path switch strategy proposed in this thesis is a perfection and supplement to the existing standards,and provides theoretical guidance for the research of Cooperation of Multiple Terminals path switch.In addition,by comparing with the existing schemes,it is verified that the path switch enhancement strategy can enhance the stability of the link.In summary,this thesis studies the handover technology from the network side and the terminal side for Cooperation of Multiple Terminals,and gives performance evaluation and simulation results.The research results provide a theoretical basis for Cooperation of Multiple Terminals handover technology.