Research And Simulation Of Mobility Management In LTE-A Heterogeneous Networks

With the development of mobile communication,LTE(long term evolution)system has been applied in many countries all over the world.The Ministry of industry and information technology of China also officially issued to the three operators 4G license,indicating the arrival of the era of China's 4G.In order to meet the requirements of IMT-Advanced,the 3GPP organization has proposed the LTE-A system which is the evolution of the LTE.Through CA(carrier aggregation),MIMO(multiple-input multiple-output),CoMP(coordinated multipoint transmission),Relay and dual-connectivity techniques,LTE-A could improve the data rate and spectrum efficiency of the wireless communication system in a effective way.What's more,the LTE-A could expand the coverage of the network and improve the user experience.In the R12 stage,dual-connectivity was introduced into small cell enhancements by 3GPP,which supports the terminal receiving and sending data from two base stations simultaneously,which makes the integration of wireless resources into a deeper level.However,the current study more regulates the application scenarios of dual-connectivity than designing for dynamic process the scene.There no relevant papers about load balancing and energy saving issues of dual-connectivity scenarios.In this paper,a load balancing algorithm based on the dual-connectivity scenario is proposed,which combines the merits of the dual?connectivity technique and adopts the concept of energy saving.Through the joint optimization strategy of energy saving and load balancing,network could allocate the load of base station dynamically.It also could switch small cell reasonably,so as to improve the system energy efficiency.Based on the traditional mechanism of cell reselection,we propose an improved reselection mechanism of random threshold offset.The simulation verified the new reselection mechanism can effectively enhance the user throughput,and minimize the frequency of cell reselection to achieve load balanced distribution in different frequency.