Research On Mobility Management For Dual Connectivity In Hetnet

Dual connectivity(DC)is considered to be one of the potential hot technologies to improve the performance of heterogeneous networks(Het Net)in the future,which can integrate multiple standard networks to form an interoperable and complementary network.However,the introduction of DC makes the network more complex and diversified,so the mobility management of DC-based Het Net faces immense challenges.This paper analyzes the mobility performance of networks in DC by system-level simulation,and then proposes a handover(HO)strategy based on the best transmission rate of the entire network.Aiming at the problems that the existing mobility management technology research is mostly carried out at the link level,and does not consider the resource scheduling situation of its dual access points to select the link reliability parameter.This paper compares and evaluates the influence of master nodes HO and secondary nodes HO on link reliability at different speeds in different bearers by system-level simulation.Particularly,Hybrid Automatic Repeat Request(HARQ),throughput,queuing time for data packets and Channel Quality Indicators(CQI)are taken as link reliability analysis indicators.Besides,we study how DC utilizes the traffic split ratio between the master nodes and the secondary nodes to maximize the superiority of throughput.Simulation results show that DC technology can significantly reduce the number of HARQs affected by HO and increase the throughput of users.When the data traffic is tilted to the side of the secondary node,the superiority of throughput is more obvious.Aiming at the access mode selection problem of Dual connectivity users during the handover process,this paper proposes a HO tactics based on the transmission rate of the whole network.Firstly,model the gain of users accessing in dual connectivity,and clarify the concept of “potential users for dual connectivity”.Secondly,before the secondary node triggers HO,the HO strategy will judge whether the user is a potential user for dual connectivity or not,and this is used to measure the necessity of accessing the DC when users are triggered HO.Finally,the impact of the difficulty of potential users accessing to DC on parameters such as end-to-end delay,throughput,load of secondary nodes and the average data transfer rate around the network is analyzed,and the judgment threshold of potential users for dual connectivity is verified.The simulation results indicate that the HO strategy based on the transmission rate of the whole network proposed in this paper can better balance the performance of potential users for dual connectivity and performance around the whole network.