Research On Mobility Management In Ultra-dense Networks

Traditional LTE networks are not enough to meet the huge traffic demands,spectrum resource requirements and high-speed data transmission demands in the future.Therefore,the next generation network(5G)came into being.The ultra-dense network(UDN)is one of the key technology in 5G to improve the spectral efficiency per unit area and improve the network capacity.However,the intensive deployment of cells poses a series of challenges to traditional mobility management.The purpose of this paper is to study related solutions and algorithms for mobility management in ultra-dense networks.This article first introduces the challenges and requirements of 5G facing in the future,and also introduces the key technologies in 5G,and the concepts and research methods of ultra-dense networks.And we summarized several current research directions on mobility management in ultra-dense networks.Then,two new handover algorithms are proposed in this paper:handover algorithm in dense indoor hotspot scenario and skip-HO algorithm based on dwell time estimation under stochastic geometric modeling.In the dense indoor hotspot scene,this paper first analyzes the shortcomings of the traditional algorithm in this scenario,and then proposes a new handover algorithm that considers the rate of change of RSRP to set different handover thresholds which avoids Too late to handover.The algorithm also uses a new candidate cell ranking method.In this paper,calculation methods of predicted dwell time and predicted RSRP are given,and candidate cells are sorted by multi-objective decision-making method.Simulation results show that the algorithm can reduce the handover failure probability and unnecessary handover.In the matter of the skip-HO algorithm,this paper first analyzes the existing alternative skip-HO algorithm,and points out its shortcomings.Then a skip-HO algorithm based on dwell time is proposed.This paper also uses stochastic geometric modeling framework to analysis.First,we use the distance distribution in the two-dimensional Poisson point to deduce the triggering probability of skip-HO,and then deduce the average outage probability and average user throughput of the proposed algorithm.Numerical results show that the proposed algorithm’s average user throughput is superior to the existing alternative skip-HO algorithm’s average user throughput.