Research On The Femtocell Handover Algorithm In LTE System

Nowadays, with the rapid development of mobile network and expanding application of LTE, data business demand increases quickly and the requirement of the mobile network for the mobile users is greater. Most of data traffics are performed in indoor environment. Therefore, providing a good indoor coverage for users has become very important. In order to provide good indoor coverage and increase customer loyalty, Femtocell technology is emerged. Femtocell improves the network environment and the quality of service for indoor users.Femtocell joining LTE framework effectively solves the problem of indoor coverage and edge coverage. But the large deployment of Femtocells also causes interference of the LTE system. it may cause the handover problems between Femtocell and macrocell and the number of handovers largely increase and unnecessary handover can be occurred by mobile station.In this paper, we research the Femtocell handover problem in LTE system. Firstly, we introduce the LTE architecture and Femtocell technology, and analyze the the major problems in the Femtocell network. Then we analyze the handover process of LTE system and research the defects of the traditional handover algorithm after Femtocell joined in LTE framework. Self-Organizing Network(SON) is a key concept in LTE systems. In this paper, we proposed a improved mobile robustness optimization(MRO) algorithm based on parameters self-optimization in LTE Femtocell system to reduce the unnecessary handovers and radio link failure(RLF) problem. Members of CSG prefer to connect to the Femtocell. Based on the characteristics of CSG cells, we proposed a new algorithm based on CAC algorithm. This algorithm can meet the needs of members of CSG community better, reducing frequent handovers.We simulate the algorithm in the paper with NS3 simulation platform. Firstly, we introduce the NS3 simulation platform and the simulation modules involved in this paper. Finally we simulate the algorithm based on the LTE module of NS3. The simulation result shows that the proposed algorithm reduces the frequent handovers and unnecessary handovers effectively.