Handover Control Study In Femtocell Networks

With the constant promotion and deployment of the Long Term Evolution(LTE), the demands for high rate communication services also increase. Although 4th Generation communication system(4G) has more advantages than 3th Generation communication system(3G), there still some problems to be solved, such as the shortage of indoor coverage. The deployment of femtocell can improve the quality of indoor communication effectively. However, due to the dense deployment of femtocell, femtocell network also faces new challenges, such as mobility management, radio resource management, and interference problem. Therefore the reasonable solutions for the above mention challenges are the critical factor for the commercialization of the femtocell.In this article, an adaptive handover control algorithm is proposed to solve the above problems. During the handover execution phase, different handover schemes are performed according to the classification of speed. As high speed users do not hand over to the femtocell, when the user is in a state of high speed, the user hand over to the Macrocell directly. During the medium speed motion, Network determine the data service of the user is the real-time or not. If so, UE hand over to femtocell according to the handover algorithm based on RSRP. At the same time, The network adjust the value of Handover Hysteresis Margin(HHM) adaptively to achieve fast handover to reduce radio link failure according to the speed. If not, it do not hand over to femtocell so as to reduce unnecessary handover times. When a user is in a low speed state,firstly, user equipment(UE) consider the load of neighbor cells and choose the cell with lowest load as the target cell. Then the network judge the SINR of service cell and target cell, so as to improve the throughput of users effectively.This article adopts simulation to the two-tier network performance based on the modeling of Macrocell-Femtocell network (as Two-tier network) for the street scenario. The simulation results show that significant reduction of the amount of handovers while improving the throughput and radio link failure, when the proposed algorithm compared with the other algorithms.