Research On Dynamic Point Blankingin LTE-Advanced Network

In recent years,with the rapid development of Internet and communication technologies,smart terminals are widespread,traditional voice services migrate to multimedia data services.In order to solve the problems of explosive growth of data traffic and cell edge users' serious interference,many new technologies are introduced into LTE-A network to improve network' performance,such as Multiple-Input Multiple-Output(MIMO),carrier aggregation,coordinated multipoint(CoMP)transmission and heterogeneous network.CoMP enables multiple nodes which locate independently to coordinate with one or more users,so that the cell edge users can reduce interference in the cooperative set and improve the performance.Dynamic point blanking(DPB)mute the nodes which interfere with the edge users seriously through the cooperation of base station.It can improve the performance of edge users,reduce power consumption,and effectively improve the system energy efficiency.In order to improve the energy efficiency of the overall network,this research mainly focuses on DPB which is one technology of CoMP,and introduces the DPB into heterogeneous networks.The contents and results of the research are concluded as follows:(1)In order to ease the heavy burden on the backhaul and guarantee the fairness,a novel DPB algorithm based on the silent pattern is proposed.Based on the LTE-A downlink system level simulation platform,the existing DPB algorithm is improved by introducing the method called muting pattern to reduce the computation.In order to decide the nodes which adopt DPB,PF factor is set as the criterion.To maximize PF in the cooperative set,DPB can ensure the fairness of the system.Simulation results show that the proposed algorithm can effectively improve the performance of edge users.(2)In order to solve the problem of cross-layer interference in heterogeneous networks,a novel energy efficiency optimization algorithm,which is based on ABS and DPB,is proposed.In frequency domain,according to the Channel State Information(CSI)of users,the central scheduler mutes some RBs of macrocells.In time domain,ABS scheme configures some macrocells,subframes as ABSs and reduce the transmission power.To improve the adaptability of the network,the ratio of muting RBs and ABSs can be configured by the traffic load.At the same time,macrocells' transmission power can be decided based on game-theory.The system level simulation shows that the proposed algorithm can effectively improve the energy efficiency of the network,and improve the performance of the edge users,while ensuring the fairness of the overall network.