Research On Network Coexistence And Interference Assessment Technology For 5G System

In the future,Internet of Thing(IoT)will be part of life of human beings,which means the types of devices as well as the number of devices accessing to the Internet will increase,followed by the rapid growth of diversified business needs and high data demands.In order to supply users with high data rate and reliable experience,5G will focus on the study of 4G evolution technologies and innovation technologies.Among with them,as the evolution of 4G technologies and key technologies of 5G,D2D technology and LAA technology have been widely concerned.At present,3 GPP and other standardization organizations have already started the standardization work for 5G.When the new technologies are introduced,some problems should be paid attention to,such as how to make network layout reasonable,how to reduce the interference introduced by the new technologies to the legacy system.In that way they can coexist peacefully.Therefore,before the actual deployment of the network is carried out,the interference and fair coexistence strategies should be evaluated to provide theoretical basis.In this thesis,the interference caused by D2D users to the cellular users is firstly evaluated by static simulation.According to 3GPP,D2D system and LTE and its evolution system take up the adjacent 10MHz bandwidth for each.The simulation compares the results in different cases.And the performance metric of the simulation is the throughput loss of legacy network.According to the results of the interference assessment,it is considered that the interference caused by D2D users in the VoIP traffic model is controllable,which could support the actual network deployment.In order to guarantee the the quality of communication,the power control scheme and the mode switching scheme are proposed in this thesis,so that the continuity of both inter-traffic and intra-traffic can be maintained.In this thesis,the static simulation method is adopted to simulate the user’s throughput.The simulation outputs the throughput and the energy saving gain of D2D users.With dynamic simulation method,the mode switch scheme is simulated to testify the effectiveness.The simulation outputs the throughput gain.The simulation results show that the power control scheme and the mode switching scheme are effective.Analyses and suggestions are given to make the network deployment more reasonable in this thesis.Then,this thesis evaluates the fairness of the network coexistence after LAA is introduced.According to 3GPP,static simulation method is adopted.The performances are recorded when two WLAN networks coexist,and then the network performance changes are evaluated after one of the networks is replaced by LAA system.The simulation results show that the LAA technology can improve the network performance and can coexist with the WLAN network friendly,which could be theoretical basis for network deployment.