Research And Standardization Of 5G Network Oriented Key Technologies Of Massive Machine Type Communication

Although the 4th Generation mobile communication system has brought profound influence and huge improvement to human society,the pace for a mobile communication system of higher performance will never stop.In 2012,International Telecommunication Union(ITU)initiated the standardization for the 5th Generation mobile communication system(5G),and proposed three usage scenarios,eight capabilities and key candidate technologies.As the main standardization organization of mobile communication industry,the 3rds Generation Partnership Project(3GPP)has responsibility for 5G standardization.With the emergence of new scenarios and new technologies,academia and standardization organizations around the world have carried out extensive research on 5G.The primary research object of this thesis is one of the three usage scenarios of 5G-that is,massive Machine Type Communication(mMTC).This scenario mainly orients Internet of Thing businesses and it requires extremely high access capability of the network.Towards this scenario,the purpose of this thesis is to handle its Radio Access Network(RAN)overload problem.As for the radio technologies of 5G,the industry puts emphasis mainly on Massive MIMO,All-spectrum Access,New Access Technology,Advanced Modulation and Coding,Full-duplex and Ultra-dense Network etc,all of these technologies are referred to as 5G New Radio(NR)technologies.In this thesis,both Massive MIMO and All-spectrum Access are simulated.After validating that these technologies can improve network performance,a solution combined with antenna array beamforming is proposed to handle the overload problem of mMTC scenario.Moreover,this thesis propose an optimization scheme named QoS-based Dynamic and Adaptive Mechanism(QDAM).This scheme can be applied to any virtual cells that are identified by beams.Simulation results show that this scheme improves three performance metrics at the same time.The major work and innovations of this thesis are as follows:For the system co-existence study of 5G,this thesis conducts simulation evaluation based on 3 GPP standardization.This thesis focuses on two outdoor deployment scenarios considered by 3GPP:Urban macro and Dense urban;Simulation assumptions strictly follow the decisions made by 3GPP,and modeling the propagation model,antenna model and adjacent channel co-existence model;Simulation methodology follows a new set of system-level simulation steps newly released by 3 GPP.It can be concluded from simulation results that massive MIMO among 5G NR technologies not only increases signal strength but also suppresses sidelobe interference.These simulation results are not merely parts of 5G standardization but provide some evidence for the solution used to handle the overload problem of mMTC.These results are submitted to 3GPP in the form of proposals.Aiming at RAN overload problem of mMTC scenario,this thesis puts forward a solution which includes massive MIMO.The RAN overload occurs when a huge number of MTC devices try to access the network at the same time,thus leading to collisions in most of the access resources.The proposed solution in this thesis mainly concerns the MTC devices that have a feature of gathering.By forming a beam to every device group respectively,space dimension can be utilized other than time dimension,frequency dimension and code dimension.Simulation result shows the effectiveness of the proposed solution.Towards any virtual cells identified by beams,this thesis brings forward an optimization scheme named QDAM.This scheme considers two different kinds of MTC devices which have different Quality of Service(QoS)requirements and combines dynamic resource allocation and adaptive access class barring.Simulation results prove that this scheme enhances three performance metrics,such as access delay,resource utilization rate and average throughput.