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Research On Access Technology Of Massive Machine Type Communication Devices

Posted on:2019-07-13Degree:MasterType:Thesis
Country:ChinaCandidate:L XuFull Text:PDF
GTID:2428330566976581Subject:Master of Engineering
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The next generation mobile communication(5G)network for 2020 and future has become the research hot spot for recent years.5G network not only solves the human-to-human(H2H)communication problem,but also focuses on achieving the interconnection of all things.Therefore,the Internet of Things(IoT)will become the main driving force for the development of mobile communication networks in the future.Machine-to-machine(M2M)communication or machine-type communication(MTC)is considered as the main component of IoT.It is predicted that the MTC market will grow rapidly in the next five years.This means that a large number of MTC devices will be deployed in future mobile cellular networks.However,current cellular network is mainly designed for H2 H communication,and massive MTC devices access may cause severe network congestion.Therefore,mitigating access congestion and supporting a large number of MTC devices have been deemed as the most important requirements in future mobile networks.Moreover,in diverse application scenarios,effective access strategies need to be designed to provide differentiated services for MTC devices with different service requirements.To address these problems mentioned above,from the MTC gateway-assisted transmission mode,we study MTC devices grouping and develop a group-based congestion-mitigating access scheme for massive delay-tolerant devices.Besides,we design a dynamic preamble allocation strategy from the perspective of service requirement.The specific contents of this thesis are as follows:(1)MTC devices grouping.For MTC devices with low mobility and delay tolerance,we distinguish the service types based on delay requirements and define the similarity between MTC devices based on their locations and delay requirements.In addition,we formulate a similarity matrix and bring it into spectral clustering algorithm to group MTC devices.The simulation results show that the proposed grouping scheme achieves better grouping results than the location based grouping method.It can allocate MTC devices with the same delay requirements to the same group as much as possible.(2)MTC gateway-assisted transmission.On the result of MTC devices grouping,we design a MTC gateway selection algorithm and implement data transmission based on MTC gateway.When selecting MTC gateway,we take into account delay requirement and energy consumption.In the data transmission progress,a two-stage data transmission mode is developed.Besides,we theoretically analyze the proposed access scheme and derive the access performance expression,and compares the simulation results with the analysis results to verify the effectiveness of the proposed access scheme.(3)Random access preamble allocation.As delay-sensitive MTC devices have strict requirements on the access delay,the proposed group-based access scheme is not sutable for them.In view of this,we design a dynamic preamble allocation strategy with QoS guarantee when two types of MTC devices coexist.In this strategy,we take the available preamble resources into two orthogonal resource pools and provide them to different types of MTC devices.Furthermore,the number of preambles in the two resource pools can be dynamically adjusted according to the network loads to meet QoS requirements of MTC devices.In order to further control network congestion,access class barring(ACB)scheme is used in the preamble allocation.The simulation results show that the designed strategy can effectively alleviate network congestion and guarantee delay requirements for delay-sensitive MTC devices.
Keywords/Search Tags:M2M Communication, MTC Gateway, Random Access, Congestion Mitigation, Preamble Allocation
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