Research On M2M Communication Random Access Technology

Machine to Machine(M2M)refers to the autonomous transfer of data between a machine and a machine through a communication network without human intervention.M2 M communication is widely used in many fields of Internet of Things(IoT)such as smart homes,smart grids and smart transportation.Below are the advantages of M2 M communication: large number of terminal devices,small data packet transmission,frequent access,delay insensitive,low rate requirements and great attention to coverage breadth and power consumption.However,the current cellular network is designed for the characteristics of Human to Human(H2H)communication,and cannot meet the frequent access requirements of massive Machine Type Communication(MTC).Therefore,how to achieve efficient access to large-scale MTC devices is an important issue that the 5th Generation mobile communication technology(5G)urgently needs to solve.This thesis focuses on the efficient access of massive low-power MTC devices in the Narrowband Internet of Things(NB-IoT).The main contributions are conclude as follows:(1)Random access scheme based on dynamic priority NB-IoT,due to the fact the large-scale random access request of massive low-power MTC equipment is likely to cause overload to NB-IoT system,we propose a dynamic priority NB-IoT random access algorithm based on Delay Life.First,defined the delay coefficient of the device as the ratio of the current waiting delay to the maximum tolerant delay.Second,designed the new access priority classification mechanism according to the device delay coefficient.Finally,proposed the access priority classification mechanism.Compared with the traditional Extend Access Barring(EAB),this scheme effectively improves the access success rate of the device,reduces the access delay of the device,and solves the system overload caused by access of massive equipment.(2)The NOMA-based uplink resource allocation scheme in the M2M/H2H co-existing cellular Internet of Things.We propose a NOMA-based uplink resource allocation scheme to the problem that the existing resource allocation algorithm cannot meet the demand of the massive M2M access scenarios.First,the M2M device which has same or similar properties is planned to the same cluster to reduce the complexity of the resource allocation.Second,according to the Quality of Service(QoS),the M2M/H2 H terminal devices at the same cluster are divided into different access priorities to reduce device access congestion.Finally,based on the access priority combined with the NOMA technology,we control the subcarrier-power joint of multiple terminals and implement devices with different QoS levels to share the same subcarrier.The simulation results show that compared with the traditional Orthogonal Multiple Access(OMA)technology,the proposed NOMA-based resource allocation scheme can significantly increase the number of successfully connected M2M devices under the condition of good access of the H2H device.