Research And Optimization Of Distributed Queuing Random Access Technology For 5G

Massive Machine-Type Communications(mMTC)focuses on serving large-scale Machine to Machine(M2M)communications,playing an important role as one of the three major application scenarios of 5G.The random access process is a necessary step for communication services.The suitability between random access mechanism and service scenarios and the adaptability to different access conditions will greatly affect the quality of communication services.A key issue in the mMTC scenario is how to use limited access resources to provide access services for a large number of devices.However,most IoT networks currently use the same access mechanism as LTE,which is obviously inappropriate.The distributed queuing random access mechanism is an access mechanism specifically designed for high-load access scenarios.Studies have shown that it has a significantly higher access successful probability than LTE under high-load access conditions.But it will also cause increased access delay.This paper takes the distributed queuing random access mechanism as the research center.while exploring its advantages,it further optimizes its disadvantages in combination with the communication requirements of the mMTC scenario.The main contributions and innovations are as follows:Firstly,random access mechanisms of current commonly used Internet of Things communication technologies are summarized and compared.And the specific access performance is observed through computer simulation to explore its disadvantages and reasons.Current researches on optimization of massive random access mechanisms are classified and summarized,and their advantages and disadvantages are also listed.Besides,the principle of distributed queuing random access mechanism is introduced,and its basic theoretical formula is derived.In order to meet the requirements of mMTC massive random access,and solve the problem of excessively high access delay of native distributed queuing random access mechanism,a resource grouping mechanism was proposed and its theoretical model was also derived.The devices and resources are further divided and isolated,which effectively shortens the length of the contention resolution queue,thereby reducing the access delay.Besides,with reference to the multi-level feedback queue mechanism,dynamic resource scheduling is added,which further improves the access resource utilization.In order to meet the requirement for low energy consumption of mMTC devices,three energy consumption states and the transition relationship among them during the access process are summarized.And we also established the system model and theoretical model of device access energy consumption.Based on the distributed queuing random access mechanism,a resource allocation strategy to achieve optimal energy efficiency is proposed,which effectively reduces devices' access energy consumption.Finally,the accuracy of theoretical models proposed in this paper and the effectiveness of the optimization strategy are verified through simulation comparison and analysis.