Study On Multiple Access Control For LoRa Enddevices By Distributed Queuing

In LoRaWAN,ALOHA is used for channel access control of end device,which resulting in low channel utilization in uplink data transmission.The Distributed Queuing(DQ)can effectively solve the concurrent conflict of end devices by centralized dispatching,and ensure the stable transmission performance of the network.In this thesis,DQ is introduced into shared channel access control to study the throughput,average delay and energy efficiency of LoRaWAN network.Firstly,this thesis discusses the channel access technology,LoRa network architecture and technical standards,as well as the working mechanism of the Distributed Queuing.Based on ns-3 and the extended LoRaWAN module,the simulation program of network throughput is designed.And then improving the logic of contention conflict,the reliability of the module is verified.Then,aiming at the efficient scheduling of channel access in LoRaWAN network,the data frame structure,sequence structure and control flow scheme of conflict backoff scheduling are proposed based on DQ.Based on the existing LoRaWAN module,the simulation platform of the scheme is implemented,and the program functionality is verifiedFinally,a network performance simulation scenario is designed to test the throughput,average delay and energy efficiency of the proposed scheme.The results show that compared with the LoRaWAN,when the number of concurrent end device is 100,the throughput of the proposed scheme is improved by 188.9%,the delay is reduced by 67.7%,and the energy consumption is reduced by78.3%.With the increase of the number of end devices,the proposed scheme shows better stability.