Research On Simulation System Design And Uplink And Downlink Optimization Algorithm Of LoRaWAN Network

With the advent of the Internet of Things era,wireless communication is playing an increasingly important role in people's lives.Compared with traditional wireless communication technology,LoRahas the advantages of low power consumption,long communication distance,and low cost,so it is more suitable for diversified Io T scenarios.However,as an emerging technology,LoRahas not yet formed a system in terms of network deployment solutions.If you deploy directly and adjust the deployment plan based on the feedback of field data,it will cause a huge waste of resources;if you use mathematical analysis to calculate the corresponding impact of different deployment plans,the calculation scale is big and complexity is high.In response to this problem,this paper designs and implements a LoRaWAN network simulation system.By modeling application scenarios and the radio frequency behavior of gateways and terminals,and simulating the data interaction of LoRaWAN gateways and terminals in different scenarios,developers can better study the impact of network deployment plans and transmission parameters on network performance,so that they can use existing resources to make the network achieve better performance.At the same time,this article also optimizes the problems of the LoRaWAN protocol in the uplink and downlink transmission.Most of the existing LoRaWAN networks use the adaptive data rate algorithm to allocate the terminals' spreading factor(SF),but this algorithm will cause a large number of data packet collisions when the network conditions are good.In response to this problem,this paper divided the uplink transmission into three situations,and modeled the conflict rate for each situation.Finally,combining the conflict rate model and the actual project situation,an optimized algorithm was proposed to allocate the spreading factor more reasonably,reducing the conflict rate.In the Wuhan Easylinkin Technology Co.Ltd's electric and water meter project,the downlink congestion was caused due to the uneven utilization of the gateways.In response to this problem,this paper proposes a gateway load balancing algorithm,which improves the network performance under the “best signal of a single gateway” situation by balancing the workload of all gateways.Based on the multi-storey building model in the simulation system designed in this paper,a LoRaWAN network was deployed in a youth apartment and field test and traversal experiments were carried out.The results show that the difference between the simulation result obtained by the LoRaWAN network simulation system and the actual conflict rate is only 2.78%,which has high practical value;the conflict rate obtained by the uplink optimization algorithm in the three situations does not differ from the optimal conflict rate by more than 0.003,indicating that the optimized SF allocation method is close to the best;the downlink optimization algorithm reduces the downlink collision rate of the original algorithm by 1.69 times,which improves the network performance.