Design And Implementation Of LoRa Anti-collision Algorithm For Dense Iot Applications

LoRa is a Low Power Wide Area Network(LPWAN)wireless communication technology,which has the communication characteristics of long distance,low power consumption and large-capacity data transmission.LoRa uses Chirp Spread Spectrum(CSS)technology.Although this method increases the communication distance,it will result in a decrease in the data transmission rate,and the effective transmission rate is only0.3kbps-5kbps.In the application scenario of mobile device nodes,in order to ensure transmission reliability,nodes use lower data rates for data transmission.When the number of device nodes increases,there will be serious broadcast conflict problems.Therefore,solving the network conflict problem caused by increased node density is very necessary.In order to solve the conflict problem,an anti-conflict mechanism be designed,the main work includes:(1)In order to solve the problem of long transmission time and channel resource occupation due to the low transmission rate of LoRa network,an adaptive rate algorithm is designed to design a mechanism to quickly determine the node communication rate for mobile terminal devices to improve network data transmission efficiency.(2)For the conflicts between request messages in the above mechanisms,a backoff algorithm is designed to optimizes the contention window to reduce the conflict probability of request messages in the network,and can also achieve fast transmission in scenarios with high network density.The effect of the request message.OPNET simulation carries out on the anti-collision mechanism designed,and compares and analyzes the collision probability and throughput of the anti-collision mechanism designed and the standard protocol.The test results show that the anti-collision mechanism proposed has increased the probability of success reaches 37.1%,which is an increase of 14.7% compared to the literature [15],throughput reaches 448bit/s,in the 50-node scenario,reaching the expected design index.The research results have certain application value for LoRa network expansion.