Research On ALOHA Anti-collision Algorithm And Data Security In LoRa Network

In recent years,a long distance and low power wireless communication technology has emerged,which is called LoRa(Long Range).The low data rate makes it mainly for the application of Internet of things,such as smart agriculture,intelligent building and so on.With the large-scale popularization and construction of LoRa network,the security problem is becoming more and more important.The research of this paper focuses on two aspects of LoRa network security:Data anti-collision and data encryption.For the anti collision data problem,this paper researches on the existing technology and algorithm,and analyzes its advantages and disadvantages;at the same time,according to the problem of too large collision probability in data anti-collision algorithm of LoRaWAN(ALOHA),introduce the CDMA idea,and proposes an improved anti-collision algorithm of the data(CD-ALOHA).The algorithm takes advantage of the multiple access of orthogonal spread spectrum code,and preserves the competitive backoff strategy of ALOHA algorithm.Compared with other algorithms,it further increases the throughput of network channel and reduces the average delay of data transmission.The validity of the CD-ALOHA algorithm is verified by theoretical derivation and simulation experiments.For the LoRa network data encryption,this paper summarizes all kinds of encryption algorithms for embedded sensor nodes and working modes matching with encryption algorithms,and analyzes their advantages and disadvantages;at the same time,the encryption algorithm in LoRa WAN(AES-128,CTR)is explored in depth,and proposed its improvement and optimization,to make the LoRa network the data encryption algorithm to better meet the requirements of the space loss and time loss in the embedded system design.The main contents are as follows:(1)Reduces the number of encryption wheels of the original algorithm.(2)Uses the property of matrix transformation of the wheel operation in the finite field GF(2~8),the complex steps of the wheel operation are optimized so that the results can be obtained by one step through the formula.(3)Increses some storage capacity,and uses look-up table method instead of more time-consuming multiplication operation.Finally,by comparing with several existing AES improvement schemes and theoretical security analysis,it is shown that the improved algorithm increases the appropriate amount of storage and the very small loss of resisting differential attack capability,and improves the encryption speed and reduces the overhead of the system.At the end of this paper,a Lo Ra network prototype system for parking management is designed,including the overall design,the network architecture design,and the hardware and software design of the components.The function of detecting the status of parking space and storing,share of data message is realized.