Research On Correlation Calculation And Application Of LT Code For Anti-eavesdropping Channel

With the advent of the communication era,modern communication methods are more inclined to wireless communication.Broadcasting,as the most prominent feature of communication,can easily lead to malicious eavesdropping of transmitted information,and wireless communication security issues cannot be ignored.The traditional anti-eavesdropping method of wireless networks is to encrypt information.This method not only increases unnecessary redundancy,but the shared key also has the risk of being deciphered or leaked.Because LT code has low decoding overhead,simple encoding and decoding,and has no bit rate characteristics,it has attracted much attention in wireless communication.In recent years,some scholars have proposed to use it as an anti-eavesdropping code,which can ensure information in eavesdropping channels efficient and safe transmission.Aiming at the problem of the probability density distribution function of the number of coded symbols received when the LT code is successfully decoded in the deleted channel,based on the experimental results,this thesis proposes an improved clustering algorithm based on the combination of GMM and K-means algorithm to construct the LT code translation Code symbol probability density distribution.The algorithm first uses the elbow method and the contour coefficient method to determine the number of clusters K,then uses the K-means algorithm to complete the initial data division,and gives the initial value of the EM algorithm iteration based on the classified clustering parameters,and finally uses the EM algorithm to determine The final parameters of the GMM fit the probability density distribution function of the number of coded symbols received when the LT code is successfully decoded in the deleted channel.Through experimental comparison,the clustering algorithm combining GMM and K-means proposed in this paper fits the probability density distribution function of the number of coded symbols received when the LT code is successfully decoded under the deleted channel,which is relatively close to the experimental results.Aiming at the LT code anti-eavesdropping channel model,this paper derives a mathematical model of the eavesdropper's bit error rate in the eavesdropping channel based on the receiver's decoding symbol distribution structure.From the experimental results,it can be concluded that the channel deletion probability of the main channel and the eavesdropping channel are different,and the receiver's decoding symbol distribution is also different.After the legal receiver's decoding work is completed,the eavesdropper's probability is earlier,equal to,and later than the legal receiver.,Combined with the probability distribution of the decoded symbols to derive the mathematical model of eavesdropper's bit error rate calculation.Compare the bit error rate equation obtained in this paper with the experimental results of eavesdropper's bit error rate.The error rate of the eavesdropper calculated by the algorithm proposed in this paper is the same as the experimental simulation value,which verifies the rationality of the LT code error rate model of the anti-eavesdropping channel proposed in this paper.