結合錯誤更正與加密方法之LDPC編碼通訊系統的性能分析

Performance of Joint Error Correction and Encryption method Based on LDPC Codes

郭信宏(Hsin-Hung Kuo)

指導教授 ： 鄭立德

中原大學/電機資訊學院/通訊工程碩士學位學程/碩士(2015年)

https://doi.org/10.6840/cycu201500729

摘要

在之前的研究中藉由整合錯誤更正碼和影像修復技術的影像傳輸系統將系統抵抗干擾的能力提升。並且將其更進一步的加入系統保密性以及遞迴式解碼技術，增加系統的保密性並且改善系統的效能。整合遞迴式解碼的錯誤更正碼主要架構是將解碼前和影像處理完的碼字做比較，利用其差值來判斷是否為擦失掉的依據，擦失完成後將剩餘的碼字送回解碼器做errors-and-erasures decoding。
近年來，因為低密度奇偶校驗碼可以依據系統特性調整碼字的長度以及具有較佳的錯誤更正能力使其變為熱門的研究項目。是以前人的系統為基礎，提出一個影像傳輸系統，利用低密度奇偶校驗碼取代里德-所羅門碼，並依據低密度奇偶校驗碼的特性提出一種影像修復以及保密性的方法。此外，也利用結合通道的資訊和影像修復完的資訊提出一個遞迴解碼的架構。透過模擬結果將計算影像的Peak signal to noise ratio (PSNR) 值來比較系統抗干擾的能力。

關鍵字

加密、低密度奇偶校驗碼、影像修復、遞迴解碼、部分頻帶雜訊干擾

並列摘要

The research years of Reed-Solomon (RS) codes for slow frequency-hopping systems have been extensively studied in recent years. Previous studies has considered to combine error-correction coding with image restoration techniques and encryption method to improve anti-jamming capability of image transmission and system security.
Low-Density Parity Check codes (LDPC) become popular because of its flexibility in codeword length and better performance than those of other channel codes. Therefore, in this paper, we propose a image transmission system which empolyed LDPC code to replace RS code under partial band noise jamming (PBNJ). Besides, we also propose a iterative decoding and encryption scheme which integrated the information after image process and channel information. Simulation results show that the proposed system can effectively improve the quality of the received images.
To compare the image performances in jamming environment, we evaluate the error probabilities and the peak signal to noise ratio (PSNR) values of transmitted images.

並列關鍵字

Encryption、Low-Density Parity Check Codes、Partial-Band Noise Jamming、Image transmission、Iterative decoding

參考文獻

[1] W. E. Stark, “Coding for frequency-hopped spread-spectrum communication with partial-band interference Part: Coded performance,” IEEE Trans. Commun., vol. COM-33, pp. 1045-1057, Oct. 1985.

[2] M. B. Pursley and W. E. Stark, “Performance of Reed-Solomon coded frequency-hop spread-spectrum communications in partial-band interference.” IEEE Trans. Commun., vol. COM-33, pp. 767-774, Aug. 1985.

[3] Yu T. Su and Li-Der Jeng, “Antijam capability analysis of RS-coded slow frequency-hopped systems,” IEEE Trans. Commun., vol. 48, no. 2. Feb, 2000.

[4] Li-Der Jeng and Chien-Hung Su, “Image restoration for Reed-Solomon coded SFH/MFSK System With Partial-Band Noise jamming,” Intelligent Signal Processing and Communication Systems, 2009. ISPACS 2009.

[5] J. Jiang and K. R. Narayanan, “Iterative soft decision decoding of Reed Solomon codes based on adaptive parity check matrices,” Information Theory, 2004.