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多元域LDPC码简化译码算法研究
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作者 李赛斯 文磊 张誉 《西南师范大学学报(自然科学版)》 CAS CSCD 北大核心 2013年第10期147-154,共8页
多元域LDPC码具有优良的纠错性能,但译码的高复杂度成为制约其应用的关键因素.基于图模型理论,分析多元域Tanner图结构,对比多元域与二元域的区别,分析了导致性能差异的原因.推导了基于对数似然比测度的合积译码算法和EMS简化译码算法,... 多元域LDPC码具有优良的纠错性能,但译码的高复杂度成为制约其应用的关键因素.基于图模型理论,分析多元域Tanner图结构,对比多元域与二元域的区别,分析了导致性能差异的原因.推导了基于对数似然比测度的合积译码算法和EMS简化译码算法,分析了EMS算法中似然比消息的震荡特性,提出相应的抑制震荡的方法.计算机仿真表明,修正型EMS算法能够提高消息收敛特性和纠错性能并降低译码迭代次数. 展开更多
关键词 多元域LDPC码 TANNER图 合积译码 扩展最小和 震荡
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Low complexity joint source-channel decoding for transmission of wavelet compressed images
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作者 殷玮玮 梅中辉 吴乐南 《Journal of Southeast University(English Edition)》 EI CAS 2006年第2期148-152,共5页
To utilize residual redundancy to reduce the error induced by fading channels and decrease the complexity of the field model to describe the probability structure for residual redundancy, a simplified statistical mode... To utilize residual redundancy to reduce the error induced by fading channels and decrease the complexity of the field model to describe the probability structure for residual redundancy, a simplified statistical model for residual redundancy and a low complexity joint source-channel decoding(JSCD) algorithm are proposed. The complicated residual redundancy in wavelet compressed images is decomposed into several independent 1-D probability check equations composed of Markov chains and it is regarded as a natural channel code with a structure similar to the low density parity check (LDPC) code. A parallel sum-product (SP) and iterative JSCD algorithm is proposed. Simulation results show that the proposed JSCD algorithm can make full use of residual redundancy in different directions to correct errors and improve the peak signal noise ratio (PSNR) of the reconstructed image and reduce the complexity and delay of JSCD. The performance of JSCD is more robust than the traditional separated encoding system with arithmetic coding in the same data rate. 展开更多
关键词 joint source-channel decoding sum-product algorithm generalized distribution law wavelet compressed image
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