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LT码和q-LDPC码级联方案在深空通信中的应用 总被引:2,自引:0,他引:2
该文针对深空通信对长纠删码的需求,提出了LT (Luby Transform)码和q-LDPC码的级联方案。在综合考虑性能和复杂度的情况下,选取8-LDPC码和8PSK的级联作为等效的删除信道,长度选择灵活、编译码简单的LT码实现纠删功能。文中设计了两种短8-LDPC码,并对整个级联系统的纠错性能进行了仿真。仿真结果表明8-LDPC码的性能优于信源信息速率和码率相同的二进制LDPC码,级联系统在等效包删除概率不超过0.1时,系统误比特率以概率1趋于0。 相似文献
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针对短码长LT码(码长在103以下)的随机编码方式,需要较高的编码冗余才能保证一定的译码性能的问题。设计了一种基于限制Tanner图连接边随机关系的随机置换展开编码算法,可以实现在较小编码冗余开销下提高短码长LT码的可译码概率。在此基础上,针对短码长LT码的传统BP译码算法效率不高的问题,充分利用BP算法译码失败的停止集剩余信息,设计了采用上述编码算法的短码长LT码的停止集高斯译码算法,可以获得接近最大似然译码的性能。仿真结果表明,所提出的编译码联合算法有效降低了短码长LT码满足10 4译码失败概率时所需的编码冗余开销。 相似文献
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LT码是一种无码率的线性分组码,具有很强的信道适应性和低复杂度。文中提出一种CRC码与LT码级联的编码方案(CRC-LT码),CRC-LT码通过调整译码开销来保证FSO系统的可通率和使LT码在FSO系统中获得的编码增益。通过建立分析模型,推导出在给定信道条件下的数据恢复率。最后,利用Gamma-Gamma信道模型进行CRC-LT码的编译码过程仿真,并给出数据恢复率与信道条件、信噪比和译码开销的关系,以及FSO系统的误码率。仿真结果表明,CRC-LT码在牺牲一定译码开销后能够获得更高的编码增益,有效保证FSO系统的可通率。 相似文献
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As a new class of forward error correcting encoding algorithm, Luby Transform codes are suitable for the erasure channel environment based on the packet communication. The encoding, decoding algorithms and the implementation of LT codes are summarized in the paper. Meanwhile simulations of the ideal soliton distribution and robust soliton distribution are conducted to evaluate the performance of LT codes in terms of successful decoding probability, mean degree and decoding time over the erasure channel. The parameter optimization rules of LT codes are deeply discussed and proposed in the paper. The research results are of great practical importance for improving the real time performance in the erasure correction applications. 相似文献
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Luby transform (LT) codes were the first practical rateless erasure codes proposed in the literature. The performances of these codes, which are iteratively decoded using belief propagation algorithms, depend on the degree distribution used to generate the coded symbols. The existence of degree‐one coded symbols is essential for the starting and continuation of the decoding process. The absence of a degree‐one coded symbol at any instant of an iterative decoding operation results in decoding failure. To alleviate this problem, we proposed a method used in the absence of a degree‐one code symbol to overcome a stuck decoding operation and its continuation. The simulation results show that the proposed approach provides a better performance than a conventional LT code and memory‐based robust soliton distributed LT code, as well as that of a Gaussian elimination assisted LT code, particularly for short data lengths. 相似文献
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This paper investigates the joint iterative decoding of low-density parity-check (LDPC) codes and channels with memory. Sequences of irregular LDPC codes are presented that achieve, under joint iterative decoding, the symmetric information rate of a class of channels with memory and erasure noise. This gives proof, for the first time, that joint iterative decoding can be information rate lossless with respect to maximum-likelihood decoding. These results build on previous capacity-achieving code constructions for the binary erasure channel. A two state intersymbol-interference channel with erasure noise, known as the dicode erasure channel, is used as a concrete example throughout the paper. 相似文献
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Dur A. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1988,34(1):70-78
When a block code is used on a discrete memoryless channel with an incomplete decoding rule that is based on a generalized distance, the probability of decoding failure, the probability of erroneous decoding, and the expected number of symbol decoding errors can be expressed in terms of the generalized weight enumerator polynomials of the code. For the symmetric erasure channel, numerically stable methods to compute these probabilities or expectations are proposed for binary codes whose distance distributions are known, and for linear maximum distance separable (MDS) codes. The method for linear MDS codes saves the computation of the weight distribution and yields upper bounds for the probability of erroneous decoding and for the symbol error rate by the cumulative binomial distribution. Numerical examples include a triple-error-correcting Bose-Chaudhuri-Hocquenghem (BCH) code of length 63 and a Reed-Solomon code of length 1023 and minimum distance 31 相似文献
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纠错编码技术通过引入冗余增加可靠性,是现代通信的关键技术之一。无速率编码是一类新兴纠错编码,其速率可以根据信道状态自适应改变,编译码算法较为简单,且性能优异,可以适用于不同的应用场景,因此受到了国内外学者和工业界的关注。介绍了4种经典或新兴的无速率编码方案,包括卢比变换(Luby Transform,LT)码、Raptor码、在线喷泉码(OFC)和BATS(Batched Sparse)码。介绍无速率编码的基本原理,通过其发展过程比较不同无速率编码的特点。阐述了这些无速率编码的编译码方法,并简要介绍其最新的研究进展。最后,介绍无速率编码在广播通信及不等差保护、无线传感器网络、车联网、存储以及分布式计算等新老场景中的应用。无速率编码是一种复杂度低、灵活度高的编码,随着新型无速率编码的发展,在未来的分布式系统等场景中将会有更广泛的应用。 相似文献