共查询到19条相似文献,搜索用时 609 毫秒
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该文给出了在译码端使用边际信息缩小译码列表的算法,深入分析了边际信息缩减译码列表的原因,给出了基于移位寄存器序列的边际信息。相比于使用稳定信道传送边际信息的方法,其不使用额外的信道,不影响译码的性能与复杂度,更易于工程实现。最后改进传统分阶统计译码法,利用少量最可靠位作为边际信息,显著缩减译码列表。 相似文献
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软判决译码中软信息的提取 总被引:1,自引:0,他引:1
本文基于单载波和多载波传输的等效基带模型的衰落信道,采用比特交织的编码调制(BICM)系统,研究了软判决译码所需的软信息的提取。通过仿真说明,反馈信道噪声信息的结合解调与译码的迭代译码方法具有一定的鲁棒性。 相似文献
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为了降低低密度奇偶校验(Low Density Parity Check,LDPC)码译码算法的复杂度,提出了一种基于量化预处理的LDPC迭代大数逻辑译码算法。该算法在迭代译码过程中,校验节点采用基于伴随式的信息处理方式,避免了外信息的计算;同时,变量节点基于回传的伴随式信息进行可靠度偏移大小的计算,并结合与当前码位相对应的调制映射信息进行可靠度偏移方向的设计。迭代更新时,变量节点采用基于信息匹配的可靠度更新规则。迭代前的量化预处理能避免实数乘法运算进入迭代过程,使其只涉及整数加法操作和逻辑操作。仿真结果表明,在保持译码性能的前提上,所提算法具有更低的译码复杂度。 相似文献
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本文提出一种新型的高存储效率的最大似然译码(MAP)译码器网格信息更新实现方法,该方法可以降低Turbo码译码器状态阵列计算对存储器的需求.利用该实现方法可以使得MAP译码器的前向网格信息和后向网格信息共享同一存储器,而且前向和后向的网格信息更新以及MAP译码产生的外部信息同时进行计算;因此该法可以提高Turbo译码的运算速度、降低存储器开销,进而降低Turbo译码电路实现时的硅片面积. 相似文献
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Turbo码并行译码算法的研究 总被引:3,自引:0,他引:3
Turbo码的译码算法大致可分为串行译码算法和并行译码算法两大类。串行译码算法如MAP、LOG-MAP等的研究已比较深入。但并行译码算法,尚有许多问题有待探讨。研究了Turbo码的并行译码算法,将Turbo码译码和图论结合起来,利用Bayesian网络图模型描述了Turbo码的译码过程,基于模型使用Pearl的信息传播算法,建立了Turbo码的并行译码算法。并对所讨论的并行译码算法进行了模拟,模拟结果表明:该并行译码在译码性能等方面比串行译码优越。 相似文献
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光通信系统中低密度奇偶校验(Low-density Parity-check,LDPC)码采用对数似然比置信传播(Log-likelihood Ratio Belief Propagation,LLR-BP)算法进行译码时,在高信噪比区域迭代译码过程中会出现变量节点外部信息振荡不收敛而导致译码纠错性能的降低.为满足光通信系统的要求,提出了一种削弱外部消息振荡的改进LLR-BP译码算法.该算法通过引入加权系数平衡前后两次迭代之间变量节点传递的外部信息,明显减缓了外部信息的振荡现象.仿真结果表明:与传统LLR-BP译码算法相比,该改进LLR-BP算法具有更佳的误码性能,同时降低变量节点外部信息振荡现象并加快了译码的收敛速度. 相似文献
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介绍一种记录系统信息表的设计方法,并根据实践经验提出优化措施.通过对信息表进行备份、对备份信息表单独刷新、对备份信息表位置的精心设计等措施,保证信息表能效记录数据关键信息,并且两份信息表不会同时被破坏.通过对备份信息表的自动读取保证系统在一个信息表遭到意外破坏时系统仍能正常工作,并自动恢复被损坏的信息表,在数据保护和系统稳定工作方面具有重要意义. 相似文献
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This paper proposes a backup path management method for time division multiple access (TDMA) based client wireless mesh networks (WMNs). In a TDMA based client WMN, as links/nodes fail or as nodes perform handover and as flows enter and leave the network, the paths between various nodes change as well as the bandwidth available along these paths. In these networks, to support the quality of service requirements of flows, backup paths with the required bandwidth need to be established dynamically. Some methods are proposed in the literature to establish backup paths which handle link/node failures and node handover in ad hoc networks, but none of these methods can provide backup paths with the required bandwidth dynamically. To address that issue, the present paper proposes a backup path management method which is adaptive to both topological changes and traffic changes in a network. Each node along the current path between a source and a destination finds backup paths with the required bandwidth in order to handle failure of the link to its downstream node and its own failure or handover. Nodes use two-hop neighborhood information and slots status information of two-hop neighbors to establish backup paths. We prove that the number of backup paths available when a node N searches for backup paths to handle its own failure are more than the number of backup paths available when some other node searches for the backup paths for the failure of node N. Performance of the proposed method is compared with the performance of a naive path management (NPM) method in which always the source establishes backup paths whenever a link/node fails or a node performs handover, and also with the performance of a backup path management method proposed in the literature. The proposed method significantly outperforms the NPM method and the method selected from the literature. For example, when the speed of the mobile nodes is 50 m/s, the packet delivery ratio with the proposed method is 63 % more than the NPM method and 35 % more than the method selected from the literature. 相似文献
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We present a method for utilizing soft information in decoding of variable length codes (VLCs). When compared with traditional VLC decoding, which is performed using "hard" input bits and a state machine, the soft-input VLC decoding offers improved performance in terms of packet and symbol error rates. Soft-input VLC decoding is free from the risk, encountered in hard decision VLC decoders in noisy environments, of terminating the decoding in an unsynchronized state, and it offers the possibility to exploit a priori knowledge, if available, of the number of symbols contained in the packet 相似文献
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针对消防管理信息系统的快速发展,对其数据备份的策略及备份方法进行了探讨,为信息系统数据备份提供借鉴和指导。 相似文献
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A method of joint equalization and decoding for block transmission with coding across blocks is presented. It is well suited for bandwidth efficient QAM transmission using large transmit symbol alphabets, whereby the blocking structure can be arbitrary in principle. The method consists in multiple iterations of equalization and decoding, whereby information is exchanged back and forth between the decoder and the equalizer. The equalizer is based on Cholesky factorization of the equivalent discrete-time channel matrix (Eur. Trans. Telecommun 10 (1999) 351; Grundlagen der Kommunikationstechnik, Springer, Berlin, 2004). The convergence behavior of the iterative equalization and decoding method is analyzed by means of an upper bound on the extrinsic information transfer. It is shown that the method has improved bit error performance versus separate equalization and decoding without decoder feedback and, thus, yields superior power efficiency. 相似文献
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介绍了低密度奇偶校验码(LDPC)的几种常用译码算法及其优缺点,特别用密度进化理论分析了归一化置信传播(Normalized BP-based)和偏移置信传播算法(Offset BP-based)的外信息概率分布和演化。基于此,分别针对Normalized BP-based和Offset BP-based算法提出了广义互信息理论(Generalized Mutual Information)及其计算公式,同时提出了改进的因子自适应LDPC译码算法,在每一次译码过程中通过一维搜索,可以获得一个最佳的修正因子,该因子能够最大化广义互信息,从而获得最佳的译码性能。分析和仿真数据表明,提出的因子自适应算法比传统的算法具有更好的性能。 相似文献