共查询到18条相似文献,搜索用时 109 毫秒
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Turbo乘积码梯度译码算法研究 总被引:1,自引:1,他引:0
Turbo乘积码(简称TPC码)是一类采用简单的行列交织器将分组码进行串行级联而构成的纠错码.文中针对二进制turbo乘积码提出了一种快速的软判决译码算法一梯度译码算法.该算法是以迭代Chase算法为基础,通过利用chase算法上次迭代译码而得到的每行(或列)最优判决码D(m-1)来代替竞争码字C,节省了寻找C的过程,从而简化了外信息和软输出的计算.仿真结果表明:梯度算法能在基本保持turbo乘积码的Chase算法译码性能基础上,提高了译码速度,降低了译码复杂度. 相似文献
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基于遗传算法与Chase译码算法的各自优势,提出了一种降低运算复杂度并加快译码速度的新颖分组Turbo码(BTC)译码算法.与传统的Chase译码算法相比,该译码算法降低了译码复杂度且加快了译码速度.仿真分析表明,该算法较传统的Chase译码算法在误码率为10-6时提高了约1.15 dB的净编码增益(NCG),具有良好的纠错性能.因而它是一种适用于光传输系统且实用性较强的新颖BTC译码算法. 相似文献
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利用编码方法搜求Turbo乘积码译码中的候选码字,对由单纠错能力分组码作为子码的乘积码进行仿真,考察不等数量的候选码字对译码性能的影响,并对两种估计无竞争码字比特外部信息值的方式在利用编码方法及Chase—II算法搜求候选码字时所形成的性能差异进行分析。 相似文献
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一种基于Chase的RS码代数软判决译码算法 总被引:1,自引:0,他引:1
为了提高RS码的纠错性能,本文提出了一种基于Chase的代数软判决译码算法,称为Chase-ASD.该算法充分利用了接收比特的可信度信息,但运算复杂度较高.针对该算法运算复杂度高的问题,本文进一步给出了简化的Chase-ASD算法.仿真结果表明,提出的Chase-ASD和简化的Chase-ASD算法均可比原ASD算法提供更多的译码增益. 相似文献
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针对Turbo乘积码(TPC)译码复杂度高、运算量大的缺点,分析了一种改进的TPC译码算法。该算法以Chase迭代算法为基础,通过对错误图样重新排序产生新的测试序列,其伴随式可从前次伴随式的基础上修正一位得到,大大简化了计算步骤。在AWGN信道下对新算法进行了Matlab仿真,结果表明,改进的算法在保持译码性能基本不变的前提下,提高了译码速度,降低了译码复杂度。 相似文献
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本文研究了在MIMO系统的接收端,采用部分干扰抵消群译码算法对接收端信号进行译码的算法,在保证码字获得满分集的同时,降低接收端的译码复杂度.通过将一个空时分组码中所包含的符号进行群组划分,对于不同的符号群组,在对接收信号经过线性滤波处理之后分别独立地进行译码操作,从而达到降低译码复杂度的目的.仿真结果显示,该算法相对于传统的最大似然译码算法,译码复杂度明显降低. 相似文献
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Fishler E. Amrani O. Be'ery Y. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1999,45(5):1406-1422
The overall number of nearest neighbors in bounded distance decoding (BDD) algorithms is given by N0,eff=N0+N BDD. Where NBDD denotes the number of additional, non-codeword, neighbors that are generated during the (suboptimal) decoding process. We identify and enumerate the nearest neighbors associated with the original generalized minimum distance (GMD) and Chase (1972) decoding algorithms. After careful examination of the decision regions of these algorithms, we derive an approximated probability ratio between the error contribution of a noncodeword neighbor (one of NBDD points) and a codeword nearest neighbor. For Chase algorithm 1 it is shown that the contribution to the error probability of a noncodeword nearest neighbor is a factor of 2d-1 less than the contribution of a codeword, while for Chase algorithm 2 the factor is 2[d/2]-1, d being the minimum Hamming distance of the code. For Chase algorithm 3 and GMD, a recursive procedure for calculating this ratio, which turns out to be nonexponential in d, is presented. This procedure can also be used for specifically identifying the error patterns associated with Chase algorithm 3 and GMD. Utilizing the probability ratio, we propose an improved approximated upper bound on the probability of error based on the union bound approach. Simulation results are given to demonstrate and support the analytical derivations 相似文献
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WILLIAM H. THESLING FUQIN XIONG 《International Journal of Satellite Communications and Networking》1996,14(4):327-332
The complexity of algorithms to perform soft decision decoding on block codes has impeded their inclusion in practical systems. A well-known class of algorithms for decoding block codes utilizing channel measurement information along with the algebraic properties of the code are the Chase algorithms.1 In this paper a decoding method similar to Chase's third algorithm is presented. However, in this method, a single test pattern or alternate codeword makes up one stage of the decoder. The method uses information from the previous decoding(s) to assist in generating a test pattern. This single stage ‘Second Chance Algorithm’ can then be extended to a ‘Third Chance Algorithm’ (and beyond) to enhance performance. The method does not invoke the hard decision decoder as often as the Chase algorithms. 相似文献
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List-based algorithms for. decoding block turbo Codes (BTC) have gained popularity due to their low computational complexity. The normal way to calculate the soft outputs involves searching for a decision code word D and a competing codeword B. In addition, a scaling factor /spl alpha/ and an estimated reliability value /spl beta/ are used. In this letter, we present a new approach that does not require /spl alpha/ and /spl beta/. Soft outputs are generated based on the Euclidean distance property of decision code words. By using the new algorithm, we achieve better error performance with even less complexity-for certain BTCs. 相似文献
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On algebraic soft-decision decoding algorithms for BCH codes 总被引:1,自引:0,他引:1
Kamiya N. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2001,47(1):45-58
Three algebraic soft-decision decoding algorithms are presented for binary Bose-Chaudhuri-Hocquengham (BCH) codes. Two of these algorithms are based on the bounded distance (BD)+1 generalized minimum-distance (GMD) decoding presented by Berlekamp (1984), and the other is based on Chase (1972) decoding. A simple algebraic algorithm is first introduced, and it forms a common basis for the decoding algorithms presented. Next, efficient BD+1 GMD and BD+2 GMD decoding algorithms are presented. It is shown that, for binary BCH codes with odd designed-minimum-distance d and length n, both the BD+1 GMD and the BD+2 GMD decoding algorithms can be performed with complexity O(nd). The error performance of these decoding algorithms is shown to be significantly superior to that of conventional GMD decoding by computer simulation. Finally, an efficient algorithm is presented for Chase decoding of binary BCH codes. Like a one-pass GMD decoding algorithm, this algorithm produces all necessary error-locator polynomials for Chase decoding in one run 相似文献
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Adaptive Chase algorithm for block turbo codes 总被引:2,自引:0,他引:2
A new adaptive implementation of the Chase algorithm for binary block codes is proposed. Compared to the two efficiently used algorithms for iterative decoding, the standard Chase and Kaneko algorithms, the proposed algorithm can give the same performance with significant complexity reduction. 相似文献
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针对分组Turbo码自适应Chase译码算法存在的缺陷,该文提出自适应量化测试序列数的分组Turbo码译码算法。该方法以测试序列数C为研究对象,依出错概率大小选择错误图样,并利用量化测试函数根据SNR的变化对测试序列数进行量化,从而达到直接控制译码复杂度的目的。仿真结果表明,所提出的译码算法保证了译码性能,并直接降低了译码复杂度。 相似文献
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《IEEE transactions on information theory / Professional Technical Group on Information Theory》1984,30(5):714-721
Soft decision decoding of binary linear block codes transmitted over the additive white Gaussian channel (AWGN) using antipodal signaling is considered. A set of decoding algorithms called generalized Chase algorithms is proposed. In contrast to Chase algorithms, which require alfloor (d- 1)/2 rfloor binary error-correcting decoder for decoding a binary linear block code of minimum distanced , the generalized Chase algorithms can use a binary decoder that can correct less thanlfloor ( d - 1)/2 rfloor hard errors. The Chase algorithms are particular cases of the generalized Chase algorithms. The performance of all proposed algorithms is asymptotically optimum for high signal-to-noise ratio (SNR). Simulation results for the(47, 23) quadratic residue code indicate that even for low SNR the performance level of a maximum likelihood decoder can be approached by a relatively simple decoding procedure. 相似文献