共查询到19条相似文献,搜索用时 125 毫秒
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由于卷积码序列的0,1 bit的概率几乎均衡,对于卷积码自同步加扰的扰码盲识别,现有的基于输入序列0, 1 bit概率不均衡性的识别方法均已失效,为此该文提出一种新的自同步扰码盲识别方法。首先将卷积码自同步加扰序列进行分块处理,通过加扰数据块与卷积码校验向量相乘产生新的序列;然后以最大化新生成序列间线性约束关系成立概率为准则,利用解调输出的软判决序列建立自同步扰码反馈多项式系数的代价函数;最后根据自同步扰码反馈多项式的项数特点,在求解代价函数时改进了动态搜索烟花算法,增加了对烟花个体元素值的约束操作,由求解出的参量值识别出自同步扰码反馈多项式。仿真实验验证了所提方法的有效性,该方法无需遍历搜索反馈多项式,且具有较好的鲁棒性,所需数据量小,随着数据量的增大和扰码阶数的降低,其识别正确率逐渐提高。 相似文献
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该文提出一种新的RS (Reed Solomon)码盲识别方法。该方法利用RS码等效二进制准循环码的代数结构,将截获到的二进制码序列映射为环上的线性码,应用中国剩余定理(Chinese Remainder Theorem, CRT)将环上的线性码进行直和分解,计算不同码长下所有本原多项式对应分量码在相应码空间的归一化维数,通过寻找归一化维数的最小值,实现对RS码码长和本原多项式的识别;最后通过对码字进行因式分解识别RS码的生成多项式。该方法具有使用数据量少,运算量低等方面的特点。仿真结果表明,能完成在较高误码率的情况下对RS码的快速盲识别。 相似文献
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本文利用信号延迟相乘,消除信息码对长扰码和扩频码的影响;利用m序列的线性移位叠加性,巧妙分段信号,提出一种分段相关的信号解扰方法;对解扰信号利用斜消矩阵法估计扩频序列本原多项式,并利用基于协方差范数的信息码盲同步法实现信息码同步;最终得到非周期长码直扩信号盲解扩方法。该方法仅需要预知信号扰码m序列本原多项式和扩频码码片速率。仿真结果表明,该算法仅利用1/8倍长码序列周期长度的信号就能在信噪比3.6dB以上达到10-2以下解扩误码率。 相似文献
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针对二进制伪随机序列生成多项式盲识别方法存在的需要预先知道生成多项式阶数、算法容错性能较差且复杂度较高的问题。该文提出首先将接收序列按照估计的生成多项式阶数建立分析矩阵,然后利用伽罗华域高斯列消元的方法识别出接收序列生成多项式的阶数,最后根据生成多项式的阶数构造关于生成多项式系数的方程组。为降低算法复杂度,在有限的多项式库中进行匹配搜索,能够满足该方程组的多项式就是接收序列的生成多项式。仿真结果表明,提出的方法能够区分接收序列是m序列、Gold序列或者是其他二进制伪随机序列,并有效识别其各自的生成多项式,且具有较好的容错性能。 相似文献
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提出了一种基于对偶码的RS码盲识别方法.建立接收序列的矩阵模型,通过统计该矩阵模型对应的低重量向量的数量,估计RS码的码长和分组起点.通过计算对偶码,估计校验矩阵、生成多项式、本原多项式等参数.实验表明在较高的误码率条件下也能达到较好的识别效果. 相似文献
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SATA作为新一代硬盘接口规范,近年来被广泛应用于固态硬盘的开发,而通信数据的加扰与解扰正是SATA接口设计的重要内容。在分析数据加扰/解扰原理的基础上,研究基于m-序列的数据扰码算法和技术。针对固态硬盘SATA接口的实现,将满足SATA规范的具有特定本原多项式的线性反馈移位寄存器(LFSR)应用于m-序列数据加扰器和扰码器的设计。仿真与综合结果表明,扰码器设计满足固态硬盘SATA数据通信接口规范要求,能够有效地实现数据的加扰和解扰,具有低的硬件开销和良好的通用性。 相似文献
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In order to overcome the poor performance of existing algorithms for recognition of BCH code in low signal-to-noise ratio (SNR),a recognition algorithm based on average cosine conformity was proposed.Firstly,by traversing the possible values of code length and m-level primitive polynomial fields,the code length was identified by matching the initial code roots.Secondly,on the premise of recognizing the code length,the GF(2m) domain was traversed under the m-level primitive polynomial and the primitive polynomial with the strongest error-correcting ability was the generator polynomial for the domain.Finally,the minimum common multiple corresponding to the minimum polynomial of code roots was obtained,and the BCH code generator polynomial was recognized.In checking matching,the statistic of average cosine conformity was introduced.The optimal threshold was solved based on the minimum error decision criterion and distribution of the statistic to realize the fast identification of the BCH.The simulation results show that the deduced statistical characteristics are consistent with the actual situation,and the proposed algorithm can achieve reliable recognition under SNR of 5 dB and code length of 511.Comparing with existing algorithms,the performance of the proposed algorithm is better than that of the existing soft-decision algorithm and 1~3.5 dB better than that of the hard-decision algorithms. 相似文献
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针对多核环境中高速无线信号的加扰、解扰,提出了一种基于稀疏矩阵的多核并行扰码方法。首先对输入信号进行串/并转换,并将各路信号分别送入对应的处理器核;考虑基于稀疏矩阵的并行扰码生成器,在单个处理器核内,将其生成的伪随机码与输入信号进行模二加运算,得到单路信号的扰码输出;最后将多路并行的扰码输出变换为串行输出。运算量分析结果表明,采用IEEE 802.11n中的扰码生成多项式,与普通矩阵乘法实现的多核并行扰码方法相比,基于稀疏矩阵的多核并行扰码方法,其运算量降低了一个数量级。 相似文献
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LiuYang ShiYin 《电子科学学刊(英文版)》2005,22(1):66-69
The complex-valued modulating vectors for the subcarrlers consist of two kinds of components: One is the information-bearing components superposed with pseudo-randomized phases and the other is the suppression components with specified scrambling phases. The pseudorandomized phases are generated according to the predefined polynomial and mapping function whereas the scrambling phases are from a gradient algorithm. The simulation results verify the rationality and validity of the phase scrambling. 相似文献
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Byoung-Hoon Kim Byeong Gi Lee 《Communications, IEEE Transactions on》2001,49(4):589-593
We propose a parallel distributed sample acquisition (PDSA) scheme applicable to a direct-sequence code-division multiple-access (DS/CDMA) system employing M-ary signaling for data transmission. While the primitive distributed sample acquisition scheme can be employed only for the binary signaling systems which transmit 1 bit per symbol, the proposed PDSA scheme extends its applicability to the general signaling systems allowing multibit transmission per symbol. The proposed PDSA technique can also be applied to fast acquisition of the scrambling code in multicarrier DS/CDMA cellular systems with a slight modification of the transceiver circuitry 相似文献
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为了解决现有图像加密算法存在随图像尺寸变大导致加密时间迅速增加的问题,采用基于logistic和Arnold映射的改进加密算法实现了快速图像加密算法的优化。该算法基于两种混沌映射对原文图像进行像素置乱和灰度值替代,像素置乱是按图像大小选择以H个相邻像素为单位进行,通过适当调整H的取值实现加密时间优化;灰度值替代是利用Arnold映射产生混沌序列对置乱图像进行操作而得到密文图像。结果表明,对于256×256的Lena标准图像,加密时间降低到0.0817s。该算法具有密钥空间大和加密速度快等优点,能有效抵抗穷举、统计和差分等方式的攻击。 相似文献
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A new class of fast maximum-likelihood estimation (MLE) algorithms for emission computed tomography (ECT) is developed. In these cyclic iterative algorithms, vector extrapolation techniques are integrated with the iterations in gradient-based MLE algorithms, with the objective of accelerating the convergence of the base iterations. This results in a substantial reduction in the effective number of base iterations required for obtaining an emission density estimate of specified quality. The mathematical theory behind the minimal polynomial and reduced rank vector extrapolation techniques, in the context of emission tomography, is presented. These extrapolation techniques are implemented in a positron emission tomography system. The new algorithms are evaluated using computer experiments, with measurements taken from simulated phantoms. It is shown that, with minimal additional computations, the proposed approach results in substantial improvement in reconstruction. 相似文献
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《IEEE transactions on information theory / Professional Technical Group on Information Theory》2002,48(10):2754-2758
A fast algorithm is presented for determining the linear complexity and the minimal polynomial of a sequence with period 2p/sup n/ over GF (q), where p and q are odd prime, and q is a primitive root (mod p/sup 2/). The algorithm uses the fact that in this case the factorization of x/sup 2p(n)/-1 is especially simple. 相似文献