共查询到18条相似文献,搜索用时 125 毫秒
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进行光传输系统发展趋势和级联码理论分析与探讨之后,基于传统级联码方案,提出一种适用于光传输系统的新颖交织型级联码方案。通过仿真分析表明:相对于传统级联码方案而言,由该新颖的交织型级联码方案所构造的级联码是一种纠错性能优良、冗余度适中、易于实现的码型。因而,这种改进的新颖交织型级联码方案更适用于光传输系统的实际应用要求。 相似文献
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光通信系统中一种新颖的随机交织型级联码方案 总被引:1,自引:1,他引:0
基于LDPC码,提出一种新颖的随机交织型级联码(RICC,random interleaved concatenatedcode)方案。在编码阶段,根据LDPC码中不同度数的变量节点采用不同纠错能力的BCH外码,分别进行保护的思想进行集分割编码;在译码阶段,采用硬判决辅助软判决的联合迭代译码。不同于传统的单极型和交织型级联方式,它是一种根据LDPC码变量节点(VN)度数来决定交织深度,因而交织方式是随机的。仿真结果分析表明,在误比特率(BER)为10-8时,四集合分割的RICC-4P的净编码增益(NCG)比无分割的单级型级联码提高了0.15dB,比ITU-T G.709和G.975.1标准中的RS(255,239)、RS(255,239)+CSOC(n/k=7/6,J=8)级联码和开销为25%的正交级联BCH码的NCG分别提高了3.0、1.5和0.4dB,其纠错性能的提升得益于采用集分割保护和硬判决辅助软判决的联合迭代译码。 相似文献
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光通信系统级联码的仿真研究 总被引:1,自引:1,他引:0
随着光通信技术向更长距离、更大容量和更高速度的进一步发展,有必要深入研究性能更好的FEC码型方案。在光通信应用的众多FEC码型中,级联码具有短码的复杂度和长码的性能,具有极强的纠突发和纠随机错误的能力,是光通信系统中高效编码的主要研究对象。文中主要对RS-BCH型级联码进行了理论分析及建模仿真,与一般循环码相比该级联码纠错性能优良、冗余度适中、易于实现,更适用于高速光通信系统。 相似文献
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为了提升系统误比特率,减小基线漂移以及海水信道的吸收散射等特性对光信号产生的影响,采用了基于水下发光二极管(LED)光通信系统的低密度奇偶校验码(LDPC)-里所(RS)级联交织码方案,在模拟水下LED光通信实验系统的情况下,分析码字方案中RS码、LDPC码以及交织参量对系统误比特率性能的影响,得到了级联交织码方案的优化参量,并进行了实验模拟验证。结果表明,优化后的级联交织码系统与未编码系统、RS码系统、LDPC码系统相比分别可获得3.8dB,2dB,1.2dB的增益,可有效提高系统的误比特率性能。该研究为提高水下无线光通信系统的可靠性提供了参考。 相似文献
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随着通信技术的飞速发展,光通信系统也对传输距离、信道容量以及传输速率有着更高的要求,而想要解决这些问题,则需要研究性能更加优良的FEC码型方案。级联码是诸多码型中纠正突发和随机错误性能较好,且可以保持较低冗余度的一种,因此成为主要研究对象。在国际电联G.975.1标准的级联码基础上提出了两种新型RS-BCH编码,在理论上对其进行了对比分析,并进行相应的建模仿真,其中一种是RS(255,239)码与BCH(31,16)码相结合的级联码,而另一种是RS(255,239)码与BCH(511,448)码相结合的级联码,这两种级联码与单一RS(255,239)编码以及原码的纠错性能相比有较大提升,且后者冗余度适中,易于实现,更加适合于高速传输的光通信系统。 相似文献
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一种光通信中基于LDPC码的新颖级联码 总被引:1,自引:0,他引:1
基于SCG(4,k)码的构造方法对SCG-LDPC码进行优化改进,构造一种适用于光通信系统的新颖LDPC(3969,3720)码,通过增大其码长,构造码率为95.1%的新颖SCG-LDPC(6561,6240)码,使其码率更符合光通信系统的高码率要求。并用SCG-LDPC(6561,6240)码与码率为94.5%的BCH(127,120)码进行级联,构造出一种新颖的BCH(127,120)+LDPC(6561,6240)级联码。仿真分析表明:在误码率为10-7时,新构造的BCH(127,120)+LDPC(6561,6240)级联码的净编码增益比已广泛应用于光通信系统的经典RS(255,239)码和SCG-LDPC(6561,6240)码分别提高了2.27dB和0.49dB。因而该级联码更适合于光通信系统。 相似文献
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Kasami T. Takata T. Yamashita K. Fujiwara T. Lin S. 《Communications, IEEE Transactions on》1997,45(5):536-543
This paper presents a method for evaluating the bit-error probability of a concatenated coding system for BPSK transmission over the AWGN channel. In the concatenated system, a linear binary block code is used as the inner code and is decoded with the soft-decision maximum likelihood decoding, and a maximum distance separable code (or its interleaved code) is used as the outer code and is decoded with a bounded distance decoding. The method is illustrated through a specific example in which the inner code is a binary (64.40.8) Reed-Muller subcode and the outer code is the NASA standard (255, 223, 33) Reed-Solomon code over GF(28) interleaved to a depth of 5. This specific concatenated system is being considered for NASA's high-speed satellite communications. The bit-error performance is evaluated by a combination of simulation and analysis. The split weight enumerators for the maximum distance separable codes are derived and used for the analysis 相似文献
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YUAN Jian-guo JIANG Ze MAO You-ju YE Wen-wei 《半导体光子学与技术》2007,13(2):126-131
A new concatenated code of RS(255,239)+BCH(2 040,1 930) code to he suitable for WDM optical transmission systems is proposed. The simulation resuhs show that this new concatenated code. compared with the RS(255,239)4-CSOC(k0/n0=6/7, J= 8) code in ITU-TG. 75.1, has a lower redundancy and better error-correction performance, furthermore, its net coding gain(NCG) is respectively 0. 46 dB, 0.43 dB morethanthatofRS(255,239)+CSOC(k0/n0= 6/7, J= 8) code and BCH(3860,3824)+BCH (2 040,1 930) code in ITU TG. 75. 1 at the third iteration for the bit error rate(BER) of 10^-12. Therefore, the new super forward error correction(Super-FEC) concatenated code can be better used in ultra long-haul, ultra large-capacity and ultra high-speed WDM optical communication systems. 相似文献
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Repetition, diversity, and single-error-correcting codes are examined for use with binary modulation techniques over a mobile communication fading channel. Both bit-error performance and bandwidth efficiency are considered for phase-shift keyed, differential phase-shift keyed, and frequency-shift keyed modulations. The error-correction capability of repetition coding is considered, and optimum repetition is found. M -tuple diversity with maximum-ratio-combining is then compared with repetition coding both with a single-error-correcting code and without coding. It is found that a minimum of a 10 dB signal-to-noise power ratio is required for an improved performance with repetition code or diversity. The repetition code is about 3 dB inferior to optimal diversity. An optimized design of moderate complexity and bandwidth expansion can be reached with twofold diversity and three repetitions as an inner layer of coding concatenated with an outer single-error-correcting code 相似文献
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基于卷积码与累加编码的PPM调制级联码(SCPPM)在泊松信道光PPM调制下具有极优异的性能。文章将这种累加编码结构引入到QAM调制中,分析其性能。将卷积码+累加编码+QAM调制串行级联(SCAQAM)纠错方案与常规基于卷积码、并行级联卷积码(Turbo)以及低密度奇偶校验码(LDPC)的比特交织编码调制迭代译码(BICM-ID)系统进行比较,并进一步比较了SCAQAM系统的自然、格雷、反格雷星座映射方式。结果表明,在高阶QAM调制下,这种纠错结构具有极优异的误码性能。对于16QAM及64QAM调制,SCAQAM相对于另外几种纠错码结构的BICM-ID系统分别有约0.3和0.5 dB的性能提升,只有卷积码与累加码结合才更具性能优势。并且SCAQAM将累加后的比特流以反格雷方式映射具有更优异的性能。 相似文献
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In this letter, a new hybrid automatic repeat request (ARQ) approach is presented to enhance receiver performance for communication systems employing forward error-correction codes in frequency-selective fading environments. This new approach involves a simple modification to the traditional turbo equalizer by combining multiple ARQ transmissions via integrated channel equalization. This modification leads to better computational efficiency, better exploitation of channel diversity, better channel-estimation ability, and improved performance (frame-error rates) when concatenated with an outer code. These improvements are verified through evaluations of extrinsic information transfer charts and ARQ simulations when compared with iterative combining of multiple transmissions. 相似文献
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Fan J.L. Calderbank A.R. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1998,44(4):1565-1574
When a block modulation code is concatenated with an error-correction code (ECC) in the standard way, the use of a modulation code with long block lengths results in error propagation. This article analyzes the performance of modified concatenation, which involves reversing the order of modulation and the ECC. This modified scheme reduces the error propagation, provides greater flexibility in the choice of parameters, and facilitates soft-decision decoding, with little or no loss in transmission rate. In particular, examples are presented which show how this technique can allow fewer interleaves per sector in hard disk drives, and permit the use of more sophisticated block modulation codes which are better suited to the channel 相似文献