基于FFT-BP算法的多元域LDPC码译码器设计与FPGA实现

GF(q)域上的LDPC码是二进制LDPC码的扩展,它具有比二进制LDPC码更好的纠错性能。FFT-BP算法是高效的LDPC码译码算法,本文在GF(4)域上探讨该算法的设计与实现。本文的创新之处在于,根据FFT-BP算法的特点设计了一种利用Tanner图进行信息索引的方式,简化了地址查询模块的设计。实验表明,在归一化信噪比为2.6dB时,译码器的误码率可达到10-6。     

弹载数据链系统实时RS译码器设计

为了提高传输可靠性,各种差错控制编码技术已经被广泛应用在弹载武器数据链系统中。RS( Reed-Solomon)码具有很强的抗错误能力,且码长可以灵活控制,十分适合在弹载数据链系统中应用。设计了三种不同码率的RS码,并在修正的欧几里德算法基础上进一步优化,实现了一种新型RS码实时译码器。为减少系统复杂度,该译码器复用4组基本运算单元以完成错误位置多项式和错误值多项式计算,同时也没有插入额外的流水线结构,译码过程所需的GF(28)域求逆运算则通过查找表结构实现。整个设计已经在Altera公司的EP2 S15器件上通过综合和验证,与同类设计相比占用资源大大减少,适合于高可靠性导弹数据链系统开发。     

高速RS(31,15)编译码器的FPGA实现

RS码由于具有优良的纠错能力而得到广泛应用。在军事通信中常以RS(31, 15)作为首选码。本文用一片现场可编程门阵列 (FPGA)芯片实现了高速RS(31, 15)编译码器。该编译码器具有体积小、性能稳定、工作速度高等优点。     

RS（255、239）译码器的流水线设计

RS码是一种性能十分良好的线性分组循环码，具有极强的纠错能力，在数字通信系统中得到广泛的应用。本文提出了一种基于流水线结构的RS(255、239)译码器的设计，并在面积上对其进行了优化。文中所提到的设计，已用VerilogHDL实现，并通过了综合以及对网表文件的仿真验证。     

RS码与LDPC码的联合迭代译码

针对RS码与LDPC码的串行级联结构,提出了一种基于自适应置信传播(ABP)的联合迭代译码方法.译码时,LDPC码置信传播译码器输出的软信息作为RS码ABP译码器的输入;经过一定迭代译码后,RS码译码器输出的软信息又作为LDPC译码器的输入.软输入软输出的RS译码器与LDPC译码器之间经过多次信息传递,译码性能有很大提高.码长中等的LDPC码采用这种级联方案,可以有效克服短环的影响,消除错误平层.仿真结果显示:AWGN信道下这种基于ABP的RS码与LDPC码的联合迭代译码方案可以获得约0.8 dB的增益.     

RS码并行编码器的设计实现

RS码是一类具有很强纠错能力的多进制BCH码,也是一类典型的代数几何码。文中分析了GF(2)8域上的RS(255,223)码编码器的基本原理,并在Xilinx Xc6vsx315t FPGA上设计实现了RS(255,223)高速并行编码器。     

高级在轨系统中的RS(255,223)译码器的设计

在差错控制域中RS(255,223)码是一种性能优异的线性分组循环码,具有很强的随机错误和突发错误的纠错能力.设计中运用FPGA技术,使用Verlog HDL硬件设计语言实现高级在轨系统(AOS)中的RS译码器,着重介绍了RS译码器中改进结构的关键方程求解算法(uiBM),与目前广泛使用的无逆Berlekamp-Mas...     

基于VHDL语言的GF(28)上快速乘法器设计

基于有限域上多项式乘法理论,采用高层次设计方法,采用CPLD实现了GF(2^8)上8位快速乘法器,利用XILINX公司的Foundation Series3．1i集成设计环境完成了快速乘法器的VHDL源代码输入、功能仿真、布局与布线、时序仿真,并用XC9572PC84可编程逻辑芯片验证了该电路设计。该乘法器可以应用于RS(255,223)码编／译码器。     

一种软判决下的RS码识别算法

针对现有RS码识别算法需要对码字符号在不同域之间进行转化,且容错性能较差的问题,该文提出一种直接利用软判决序列完成RS码识别算法。算法首先从RS码定义出发,给出了RS码校验关系从GF(2m)到GF(2)上的等价转换方式,从而避免了不同域下复杂的符号转化;其次引入了能够衡量校验关系成立大小的平均校验符合度概念,然后基于其统计特性以及极大极小判决准则,遍历可能的码长以及对应的m级本原多项式,进行初始码根校验匹配,从而完成码长以及本原多项式识别;最后利用识别出的码长以及本原多项式,构建本原多项式下GF(2m),进行连续码根匹配判决,最终完成码生成多项式识别。仿真结果表明:推导的平均校验符合度统计特性与实际情况一致,算法能在低信噪比下有效完成参数识别;同时该算法具有较好的低信噪比适应能力,在信噪比为6 dB条件下,工程中常见的RS码识别率均能达到90%以上。与现有算法相比,该文算法性能明显好于硬判决算法,且比传统算法提升1 dB以上性能。     

Reed-Solomon编译码器的设计与FPGA实现

RS(Reed-Solomon)码是一类重要的线性分组码,具有很强的纠错能力,被广泛地应用于各种现代通信系统中。译码器采用修正的欧几里德算法(MEA),并在实现中使用一种新的伽罗华域乘法器,从而降低RS码编译码硬件实现的复杂度。并利用VerilogHDL语言实现了RS(255,249)码的编译码器各个模块的功能。     

一种兼容Turbo码的LDPC解码器

提出了一种兼容Turbo码的低密度校验码(LDPC)解码器,它可以将Turbo码完全转化为LDPC码来进行解码,由于采用了校验分裂方法来处理由Turbo码转化而来的LDPC码中所存在的短环,从而使其解码性能优于联合校验置信度传递(JCBP)算法0.8 dB,仅仅比Turbo码专用的BCJR算法损失约为1dB.本文提出的通用解码器,为多系统兼容通信设备的应用提供了一种新的、灵活方便的实现途径.     

一种改进的极化码置信译码器

在极化码置信（ BP）译码的因子图中,当承载确定信息的节点的对数似然信息计算错误时,可以被检测到。此时,对于因子图中参与该似然信息计算的节点,引入一个修正参数,以修正该节点承载的信息的对数似然信息。修正参数可以由密度进化的高斯近似算法得到。给出了置信译码原理及相应的改进算法,最后给出了复杂度分析和性能仿真。数据结果表明,在牺牲很小的复杂度的条件下,相比原算法,修正算法能够获得0.2 dB左右的比特信噪比增益。     

Concurrent Error Detection in Reed–Solomon Encoders and Decoders

Reed-Solomon (RS) codes are widely used to identify and correct errors in transmission and storage systems. When RS codes are used for high reliable systems, the designer should also take into account the occurrence of faults in the encoder and decoder subsystems. In this paper, self-checking RS encoder and decoder architectures are presented. The RS encoder architecture exploits some properties of the arithmetic operations in GF(2^m). These properties are related to the parity of the binary representation of the elements of the Galois field. In the RS decoder, the implicit redundancy of the received codeword, under suitable assumptions explained in this paper, allows implementing concurrent error detection schemes useful for a wide range of different decoding algorithms with no intervention on the decoder architecture. Moreover, performances in terms of area and delay overhead for the proposed circuits are presented.     

基于FPGA的RS译码器的设计与实现

针对Reed-Solomon（RS）码译码过程复杂、译码速度慢和专用译码器价格高等问题,以联合信息分发系统终端J系列报文信息位采用的RS（31,15）码为例,介绍了基于改进的无求逆运算的Berlekamp-Massey（BM）迭代算法的RS译码原理,采用Verilog硬件描述语言对译码器中各个子模块进行了设计,并基于现场可编程门阵列平台,在QuartusII6.0环境下进行了仿真,验证了RS译码器的纠错能力,实现了参数化与模块化的RS译码器设计。     

A versatile time-domain Reed-Solomon decoder

A versatile Reed-Solomon (RS) decoder structure based on the time-domain decoding algorithm (transform decoding without transforms) is developed. The algorithm is restructured, and a method is given to decode any RS code generated by any generator polynomial. The main advantage of the decoder structure is its versatility, that is, it can be programmed to decode any Reed-Solomon code defined in Galois field (GF) 2^m with a fixed symbol size m. This decoder can correct errors and erasures for any RS code, including shortened and singly extended codes. It is shown that the decoder has a very simple structure and can be used to design high-speed single-chip VLSI decoders. As an example, a gate-array-based programmable RS decoder is implemented on a single chip. This decoder chip can decode any RS code defined in GF (2⁵) with any code word length and any number of information symbols. The decoder chip is fabricated using low-power 1.5-μ, two-layer-metal, HCMOS technology     

Variable shortened-and-punctured Reed-Solomon codes for packet loss protection

Techniques using Reed-Solomon (RS) codes to recover lost packets in digital video/audio broadcasting and packet switched network communications are reviewed. Usually, different RS codes and their corresponding encoders/decoders are designed and utilized to meet different requirements for different systems and applications. We incorporate these techniques into a variable RS code and present encoding and decoding algorithms suitable for the variable RS code. A mother RS code can be used to produce a variety of RS codes and the same encoder/decoder can be used for all the derivative codes, with adding/detecting zeros, removing some parity symbols and adding erasures. A VLSI implementation for erasure decoding of the variable RS code is described and the achievable performance is quantitatively analyzed. A typical example shows that the signal processing speed is up to 2.5 Gbits/second and the processing delay is less than one millisecond, when integrating the decoder on a single chip. Therefore, the proposed algorithm and the encoder/decoder can universally be utilized for different applications with various requirements, such as transmission data rate, packet length, packet loss protection capacity, as well as layered protection and adaptive redundancy protection in DVB/DAB, Internet and mobile Internet communications.     

Low complexity NB-LDPC decoder based on shared comparator architecture for ECN/EVN

Non-binary low density parity check (NB-LDPC) codes are considered as preferred candidate in conditions where short/medium codeword length codes and better performance at low signal to noise ratios (SNR) are required. They have better burst error correcting performance, especially with high order Galois fields (GF). A shared comparator(SCOMP) architecture for elementary of check node (ECN)/elementary of variable node (EVN) to reduce decoder complexity is introduced because high complexity of check node (CN) and variable node (VN) prevent NB-LDPC decoder from widely applications. The decoder over GF(16) is based on the extended min-sum (EMS) algorithm. The decoder matrix is an irregular structure as it can provide better performance than regular ones. In order to provide higher throughput and increase the parallel processing efficiency,the clock which is 8 times of the system frequency is adopted in this paper to drive the CN/VN modules. The decoder complexity can be reduced by 28% from traditional decoder when shared comparator architecture is introduced. The result of synthesis software shows that the throughput can achieve 34 Mbit/s at 10 iterations. The proposed architecture can be conveniently extended to GF such as GF(64) or GF(256). Compared with previous works, the decoder proposed in this paper has better hardware efficiency for practical applications.