Viterbi译码中解删除模块的FPGA设计与实现

给出了由(2,1,N)系列卷积码作为母码产生的Punctured卷积码的V iterbi译码中Depunctured模块使用FPGA(现场可编程门阵列)实现时的通用方法,从而为不同码率的卷积码的译码给出了一种通用的方法,并为多级编码分量码的设计提供了条件。     

802.11b中卷积码和Viterbi译码的FPGA设计实现

卷积码是一种重要的信道纠错编码方式,其纠错性能通常优于分组码,目前(2,1,6)卷积码已广泛应用于无线通信系统中,Viterbi译码算法能最大限度地发挥卷积码的纠错性能。阐述了802.11b中卷积码的编码及其Viterbi译码方法,给出了编译码器的设计方法,并利用Verilog HDL硬件描述语言完成编译码器的FPGA实现。使用逻辑分析仪,在EP2C5T144C8芯片上完成了编译码器的硬件调试。     

卷积编码及Viterbi解码的FPGA实现及应用

卷积码在现代无线通信系统中应用十分广泛,Viterbi译码是最常用的一种对卷积码的译码算法。介绍了卷积编码及Viterbi串行解码的原理及其FPGA的实现。在保证系统性能的前提下讨论了分帧式编解码在实际系统中的应用。     

TD-LTE系统咬尾卷积码译码算法研究

在TD-LTE系统中,要获得准确可靠的信道传输,就要在发送端采用差错控制编码。而卷积码作为一种前向纠错技术被应用于很多现代通信系统中,此外采用卷积码编码的数据在接收端通常都采用Viterbi译码来实现。首先介绍了咬尾卷积码编码原理,然后研究了译码的两种方法并在此基础上提出改进算法,最后通过性能仿真以及译码复杂度的比较来分析这三种译码算法。     

(2,1,7)卷积码Viterbi译码器FPGA实现方案

移动通信系统标准中普遍采用卷积码作为信道编码方案。本文阐述了目前最常用的卷积码译码算法——Vit-erbi译码算法,然后给出了(2,1,7)卷积码编码电路FPGA实现方法。该方法给出了新的Viterbi幸运路径算法和高效的状态度量存储技术,可以充分利用FPGA的优势获得较好的译码结果。利用幸存路径交换寄存器模块,能有效减少存储量并降低功耗。     

卷积码编码及其Viterbi译码算法的FPGA实现

探讨了卷积码编码及其Viterbi译码算法的FPGA（Field-Programmable GateArray）实现,根据编码器的结构,分别采用了有限状态机转换的编码法和基于流水线结构的状态转换译码法,有效地提高了编译码的速度.最后给出了（2,1,2）卷积码的编码及其Viterbi译码算法的实验仿真结果。     

一种实现3G卷积码Viterbi译码的优化算法

对3G系统中定义的卷积码编码进行了分析,并以3GPP提出的1/2卷积码为例重点讨论了Viterbi译码算法的实现方案,并对Viterbi译码实现中的留存路径更新、数据溢出处理和输出判决部分进行了优化,优化的结果使得系统的性能和效率有所提高。     

改进型全并行Viterbi译码器设计与实现

卷积码作为一种重要的前向纠错信道编码方式,广泛应用于现代无线通信系统之中。Viterbi译码方式在约束长度较小的前提下能够最大限度地发挥出卷积码的优异性能。对(2,1,5)最佳非系统卷积码的Viterbi译码器的误码率进行了Matlab仿真。针对传统Viterbi译码设计上的不足进行了改进和优化,给出了硬件实现的逻辑原理框图,并利用EDA设计工具基于FPGA来设计实现Viterbi译码模块。最后分析了译码器综合后的资源占用情况并通过时序仿真验证了译码可靠性。     

一种应用于LTE系统的Viterbi译码算法

LTE(long term evolution,长期演进)系统中采用了咬尾卷积码和Turbo码来实现前向纠错,Viterbi译码是卷积码的一种杰出的译码算法,它是一种最大似然译码方法。本文基于LTE系统中的咬尾卷积码,详细分析了几种较成熟的Viterbi译码算法,并综合现有算法,提出了一种改进算法,减小了译码计算的复杂度。仿真结果表明,改进算法在降低译码计算复杂度的同时还降低了译码误比特率,因此非常适合LTE系统的译码要求。     

通信系统中Viterbi译码的Matlab仿真与实现

数字通信作为一种前向纠错编码技术卷积码起着重要的作用。相应地,信息接收端对卷积码的译码实现也提出了更高的要求。文中提出的卷积码译码Matlab仿真方案,旨在用Viterbi译码实现对卷积码译码的功能。仿真结果表明,维特比是一种良好的译码方式。     

Determinate state convolutional codes

A determinate state convolutional code is formed from a conventional convolutional code by pruning away some of the possible state transitions in the decoding trellis. This staged power transfer proves to be an extremely efficient way of enhancing the performance of a concatenated coding system. The authors analyze the decoding complexity and free distances of these new codes, determine some important statistical properties of the decoder output, and provide simulation results for performance at the low signal-to-noise ratios where a real communications system would operate. Several concise, practical examples are presented     

Coding for Satellite Communication

This paper discusses a number of coding techniques for future satellite communication; they include Reed-Solomon error decoding for message blocks, probabilistic decoding techniques for punctured convolutional codes, and planar Euclidean geometry difference set codes for random multiple access applications. The provision of code concatenation, helical interleaving, and simulation results of new punctured convolutional codes are included. A number of coded satellite systems that demonstrate the usefulness of coding in satellite communications are described.     

Signal editing: A new approach to upgrade concatenated coding communications

Based on the property that correction coding is more sensitive to the number of errors than the number of erased code symbols, results of an analytical investigation to improve the performance of concatenated coding communications are presented. We propose a new tactic, ‘signal editing’, to estimate and erase unreliable data prior to the final outer decoding process. We show that signal editing has a capability to detect and delete individual erroneous digits that has not been achieved by other methods. As a result, system performance can be markedly improved. Specific recommendations for using the procedure are suggested and discussed. We illustrate how signal editing is implemented in the case of a convolutional code with Viterbi decoding. A new concatenated (or hybrid) coding technique is constructed integrating the code with interleaving and signal editing. Performance improvement is evaluated and analysed. In this study, signal editing is derived from the information available in the Viterbi decoding process. Not limited to convolutional code with Viterbi decoding, signal editing can be applied to other linear codes without any restriction.     

Concatenated coding for frequency-hop spread-spectrum withpartial-band interference

Concatenated coding techniques are applied to slow frequency-hop packet radio communications for channels with partial-band interference. Binary orthogonal signaling (e.g., binary FSK) is employed with noncoherent demodulation, Reed-Solomon codes are employed for the outer code while both block and convolutional codes are considered for the inner code. Hard-decision and soft decision decoding methods are considered for the inner codes. A method is devised for estimating the reliability of the outer Reed-Solomon code symbols, and this estimate is used to determine which code symbols should be erased. Comparisons are made between the performance of concatenated codes and the performance of Reed-Solomon codes alone     

Low-rate channel coding with complex-valued block codes

This paper addresses aspects of channel coding in orthogonal frequency-division multiplexing-code-division multiple access (OFDM-CDMA) uplink systems where each user occupies a bandwidth much larger than the information bit rate. This inherent bandwidth expansion allows the application of powerful low-rate codes under the constraint of low decoding costs. Three different coding strategies are considered: the combination of convolutional and repetition codes, the code-spread system consisting of one single very low-rate convolutional code and a serial concatenation of convolutional, Walsh-Hadamard and repetition code. The latter scheme is improved by combining the Walsh-Hadamard codes with an additional M-phase-shift keying modulation resulting in complex-valued Walsh-Hadamard codes (CWCs). Analytical performance evaluations will be given for these codes for the first time. The application of CWCs as inner codes in a serial code concatenation is also addressed. We derive a symbol-by-symbol maximum a posteriori decoding algorithm in the complex signal space in order to enable iterative decoding for the entire code. A comprehensive performance analysis by simulation of all the proposed coding schemes shows that the Walsh-Hadamard-based schemes are the best choice for low-to-medium system load. Note that even for fully loaded OFDM-CDMA systems, the concatenation with an inner complex-valued Walsh-Hadamard code leads to a bit-error rate less than 10/sup -5/ for an E/sub b//N/sub 0/ of about 6 dB.     

卷积码的通用编译码

介绍了实现各种不同码型卷积码的编、译码的通用算法.在考虑程序代码效率、执行效率和程序的可读性的情况下,给出它的程序实现,只需要给定不同的生成多项式,就可以实现各种不同码率和不同约束长度的卷积码编码和译码,能简化通信系统中的软件实现.     

Concatenated Coding Systems Employing a Unit-Memory Convolutional Code and a Byte-Oriented Decoding Algorithm

Concatenated coding systems utilizing a convolutional code as the inner code and a Reed-Solomon code as the outer code are considered. In order to obtain very reliable communications over a very noisy channel with relatively modest coding complexity, it is proposed to concatenate a byte-oriented unit-memory convolutional code with an RS outer code whose symbol size is one byte. It is further proposed to utilize a real-time minimal-byte-error probability decoding algorithm, together with feedback from the outer decoder, in the decoder for the inner convolutional code. The performance of the proposed concatenated coding system is studied, and the improvement over conventional concatenated systems due to each additional feature is isolated.     

维特比译码及其纠错能力的研究

在现代数字通信系统中,纠错编码技术的作用是很重要的,本文以卷积码为例,分析了纠错码的原理,并利用matlab实现了卷积码的编码和解码,对卷积码纠错原理进行了仿真研究。     

迭代译码的级联Reed-Solomon乘积码与卷积码

该文提出用Reed Solomon(RS)乘积码作为外码,卷积码作为内码的级联码方案并且内外码间用Congruential向量生成的交织图案对RS码符号进行重排列。对此级联码采用的迭代译码基于成员码的软译码算法。当迭代次数达到最大后,通过计算RS码的校正子,提出一种纠正残余错误的方法,进一步提高了系统的误比特性能。仿真结果表明,在AWGN信道中与迭代译码的级联RS/卷积码相比,当误比特率为1e-5时,新系统的编码增益大约有0.4 dB。     

Performance of chip coding in FFH SSMA systems

This paper proposes chip coding using convolutional codes for fast frequency-hopping spread-spectrum multiple-access (FFH-SSMA) systems. Its performance is evaluated and compared with that of repetition coding which is most commonly used in FFH systems. In our proposal, an information symbol is encoded by a convolutional code of rate 1/n and n chips are transmitted through a frequency hopper. We consider three models when perfect side information (PSI) is available, no side information (NSI) is available, and the ratio threshold test (RTT) is used. The probability density functions (PDFs) of the received signal are derived for asynchronous hopping systems. The performances of convolutional coding with threshold decoding and Viterbi decoding are presented under the constraint of fixed total bandwidth and information bit rate. In comparison with repetition codes, it is found that convolutional codes drastically enhance the system performance. It is identified that Viterbi decoding with RTT offers the most significant performance improvement