共查询到18条相似文献,搜索用时 109 毫秒
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文中首先简单地说明Viterbi译码算法原理,接着分析Viterbi译码算法设计及伪代码实现,然后根据软判决和硬判决对译码性能的影响以及改进的译码器和MATLAB库函数的译码器作了仿真比较.仿真表明:改进的译码器具有良好的性能. 相似文献
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本文分析了在第三代移动通信系统中,将数据解调和卷积码译码结合的译码方法,并与传统的Viterbi软判决译码和硬判决译码算法进行了比较。在3GPP所规定使用的调制和编码方式下进行了仿真,结果表明,在不增加复杂度和保持相同的误码率的条件下系统所需信噪比比Viterbi软判决译码降低1—2dB。本文给出的方法也可推广到其它通信系统中。 相似文献
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本文分析了高阶调制通信系统中将解调和卷积码的译码联合的解码方法,并与传统的Viterbi软判决译码和Viterbi硬判决译码算法进行了比较.仿真结果表明,在不增加复杂度和保持相同的误码率的条件下系统所需信噪比比Viterbi软判决译码降低0.2-0.3dB.本文给出的方法也可推广到更高阶调制通信系统中. 相似文献
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一种新的π/4DQPSK解调译码方案 总被引:1,自引:0,他引:1
本文提出了一种新的π/4DQPSK解调译码方案.该方案利用非冗余纠错差分解调的硬判决信息对Viterbi软判决译码时的量度加权,从而改变了传统的差分解调结合软判决译码的量度值,使差分解调软输出的信噪比得到改善,提高了Viterbi软判决译码的性能.计算机仿真表明,相对于传统的差分解调结合软判决译码,该算法在误比特率BER为10-5时在AWGN信道中有1.4dB的性能改善,在Rician信道中同样有显著的性能改善.这使得在普遍采用差分解调软判决译码的卫星通信系统中系统容量和通信质量都得到显著改善. 相似文献
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根据系统高速、稳定的要求,采用FPGA技术实现了针对(2,1,7)卷积编码的软判决Viterbi译码器.考虑到芯片的速度、面积和功耗,通过对Viterbi译码和前端接口部分设计的若干优化算法进行研究和讨论,选择4bit量化、差分软译码、大回朔深度和最小状态判决准则等方案以保证性能.采用全并行ACS结构和寄存器交换法以提高速度,并且采用分支度量预计算、度量存储溢出控制及对译码器其他部分的优化设计,在保证时序稳定的情况下有效减少了硬件消耗. 相似文献
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在LTE系统中,物理广播信道和物理下行控制信道均采用了咬尾卷积编码,咬尾卷积编码拥有很多优良的性能.针对咬尾卷积译码,提出了一种基于Viterbi译码的修正算法——正逆序结合译码算法,根据分支度量确定误码在数据帧的分布,最后确定采用正序还是逆序译码结果.仿真结果表明,Viterbi的修正方法有效地降低了系统误码率,而且具有普适性,适合应用于LTE系统. 相似文献
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The performance of coherent optical communication systems is significantly degraded by semiconductor laser phase noise. A rate 1/2, constraint length K=7, convolutional error correcting code with Viterbi decoding is used to improve a 3.5-10 Mbit/s DPSK system. Error correcting coding demonstrates the reduction of the influence of phase noise on BER performance, and significantly lowers the BER floor. Soft decision decoding and hard decision decoding performance is investigated and compared 相似文献
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Soft-Decision Decoding of Punctured Convolutional Codes in Asynchronous-CDMA Communications Under Perfect Phase-Tracking Conditions 总被引:1,自引:0,他引:1
Vidhyacharan Bhaskar 《International Journal of Wireless Information Networks》2006,13(3):229-237
In this paper, the performance of punctured convolutional codes of short constraint lengths is discussed. The punctured codes are used to provide error protection to a particular user in an asynchronous CDMA system. A perfect phase reference is assumed to be available throughout this paper. A slow fading Rician channel is assumed. Maximum likelihood decoding through a Viterbi algorithm is used to decode the information symbols. Soft-decision decoding of punctured convolutional codes is considered in this paper. The upper bounds with Viterbi decoding are derived and plotted for the various punctured codes considered. The simulated results are found to agree very well with their upper and lower bounds. 相似文献
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Viterbi译码器的应用及其硬件设计与实现 总被引:1,自引:1,他引:0
维特比译码器是人们广泛采用的卷积码的译码器,在IS-95,GSM,3GPP中都有广泛的应用.文中首先简单说明Viterbi译码算法原理,接着分析Viterbi译码算法设计及伪代码实现,根据TD-SCDMA卷积码编码方案,设计了一种采用软判决方式的维特比译码器,并采用合理的归一化方式,保证了计算路径值的过程中不会发生溢出.仿真表明:改进的译码器具有良好的性能. 相似文献
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Use of the Viterbi decoder to decode the (63, 57) Hamming code is considered, Implementation and performance of systematic and nonsystematic codes are addressed. It is shown that a Viterbi decoder for the constraint length seven, rate-½ convolutional code can be used to decode both systematic and nonsystematic (63, 57) Hamming codes, but an additional step is needed to complete the decoding of the systematic code. Bounds and simulation results for postdecoding bit-error probability are given and it is shown that the systematic code performs 0.4 dB better than the nonsystematic code. A heuristic explanation is provided 相似文献
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A new algorithm for erasurefree sequential decoding of convolutional codes is introduced which achieves low error probabilities at substantially higher decoding speeds than the Viterbi decoding algorithm. The algorithmic properties of the Multiple Stack Algorithm (MSA) are investigated and it is demonstrated that the MSA reaches a decision with an exponentially rather than Pareto distributed computational effort. The MSA's error probability on the binary symmetric channel is studied as a function of its parameters and its performance and complexity compared to that of the Viterbi algorithm. The MSA is seen to achieve equal and lower error probabilities with a significantly lower average decoding effort. The new algorithm can thus be considered an attractive alternative to the Viterbi algorithm where low error probabilities and high decoding speeds are required simultaneously. 相似文献
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