Coding gains and error rates from the Big Viterbi Decoder
Coding gains and error rates from the Big Viterbi Decoder
复制标题
大维特比解码器的编码增益和错误率
DOI：
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发表时间：
1991
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通讯作者：
I. Onyszchuk
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作者：
I. Onyszchuk
完成了一个硬件大维特比解码器（BVD）的原型，用于伽利略号航天器的实验。搜索新的卷积码，研究维特比解码器硬件设计和架构，数学公式，将deBruijn图分解为相同和分层子图，以及超大规模集成（VLSI）芯片设计只是该项目完成的任务的几个例子。通过硬件和软件仿真测量的BVD误码率（BER）是加性高斯白噪声信道上比特信噪比E下标b/N下标0的函数。使用约束长度为15，速率为1/4的伽利略任务实验卷积码，BVD比NASA标准（7,1/2）最大似然卷积解码器（MCD）增加1.5 dB，误码率为0.005。在这个误码率下，当使用（255,233）NASA标准里德-所罗门解码器时，获得相同的增益，其产生的单词错误率为2.1 x 10(exp -8)，误码率为1.4 x 10（exp -9）。彗星交会小行星飞越(CRAF)/卡西尼号任务使用的（15.1 /6）编码产生1.7 dB的编码增益。这些增益是相对于输入到BVD的符号来测量的，并且随着误码率的降低而增加。此外，8位输入符号量化使BVD抵抗解调信号电平变化，这可能导致比NASA（7,1/2）代码更高的带宽，这些增益被大约0.1 dB的预期额外接收器损失抵消。通过压缩所有航天器数据，可以获得几个分贝的编码增益。
A prototype hardware Big Viterbi Decoder (BVD) was completed for an experiment with the Galileo Spacecraft. Searches for new convolutional codes, studies of Viterbi decoder hardware designs and architectures, mathematical formulations, and decompositions of the deBruijn graph into identical and hierarchical subgraphs, and very large scale integration (VLSI) chip design are just a few examples of tasks completed for this project. The BVD bit error rates (BER), measured from hardware and software simulations, are plotted as a function of bit signal to noise ratio E sub b/N sub 0 on the additive white Gaussian noise channel. Using the constraint length 15, rate 1/4, experimental convolutional code for the Galileo mission, the BVD gains 1.5 dB over the NASA standard (7,1/2) Maximum Likelihood Convolution Decoder (MCD) at a BER of 0.005. At this BER, the same gain results when the (255,233) NASA standard Reed-Solomon decoder is used, which yields a word error rate of 2.1 x 10(exp -8) and a BER of 1.4 x 10(exp -9). The (15, 1/6) code to be used by the Cometary Rendezvous Asteroid Flyby (CRAF)/Cassini Missions yields 1.7 dB of coding gain. These gains are measured with respect to symbols input to the BVD and increase with decreasing BER. Also, 8-bit input symbol quantization makes the BVD resistant to demodulated signal-level variations which may cause higher bandwidth than the NASA (7,1/2) code, these gains are offset by about 0.1 dB of expected additional receiver losses. Coding gains of several decibels are possible by compressing all spacecraft data.