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首页> 外文学位 >Decodage a seuil iteratif sans entrelacement des codes convolutionnels doublement orthogonaux (French text).
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Decodage a seuil iteratif sans entrelacement des codes convolutionnels doublement orthogonaux (French text).

机译：使用迭代阈值进行解码，而无需交织双正交卷积码（法语文本）。

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摘要

The object of this thesis is to explore a new coding and iterative decoding technique without the use of interleaving and propose some practical solutions that circumvent the complexity and the latency shortcomings of the usual coding and Turbo decoding techniques.; Using threshold decoding at each iteration step, the independence constraint on the observables must be satisfied. This problem is solved by defining the new convolutional self doubly orthogonal codes which are threshold decodable. The parity check equations generated at each iteration step of the decoding procedure are then orthogonal over two consecutive iteration steps.; From the analysis of the iterative threshold decoding for convolutional self doubly orthogonal codes defined in the wide sense, some modifications of this decoding procedure improving the error performances are proposed. One of these modifications consists in the use of weighting each parity check equation by appropriate coefficients which minimize the bit error probability at the last iteration step. The simulation results show that for high signal to noise ratio, all coefficients can take the same value without degradation of error performances as compared to the use of different coefficient values. For many convolutional self doubly orthogonal codes defined in wide sense, coding gain improvements of about 0.5 to 1.0 dB are obtained using this modification. Furthermore, for convolutional self doubly orthogonal codes defined in the strict sense, at high signal to noise ratio, the use of weighting does not improve the error performances but, for lower signal to noise ratio values, substantial improvements in error performances are also possible with the use of appropriate weighting coefficients.; The error performance analysis of iterative threshold decoding without interleaving using the convolutional self multi-orthogonal codes defined in the strict sense is presented. This analysis shows that beyond the double orthogonality, only marginal improvements in error performances are obtained.; The recursive convolutional self doubly orthogonal codes are also defined. An appropriate iterative decoding method is developed and explored. Some simulation results show that the use of the recursive convolutional self doubly orthogonal codes defined in the strict sense provides very good error performances. (Abstract shortened by UMI.)
机译：本文的目的是在不使用交织的情况下探索一种新的编码和迭代解码技术，并提出一些实用的解决方案来规避常规编码和Turbo解码技术的复杂性和时延缺点。在每个迭代步骤使用阈值解码，必须满足对可观察对象的独立性约束。通过定义可阈值解码的新卷积自双正交码来解决该问题。然后，在解码过程的每个迭代步骤中生成的奇偶校验方程在两个连续的迭代步骤上正交。通过对广义上定义的卷积自双正交码的迭代阈值解码的分析，提出了对该解码过程的一些改进，以改善误码性能。这些修改之一包括使用通过适当的系数对每个奇偶校验方程加权的方法，该系数使在最后迭代步骤中的误比特率最小。仿真结果表明，与使用不同的系数值相比，对于高信噪比，所有系数都可以取相同的值而不会降低错误性能。对于广义上定义的许多卷积自双正交码，使用此修改可获得约0.5至1.0 dB的编码增益提高。此外，对于严格意义上定义的卷积自双正交码，在高信噪比的情况下，使用加权不会改善错误性能，但是对于较低的信噪比值，使用使用适当的加权系数。提出了严格意义上定义的卷积自多正交码不交织的迭代阈值解码的误码性能分析。该分析表明，除了双重正交性之外，在错误性能方面仅获得了少量改进。还定义了递归卷积自双正交码。开发并探索了一种合适的迭代解码方法。一些仿真结果表明，严格意义上定义的递归卷积自双正交码的使用提供了很好的错误性能。 （摘要由UMI缩短。）

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