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arXiv 1907.08063cs.ITmath.IT
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基于图的编码器及其在带反馈双态信道中的性能

Graph-Based Encoders and their Performance for Finite-State Channels with Feedback

Oron Sabag, Bashar Huleihel, Haim Permuter

摘要:

研究了存在反馈的单股有限状态信道的容量。我们推导出一种新的评估方法来提取基于图的编码器与其可实现的速率,并计算上限来检查其性能。的评价方法是建立在最近的方法来获得简单的界限上的能力,使用辅助有向图。虽然尚不清楚上界是否是凸的,但我们使用适当约束的参数变换将其表述为凸优化问题。下界被公式化为非凸优化问题,然而,优化问题的任何可行点都会导致基于图的编码器。在所有的例子中,数值结果显示出近紧的上限和下限,可以很容易地转换为解析结果。对于非对称陷门信道和二进制衰落信道,通过计算相应的界,得到了新的容量结果。对于所有其他情况下,包括伊辛信道,通过与相应的上限比较,显示了可实现的速率的接近紧密性。最后,我们表明,任何基于图的编码器意味着一个简单的编码方案,是基于后验匹配原则,并达到下界。

英文摘要:

The capacity of unifilar finite-state channels in the presence of feedback is investigated. We derive a new evaluation method to extract graph-based encoders with their achievable rates, and to compute upper bounds to examine their performance. The evaluation method is built upon a recent methodology to derive simple bounds on the capacity using auxiliary directed graphs. While it is not clear whether the upper bound is convex, we manage to formulate it as a convex optimization problem using transformation of the argument with proper constraints. The lower bound is formulated as a non-convex optimization problem, yet, any feasible point to the optimization problem induces a graph-based encoders. In all examples, the numerical results show near-tight upper and lower bounds that can be easily converted to analytic results. For the non-symmetric Trapdoor channel and binary fading channels (BFCs), new capacity results are eastablished by computing the corresponding bounds. For all other instances, including the Ising channel, the near-tightness of the achievable rates is shown via a comparison with corresponding upper bounds. Finally, we show that any graph-based encoder implies a simple coding scheme that is based on the posterior matching principle and achieves the lower bound.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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