EXIT chart based design of LDPC codes for higher order constellations
EXIT chart based design of LDPC codes for higher order constellations
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基于 EXIT 图的高阶星座 LDPC 码设计
DOI：
10.1109/ncc.2013.6487953
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
A. Thangaraj
中科院分区：
文献类型：
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作者：
Bhargav Joshi;A. Thangaraj
外部信息传递(EXIT)图是用于分析低密度奇偶校验(LDPC)和其他具有迭代译码的码的图形化工具。在本文中，我们提出了用线性规划的方法来设计编码调制方案中的LDPC码。首先使用分析或通过模拟计算BIT和CHECK节点操作的退出曲线上的点。然后通过线性插值法得到整个出射曲线。最后，对退出曲线进行优化，以获得在给定阈值条件下该码的最大可能速率。为了演示设计过程，我们考虑了加性高斯白噪声(AWGN)信道上的M-PAM和8-PSK的情况。该优化方法通用性强，易于推广到其他星座和场合。
EXtrinsic Information Transfer (EXIT) chart is a graphical tool for analysis of low density parity check (LDPC) and other codes with iterative decoding. In this paper, we propose the design of LDPC codes for coded modulation schemes by application of linear programming with conditions derived from EXIT charts. Points on the EXIT curve for bit and check node operations are first computed either using analysis or by simulation. The entire EXIT curve is then obtained by linear interpolation. Finally, the EXIT curves are optimized to obtain the maximum possible rate for the code under a given threshold condition. To demonstrate the design procedure, we consider the cases of M-PAM and 8-PSK over the additive white Gaussian noise (AWGN) channel. The optimization method presented is versatile, and can be extended to other constellations and situations easily.