By the graph representation, we discuss the girth and diameter of a bipartite graph, and their roles in improving the efficiency of decoding algorithms and the performance of the code.
根据低密度码的图结构表示，研究双向图的周长、直径，及其对提高译码算法效率和码的性能所起的作用。
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However, the performance of LDPC code depends on the girthof its bipartite graph, that is it depends on its sparse parity-check matrices H, especially the complexity of encoding with H.