在加性白高斯信道下，比较了补码键控最优译码和大数逻辑软判决译码的性能，分析了补码键控在衰落信道的性能，并提出了补码键控外层级联低密度极性校验码的结构，提供了补码键控的软判决输出算法，仿真结果证明补码键控外层级联低密度极性校验码在衰落信道下有明显的性能增益。关 键 词 补码键控; 低密度极性校验码; 外码级联; 大数逻辑译码; 最大似然译码Abstract In this thesis, the performance of complementary code keying is compared between optimal decoding and majority logic decoding algorithm, and analyzed in fading channels. A structure concatenating low-density parity-check code and complementary code keying and the algorithm of soft-decision output for complementary code keying are presented, the simulation result show more better performance than complementary code keying in rayleigh fading channels.Key words complementary code keying; low-density parity-check; outer code concatenated; majority logic decoding; maximum likelihood decoding