中文摘要：

低密度奇偶校验码（LDPC）具有码字构造灵活、译码复杂度低、性能优异以及频谱利用率高等特点。本文简介了LDPC码及位交织编码调制迭代译码（BICM—ID）方案，提出了将LDPC码作为分量码的BICM—ID方案用于多电平正交幅度调制（M—QAM）的OFDM通信系统中，并给出了多电平正交幅度调制的对数似然比置信传播（LLR—BP）译码算法。最后，根据数字广播信道的特点，比较了基于LDPC—BICM—ID方案与DRM标准中码率匹配的删除卷积码多级编码方案（RCPC／MLC）的OFDM系统在中、短波广播信道中的误码率性能。仿真结果表明，本文所提出的方案的性能优于RCPC／MLC方案。

英文摘要：

Low density parity check （LDPC） code is flexible in construction, simple in decoding, excellent performance and high spectrum efficiency. This paper introduces the LDPC codes and bit-interleaved coded modulation with iterative de- coding （BICM-ID） scheme, proposed an LDPC codes as component codes in BICM-ID scheme is applied to Multi-Level Quadrature Amplitude Modulation （M-QAM） in the OFDM communication system, and given its log-likelihood ratio belief propagation （LLR-BP） decoding algorithm. Finally, according to the characteristics of the digital broadcast channel, sys- tem performance based on LDPC-BICM-ID scheme is compare with the rate compatible punctured convolutional code （RCPC） scheme over MF and HF radio broadcastirig channels. Simulation results show that the proposed scheme is better than RCPC-MLC system.