中文摘要：

正交频分复用（OFDM）是一种多载波调制技术，已成为实现高速数据传输的主流技术，在无线局域网、HDTV中得到广泛应用；低密度奇偶校验（LDPC）码是一种译码复杂度低的纠错码，可获得接近香农限的优异性能。本文提出了结合LDPC码的COFDM系统方案，阐述了相关原理，对其性能进行了仿真分析，比较了在不同调制方法下系统的性能差异，并将基于LDPC码和Turbo码的COFDM系统在不同信道中的误码性能进行了对比。仿真结果表明，基于LDPC码的COFDM系统在提供较高比特传输速率的同时也具有良好的纠错性能。

英文摘要：

Orthogonal Frequency Division Multiplexing （OFDM） is a multi-carrier modulation technique, which proved to be a main method for high-speed data transmission. It is widely used in WAN and HDTV. LDPC（low-density parity-check） is an effective error- correcting code. Its performance is very close to the Shannon limit and it has lower decoding complexity. This paper combined OFDM with LDPC. It simulates and analyses the performance of LDPC-COFDM system with different modulation. It also compares LDPC COFDM with Turbo-COFDM in dissimilar Channel. It comes to conclusion that LDPC- COFDM method is effective in the high-speed data transmission.