利用一种新LDPC码的编码OFDM系统性能分析

提出了一种新的构造LDPC码的方法, 并把用该方法产生的LDPC码应用到编码正交频分复用(OFDM)系统中进行了研究. 该方法拓展了单位阵移位构造的LDPC码, 它利用简单的不等式可确保在置换单位阵构造中不会产生Tanner图中的短圈, 使得产生的LDPC码的Tanner图最小圈长为8. 由于该类码是准循环码以及其校验矩阵所固有的分层结构, 编码器和解码器都易于实现, 它们分别是线性可编和线性可译的. 所提出的LDPC码码率范围较大, 可以灵活选取. 利用迭代解码进行计算机仿真, 发现新的LDPC码比其他的规则LDPC码在编码OFDM系统中具有更好的性能.

Performance analysis of coded OFDM systems using a novel class of LDPC codes

A new method of constructing regular low-density parity-check (LDPC) codes is proposed. And the novel class of LDPC codes is applied in a coded orthogonal frequency division multiplexing (OFDM) system. This method extends the class of LDPC codes which can be constructed from shifted identity matrices. The method can avoid short cycles in Tanner graphs with simple inequation in the construction of shifting identity matrices, which makes the girth of Tanner graphs 8. Because of the quasi-cyclic structure and the inherent block configuration of parity-check matrices, the encoders and the decoders are practically feasible. They are linear-time encodable and decodable. The LDPC codes proposed have various code rates, ranging from low to high. They perform excellently with iterative decoding and demonstrate better performance than other regular LDPC codes in OFDM systems.