一种短小的高码率LDPC码设计

Construction of High Rate LDPC Codes with Short Block Length

提出一种高码率系统—–LDPC码的构造方法.在列重量一定的情况(通常列重量Wc3)下,构造满足给定围长条件的子矩阵,然后将该子矩阵和单位阵合并成LDPC码的校验矩阵.构造了28×76和64×328的校验矩阵.仿真表明,这两个LDPC码与校验矩阵为42×105、170×425、66×330的LDPC码在AWGN信道下的性能相比具有更好的BER.同时还基于拟阵理论给出了Tanner图的围长的充分条件,可用来构造给定的短围长LDPC码.短的高码率LDPC码可用于未来的手持数字视频广播.

A method of constructing low-density parity-check （LDPC） codes is presented, where an identity matrix is combined with another sub-matrix constructed under the condition of a given girth and fixed weight of column to generate a parity check matrix. Let Wc denote the fixed weight of column, which is usually not less than 3. Two kinds of check matrices sized 28~76 and 64~328 are constructed. Simulation results over additive white Gaussian noise （AWGN） channels show that performance of the codes is better than that of check matrices sized 42x105, 170x425 and 66x330. Meanwhile, sufficient conditions for the girth of Tanner graph based on Matroid theory are present. The girth conditions can be used to construct LDPC codes with given short girths. High-rate LDPC codes with short block length can be applied to the future digital video broadcast-handsets.