中文摘要：

LDPC码具有接近香农极限的性能和适中的编译码复杂度，在深空通信中具有较大应用前景。该文介绍了空间数据系统咨询委员会标准推荐的累积重复累积码，根据码字的原模图对ARA码进行了设计和分析。经过改进得到AR4JA码性能良好，具有系列性，采用并行结构解码，编解码复杂度较低。相关的仿真结果表明，采用该文所提出的改进原模图构造方法，在4/5码率，3．7 dB信噪比下，可以获得接近10-6的误码性能。

英文摘要：

Low density parity check （ LDPC ） codes has good performance close to the Shannon limit with moderate codec complexity , which endows it with large application prospects in deep space communications . The accumulate repeat accumulate （ ARA ） codes which can be described by protograth is recommended by CCSDS for application in deep space telemetry channel coding , is introduced.The AR4JA codes perform well under iterative decoding and feature a simple encoder structure and a fast decoder structure .Simulation results show that, adopt the proposed improvements protograph construction method , in 4/5 rate, 3.7 dB SNR, BER get close to 10 -6 .