深空通信的级联码方案研究

Research on a concatenated code scheme for deep space communication

针对传统卢比变换-低密度奇偶校验(LT-LDPC)码不能有效解决深空通信中的通信中断与高通信误码率等问题,该研究采用弱鲁棒孤子分布以及改进型置信传播算法对LT码进行了优化,然后将优化的LT码(ILT)码与LDPC码级联生成ILT-LDPC码,并应用于深空通信中。通过模拟深空实验,从译码效率与译码开销两方面比较了LT-LDPC码与ILT-LDPC码的性能,同时从误码率与中断概率两方面比较了两者的性能。仿真结果表明,相比于LT-LDPC码,ILT-LDPC码译码效率增大,译码开销下降,且在深空通信中,其通信误码率更低,信噪比阈值更高。因此,该级联码能提高深空通信数据的可靠性。

In view of the problem that traditional Luby transform-low density parity check（ LT-LDPC） codes can not effectively solve the communication interrupt and the higher communication bit error rate of deep space communications,this study uses the weak robust soliton distribution and the improved belief propagation algorithm to optimize LT codes to create improved LT（ ILT） codes,and then,combins the ILT codes with LDPC codes to form ILT-LDPC codes and applies them to deep space communications. By deep space simulation,the performance of LT-LDPC codes and ILT-LDPC codes is compared from the two aspects of decoding efficiency and decoding overhead,and also from the bit error rate and the outage probability. The simulation shows that compared with LT-LDPC codes,ILT-LDPC codes have higher decoding efficiency and lower decoding overhead,and the communication bit error rate is lower,while the threshold of signal to noise ratio is higher. Therefore,concatenated codes can improve the reliability of deep space communication data.