太阳闪烁下的深空信道中LDPC-MPSK系统性能分析

Performance Analysis of LDPC-MPSK System in Deep Space Communications under Solar Scintillation Condition

针对深空通信中传输数据量大、接收信号信噪比低的问题,分析太阳闪烁对深空通信信道的影响,将存在太阳闪烁的深空通信信道近似为莱斯信道,进而提出在该通信环境下采用LDPC编码与MPSK调制相结合的数据传输通信方案,研究太阳闪烁强度、调制进制数、LDPC码长码率对系统性能的影响。仿真结果表明,LDPC编码与MPSK调制相结合的数据传输通信方案在深空信道下具有良好的性能,可有效地抵御太阳闪烁引起的通信性能下降,当使用码率为1/2、码长为1024的非规则LDPC编码时,在误码率为10–5的条件下,QPSK的传输速率为BPSK两倍,其所需的信噪比仅比BPSK高0.2d B。

In deep space communication links,the transmitting data are quite large and the signal-to-noise ratio ofreceived signal is very low.To deal with these problems,we analyze the effects of solar scintillation on the links and use Ricianchannel to set up the simulation model of the deep space communication channel.Then we propose to apply the low densityparity check(LDPC)coded multiple phase shift keying(MPSK)system in the deep space communication channel.In thispaper,we analyze the effects of solar scintillation intensity,code rate and length of LDPC and different types of MPSK oncommunication performance.Simulation results reveal that the performance of LDPC coded MPSK system is excellent in deepspace communication links.This system can effectively resist performance degradation caused by solar scintillation.When theBER is10–5under the condition of irregular LDPC codes with the rate of1/2and the length of1024,the bit rate of QPSKsystem is twice as fast as that of BPSK system,and the QPSK system needs a higher SNR of just0.2dB than the BPSK system.