32APSK-TCM技术在中继卫星通信系统中的应用研究

Research on the Application of 32APSK-TCM Technology in Relay Satellite Communication System

32APSK(Amplitude Phase Shift Keying,幅相键控)技术与32QAM(Quadrature Amplitude Modulation,正交幅度调制)技术相比,减少了幅值数目,适合于中继卫星通信系统非线性信道。TCM(Trellis Code Modulation,网格编码调制)技术将信道编码与多元调制相结合,在不增加频谱带宽的条件下,可以降低发射功率,减少能耗,降低对功率放大器技术指标的要求,有利于实现卫星有效载荷的轻型化与小型化。本文将32APSK技术与TCM技术相结合,提出了一种32APSK-TCM技术,详细论述了基于32APSK-TCM技术的星座子集分割方法和星座点选择方法,并对32APSK-TCM技术的性能进行了理论分析。在项目组自研的中继卫星通信系统仿真平台上,对32APSK-TCM技术进行了仿真验证。仿真结果表明:在理想信道条件、I/Q(Inphase/Quadrature,同相/正交)幅相不平衡、幅频特性、群时延、相位噪声、功率放大器饱和点、非线性信道条件下,需要的最大误比特率为1E-6时,32APSK-TCM技术的最小信噪比与16APSK调制技术的最小信噪比相比,分别节省了13.29 dB,13.29 dB,14.84 dB,15.54 dB,15.11 dB,15.77 dB,16.37 dB。

Compared to 32QAM technology,32APSK technology reduces the number of amplitudes and is suitable for a non-linear channel in a relay satellite communication system.TCM technology combines channel coding and multi-level modulation,doesn't increase the spectrum bandwidth,decreases the transmission power,cuts down energy consumption,lowers the requirements for technical indexes of the power amplifier,and is beneficial for achieving lightweight and miniaturization of satellite payloads.This paper combines 32APSK technology and TCM technology,proposes a kind of 32APSK-TCM technology,discusses details of the 32APSK-TCM technology constellation subset splitting method and constellation point selection method,and analyzes the performance of the 32APSK-TCM technology.This paper simulates the 32APSK-TCM technology and 16APSK technology using the simulation platform of the relay satellite communication system developed by our research team.Simulation results demonstrate that under the condition of an ideal channel,I/Q amplitude phase imbalance,amplitude frequency characteristics,group delay,phase noise,power amplifier saturation point,and nonlinear channel,if the maximization value of the required bit error rate is 1E-6,compared to 16APSK technology,the minimization value of the signal-to-noise ratio of 32APSK-TCM technology saves 13.29 dB,13.29 dB,14.84 dB,15.54 dB,15.11 dB,15.77 dB,and 16.37 dB,respectively.