卫星转发信道饱和条件最优功率增益设计与分析

为了优化卫星转发信道饱和条件下信号的接收性能，分析透明转发器饱和状态下互调噪声的产生原因，削弱互调噪声对转发信道载噪比(CNR)恶化的影响. 本文通过建立信道模型、计算信道参数、仿真优化分析的方法对问题进行研究. 分别研究转发器增益调整对接收端CNR的直接影响与互调信号对CNR的间接影响，并进行了理论计算与仿真分析. 仿真结果表明:在饱和条件下，转发器增益回退可以改善CNR损耗. 当干扰信号发射功率为45 dBW时，转发器回退?1 dB可以达到最小的CNR损耗为?1.55 dB. 随着干扰增强，最优的增益回退值会逐渐增长，同时最小的CNR损耗也会增加，研究成果可应用于卫星转发信道中，为饱和条件下转发器增益调整优化提供指导借鉴. 

Design and analysis of optimal power gain for satellite transponder channel saturation condition

In order to optimize the signal reception performance under the saturation condition of the satellite transponder channel, the generation of the intermodulation signal in the saturated state of the transparent transponder is analyzed, and the influence of the intermodulation signal on the deterioration of the channel carrier-to-noise ratio (CNR) is weakened. This paper studies the problem by establishing the channel model, calculating the channel parameters, optimizing the analysis and simulation. The direct influence of the transponder gain adjustment on the CNR of the receiver and the indirect influence of the intermodulation signal on the CNR of the receiver are respectively studied, and did the theoretical calculation and simulation analysis. The results show that under saturation conditions, the transponder gain back off can improve the CNR loss. When the transmit power of the interfering signal is 45 dBW, the minimum CNR loss of ?1.55 dB can be achieved by the back-off of the transponder ?1 dB. As the interference increases, the optimal gain back off value will gradually increase, and the minimum CNR loss will also increase. The research results in this paper can be applied to satellite transponder channels to provide guidance for the optimization of transponder gain adjustment under saturation conditions.