宽带低轨卫星通信系统与5G融合是卫星通信的发展趋势，为满足高速数据传输的需求，基于大规模数字相控阵的多波束技术不可或缺。多波束信号的峰均比问题使得星上功放存在非线性失真，同时功率放大器的非线性失真又使得多波束间存在严重的干扰。针对采用大规模相控阵的低轨卫星通信系统，提出一种面向多波束的数字预失真结构，建立预失真模型，有效抑制了非线性、互调失真和多波束干扰问题。通过仿真实验可知，相比传统预失真结构，所提结构在性能和复杂度的均衡上更具优势，为星上实现多波束、克服非线性提供了一种可行方案。
The convergence of broadband LEO satellite communication systems with 5G is the development trend of satellite communication. To meet the demand for high-speed data transmission, multibeam technology based on large-scale digital phased arrays is indispensable. The peak-to-average ratio problem of multibeam signals induces the non-linear distortion of onboard power amplifiers, while the non-linear distortion of power amplifiers leads to serious interference between multibeams. A digital pre-distortion structure for multibeam is proposed for low-orbit satellite communication systems using large-scale phased arrays. A pre-distortion model is developed to solve the problems of non-linearity, intermodulation distortion and multibeam interference. Through simulation experiments, it is found that the proposed structure is more advantageous than the traditional pre-distortion structure in terms of performance and complexity balance, providing a feasible solution for the implementation of multibeam and overcoming non-linearity on board.
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