卫星数传系统中16APSK调制解调技术研究

发布时间：2018-02-16 05:35

本文关键词： 16APSK 调制解调星座优化 AGC 资源占用　出处：《中国科学院国家空间科学中心》2016年硕士论文　论文类型：学位论文

【摘要】：近年来,我国航天事业取得了飞速的发展和进步,各种不同任务的卫星需要传输的数据量越来越大,造成了频谱资源越来越紧张,因此高阶调制是未来数传系统的发展方向之一。APSK的圆形星座分布形式使得调制之后的信号幅度范围较小,较传统的QAM调制方式更加适合卫星数传信道的非线性特性,能提高频谱利用率。本课题以ETSI推荐的DVB-S2相关规范为指导,深入展开了对于16APSK调制解调技术的研究。主要研究内容如下:16APSK的调制方案。设计了16APSK的星座优化方案,研究了调制信号的产生,简化了调制信号的成型过程,结合EVM指标从工程实际的角度给出了调制信号的实现方式。16APSK的解调方案。提出了变采样/重采样的方法解决采样率与符号速率非整数倍的问题,利用内环鉴相方法来完成载波同步,在深入讨论Gardner差值的基础上完成位同步过程。从“平均幅度”和“平均功率”的角度设计了AGC控制过程。提出了基于CMA的适用于16APSK的信道均衡算法。从资源占用的角度来分析择优完成16APSK的硬判决过程。
[Abstract]:In recent years, China's aerospace industry has made rapid development and progress. The amount of data needed to be transmitted by satellites with different missions is becoming larger and larger, resulting in a growing shortage of spectrum resources. Therefore, higher order modulation is one of the developing directions of data transmission system in the future. The circular constellation distribution of APSK makes the amplitude range of the modulated signal smaller, which is more suitable for the nonlinear characteristics of the satellite data transmission channel than the traditional QAM modulation. Under the guidance of the relevant DVB-S2 standard recommended by ETSI, the research on 16APSK modulation and demodulation technology is carried out in depth. The main research contents are as follows: 1. The optimal constellation scheme of 16APSK is designed. The generation of modulation signal is studied, and the molding process of modulation signal is simplified. According to the EVM index, the demodulation scheme of the modulated signal is given from the point of view of engineering practice. The method of variable sampling / resampling is proposed to solve the problem of non-integer multiple of sampling rate and symbol rate. Using the inner loop phase detection method to complete carrier synchronization, On the basis of deeply discussing the difference of Gardner, the bit synchronization process is completed. The control process of AGC is designed from the angle of "average amplitude" and "average power". A channel equalization algorithm for 16APSK based on CMA is proposed. In this paper, we analyze the hard decision process of 16APSK from the point of view of selective selection.
【学位授予单位】：中国科学院国家空间科学中心
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN911.3

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