卫星通信中的自适应编码调制技术研究

发布时间：2019-01-19 12:29

【摘要】：卫星通信作为地面通信的补充和延伸,因其具有覆盖范围广泛、不受地理环境限制、对抗自然灾害能力优异等优势,具有不可替代的地位。然而,卫星通信由于信道条件开放,会受到各种大气因素的影响,尤其是降雨造成的雨衰会对Ka波段的高频信号造成严重的干扰。自适应编码调制技术作为衰落补偿技术的一种,可以根据信道状况调整编码和调制方式,能够解决衰落对卫星通信的影响问题。因此,卫星通信中的自适应编码调制技术成为卫星通信领域的研究热点之一。论文研究了卫星通信中的自适应编码调制技术,分析了雨衰随时间变化对信道的影响和卫星通信中的信噪比估计技术,主要研究工作如下： 1.研究了卫星通信系统组成及其物理层技术,对包括卫星信道模型、信噪比估计技术和自适应编码调制技术进行了深入调研。 2.分析了天气状况对Ka波段高轨固定卫星信道的影响,建立了包络和相位服从高斯分布的Ka波段高轨固定卫星信道静态模型,并对不同天气状况对信道的影响进行了仿真分析。在研究衰落斜率的基础上,设计了适合于Ka波段高轨卫星信道的基于马尔科夫状态的短期雨衰时间序列动态模型,并进行仿真研究,研究结果表明该模型能够较好地反映雨衰对Ka波段卫星信道的影响。 3.研究了适用于卫星通信系统的信噪比估计算法,仿真对比了EVM算法、SSME算法、M2M4算法、SVR算法、MMSE算法和ML算法在相同条件下的性能。 4.研究了自适应编码调制技术的原理和关键技术,DVB-S2标准中的编码、调制等内容,建立了基于DVB-S2标准的仿真平台,对不同编码调制方式进行仿真。基于所设计的短时间降雨雨衰时间序列模型,提出了DVB-S2标准自适应编码调制的优化方案,并进行了仿真研究。研究结果表明,优化方案能够有效降低DVB-S2标准原方案的复杂度。基于马尔科夫状态理论,设计了一种新型的自适应编码调制方式选择算法,并进行了仿真研究。仿真结果表明,该算法的性能优于传统的门限法。
[Abstract]:Satellite communication, as a supplement and extension of terrestrial communication, has an irreplaceable position because of its advantages such as wide coverage, not limited by geographical environment, excellent ability to resist natural disasters and so on. However, because of the open channel conditions, satellite communications will be affected by various atmospheric factors, especially the rain decline caused by rainfall will cause serious interference to the high frequency signal in Ka band. As one of the fading compensation techniques, adaptive coding modulation can adjust the coding and modulation methods according to the channel conditions, and can solve the problem of the influence of fading on satellite communication. Therefore, adaptive coding modulation technology in satellite communication has become one of the research hotspots in satellite communication field. In this paper, the adaptive coding modulation technology in satellite communication is studied, and the influence of rain attenuation with time on channel and SNR estimation in satellite communication are analyzed. The main research work is as follows: 1. The composition of satellite communication system and its physical layer technology are studied, including satellite channel model, SNR estimation technology and adaptive coding modulation technology. 2. This paper analyzes the influence of weather condition on the Ka band high orbit fixed satellite channel, establishes the static model of the Ka band high orbit fixed satellite channel with the distribution of envelope and phase suit from Gao Si, and simulates the influence of different weather conditions on the channel. Based on the study of fading slope, a dynamic model of short term rain decline time series based on Markov state for Ka band high orbit satellite channel is designed and simulated. The results show that the model can well reflect the influence of rain failure on the Ka band satellite channel. 3. The SNR estimation algorithm for satellite communication system is studied. The performance of EVM algorithm, SSME algorithm, M2M4 algorithm, SVR algorithm, MMSE algorithm and ML algorithm under the same conditions are simulated and compared. 4. The principle and key technology of adaptive coding modulation, the coding and modulation of DVB-S2 standard are studied. The simulation platform based on DVB-S2 standard is established to simulate the different coding modulation methods. Based on the designed model of short time rainfall and rain decline time series, an optimized scheme of DVB-S2 standard adaptive coding modulation is proposed, and the simulation research is carried out. The results show that the optimized scheme can effectively reduce the complexity of the original DVB-S2 standard scheme. Based on Markov state theory, a novel adaptive coding modulation selection algorithm is designed and simulated. Simulation results show that the performance of the algorithm is better than the traditional threshold method.
【学位授予单位】：北京邮电大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN927.2

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