卫星移动通信系统多波束形成技术研究

发布时间：2018-05-20 23:13

本文选题：卫星移动通信系统 + 多波束天线　；参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：卫星通信技术作为实现移动通信的重要手段,在通信领域占有越来越重要的地位。多波束天线技术作为下一代卫星通信系统的关键技术之一,成为近年来研究的热点。多波束卫星系统可以利用多个点波束实现对整个服务区域的覆盖,类似于地面的蜂窝系统,可以有效地实现频率复用,增加系统吞吐量;通过窄波束对地面的覆盖,系统可以为服务区域提供更高的EIRP和G/T值,有利于地面终端的小型化;通过对波束指向的灵活调整,还可以根据需要进行波束重构,提升系统的灵活性。为发展我国空间通信技术,建立新一代的卫星移动通信网络,有必要对多波束技术进行深入研究。论文首先结合卫星多波束技术的国内外研究现状和现有使用多波束技术的卫星移动通信系统对涉及到的关键技术进行了分析。从系统架构、星载天线体制、波束形成方式三个方面对多波束卫星系统进行了剖析,比较了不同技术之间的优缺点,并结合实例分析了多波束技术的发展趋势,为我国选择多波束卫星系统的发展方向提供了理论参考。接下来,在之前的基础上,对卫星多波束形成算法进行了深入研究,并在经典算法的基础上提出了一种基于卡尔曼估计的变步长LMS算法(KBLMS)。该算法利用卡尔曼滤波器的优良特性,在进行权值迭代求解的过程中,使用了随采样信号变化的估计步长。相比于传统算法,新算法的复杂度介于LMS和RLS算法之间,但在收敛速度和最终残差剩余方面均优于两种经典算法。最后,针对多波束卫星移动通信系统经常面对突发业务的特点,对热波束的形成技术进行了研究。首先分析了现有可供选择的波束覆盖方案并进行了优缺点比较,之后从LMS算法中受到启发,提出了一种基于梯度思想的“凝视波束”形成算法。该算法通过对阵列权值的不断调整,可以使卫星实现对特定用户或地区的持续覆盖,进而可以令卫星有效地应对突发业务。
[Abstract]:As an important means to realize mobile communication, satellite communication technology plays a more and more important role in the field of communication. As one of the key technologies of the next generation satellite communication system, multi-beam antenna technology has become a hot topic in recent years. Multi-beam satellite systems can use multiple spot beams to cover the entire service area, similar to cellular systems on the ground, which can effectively achieve frequency multiplexing, increase system throughput, and cover the ground with narrow beams. The system can provide higher EIRP and G / T values for the service area, which is conducive to the miniaturization of the ground terminal. Through the flexible adjustment of the beam direction, the system can also be reconstructed according to the needs of the system, and the flexibility of the system can be enhanced. In order to develop the space communication technology and establish a new generation of satellite mobile communication network, it is necessary to study the multi-beam technology deeply. Firstly, this paper analyzes the key technologies of satellite multi-beam technology based on the current research situation at home and abroad and the existing satellite mobile communication system using multi-beam technology. This paper analyzes the multi-beam satellite system from the aspects of system architecture, space-borne antenna system and beamforming mode, compares the advantages and disadvantages between different technologies, and analyzes the development trend of multi-beam technology in combination with an example. It provides a theoretical reference for selecting the development direction of multi-beam satellite system in China. Then, on the basis of the previous research, the satellite multi-beam forming algorithm is deeply studied, and a variable step size LMS algorithm based on Kalman estimation is proposed based on the classical algorithm. The algorithm utilizes the excellent characteristics of Kalman filter and uses the estimated step size with the change of sampling signal in the process of iterative calculation of weight value. Compared with the traditional algorithm, the complexity of the new algorithm is between LMS and RLS, but it is superior to the two classical algorithms in terms of convergence speed and residual. Finally, the hot beamforming technology is studied in view of the characteristic that multi-beam satellite mobile communication system often faces burst traffic. In this paper, the existing alternative beam-coverage schemes are analyzed, and the advantages and disadvantages are compared. Then, an "staring beamforming" algorithm based on gradient is proposed, inspired by the LMS algorithm. By adjusting the array weight continuously, the algorithm can make the satellite realize the continuous coverage of a particular user or area, and then make the satellite respond to the burst traffic effectively.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN927.23

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