【作者】 张晓晨；

【导师】 顾学迈；

【作者基本信息】 哈尔滨工业大学 ， 信息与通信工程， 2008， 硕士

【摘要】 低轨卫星移动通信系统由于其较低的传输时延和较低的终端要求已经成为当前通信领域中发展非常迅速的研究方向和现代化通信强有力的手段。很多国家在建立了低轨卫星系统的同时,进行了卫星信道模拟器的研究。本文首先详细研究Lutz信道模型,对其进行了仿真和性能分析,提取信道特性的指标,为硬件实现提供理论支撑和指标要求。其次,卫星通信系统中关键技术参数进行分析,研究了卫星通信中自由空间传播特性,在此基础上对卫星信道模拟器系统的总体结构和中频接口电路的硬件实现进行设计。在信道模拟器总体结构和系统性能指标的基础上,进而确定信道模拟器中频接口电路系统的设计方案。对中频接口电路系统的硬件的设计主要包括数模、模数转换及其调理电路和信道切换开关的设计。结合中频信号数字化理论,对数模、模数转换及其调理电路、以及信道波束切换设计方和实现进行了详细阐述。此外,在分析卫星信道模拟器中频接口电路系统基础上,提出了验证系统性能的设计方案。此外,本文还针对系统的实际应用要求,对系统专用通信协议的进行设计。在此基础上,结合通信协议,详细介绍了信道切换开关的状态转换的方案设计,并在最后给出状态机在Quartus II的仿真结果。最后,结合测试系统,对中频接口电路系统及信道模拟器总体系统的性能进行了验证,证明信道模拟器的中频接口电路设计合理、实时性、精度高、满足卫星通信中对信道特性的模拟,所完成的设计达到了课题要求,而且对进一步提高原有卫星信道模拟器系统有很大的理论和实践意义。更多还原

【Abstract】 LEO satellite mobile communication system has become one of the most galloping communication research fields and a useful means of modern communication.Many countries get to research satellite communication channel emulator while building up low-orbiting satellite communication system.Our country is also researching and developing satellite communication channel emulatorBased on the study of the channel model of Lutz, then carefully analyzed the data form simulates the model by using Matlab; we can got some useful parameters used in the design of hardware board. This give sufficient theory of the hardware implementation.In addition, the dissertation is also design the general scheme and the hardware implementation. The key technologies for the satellite channel are analyzed in the first part of the dissertation the paper. Base on depth research on the basic principles of propagating characteristics and the require of the system,we can designed the general scheme of the satellite mobile communication system fully.The main part of the design of the MF multi-interface hardware borad include A/D、D/A conversion and its carrying on signal to adjust reason electric circuit. The topic chosen as the core FPGA design a channel switch circuit at last part.Base on the direct IF sampling theory,we can select the appropriate chips using in the A/D、D/A conversionits、carrying on signal to adjust reason electric circuit and the channel switch circuit.Then followed by the detailed design of the MF multi-interface hardware borad.Also, through analysis over the MF multi-interface hardware borad of LEO satellite communication channel simulator, put forward the system testing scheme of this borad.In addition, the dissertation is also dedicated to the communication protocol design on the basis of the practical application.Details of function of the channel switch and the design of general finite state machines correctly on the protocol basis, and use the software QuartusII to prove its function correcttly.Finally, with the actual LEO satellite communication channel simulator testing, the system’s overall performance, communications reliability and the situation of implement statistical models with hardware proved that the system design is reasonable.Further more,the research on the system has great theoretical and practical significance for improving the existingLEO satellite communication channel simulators.更多还原