低轨卫星信道模拟器控制终端设计与实现信息与通信工程专业论文.docxVIP

哈尔滨工业大学工学硕士学位论文 哈尔滨工业大学工学硕士学位论文 - - II - Abstract Recent years, Low Earth Orbit (LEO) satellite communication is widely applied, and will play an important role in the future personal communication. In satellite mobile communication system, because the signals are affected by the Doppler Effect, shadow effect, multi-path fading and transmission noise, the communication channel between the satellite and the mobile terminal constrains the performance of the whole system. Before the designing of one satellite communication system, develop a satellite channel emulator to simulate the signals’ characteristics while transmitted, which could provide powerful proof for selecting appropriate technologies (such as modulation, channel coding and power control). So, it is a meaningful work. The satellite channel emulator designed in this project will applied in the constellation half-physical simulate system, we use software and hardware methods to complete the simulation of channel characteristics in multi mobile environments. This channel emulator works at 70MHz, and it mostly allows three types mobile terminal access and six wave beams output. Simultaneously, the parameters of the fading channel models are from actual measurement data, so it could reflect the LEO satellite channel transmit characteristic truly. In this paper, we mainly research on three aspects content: first, base on the research of classical channel models, choose appropriate channel model and analyze correlative channel parameters. According to the European Space Agency test and analytical results, fading characteristics of satellite mobile communication channel couldn’t be described by single probability distributing function, so we choose three-state switched model which could describe the transformation more accurately, and make each state became into Loo model. Thereby, we find a balance between performance and complexity; second, after selecting appropriate model, we make a software simulation to pro