（毕业设计论文）《移动通信中的电波衰落与抗衰技术分析》.docVIP

精品 精品 电 子 科 技 大 学 毕 业 设 计（论 文） 论文题目： 移动通信中的电波衰落与抗衰技术分析 教学中心： 电子科技大学网络教育重庆学习中心 指导老师： 职 称： 学生姓名： 学 号: 专 业： 通信工程 精品 PAGE 精品 精品 PAGE 摘 要 ? 电波传输是任何无线电通信系统都离不开的手段。在当今，电波传输已遍及科技领域和国民经济的各个方面。从电视、广播、移动通信，到雷达、导航、气象、定位、卫星，再到军事领域中的制导武器、电子对抗等应用领域，取得了极为丰硕的研究成果。无论是理论上还是工程实际中，由于天气、地形、建筑物等的影响，电波传输过程中不可避免的存在衰落现象，电波传输问题的核心都是使电波信号的衰落最小。抗干扰误码会造成误跟踪和附加相位误差，并使输出质量恶化；系统复杂度取决于算法复杂度及目标移动速度等因素，附加相位误差难以抵消。解决方法是要求各阵元方向图相同。虽然两种系统都能在用户方向提供高增益，但只有自适应阵能提供最佳增益，并且同时识别并跟踪有用信号，最小化干扰。 论文简要介绍了移动通信电波传输过程中出现的衰落现象以及衰落的定义、分类情况。详细分析了移动通信中几种主要的抗衰落技术。 ? 关键词:　移动通信? 电波? 衰落? 抗衰落 ? Abstract It is the means that any wireless communication system can not all leave that the electric wave of the summary is transmitted. Nowadays, transmit all respects that have already spread all over the scientific and technological field and national economy in electric wave. From TV and broadcast, mobile communication, to the radar, navigation, meteorological phenomena, makes a reservation, the satellite, and then reach applications such as guidance weapon, electronic countermeasure in the military field,etc., have made the extremely rich research results. No matter in theory or in project reality, because of the influence of weather, topography, building,etc., electric wave unavoidable existence phenomenon of declining of the transmission course, electric wave transmit core of issue to make electric wave decline of signal minimum. Interference error will cause an additional phase error tracking and error, and to output quality deterioration; system complexity depends on the complexity of the algorithm and the target speed and other factors, additional phase error is difficult to offset. The solution is to require the same array pattern. Although the two systems can provide high gain in the user direction, but only the adaptive array can provide the best gain, and also t