摘要
下一代移动通信系统网络融合加快，移动互联网应用高速发展，使得有关的新技术和新应用成为移动通信系统研究的重大内容。在新的应用场景下，由于存在多径传播和时变性，作为传播媒介的无线信道，对无线通信系统的性能有着巨大的影响。因此，无线信道的测量与建模对于其传输技术的研究有着重要的指导意义。
本文基于无线信道的传播特性，对无线信道的测量与建模方法进行研究。主要研究内容如下：
首先，简单回顾了无线信道的传播特性，包括大尺度传播特性和小尺度传播特性。介绍了无线信道测量与建模的基本原理，对现有的测量方法和建模方法进行了归纳和总结。最后以信道模型在无线电导航频率规划中的应用，说明信道建模的工程实践意义，通过仿真计算，指配结果与美国联邦航空局标准吻合，提供了一种简单有效的频率指配方法。
然后，本文研究了大尺度衰落信道建模方法，对采用最小二乘法的经典大尺度衰落建模作了说明。基于确定性的环境地形，重点对基于射线跟踪的信道建模方法做了介绍，并采用WinProp的传播估计模型，对典型场景进行了传播预测。预测结果显示，基于射线跟踪的建模方法能够适应性地跟踪具体传播环境，对场景信道实现更精准地建模。
类似地，研究了小尺度衰落信道建模方法。首先介绍了小尺度衰落信道的特性描述和抽头延迟线模型，为了建立小尺度衰落信道模型，重点对基于解相关算法、扩频滑动相关法、压缩感知的信道估计方法进行了研究，对其原理分别做了介绍，并在一定条件下作了仿真分析。结果表明：解相关算法不依赖于探测波形，都能够实现原始信道的估计，但其估计性能的优劣与探测脉冲的形状有关，更符合理想冲激脉冲的波形有着更高的估计性能；扩频滑动相关法抗噪声性能良好，能够很好地估计出多径信道。在多种伪噪声序列中，m序列实现简单，有着优良的自相关性能，是最为常用的伪噪声序列；压缩感知算法充分利用无线信道的稀疏性，可以在一定条件下实现信道的精确估计，其中正交匹配追踪算法实现简单，重构效果良好，应用较为广泛。由于扩频滑动相关法有着优良的估计性能，并且配置灵活，可适应不同需求的系统测量方案，是目前最常用的多径信道测量方法。王的英语
最后，理论诉诸实践，利用实验室的仪器设备搭建了信道测量系统，并针对
校园场景开展了外场测量活动。详细描述了测量方案设计和参数提取方法，采用扩频滑动相关法获取了信道冲激响应样本，并通过建模分析给出了测量场景下的信道统计描述。结果显示：在测试场景下，大尺度衰落建模结果与基于射线跟踪的传播估计结果接近，同时由于测量场景的开阔性，其小尺度衰落模型的均方根时延扩展相对较小。
关键词：无线信道特性，扩频滑动相关测量，信道测量，信道建模，多径信道估计
ABSTRACT
With the rapid development of mobile communication network convergence and mobile Internet applications, the relevant new technologies and new applications becomes a major rearch content in the field of wireless communication. Under the new scenario, due to the multipath propagation and time variation, the wireless channel has a huge impact on the performance of wireless communication system. Therefore, measurement and modeling of wireless channel is of great guiding significance for the rearch of transmission technology.
In this paper, measurement and modeling methods of wireless channel are studied bad on the propagation characteristics of wireless channel. The main contents are as follows:
郑板桥竹石Firstly, it briefly reviews the propagation characteristics of wireless channel, including large-scale propagation characteristics and the and small-scale propagation characteristics. Then the basic principle of measurement and modeling for wireless channel is introduced, as well as an overview of existing methods. In order to prent the practical significance of channel modeling, the paper gives an application ca in the field of radio navigation frequency planning. The simulation shows that the results matches well with the FAA standard, and provides a simple and effective method for frequency assignment.
关于风雨的诗句
Secondly, the large-scale fading channel modeling method is studied in this paper, and the classical large-scale fading modeling using least squares is described in detail. The main work in this part is focud on the channel modeling method of ray tracing, which is bad on the deterministic environmental terrain, and the estimated results of a typical scenario is shown with propagation prediction models supported by WinProp. It turned out ray tracing modeling method can adaptively track the specific propagation environment and achieve higher accuracy.
Similarly, this paper studies the small-scale fading channel modeling method also, and introduces the characteristic description and tap delay line model of small-scale fading channel. Then the methods of multipath channel estimation, including deconvolution algorithm, spread spectrum sliding correlation method and compresd
nsing, are studied. Their principles are described and the simulation analysis under specific conditions is prented respectively. In particular, deconvolution algorithm’validity is independent of detecting waveforms, i.e. original channel can be estimated by any puls. However, the shape of detecting pul affect the estimated performance: the more likely to ideal impul, the higher performance can be achieved; spread spectrum sliding correlation method has good anti-noi performance and can estimate multipath channel well. Compared with other PN quences, becaus
e of its simplicity and excellent autocorrelation, m quence is the mostly commonly ud; Compresd nsing algorithm makes full u of the sparsity of the wireless channel, and can realize accurate channel estimation under certain conditions. The OMP algorithm has low complexity and satisfactory reconstruction performance, so it is applied widely in many fields. With its excellent estimation performance and flexible configuration, spread spectrum sliding correlation method is the most prevailing on multipath channel estimation.
Finally, from the theory to practice, we u the existing instruments and devices of laboratory to conduct a measurement campaign under the campus scenario. The paper describes design scheme of measurement system and parameters extraction method in detail, and corresponding channel impul respon samples are obtained by the spread spectrum sliding correlation method. Through channel modeling, it prent statistical characterization of the measured channel. The results suggest that the constructed large-scale fading model is very clo to the prediction results of ray tracing-bad models; and owing to the openness of the measured scenario, the root mean square delay spread of small-scale fading model is relatively small.
Key words: wireless communication characteristic, spread spectrum sliding correlation measurement, channel measurement, channel modeling, multipath channel estimation
目录
目录
第一章绪论 (1)
1.1研究背景及意义 (1)
1.1.1研究背景 (1)
1.1.2研究意义 (1)
1.2国内外研究现状 (2)
1.3主要研究内容及结构安排 (4)
第二章无线信道测量与建模原理 (6)
2.1引言 (6)
2.2无线信道传播特性 (6)梦见被狼追是什么意思
2.2.1传播与衰落 (6)
2.2.2大尺度衰落 (7)
2.2.3小尺度衰落 (9)
登泰山古诗
2.3无线信道测量与建模原理 (10)
2.3.1信道测量原理 (11)
2.3.2信道建模原理 (12)
2.4信道模型在无线电导航频率规划中的应用 (13)
2.4.1导航频率规划概述 (13)
2.4.2无线电导航传播模型 (14)
2.4.3导航台站保护间隔计算 (15)
2.5本章小结 (18)适合送朋友的花
答谢宴
第三章大尺度衰落信道建模方法 (19)
3.1引言 (19)
3.2经典大尺度衰落建模 (19)
3.2.1路径损耗指数 (19)
3.2.2阴影衰落标准差 (20)
3.2.3仿真与验证 (21)
3.3基于射线跟踪法的建模 (22)
3.3.1射线跟踪理论 (23)
3.3.2射线跟踪建模 (25)
3.4基于传播估计的建模 (29)
3.4.1传播估计模型 (30)
鸿鹄之志3.4.2仿真与分析 (32)
3.5本章小结 (34)
第四章小尺度衰落信道建模方法 (35)
