短距离室内无线信道传播特性研究

发布时间：2018-01-15 20:27

本文关键词：短距离室内无线信道传播特性研究　出处：《南京邮电大学》2014年博士论文　论文类型：学位论文

【摘要】：无线信道传播特性是无线通信系统中提高性能、降低成本的关键因素。随着无线传感网应用的迅速发展和第四代移动通信系统的逐步商用，短距离室内无线通信的业务需求和应用场景日渐丰富。短距离室内无线通信由于场景、频段、人员密集程度等因素的影响，电磁传播环境更为复杂，因此亟待对短距离室内无线信道传播特性展开深入研究。本文在室内办公室、楼梯等典型场景，选择5.8GHz和2.6GHz频段进行单输入单输出（SISO）和多输入多输出（MIMO）信道频域测量。通过积累大量实测数据，重点分析路径损耗、多径传播、交叉极化鉴别率（XPD）等信道传播特性，并结合环境、频率、人员等因素建立经验统计模型。本文的主要研究及贡献如下：首先，详细分析比较了目前成熟的短距离室内时域和频域无线信道测量技术。频域测量方法与时域测量方法相比，实验设备简单并且节省测量时间，并且在短距离室内环境中，易于实现收发两端的精确时间定位及严格同步。综合考虑选择频域测量方法对信道传播特性进行研究，并结合现有实验设备，分别设计SISO和MIMO测量系统。随后，在短距离室内环境5.8GHz频段选取多个房间设计SISO实验方案研究路径损耗。在分析大量视距和非视距实验数据后，先对路径损耗指数n和频率f进行拟合，使用最小二乘法确定幂函数表达式进行拟合，，然后对路径损耗指数n和阴影衰落X进行概率统计分析，随后在此基础上建立频域和空域联合架构的路径损耗模型。研究表明路径损耗指数n随着频率的增高逐渐变小，路径损耗指数n和阴影衰落X两个参量的标准偏差都是频率相关参量且服从高斯分布。接着，在短距离室内环境中统计人员密度定义“闲时”和“忙时”场景，在2.6GHz频段设计SISO实验方案进行“闲时”和“忙时”测量，研究这两种场景中的路径损耗和多径传播统计特性。研究表明室内多人引起的附加路径损耗与收发天线间距离成线性关系δ·d，利用指数表达式可以定量描述均方根时延扩展与3-dB相干带宽之间的反比关系。统计研究发现“忙时”均方根时延扩展的统计中值比“闲时”有所增加，并且“忙时”3-dB相干带宽的统计分布服从正态分布，“闲时”与t分布相吻合。特别在非视距情形“忙时”场景中，到达接收端的多径分量不能很明显形成簇，多径分量的幅度和数目的最佳分布分别服从Nakagami分布和t分布。最后，在室内典型应用场景楼梯环境中选择2.6GHz频段进行2×2MIMO信道测量。研究发现在楼梯环境非视距情形中，路径损耗并不随收发天线间距离的增加而增加，通过定义关于楼梯台阶和平台的路径损耗变量对路径损耗进行经验建模。楼梯环境非视距情形中测量得到的MIMO信道容量接近于理想独立同分布瑞利信道容量，信道矩阵特征值的统计分布与Nakagami分布相吻合。然后在短距离室内视距情形进行混合极化2×2MIMO信道测量研究XPD，分析大量数据后采用线性函数对XPD-频率指数和距离进行拟合，在频域和空域建立XPD经验模型。研究表明XPD随着频率的增加轻微增加，而随着距离的增加缓慢减小，XPD-频率指数和XPD阴影衰落的标准偏差服从Nakagami分布。本学位论文研究为短距离室内无线通信系统中功率控制、节点设置和频谱使用等设计工作提供理论依据和实践基础。
[Abstract]:Propagation characteristics of wireless channel is to improve the performance of wireless communication system, a key factor in reducing cost. With the gradual development of commercial rapid application of wireless sensor networks and the fourth generation mobile communication system, short distance wireless communications business requirements and scenarios of increasingly rich. The short distance wireless communication because of indoor scenes, frequency, impact factors crowded the extent of the electromagnetic propagation environment is more complex, so it is urgent to indoor propagation characteristics of short distance wireless channel research. Based on the indoor office, stairs and other typical scenes, choose 5.8GHz and 2.6GHz band single input single output (SISO) and multiple input multiple output (MIMO) channel frequency measurement. Through the accumulation of a large number of measured focus on the analysis of data, path loss, multipath propagation, cross polarization discrimination (XPD) channel propagation characteristics, and combined with the environment, frequency, and other factors set up by staff The main research and contribution of this paper are as follows:
First, a detailed analysis and comparison of the current mature short-range indoor wireless channel measurement technique in time domain and frequency domain. Compared with the time domain measurement method, experimental equipment is simple and saves measuring time, and in a short distance in the indoor environment, easy to locate the precise time of sending and receiving ends and strict synchronization. Considering the choice of frequency measurement method study on the channel propagation characteristics, combined with the existing experimental equipment, design SISO and MIMO measurement system.
Then, in a short distance indoor environment 5.8GHz band selected a number of room design SISO experimental scheme of path loss. In the analysis of a large number of LOS and NLOS experimental data, first by fitting the path loss exponent n and frequency f, determine the power function for fitting using least square method, and then the path loss exponent n and shadow fading X statistical analysis, then established on the basis of frequency domain and spatial structure of the path loss model. The results show that the path loss exponent n with the frequency increases gradually, the standard deviation of the path loss exponent n and X shadow fading two parameters are frequency dependent parameters and obey the Gauss distribution.
Then, the statistical personnel density definition of "leisure" and "busy" scene in the short distance in the indoor environment, "leisure" and "busy" measurement in the range of 2.6GHz SISO experimental design scheme of path loss and multipath propagation statistics of the two scenarios. Studies show that many people caused by indoor additional path loss and the distance between the antenna is a linear relationship between the delta D, can quantitatively describe the RMS delay spread and coherence bandwidth of 3-dB inverse relationship between the expression index. Statistical study found "statistical median busy" RMS delay spread increased compared to "leisure", and "busy" coherent statistics 3-dB the bandwidth distribution obeys normal distribution, "leisure" and "t" distribution coincide. Especially in the case of non line of sight "busy" in the scene, at the receiving end of the multipath component can not be obviously forming clusters, the amplitude of the multipath components Nakagami distribution and t distribution are subordinate to the optimal distribution.
Finally, in the indoor environment in the typical application scenarios stairs 2.6GHz frequency range of 2 * 2MIMO channel measurement. The study found in the stair environment NLOS situation, increase the path loss doesn't increase with the distance between the antenna increases, through the empirical modeling of path loss path loss variables on the stairs and platform stairs environment definition. MIMO channel capacity is measured in the horizon case close to ideal i.i.d. Rayleigh channel capacity, distribution channel matrix eigenvalues and Nakagami distribution coincide. Then in the situation of short distance indoor Los 2 x 2MIMO mixed polarization XPD channel measurement, analysis of a large amount of data using the linear function to fit the XPD- frequency index and distance, establish XPD empirical model in frequency domain and spatial domain. The research showed that XPD increased slightly with the increase of frequency, and with the increase of the distance slowly The slow decrease, the standard deviation of the XPD- frequency index and the XPD shadow fading are subject to the Nakagami distribution.
This dissertation provides a theoretical and practical basis for the design of power control, node setting and spectrum use in a short distance indoor wireless communication system.

【学位授予单位】：南京邮电大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN92

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