LTE下行链路信道估计技术研究
发布时间：2018-11-13 15:49
【摘要】：LTE-Advanced系统是当前国际上公认的第四代移动通信(即4G)系统。LTE-Advanced数据传输速率更快,系统容量进一步提高,峰值速率显著增加,系统的频谱利用率更高。LTE-Advanced系统采用的关键技术有正交频分复用(OFDM)、多输入多输出(MIMO)等技术。 高速移动环境下,LTE-Advanced系统信道在短时间内会发生快速的变化,精确的信道估计技术对于接收端准确恢复发送信号必不可少。 本文首先分析信道估计技术的国内外研究现状,介绍了LTE下行链路物理信道的结构、LTE下行链路基带信号的处理流程以及关键技术。在对高速移动场景下的衰落信道特性进行分析的基础上,研究基扩展拟合时频双选信道模型,介绍复指数基、离散余弦变换基、多项式基、离散卡-洛基函数、椭圆基函数以及结合过采样技术的修正复指数基等常见的基扩展模型,仿真分析各个基扩展模型归一化均方误差以及拟合实际信道的性能。 随后,搭建LTE下行链路基带系统信道估计仿真平台,介绍了LTE系统无线帧结构,导频结构及导频序列生成,LTE下行信号处理流程的发射系统模块、物理信道与LTE下行链路接收系统模块,仿真验证平台的准确性。 其次,在LTE下行链路仿真平台上分别仿真分析了不同发送接收天线、不同MIMO检测算法、不同调制方式、不同信道模型场景下以及不同终端移动速度下,基于导频的LS、LMMSE、SVD-MMSE和简化SVD信道估计算法性能,仿真分析得到LS信道估计算法的估计性能最差,LMMSE估计算法和简化SVD算法性能最优。 最后,研究高速移动环境下的信道估计算法性能仿真,仿真结果表明在高速移动场景下,多天线多径LTE下行链路中基扩展模型可以更好的拟信道,信道估计算法性能比LS算法更优。特别在分析研究120km/h和350km/h两种不同终端移动速度下,基扩展信道估计性能的变化,发现终端移动速度的变化对估计性能有很大的影响。
[Abstract]:LTE-Advanced system is currently recognized as the fourth generation mobile communication (4G) system in the world. The data transmission rate of LTE-Advanced is faster, the system capacity is further increased, and the peak rate is increased significantly. The key techniques used in LTE-Advanced system include orthogonal Frequency Division Multiplexing (OFDM),) multiple input multiple output (MIMO) and so on. In high speed mobile environment, the channel of LTE-Advanced system will change rapidly in a short time, and accurate channel estimation technology is essential for the receiver to recover the transmitted signal accurately. In this paper, firstly, the research status of channel estimation technology at home and abroad is analyzed, and the structure of LTE downlink physical channel, the processing flow of LTE downlink baseband signal and the key technology are introduced. Based on the analysis of fading channel characteristics in high-speed mobile scene, the time-frequency double-selective channel model based on extended basis fitting is studied, and the complex exponential basis, discrete cosine transform basis, polynomial basis, discrete card-Lowe function are introduced. The elliptic basis function and the modified complex exponential basis based on over-sampling technique are used to simulate and analyze the normalized mean square error of each base expansion model and the performance of fitting the actual channel. Then, the channel estimation simulation platform of LTE downlink baseband system is built, and the wireless frame structure, pilot structure and pilot sequence generation of LTE system, the transmitting system module of LTE downlink signal processing flow are introduced. Physical channel and LTE downlink receiving system module, simulation verify the accuracy of the platform. Secondly, different transmit and receive antennas, different MIMO detection algorithms, different modulation methods, different channel model scenarios and different terminal moving speeds are simulated on the LTE downlink simulation platform, and the LS,LMMSE, based on pilot frequency is analyzed respectively. The performance of SVD-MMSE and simplified SVD channel estimation algorithms is the worst, and that of LMMSE estimation algorithm and simplified SVD algorithm is the best. Finally, the performance simulation of channel estimation algorithm in high-speed mobile environment is studied. The simulation results show that the base expansion model in multi-antenna multipath LTE downlink is better for quasi-channel under high-speed mobile environment. The performance of channel estimation algorithm is better than that of LS algorithm. Especially, the performance changes of base spread channel estimation are analyzed and studied under two different terminal moving speeds of 120km/h and 350km/h. It is found that the change of terminal moving speed has a great influence on the estimation performance.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.5
本文编号：2329601
[Abstract]:LTE-Advanced system is currently recognized as the fourth generation mobile communication (4G) system in the world. The data transmission rate of LTE-Advanced is faster, the system capacity is further increased, and the peak rate is increased significantly. The key techniques used in LTE-Advanced system include orthogonal Frequency Division Multiplexing (OFDM),) multiple input multiple output (MIMO) and so on. In high speed mobile environment, the channel of LTE-Advanced system will change rapidly in a short time, and accurate channel estimation technology is essential for the receiver to recover the transmitted signal accurately. In this paper, firstly, the research status of channel estimation technology at home and abroad is analyzed, and the structure of LTE downlink physical channel, the processing flow of LTE downlink baseband signal and the key technology are introduced. Based on the analysis of fading channel characteristics in high-speed mobile scene, the time-frequency double-selective channel model based on extended basis fitting is studied, and the complex exponential basis, discrete cosine transform basis, polynomial basis, discrete card-Lowe function are introduced. The elliptic basis function and the modified complex exponential basis based on over-sampling technique are used to simulate and analyze the normalized mean square error of each base expansion model and the performance of fitting the actual channel. Then, the channel estimation simulation platform of LTE downlink baseband system is built, and the wireless frame structure, pilot structure and pilot sequence generation of LTE system, the transmitting system module of LTE downlink signal processing flow are introduced. Physical channel and LTE downlink receiving system module, simulation verify the accuracy of the platform. Secondly, different transmit and receive antennas, different MIMO detection algorithms, different modulation methods, different channel model scenarios and different terminal moving speeds are simulated on the LTE downlink simulation platform, and the LS,LMMSE, based on pilot frequency is analyzed respectively. The performance of SVD-MMSE and simplified SVD channel estimation algorithms is the worst, and that of LMMSE estimation algorithm and simplified SVD algorithm is the best. Finally, the performance simulation of channel estimation algorithm in high-speed mobile environment is studied. The simulation results show that the base expansion model in multi-antenna multipath LTE downlink is better for quasi-channel under high-speed mobile environment. The performance of channel estimation algorithm is better than that of LS algorithm. Especially, the performance changes of base spread channel estimation are analyzed and studied under two different terminal moving speeds of 120km/h and 350km/h. It is found that the change of terminal moving speed has a great influence on the estimation performance.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.5
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