【作者】 唐宗礼；

【导师】 张曙；

【作者基本信息】 哈尔滨工程大学 ， 通信与信息系统， 2005， 博士

【摘要】 智能天线作为第三代移动通信中的关键技术,目前正得到迅速的发展,已经是当前通信技术中的研究热点。通过有效的自适应算法,智能天线能在期望信号的方向形成最大的处理增益,而在强干扰位置形成零陷,从而有效的提高系统性能。但到目前为止,智能天线的的具体实现还存在较多的问题,其中主要表现为两个方面。一方面,智能天线的现有算法都是在理想情况下得到的,试验的结果也是在室内环境下的数据,而实际系统往往存在很多误差,这些误差的存在大大影响系统的输出效果。另一方面,由于智能天线处理的是天线阵列,因而需要处理的数据量很大,对处理器的速度要求非常高。研究者一方面在提高算法的稳健性,另一方面也在积极的研究快速的算法。事实上,这两个方面的研究内容构成了目前智能天线的研究热点和难点。 本文在分析智能天线及其信道模型的基础上,对均匀线阵和均匀圆阵分别进行了研究,通过巧妙的构造二阶统计量,最后得到几种新的DOA估计算法。并且较有效的降低了估计的运算量。 首先文章分析了智能天线及其矢量信道模型,针对目前研究较多的几何单反射圆周模型和几何单反射椭圆模型,详细推导了该模型中的各种参数,对在该模型下的DOA估计的意义进行了说明,为文章论述的开展做了预先的准备。 针对均匀线阵的DOA估计中存在SVD分解的缺点,本文通过对均匀线阵中任意相邻的三个阵元之间构造二阶统计量,并通过数学运算,得到DOA估计的闭式解。该闭式解可以在噪声特性为空间白噪声的情况下,工作于较低信噪比的情况,并有效的降低了运算量。 均匀圆阵由于其平面阵列的结构特点,在实际使用时有很多的优点,比如在全方向内形成的波束主瓣基本相同,能估计信号的二维达到角等,本文针对均匀圆阵,构造了一种新的二维DOA估计算法,并得到了期望信号方位角和俯仰角的闭式结果。理论分析表明,该算法可以有效的工作于低信噪比环境下,并且运算量很小。文章针对该算法的应用环境也做了说明。更多还原

【Abstract】 Smart antenna is one of the key techniques in 3G mobile communication, its development is very fast, and it is for the moment the hotspot of research. Adopting the suitable adaptive algorithm, smart antenna may obtain the maximum processing gain in the direction of the desired signal and null the strong interferer, so can enhance the performance of the system. Up to date, many problems need to be resolved in the implement of the smart antenna; these problems include primarily two categories. First, the existing algorithms about smart antenna are applicable to the perfect case. The obtained results are based on the computer simulation, but there are many errors in the real system and those errors influence the performance of the system to some enormous extant. Second, smart antenna signal processing is multi-dimensional signal processing, hence, the computation effort is very large, and need the higher speed DSP device. The researchers are actively studying the fast algorithm; on the other hand, they are studying how to increase the robustness of the algorithm. In fact, these two cases are presently the difficulty and the hotspot.This thesis analyzes the smart antenna and the channel model, and studies the uniform linear array and uniform circular array respectively, in the end, presents several new DOA estimation algorithm by constructing felicitously the second order statistics. Those algorithms reduce efficiently the computation effort of the estimation.Above all, the thesis analyzes the smart antenna and the vector channel model, derives detailedly various parameter of the model aiming at GSBCM and GSBEM, describes the sense of the DOA estimation about these model, prepare for the expansion of the thesis.Aiming at the shortcoming that need to perform SVD decomposition about ULA DOA estimation, the thesis presents the closed-form solution of the DOA estimation by constructing second order statistics in the arbitrary adjacent threeelements and perfoming mathematical operator. When SNR is very low, this closed-form solution can work perfectly in the presence of the spatial white noise and reduce the computation effort.Because the circular array is planar array, it has many advantages. For example the pattern of the circular array does not change as the direction of main lobe change and can estimate the two-dimensional DOA just to name a few. The thesis presents a novel two-dimensional DOA algorithm and obtains the closed-form solution of the azimuth and elevation angle of the desired signal. Theory analysis illustrates the method can operate perfectly, when SNR is very low. The computation effort is very small. The thesis specifies the applicable scenario of the method.The thesis derives the two-dimension DOA estimation algorithm based on variance matrix in the uniform circular array and resolves the problem in the two-dimension DOA estimation using variance matrix by constructing second-order statistics. The computer simulation verifies the efficiency of the method proposed by this thesis.更多还原