| At present, general sensor arrays are often used in array antennas of 3G systems. However, it is proved that the introduction of polarization sensitive array can enhance accuracy in localization parameter estimation. Polarization sensitive array is a new pattern of array which is sensitive to the polarization information of electromagnetic signals. It has a broad application prospect in radar, communication, navigation and many other fields. The antenna arrays make it possible to joint angle and delay estimate (JADE)for the multipath propagation channel in mobile communications systems. However, it often occurs that two paths are close temporally or spatially, making their estimation difficult with classical method. Polarization diversity has been incorporated in many high resolution angles of arrival estimation algorithms to ameliorate their resolution performance. This is achieved by means of diversely polarized arrays, consisting of sensors such as crossed-dipoles sensors, which are sensitive to the polarization of the received signal. Such antennas are studied for future base station. Taking account for the polarization diversity is thus expected to improve the channel estimate. A few literatures have extended the work to include polarization in the area of joint space-time channel estimation. However, joint Angle, Delay and Polarization Estimation (JADPE) method based on the subspace MUSIC requires an expensive bi-dimensional search. Another JADPE method based on ESPRIT principle has improved channel estimation accuracy, however it can only obtain one-dimensional (1-D) angle parameter using a uniform linear array of crossed dipoles.In this paper, joint two-dimensional direction-of-arrival (DOA), delay and polarization estimation methods for TDD CDMA system are mainly studied. The previous joint estimation methods involved angle/delay or angle/polarization or one-dimensional angle/delay/polarization are first analyzed. These algorithms are analyzed and compared. Based on these, two kinds of joint multi-parameter estimation methods are proposed in this paper. First, we propose an effective method to estimate the two-dimensional angle, delay and polarization parameters in multipath channels for TDMA systems. Second, we propose a novel method to estimate the two-dimensional angle, delay and polarization parameters in multiuser and multipath channels for TDD CDMA systems. In this paper, the main research work are as follows:1. The DOA geometrical localization theory of mobile stations has described, then the classical one-dimensional and two-dimensional models and methods for DOA estimation are introduced. Joint angle/delay parameter estimation problem is studied, and the JADE method of joint parameter estimation in the literature is simulated and analyzed.2. Some polarization sensitive arrays based parameters estimation methods are introduced in this paper, and then the simulation analysis and comparison are given. The simulation result of JADE method is compared with that of JADPE method, the simulations show that the estimation accuracy of JADPE method is higher than that of JADE method.3. Based on the previous JADPE method of ESPRIT algorithm, the algorithm is expanded to two-dimension (2-D) angle in this paper. A novel and computationally efficient method is proposed for joint two-dimensional angle, delay and polarization estimation in multipath channels for TDMA systems. A uniform planar array of crossed dipoles is used to measure the signals of arrival. The method effectively estimate elevation, azimuth, delay and polarization via the shift invariance structure of ESPRIT algorithm and based on polarization diversity. Also, it avoids peak search and reduces the computational cost. The method can be applied in TDMA system that the paths are close spatially. The obtained space-time channel parameter is helpful for accurate three-dimensional (3-D) wireless localization.The simulations verify the effectiveness of the algorithm.4. The polarization sensitive array antennas are organically integrated with TDD CDMA systems in this paper, the problem of 2D angle/delay/polarization joint estimation parameters under multi-user and multi-path circumstances for TDD CDMA systems are studied. A new multi-parameter estimation algorithm is proposed. Using Orthogonal characteristic of user spread spectrum codes in TDD CDMA systems, the method can effectively achieve 2D angle/ delay/polarization joint estimation parameter for TDD CDMA systems in multi-user, multi-path circumstances. The simulations verify the effectiveness of the algorithm.The proposed method avoids peak search and reduces the computational cost. The method can be applied in TDD CDMA systems that the paths are close spatially. The obtained space-time channel parameter is helpful for accurate three-dimensional (3-D) wireless localization and SDMA. The simulations show that the use of the proposed method can provide high-resolution joint estimates.In the actual communication circumstances, users locate in three- dimensional space, if one-dimensional DOA is merely estimated, it can only confirm the existence of users in a plane, and can't realize accurately location positioning. The proposed two methods perform high-resolution estimations of two-dimensional angle, delay and polarization. Using ESPRIT algorithm enables to reduce the amount of calculation. The simulations show the advantages of space-time channel estimation based on polarization sensitive array.By the introduction of polarization sensitive array, the proposed methods improve the accuracy in localization parameter estimation and effectively estimate elevation, azimuth, delay and polarization in high-resolution. The two methods can be applied in TDMA and TDD CDMA systems, respectively.This paper is divided into six chapters, as follows:Chapter 1, introduction, the background and significance of the research project, the history and development of array signal processing techniques and multi-parameters joint estimation, the present status and the current problems are discussed.Chapter 2, basic knowledge, the principle of TDD CDMA system, the basic concept of polarization and its characterization, and the basic knowledge of matrix algebra are introdced, which is the basis of the follow-up chapters.Chapter 3, the DOA geometrical localization theory of mobile stations has described, the classical one-dimensional and two-dimensional models and methods for DOA estimation are introduced. Then joint angle/delay parameter estimation problem is analyzed, and the JADE method of joint parameter estimation in the literature is simulated and analyzed.Chapter 4, firtly, some polarization sensitive arrays -based parameters estimation methods are introduced, and the simulation and analysis of these methods are given. Based on studing on the previous algorithms, a novel method is proposed for joint two-dimensional angle, delay and polarization estimation in multipath channels for TDMA systems.Chapter 5, the polarization sensitive array antennas are organically integrated with TDD CDMA systems in this chapter, the problem of multi-parameter joint estimation under multi-user and multi-path circumstances for TDD CDMA systems are studied. A new algorithm of joint two-dimensional angle, delay and polarization parameters estimation based on polarization sensitive array are proposed. The method can be applied in TDD CDMA systems. The proposed method effectively performs the two-dimensional angle, delay and polarization estimations under multi-user and multi-path circumstances. The simulations verify the effectiveness of the algorithm.Chapter 6, the whole paper is summarized and the prospects are given. |
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