Zhang Ye-rong

Maximum MIMO capacity of Rice channel

In this paper, we investigate the capacity limits of Multiple-Input, Multiple-Output (MIMO) communication systems in Rice environments. Under this scenario, In Rice environments the channel response matrix is modeled as the weighted sum of the Line-of-Sight (LOS) and the Non-Line-of-Sight (NLOS) matrices. The LOS transmission matrix is used in a Ricean fading channel model which incorporates spatial correlation between the NLOS components, and performance is evaluated with respect to the average capacity. There are many factors impact the capacity, while the antenna spacing is considered in detail. We derive the criteria for the maximum theoretical capacity in terms of the positioning of the antenna elements in a way that can help in the design of optimal MIMO architectures. Different displacement of antennas can impact the channel rank, the capacity becomes larger when the rank increases. In this paper, we compare the Uniform Linear Arrays (ULAs) and the Uniform Circular Arrays (UCAs), in order to get the impact on capacity of the different displacement of the antennas.

Simulation and Analysis of Indoor Visible Light Propagation Characteristics Based on the Method of SBR/Image

The indoor visible light propagation characteristics are simulated and analyzed using the method of SBR/Image (shooting and bounding ray tracing/Image). A good agreement is achieved between the results simulated and the results given in published literature. So the correctness of the method has been validated. Some propagation parameters are obtained in the simulation, such as the indoor received power distribution, statistical distribution of phase angle of received power, RMS (root mean square) delay spread, direction of arrival, and Doppler shift. The foundation for the wireless network coverage of indoor visible light communication system is provided by the analysis of the above results.

Tropospheric refractivity profiling based on single ground-based GPS

Based upon the zenith delay and slant-path delay of single ground-based GPS receivers, the retrieving methods are developed to obtain atmospheric refractivity profiles, which include the statistical method based on zenith wet delay, the method based on refractivity profile model, and the neural network method based on slant-path delay. Using historical radiosonde data by these methods, the atmospheric refractivity profiles are retrieved by simulating, which show that the methods in this paper can obtain better results than the general meteorological models.

Efficient closed-form solution for target localization using TDOA measurements in the presence of sensor position errors

Abstract An efficient solution for locating a target was proposed, which by using time difference of arrival (TDOA) measurements in the presence of random sensor position errors to increase the accuracy of estimation. The cause of position estimation errors in two-stage weighted least squares (TSWLS) method is analyzed to develop a simple and effective method for improving the localization performance. Specifically, the reference sensor is selected again and the coordinate system is rotated according to preliminary estimated target position by using TSWLS method, and the final position estimation of the target is obtained by using weighted least squares (WLS). The proposed approach exhibits a closed-form and is as efficient as TSWLS method. Simulation results show that the proposed approach yields low estimation bias and improved robustness with increasing sensor position errors and thus can easily achieve the Cramer-Rao lower bound (CRLB) easily and effectively improve the localization accuracy.

Analysis for three-dimension model of radio propagation based on ray tracing

The characteristics of radio propagation is the important part of communication system.The polarization model is the crucial characteristics of radio propagation.The prapogation characteraction of indoor micorcelluar wireless radiowave has been studied based on the method of Ray tracing. Furthermore, the polarization characteraction of reflection has been analyzed and the three-dimension model of ray tracing has been founded. The prediction of field strength has been done with this model in indoor environment.A good agreement is achieved between the simulated results and the published results.

Relevance vector machine technique for the inverse scattering problem

A novel method based on the relevance vector machine (RVM) for the inverse scattering problem is presented in this paper. The nonlinearity and the ill-posedness inherent in this problem are simultaneously considered. The nonlinearity is embodied in the relation between the scattered field and the target property, which can be obtained through the RVM training process. Besides, rather than utilizing regularization, the ill-posed nature of the inversion is naturally accounted for because the RVM can produce a probabilistic output. Simulation results reveal that the proposed RVM-based approach can provide comparative performances in terms of accuracy, convergence, robustness, generalization, and improved performance in terms of sparse property in comparison with the support vector machine (SVM) based approach.