G.-F. Shao’s scientific contributions

To establish scattering models that match realistic street transmission scenarios for more efficient M2M mobile communication systems, existing models mainly focus on single-scattering and double-scattering,while for narrow urban street environment, single-scattering assumption is rather restrictive.To overcome this problem, a modified multi-bounced channel model based on EBSBM was provided, in which the concept of equivalent scattering point is assumed.The multi-bounced propagation paths are considered as an one-bounced ellipse scattering path and characteristics of the model were further analyzed. General formulations of several important parameters such as the probability density function (PDF) of the angle-of-departure(AOD), angle-of-arrival (AOA) and Doppler shift were derived, which were applied to the performance of multiple-input-multiple-output(MIMO)system employing a circular array antenna.Doppler frequency distribution was also taken into account.The results show good agreement with the previously models, which validates the rationality of proposed model. © 2017, Editorial Board of Journal on Communications. All right reserved.

A MIMO multi-antenna system of compact double uniform circular array (DUCA) in three dimensional directional frequency non-selective Rayleigh fading channel was analyzed and investigated. Equivalent network model of MIMO multi-antenna array considering MC effect was established, general expressions of correlations were derived and the relationship between correlations with and without MC was classfied. Then, the results were compared with general uniform linear array (ULA) and uniform circular array (UCA). It was concluded that the deployment of antennas plays a decisive role in correlations between antennas. The research has a good sense on designation of spatial massive MIMO multi-antenna array and system optimization. © 2016, Editorial Board of Journal on Communications. All right reserved.

The vehicular-to-vehicular (V2V) communications have recently received great attention due to some traffic telematic applications that make transportation safer, more efficient, and more environmentally friendly. Reliable traffic telematic applications and services require V2V wireless communication systems to be able to provide robust connectivity. To develop such wireless communication systems and standards, accurate channel models for the V2V communication systems are required. In this paper, a geometric street scattering channel model for a V2V communication system is presented under line-of-sight (LOS) and non-LOS (NLOS) propagation conditions. Starting from the geometric model, a stochastic reference channel model is developed, where the scatterers are uniformly distributed in rectangles in the form of stripes parallel to both sides of the street. A typical propagation scenario for the proposed model is presented, where the buildings and the trees can be considered as scatterers. Analytical expressions for the probability density functions (PDFs) of the angle-of-departure (AOD) and the angle-of-arrival (AOA) are derived. By obtaining the PDF of the total Doppler frequency, the Doppler power spectral density (PSD) and the autocorrelation function (ACF) of the proposed model are also investigated and computed, assuming that the mobile transmitter (MT) and the mobile receiver (MR) are moving, while the surrounding scatterers are fixed. In this respect the underlying radio channel model differs from the traditional cellular channels. We can draw the conclusion that the PDFs of AOD and AOA first increase and then decrease within a certain angle range; the Doppler power spectral density of the signal in the outdoor street environment presents the peak value in fmax. In addition, while the Rice distribution factor is larger, the value of the autocorrelation function increases relatively, the stability of the fluctuation increases correspondingly as well. To validate the reference channel model, its Doppler parameters are compared with those of a real-world measured channel for urban and rural areas. The numerical results show a good fitting of the theoretical results to the computer simulations. In the proposed geometry-based channel model, we not only study the influence of the street scatterers on the performance of V2V communication system, but also broaden the research of the channel modeling of outdoor wireless communication in turn. To evaluate the propagation characteristics of the outdoor V2V communication systems and the simulation of wireless communication system, this paper provides a powerful research tool.

The method of receiving the antenna array vector was proposed under the sparse angle domain and Doppler domain. The direction-of-arrival (DOA) estimation problem in the Doppler frequency domain was discussed to extract the relatively large impulse response at the band's effective range. The L2,0 estimation algorithm was used in the recovery process of DOA estimation, which took full advantage of the inherent sparse characteristics of DOA under the architecture of multi-antenna spectrum sensing. As for the unavoidable noise problem in the testing environment, the mean square error of DOA estimation was also analyzed for different noise distributions. Simulation results show that the computational complexity of the L2,0-DOA estimation algorithm in the frequency domain is low and the accuracy is high. Besides, the proposed method is not sensitive to noise and has high robustness.

This paper mainly deals with the indoor wireless propagation channel under line of sight (LOS) and non-line of sight (NLOS) propagation conditions, introducing the reference model and studing the design and simulation of modeling and the relevant statistical properties. This paper will present a comprehensive and improved indoor reference channel model based on a geometric scattering model. The reference channel model assumes that infinite number of scatterers will be uniformly distributed on the two-dimensional (2D) horizontal plane of a three-dimensional space. This paper also derives analytical expressions for the probability density function (PDF) of the angle-of-arrival (AOA), the Doppler power spectral density (PSD), and the temporal autocorrelation function (ACF) of an electromagnetic arrival signal; it also analyzes the influences of the important parameters of the functions. It presents a highly efficient sum-of-cisoids (SOC) channel simulation model from the unrealistic reference model, also proposes two efficient parameter computation methods for the design of sum-of-cisoids indoor channel simulation model and compares the computing performances of both. It is shown by simulation results that the statistical properties of the sum-of-cisoids channel simulation model match perfectly the reference channel model. It turns out that the indoor reference model can be approximated by an SOC channel simulation model. Meanwhile the channel simulation model can be well applied to evaluate the performance of indoor wireless communication systems. It also extends the research for indoor wireless channel modeling while reduces the realization expenditure.