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无线电波在传播时,由于大气湍流的作用其相位会发生起伏,这是在高速铁路环境中无线通信常常遇到的问题。大气湍流造成不同部分大气的折射率起伏,使得不同部位空间电波具有不同的相移,这些相移导致随机起伏形状的等相面,这种相位形变导致波前到达角的起伏。到达角的起伏会影响通信的质量,尤其是在列车行驶时,到达角起伏会使得有用信号在传输给列车时产生偏移,从而丢失有用信号,既造成通信质量下降也造成能量利用率降低。研究到达角起伏对无线通信的影响,得到了用于描述强弱湍流条件下含有到达角起伏的信噪比的理论模型。同时数值模拟了到达角起伏信噪比和误码率的关系,对实际工程中提高无线通信系统质量具有一定的参考价值。
When radio waves are transmitted, their phases fluctuate due to turbulence in the atmosphere, a problem frequently encountered in wireless communications in high-speed railroad environments. Atmospheric turbulence causes refractive index fluctuations in different parts of the atmosphere, resulting in different phase waves in different parts of the space. These phase shifts lead to isosurfaces of random undulating shapes, which leads to fluctuations in the arrival angle of the wavefront. The fluctuation of the arrival angle will affect the quality of communication. In particular, when the train travels, the arrival fluctuation will cause the useful signal to be offset when it is transmitted to the train, thus losing the useful signal, resulting in the degradation of communication quality and energy utilization rate. The effect of arrival angle fluctuation on wireless communication is studied, and a theoretical model for describing the signal-to-noise ratio (SNR) with angle-of-arrival fluctuations under strong and weak turbulence conditions is obtained. At the same time, the numerical simulation of the relationship between the signal-to-noise ratio of arrival angle fluctuation and the bit error rate has certain reference value to improve the quality of wireless communication system in practical engineering.