基于FDTD方法的无线信道衰落特性模拟研究

为了表述无线信道衰落的时变及远区分布特性，提出了利用时域有限差分(FDTD)方法研究由多径效应引起的时变无线信道衰落的方法。在此将无线信道的衰落建模为随机过程，而不是通常的确定性随机变量。首先基于Clarke统计模型，利用FDTD方法研究了时变无线信道的小尺度平坦衰落特征；然后利用Monte Carlo方法和FDTD方法产生了具有信道多普勒功率谱特性的色高斯随机过程，再基于无线信道的时变统计特性建模，用Suzuki模型研究了时变无线信道的快衰落；最后将无线信道衰落特性分布和理论分布做了比较，验证了方法的有效性。

Simulation of Fading Characteristics of Outdoor Time-variant Wireless Channel Using FDTD Method

In order to represent the time-variant and far zone electromagnetic fading characteristics of wireless channel, the methodology to investigate the fading behavior of time-variant wireless channel caused by multi-path effects using FDTD method is proposed. The fading characteristic of wireless channel is modeled as stochastic process rather than stochastic variable as used in usual method. At first, small-scale flatness fading characteristics of wireless channel is studied using FDTD method based on Clarke model. Then, the color-Gaussian stochastic processes with Doppler spectrum are generated with Monte Carlo and FDTD methods. The model of time-variant wireless channel based on its time-variant statistical fading behavior is presented, and Suzuki model is reviewed. After above work done, the fast fading characteristics of wireless channel can be analyzed comprehensively. At last, the comparison between the stochastic distribution obtained here and the theoretic distribution is made as to validate the effectiveness of proposed method.