基于蒙特卡罗方法的多散射修正模型

A modified multiple-scattering model based on Monte Carlo method

针对现有的基于蒙特卡罗方法的非视线传输模型的不足和局限性,提出了基于蒙特卡罗方法的多散射修正模型,给出了模型的数学描述。利用坐标系变换方法,得出了光子迁移的坐标递推公式。设计了接收判断机制,给出了到达时间的计算公式。通过跟踪大量光子的随机迁移,验证了光子传输的多散射现象。绘制了接收天线功率密度曲线,模拟了脉冲展宽效应。比较结果表明,在满足单散射近似的条件下,该模型与Luett-gen单散射模型吻合较好;在不满足单散射近似条件时,该模型得出的接收功率密度大于Luettgen单散射模型的接收功率密度,分析了结果的正确性,并指出了现有模型信道零延迟的错误。理论分析表明,模型能准确反映信道的时延特性。

As for the limitation of the existing NLOS propagation model based on Monte Carlo method, a modified multiple-scattering model based on Monte Carlo method was presented, and the mathematical description of the model was made. The recurrence formula of photon migration was deduced through the method of coordinate transformation. The receiving judgment mechanism was designed, and the calculating formula of arrival time was obtained. The multiple-scattering phenomenon of photon transmission was verified via tracing the random migration of enormous number of photons. The curve of power density of receiving antenna was plotted and the pulse stretching effect was simulated. The comparison shows that the model proposed is compatible well with Luettgen single-scattering model under the conditions of single-scattering approximation. When the single-scattering approximation is invalid, the receiving power density of the model presented is larger than that of Luettgen single-scattering model. Based on analyzing the correctness of the result and pointing out the zero- delay error of the existing propagation model, the theoretical analysis indicates that the model exactly reflect the characteristics of transmission delay.