无线电波传播的随机游动模型及其应用

Random Walk Model of Radio Wave Propagation and its Applications

使用二维渗流网格描述城市无线传播环境,使用随机游动过程对在该环境中传播的无线电波进行建模,在此基础上分别使用Bernoulli等概率试验和最大熵原理方法计算随机射线在传播空间的概率分布。建立无线电波传播的概率模型后,得到做随机游动的电磁射线在二维随机网格信道中平均接收功率的解析表达式,结果发现信道中平均接收功率随距离呈指数函数形式衰减。对该解析公式的数值特性进行研究,表明其计算精度非常高。对接收功率随环境参数的变化规律进行分析,使用实验数据验证本文得到的平均接收功率模型,证实理论值与实验值吻合较好。

Two-dimensional percolation lattices are used to describe urban wireless propagation environment, and random walks are employed to model radio wave propagation. The probability that a generic ray undergoes certain number of collisions at specific spatial location is derived from the Bernoulli equiprobable experiments and the maximum entropy principle. After a probabilistic model of electromagnetic wave propagation is constructed,the analytic closed form of mean received power of electromagnetic rays undergoing random walks at each location is obtained in 2-dimensional channels,which obeys an exponential function of distance. Numerical analysis is used to discuss the precision of the analytic form, which is very satisfied in very wide ranges of parameters. The dependence of received power on geometrical parameters of lattices is also investigated. The results are validated by comparison with experimental data,and the theoretic results correspond well with the experimental data.