Basic Research Related to Spread Use of Sensor Network

本研究项目研究了传感器网络物理层中无线通信在沙漠或森林丘陵等粗糙表面上的传播特性。在数值分析中，我们使用了FVTD方法，并研究了粗糙面参数，如粗糙面的平均高度和相关长度对传输特性的影响。其次，我们提出了一种简化形式的FVTD方法的外推吸收边界条件(EABC)，以减少应用于沿粗糙表面传播问题时的计算机内存。在此基础上，提出了一种估计接收衰落电磁波包络统计特性的算法，该算法通常在城市地区或住宅中观察到。该算法已被应用于一些实验和理论数据，以估计入射波与散射波之比。

The present research project studied propagation characteristics along rough surfaces such as a desert or a forest hill in connection with wireless communications in the physical layer of a sensor network. In the numerical analyses, we have used the FVTD method, and we have investigated the effect of the rough surface parameters, such as average height and correlation length of the rough surface, on the propagation characteristics. It has been demonstrated that the attenuation characteristics are well expressed in terms of power of the straight distance from source to destination.Second, we have proposed an Extrapolated Absorbing Boundary Condition (EABC) for the FVTD method in a simplified form in order to reduce computer memory when applying it to propagation problems along rough surfaces. It has been shown that the EABC is effective for the numerical analysis of some electromagnetic problems which require much computer memory.Third, we have proposed an algorithm to estimate statistic properties of the envelope of received fading electromagnetic waves usually observed in urban areas or in houses. The algorithm has been applied to some experimental and theoretical data to estimate the incident wave to scattered wave ratio.