New Modeling Procedure for Indoor/Outdoor Propagation Environments in Micro- and Pico-Cell Wireless Communication Systems

[1022553]在这个提案中，PI恭敬地请求NSF支持开发一个详细的、准确的、计算效率高的传播模型，用于微单元和微单元系统中的无线通信。一种新的3D模型[或具有先进计算能力的2D模型，如垂直平面发射（VPL）技术]将在集成三种新的创新方法的基础上开发，以提高计算精度和计算效率。这包括以下用法：一种新的非结构三角形网格射线追踪方法（TGRM）在室外区域建模时显著节省了计算时间。初步结果表明，tgrm方法的CPU时间约为可见光射线跟踪方法的30%。基于均匀矩形网格法（URGM）的室内区域空间划分方法，假设反射/透射面与网格线重合。初步结果表明，所提出的室内传播区域均匀网格法的CPU时间约为可见光光线追踪法的14%。采用时域有限差分法计算复合墙体的反射系数和透射系数，并将这些系数合并到整个光线追踪代码中。这对于短期预测很重要，因为墙体材料特性的平均值或有效值可能会提供不准确的预测。多网格时域有限差分（multigrid Finite差分Time Domain，简称FDTD）代码也将用于计算难以解析建模的室内和室外物体的衍射系数。衍射系数结果将与实现上述建议程序的3D光线跟踪代码合并。衍射系数将以数据库和查找表的形式作为程序的一部分。提出的光线追踪代码的3D版本的开发将基于在TGRM程序中使用金字塔或四面体单元，以及在URGM方法中使用实体矩形单元。所提出的方法不涉及搜索算法，因此在计算效率显著提高是预期的。开发的新传播模型的总体结果将在犹他大学可用的60'x40‘x23’室内天线范围的比例模型上进行实验验证。比例模型将被仔细选择，以便一方面呈现感兴趣的物理结构，另一方面可以作为构建块，用于开发完全可理解的基于物理的传播模型。有了可用的实验设备（HP8510高达40 GHz），将有可能使用高达20的比例因子来模拟目前在地面无线通信系统中使用的更高频率（2GHz）的实际结构。除了基于确定性电磁传播模型的发展之外，PI还建议使用计算出的电磁功率分布模式来确定可用于无线通信系统模拟的统计参数。这包括覆盖范围、延迟扩展、误码率和到达角的计算。该项目将包括两名研究生，负责项目的仿真部分，另外一名研究生和一组大四本科生，负责构建比例模型，并进行项目的实验验证部分。

0102253IskanderWith this proposal the PI's respectfully request NSF support to develop a detailed, accurate, andcomputationally efficient propagation model for wireless communications in micro- and pico-cell systems.A new 3D model [or alternatively a 2D model with advanced calculation capabilities such as the vertical-plane-launch (VPL) technique] will be developed based on integrating three new and innovativeapproaches to improve calculation accuracy and increase the computational efficiency. This includes theuse of the following:1. A new unstructured triangular grid ray tracing method (TGRM) to provide significant savings incomputational time when modeling outdoor regions. Preliminary results show that CPU time for theTGRM method is approximately 30% of that of the visibility ray tracing.2. A space division procedure based on a uniform rectangular grid method (URGM) for indoor regionsand assuming that the reflection/transmission surfaces coincide with the grid lines. Preliminaryresults show that the CPU time for the proposed uniform grid method for indoor propagation regionsis approximately 14% of that of the visibility ray tracing method.3. An FDTD approach to calculate reflection (F ) and transmission (F ) coefficients of composite wallsand incorporate these coefficients in the overall ray tracing code. This is important for short rangesignal prediction where average or effective values of materials properties of walls may provideinaccurate predictions. The multigrid Finite Difference Time Domain (multigrid FDTD) code willalso be used to calculate diffraction coefficients from indoor and outdoor objects that are difficult tomodel analytically. Diffraction coefficient results will be incorporated with a 3D ray tracing code thatimplements the proposed procedures described above. Diffraction coefficients will be included as partof the program in the form of a database and look-up tables.4. The development of the 3D version of the proposed ray tracing code will be based on using pyramidalor tetrahedral cells in the TGRM procedure, and solid rectangular cells in the URGM method. Theproposed methods do not involve search algorithms and hence significant improvement in thecomputational efficiency is expected. The overall results from the developed new propagation model will be validated experimentally on scaledmodels in the 60'x40'x23' indoor antenna range available at the University of Utah. Scaled models will becarefully selected so as to present physical structures of interest, on the one hand, and an object that can beused as a building block towards the development of a fully understandable and physics-based propagationmodel, on the other. With the available experimental facilities (HP8510 up to 40 GHz), it will be possibleto use scale factors as large as 20 to model realistic structures at the higher frequencies (2GHz) presentlybeing used in terrestrial wireless communication systems.In addition to the development of the deterministic EM-based propagation model, the PI's propose to use the calculated EM power distribution pattern to determine statistical parameters that may be used in thesimulation of wireless communications systems. This includes calculations of coverage, delay spread, biterror rate, and angle of arrival. The project will involve two graduate students to work on the simulationpart of the project, and one additional graduate student together with a team of undergraduate seniorstudents to work on building the scaled models and conducting the experimental verification part of theproject.