Radio wave propagation modeling by combining ray-tracing with integral representations

无线电波传播建模对于移动的通信和雷达变得越来越重要。移动的通信朝着诸如具有非常大量天线的大规模MIMO的技术发展。雷达传感和成像在我们的日常生活中无处不在。特别是在实现自动驾驶解决方案时，通过模拟在现实环境中生成准确的雷达数据至关重要，以避免在无休止的驾驶场景中收集雷达测量数据。光线跟踪显然是复杂环境中无线电波传播建模的最有效方法。然而，它仍然具有某些缺点，这使得它难以在微波和毫米波频率下使用。特别是在需要多次后续衍射的情况下，高频定位的假定优势可能成为严重的缺点，因为许多（后续）衍射可能导致大量的计算时间，甚至更糟的是，多次衍射计算的准确性通常非常差。这种精度下降的主要原因是，通过评估边缘上的仅一个点的衍射系数的局部衍射计算不适合于现实环境的处理。申请人最近建立了结合互易定理的双向射线追踪方法，其已经可以减轻常规单向射线追踪的一些缺点。这种方法的一个关键要素是包括积分表示，以克服传统的基于射线的传播建模的严格的本地化要求。该策略应在拟议项目中得到扩展，在该项目中，应根据惠更斯原理和等效原理并结合已确立的互惠考虑因素对复杂的传播场景进行划分。各个分区将被处理的光线跟踪和分区之间的相互作用得到相应的积分表示的基础上。特别是对于雷达场景，该程序将允许解耦雷达目标本身和传播环境的电磁建模。将制定混合方法的配方，并在图形处理单元（GPU）上实现强大的计算算法，验证和优化，其中将考虑各种复杂性的测试和验证方案。

Radio wave propagation modelling becomes increasingly important for mobile communications and radar. Mobile communications develops towards techniques such as massive MIMO with very large numbers of antennas. Radar sensing and imaging become ubiquitous in our daily lives. In particular towards the realization of autonomous drive solutions it is of paramount importance to generate accurate radar data in realistic environments by simulation, in order to avoid the collection of radar measurement data in endless drive scenarios. Ray-tracing is clearly the most powerful approach for radio wave propagation modelling in complex environments. However, it has still certain drawbacks, which make it difficult to use at microwave and millimeter wave frequencies. Especially in scenarios, which require several subsequent diffractions, the supposed advantage of high-frequency localization can become a severe drawback, since many (subsequent) diffractions can lead to an enormous amount of computation time and, even worse, the accuracy of multiple diffraction computations is often very bad. The major reason for this accuracy drop is that the localized diffraction computation by evaluating the diffraction coefficients for just one point on an edge is not suitable for the treatment of realistic environments. The applicant has recently established a bidirectional ray-tracing approach combined with the reciprocity theorem, which can already relieve some of the shortcomings of the conventional unidirectional ray-tracing. A key element of this approach is the inclusion of integral representations in order to overcome the stringent localization requirements of the traditional ray-based propagation modelling. This strategy shall be extended in the proposed project, where complex propagation scenarios shall be partitioned based on the Huygens’ and equivalence principles in combination with the already established reciprocity considerations. The individual partitions will be treated by ray-tracing and the interactions between the partitions are obtained based on the corresponding integral representations. In particular for radar scenarios, the procedure will allow to decouple the electromagnetic modelling of the radar targets itself and of the propagation environment. The formulations of the hybrid approach will be worked out and powerful computation algorithms on graphical processing units (GPUs) will be implemented, validated, and optimized, where test and validation scenarios of various complexities will be considered.