A hybrid technique based on combining ray tracing and FDTD methods for site-specific modeling of indoor radio wave propagation

The paper presents a hybrid technique based on combining ray tracing and fi nite-difference time-domain (FDTD) methods for site-specific modeling of in door radio wave propagation. Ray tracing is used to analyze wide area and F DTD is used to study areas close to complex discontinuities where ray-based solutions are not sufficiently accurate. The hybrid technique ensures impr oved accuracy and practicality in terms of computational resources at the s ame time since FDTD is only applied to a small portion of the entire modeli ng environment. Examples of applying the method for studying indoor structu res and penetration of wave from outdoor to indoor are given at 2.4 GHz, Nu merical results are compared with known exact solutions or results of the f ull wave analysis or traditional ray model to demonstrate the accuracy, eff iciency, and robustness of the novel method. Numerical results are also com pared with reported measurement results for waves at 1.29 GHz penetrating a n external wall with metal-framed windows. Cumulative distributions of fiel d envelope obtained from the hybrid method show close resemblance to the Ra yleigh distribution, which conforms to the reported measurement results.