Outdoor/indoor propagation modeling for wireless communications systems

The development of accurate propagation prediction models for outdoor/indoor communication environments is challenging and requires the development of innovative approaches to: (a) improve the accuracy of available models; (b) improve the computation efficiency; and (c) implement sufficiently general calculation procedures that would help in characterizing complicated and unique outdoor/indoor propagation features and environments. In this paper we describe a new propagation prediction model that addresses the above stated requirements. Specifically, the computational efficiency of the shooting-and-bouncing ray (SBR) was significantly improved by employing ray tracing techniques based on computer graphics approaches. The accuracy issue was addressed by employing a multi-grid FDTD method to calculate diffraction coefficients from unique and difficult to handle analytically indoor and outdoor structures. Additional improvement in accuracy was achieved by calculating reflection and transmission coefficients from walls of complex structures. Finally, the multi-grid FDTD method was used to characterize unique outdoor/indoor environments such as windows, doors, etc. The overall model was integrated, and propagation prediction results for typical outdoor/indoor communication environments are presented and compared with available data.