Path loss estimation in 3D environments using a modified 2D Finite-Difference Time-Domain technique

Interest has been growing regarding the use of Wireless Sensor Networks (WSNs) for monitoring and assessing the conditions of infrastructure such as tunnels, bridges and water supply systems. Therefore it is vitally important for us to understand the radio propagation characteristics, especially the Path Loss of these specific environments prior to the deployment of a WSN. The Finite-Difference Time-Domain (FDTD) technique using the Yee algorithm [1] is well-known for its ability to produce accurate predictions of received signal levels. However, when facing the challenges of large-scale systems e.g., nodes located in fire hydrants, tunnels, etc, the computational requirements of this technique become overwhelming, particularly for 3D simulations. In this paper, based on comparisons between conventional 2D FDTD simulations and existing analytical models of Free Space Path Loss and Plane Earth Path Loss, we propose a Modified 2D FDTD method. A unique path loss correction factor is determined. It converts a 3D signal source into an equivalent 2D source and provides path loss results which are identical to those of a full 3D model in both free space and plane earth scenarios.