Path loss prediction analysis by ray tracing approach for NLOS indoor propagation

Abstract

The performance of the wireless systems is significantly influenced by multiple reflections in addition to diffraction and scattering propagation effects. The geometric and dielectric properties of the obstacles vary to a large extent in the indoor environment and it is required to model these propagation effects accurately. In this paper, indoor mobile signal strengths are recorded at 2.4 GHz frequency for a wide corridor with glass partitions, in the premises of Deccan College of Engineering and Technology at Hyderabad. The data is collected within 10m from the source of the wireless router. Path loss is extracted from the measurements and comparisons are made with results derived by using two ray, four ray, six ray, and ten ray model. An N ray model is also implemented. Further a generalised ray tracing model is proposed by including diffraction and scattering effects. Diffraction losses due to the partitions are modelled using Fresnel-Kirchoff diffraction parameter and the spreading loss due to scattering is estimated using radar bi static equation. The performance of the proposed ray tracing model is evaluated by computing the error between the measurements and the proposed model. The least values of the error metrics for the proposed model indicate its accuracy in predicting the path loss for Wireless LAN mobile signals in the indoor environment.