Site-Specific Propagation Loss Prediction in 4.9 GHz Band Outdoor-to-Indoor Scenario

Abstract

Owing to the widespread use of smartphones and various cloud services, user traffic in cellular networks is rapidly increasing. Especially, the traffic congestion is severe in urban areas, and effective service-cell planning is required in the area for efficient radio resource usage. Because many users are also inside high buildings in the urban area, the knowledge of propagation loss characteristics in the outdoor-to-indoor (O2I) scenario is indispensable for the purpose. The ray-tracing simulation has been widely used for service-cell planning, but it has a problem that the propagation loss tends to be underestimated in a typical O2I scenario in which the incident radio waves penetrate indoors through building windows. In this paper, we proposed the extension method of the ray-tracing simulation to solve the problem. In the proposed method, the additional loss factors such as the Fresnel zone shielding loss and the transmission loss by the equivalent dielectric plate were calculated for respective rays to eliminate the penetration loss prediction error. To evaluate the effectiveness of the proposed method, we conducted radio propagation measurements in a high-building environment by using the developed unmanned aerial vehicle (UAV)-based measurement system. The results showed that the penetration loss of direct and reflection rays was significantly underestimated in the ray-tracing simulation and the proposed method could correct the problem. The mean prediction error was improved from 7.0 dB to −0.5 dB, and the standard deviation was also improved from 8.2 dB to 5.3 dB. The results are expected to be utilized for actual service-cell planning in the urban environment.

V2I Propagation Loss Predictions in Simplified Urban Environment: A Two-Way Parabolic Equation Approach

“…The advantages of the RT method also include the interpretability of the computation results. The RT method is used in indoor [13], outdoor [14] and outdoor-to-indoor [15] propagation scenarios. There are several studies [16,17] dedicated to the application of the RT method to V2I radio channel modeling in urban areas.…”

Antennas and Propagation Aspects for Emerging Wireless Communication Technologies

“…Saito et al [8] propose an extension of the ray tracing simulation method for a typical outdoor-to-indoor (O2I) scenario, in which the incident radio waves penetrate indoors through building windows. The presented method consists of the Fresnel zone shielding loss calculation and the transmission loss calculation by equivalent dielectric plate.…”