Cityscape LoRa Signal Propagation Predicted and Tested Using Real-World Building-Data Based O-FDTD Simulations and Experimental Characterization

Abstract

The age of the Internet of Things (IoT) and smart cities calls for low-power wireless communication networks, for which the Long-Range (LoRa) is a rising star. Efficient network engineering requires the accurate prediction of the Received Signal Strength Indicator (RSSI) spatial distribution. However, the most commonly used models either lack the physical accurateness, resolution, or versatility for cityscape real-world building distribution-based RSSI predictions. For this purpose, we apply the 2D electric field wave-propagation Oscillator Finite-Difference Time-Domain (O-FDTD) method, using the complex dielectric permittivity to model reflection and absorption effects by concrete walls and the receiver sensitivity as the threshold to obtain a simulated coverage area in a 600 × 600 m2 square. Further, we report a simple and low-cost method to experimentally determine the signal coverage area based on mapping communication response-time delays. The simulations show a strong building influence on the RSSI, compared against the Free-Space Path (FSPL) model. We obtain a spatial overlap of 84% between the O-FDTD simulated and experimental signal coverage maps. Our proof-of-concept approach is thoroughly discussed compared to previous works, outlining error sources and possible future improvements. O-FDTD is demonstrated to be most promising for both indoors and outdoors applications and presents a powerful tool for IoT and smart city planners.

Experimental Visualization of the LoRaWAN Variable Correlation in Jakarta

“…This equation is made by measuring the signal strength at a certain distance from the gateway performance. Linear regression VOLUME 11, 2023 models the relationship between variables affecting RSSI, gateways, building distribution, SNR, and distance to increase the number of gateways or rearrange the frequency of data transmission [25], [34].…”

A Critical Review of the Propagation Models Employed in LoRa Systems

“…The simulation results show the received signal estimation for an area of 100 × 200 m 2 . Dão et al [ 63 ] predicted the received signal using the Oscillator Finite-Difference Time-Domain (O-FDTD) method. The authors state that this model may become unsustainable for LoRa maps much larger than 600 × 600 m 2 .…”