Development and Validation of a Lightweight Physics-Based Indoor Cellular Propagation Simulator

Cellular calls and mobile data became unstable at locations in the author’s dormitory while outdoor signal remained strong. It was hypothesized that indoor cellular signal strength could be simulated with useful accuracy using a lightweight model utilizing extended high school physics equations without an electromagnetic simulator. To test this hypothesis, the author developed an indoor cellular propagation simulator using ray tracing and extended high school physics equations. The program converted the dorm floor plan into a calculation grid and modeled distance loss and material-crossing loss. Building materials were identified with dormitory supervisors’ assistance, and the floor plan was measured and modeled with Blender and FreeCAD. Signal strength was measured five times at nine indoor and two outdoor locations with the same handset, carrier, and SIM. For validation, the measurements were compared with calculations from the program and reference results from an electromagnetic simulator. The program produced a mean absolute error (MAE) of 6.57 dB, versus 7.78 dB for the simulator, and placed the two weakest measured locations among its three lowest estimates. These results suggest that extended high school physics can simulate indoor cellular propagation with useful accuracy and assist students in identifying weak-reception areas within dormitories.