Investigation of Prediction Accuracy, Sensitivity, and Parameter Stability of Large-Scale Propagation Path Loss Models for 5G Wireless Communications

TLDR

The models have recently been examined by standards bodies such as 3GPP for designing 5G systems in urban macrocell, microcell, indoor office, and shopping mall scenarios. This paper compares three large‑scale propagation path‑loss models—the alpha–beta–gamma (ABG), the close‑in (CI) free‑space reference distance, and the CI with frequency‑weighted path‑loss exponent (CIF)—across the entire microwave and millimeter‑wave spectrum. The authors evaluate the models using 30 measurement data sets covering 2–73 GHz and 4–1238 m, performing sensitivity analyses that show the CI and CIF models have comparable fit, more stable parameters, and lower prediction error than the ABG model. The study finds the CI model is best for outdoor environments and the CIF model for indoor scenarios, and both can be incorporated into 3GPP models with minimal changes.

Abstract

This paper compares three candidate large-scale propagation path loss models for use over the entire microwave and millimeter-wave (mmWave) radio spectrum: the alpha–beta–gamma (ABG) model, the close-in (CI) free-space reference distance model, and the CI model with a frequency-weighted path loss exponent (CIF). Each of these models has been recently studied for use in standards bodies such as 3rd Generation Partnership Project (3GPP) and for use in the design of fifth generation wireless systems in urban macrocell, urban microcell, and indoor office and shopping mall scenarios. Here, we compare the accuracy and sensitivity of these models using measured data from 30 propagation measurement data sets from 2 to 73 GHz over distances ranging from 4 to 1238 m. A series of sensitivity analyses of the three models shows that the physically based two-parameter CI model and three-parameter CIF model offer computational simplicity, have very similar goodness of fit (i.e., the shadow fading standard deviation), exhibit more stable model parameter behavior across frequencies and distances, and yield smaller prediction error in sensitivity tests across distances and frequencies, when compared to the four-parameter ABG model. Results show the CI model with a 1-m reference distance is suitable for outdoor environments, while the CIF model is more appropriate for indoor modeling. The CI and CIF models are easily implemented in existing 3GPP models by making a very subtle modification.