Extension of ITU-R Site-General Path Loss Model in Urban Areas Based on Measurements from 2 to 66 GHz Bands

Path loss in high frequency bands above 6 GHz is the most fundamental and significant propagation characteristic of IMT-2020. To develop and evaluate such high frequency bands, ITU-R SG5 WP5D recently released channel models applicable up to 100 GHz. The channel models include path loss models applicable to 0.5–100 GHz. A path loss model is used for cell design and the evaluation of the radio technologies, which is the main purpose of WP5D. Prediction accuracy in various locations, Tx positions, frequency bands, and other parameters are significant in cell design. This article presents the prediction accuracy of UMa path loss models which are detailed in Report ITU-R M.2412 for IMT-2020. We also propose UMa A’ as an extension model of UMa A. While UMa A applies different equations to the bands below and above 6 GHz to predict path loss, UMa A’ covers all bands by using the equations of UMa A below 6 GHz. By using the UMa A’ model, we can predict path loss by taking various parameters (such as BS antenna height) into account over a wide frequency range (0.5–100 GHz). This is useful for considering the deployment of BS antennas at various positions with a wide frequency band. We verify model accuracy by extensive measurements in the frequency bands from 2 to 66 GHz, distances up to 1600 m, and an UMa environment with three Tx antenna heights. The UMa A’ extension model can predict path loss with the low RMSE of about 7 dB at 2–26.4 GHz, which is more accurate than the UMa A and UMa B models. Although the applicability of the UMa A’ model at 66 GHz is unclear and needs further verification, the evaluation results for 66 GHz demonstrate that the antenna height may affect the prediction accuracy at 66 GHz. key words: 5G, propagation, path loss model, UMa, IMT-2020, Rep. ITUR M.2412