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

Motoharu SASAKI
Nobuaki KUNO
Naoki KITA
Koshiro KITAO
Tetsuro IMAI

IEICE TRANSACTIONS on Communications   Vol.E104-B    No.7    pp.849-857
Publication Date: 2021/07/01
Publicized: 2021/01/08
Online ISSN: 1745-1345
DOI: 10.1587/transcom.2020EBP3034
Type of Manuscript: PAPER
Category: Antennas and Propagation
5G,  propagation,  path loss model,  UMa,  IMT-2020,  Rep. ITU-R M.2412,  

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Path loss in high frequency bands above 6GHz 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 100GHz. The channel models include path loss models applicable to 0.5-100GHz. 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 6GHz to predict path loss, UMa_A' covers all bands by using the equations of UMa_A below 6GHz. 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 (0.5-100GHz). 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 66GHz, 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 7dB at 2-26.4GHz, which is more accurate than the UMa_A and UMa_B models. Although the applicability of the UMa_A' model at 66GHz is unclear and needs further verification, the evaluation results for 66GHz demonstrate that the antenna height may affect the prediction accuracy at 66GHz.