Indoor Office Plan Environment and Layout-Based MmWave Path Loss Models for 28 GHz and 73 GHz

TL;DR

This study develops and compares site-specific large-scale path loss models for indoor office environments at 28 GHz and 73 GHz, emphasizing the effectiveness of close-in free space reference models for accurate and simple path loss prediction.

Contribution

It provides detailed, site-specific path loss models for different indoor office layouts at two mmWave frequencies, improving upon previous generalized models by separating layouts for better accuracy.

Findings

Close-in free space reference models are effective and simple for path loss prediction.

Site-specific models outperform generalized models in accuracy.

Modifications to existing 3GPP models are minimal for adaptation.

Abstract

This paper presents large-scale path loss models based on extensive ultra-wideband millimeter-wave propagation measurements performed at 28 GHz and 73 GHz in three typical indoor office layouts -- namely: corridor, open-plan, and closed-plan. A previous study combined all indoor layouts together, while this study separates them for site-specific indoor large-scale path loss model analysis. Measurements were conducted using a 400 megachips-per-second broadband sliding correlator channel sounder with 800 MHz first null-to-null RF bandwidth for 48 transmitter-receiver location combinations with distances ranging 3.9 m to 45.9 m for both co- and cross-polarized antenna configurations in line-of-sight and non-line-of-sight environments. Omnidirectional path loss values were synthesized from over 14,000 directional power delay profiles and were used to generate single-frequency and multi-frequency path loss models for combined, co-, and cross-polarized antennas. Large-scale path loss models that include a cross-polarization discrimination factor are provided for cross-polarized antenna measurements. The results show the value of using the close-in free space reference distance single and multi-frequency path loss models, as they offer simplicity (less parameters) in path loss calculation and prediction, without sacrificing accuracy. Moreover, the current 3GPP floating-intercept path loss model only requires a simple and subtle modification to convert to the close-in free space reference distance models.