# Calibration of NYURay, a 3D mmWave and sub-THz Ray Tracer using Indoor, Outdoor, and Factory Channel Measurements

## TL;DR

This paper introduces NYURay, a calibrated 3D mmWave and sub-THz ray tracer, which accurately predicts wireless channel characteristics across various environments using a simple calibration method based on material reflection coefficients.

## Contribution

The paper presents a novel low-complexity calibration procedure for NYURay that models material reflection coefficients as angle-independent, enabling accurate predictions across diverse environments.

## Key findings

- Prediction error standard deviation < 3 dB indoors
- Prediction error standard deviation < 2 dB outdoors and in factories
- Calibration method effective across multiple frequency bands and environments

## Abstract

Ray tracing is a powerful tool that can be used to predict wireless channel characteristics, reducing the need for extensive channel measurements for channel characterization, evaluation of performance of sensing applications such as position location, and wireless network deployment. In this work, NYURay, a 3D mmWave and sub-THz ray tracer, is introduced, which is calibrated to wireless channel propagation measurements conducted at 28, 73, and 140 GHz, in indoor office, outdoor, and factory environments. We present an accurate yet low-complexity calibration procedure to obtain electrical properties of materials in any environment by modeling the reflection coefficient of building materials to be independent of the angle of incidence, a simplification shown to be quite effective in [1] over 30 years ago. We show that after calibration, NYURay can accurately predict individual directional multipath signal power. The standard deviation in the error of the directional multipath power predicted by the ray tracer compared to the directional measured power was less than 3 dB in indoor office environments and less than 2 dB in outdoor and factory environments.