# An Empirical Air-to-Ground Channel Model Based on Passive Measurements in LTE

## TL;DR

This paper presents an empirical UAV air-to-ground channel model based on LTE measurements, analyzing multipath components and channel characteristics across various flight routes and heights.

## Contribution

It introduces a new empirical model for UAV LTE channels derived from extensive measurement data and high-resolution parameter estimation.

## Key findings

- Channel characteristics vary with height and distance
- Path loss and fading parameters are quantified
- A stochastic model for UAV LTE channels is developed

## Abstract

In this paper, a recently conducted measurement campaign for unmanned-aerial-vehicle (UAV) channels is introduced. The downlink signals of an in-service long-time-evolution (LTE) network which is deployed in a suburban scenario were acquired. Five horizontal and five vertical flight routes were considered. The channel impulse responses (CIRs) are extracted from the received data by exploiting the cell specific signals (CRSs). Based on the CIRs, the parameters of multipath components (MPCs) are estimated by using a high-resolution algorithm derived according to the space-alternating generalized expectation-maximization (SAGE) principle. Based on the SAGE results, channel characteristics including the path loss, shadow fading, fast fading, delay spread and Doppler frequency spread are thoroughly investigated for different heights and horizontal distances, which constitute a stochastic model.