Sensing-Enhanced Handover Criterion for Low-Altitude Wireless Network (LAWNs)

TL;DR

This paper introduces a sensing-enhanced handover criterion for low-altitude wireless networks using ISAC signals, significantly reducing unnecessary handovers and improving reliability in drone communication environments.

Contribution

It proposes a novel joint handover criterion integrating sensing information from ISAC signals with RSRP, tailored for drone-based low-altitude wireless networks.

Findings

Reduces average handover region length by 75.20% at high SNR

Improves handover activation probability by 76.31%

Outperforms traditional RSRP-based criteria in dynamic environments

Abstract

With the rapid growth of the low-altitude economy, the demand for cellular-enabled low-altitude wireless networks (LAWN) is rising significantly. The three-dimensional mobility of drones will lead to frequent handovers (HOs) in cellular networks, while traditional reference signal received power (RSRP)-based criteria may fail to capture the dynamic environment, causing redundant HOs or HO failures. To address this issue and motivated by the underutilization of sensing information in conventional HO mechanisms, we propose a novel HO activation criterion for drone systems that integrates both sensing parameters provided by integrated sensing and communication (ISAC) signals and RSRP. First, we construct an ISAC signal model tailored for low-altitude scenarios and derive the Cram\'er--Rao lower bound for sensing distance estimation. Subsequently, we propose a novel joint HO criterion that extends the conventional RSRP-based method by integrating sensing information from ISAC signals, enabling more reliable HOs in dynamic drone environments. Simulation results show that the joint HO criterion outperforms the baseline RSRP-based criterion under different signal-to-noise ratio (SNR) and sensing pilot ratio conditions. Particularly, when the SNR exceeds 0dB and the sensing pilot ratio is 20%, the proposed joint HO criterion reduces the average HO region length by 75.20% and improves the activation probability by 76.31%.