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

2025-05-22

AI Summary

In low-altitude wireless networks (LAWN), frequent redundant handovers and handover failures arise from the three-dimensional mobility of unmanned aerial vehicles (UAVs), rendering conventional RSRP-based handover criteria inadequate for characterizing dynamic channel conditions. To address this, we propose, for the first time, an ISAC (integrated sensing and communication)-enabled handover activation criterion that incorporates sensing-derived distance estimates into handover decision-making. We establish an ISAC signal model tailored to low-altitude scenarios and derive its theoretical Cramér–Rao lower bound (CRLB) for distance estimation accuracy. By jointly leveraging RSRP and sensing distance in handover triggering, our method achieves a 49.97% reduction in average handover zone length and a 76.31% increase in handover activation probability under SNR > 0 dB and 20% sensing pilot overhead—significantly outperforming the RSRP-only baseline. The core contribution lies in establishing a dynamic, sensing–communication co-driven handover decision metric.

Technology Category

• Intelligent Robots: State Estimation
• Planning, Routing, and Scheduling: Scheduling under Uncertainty
• Reasoning under Uncertainty: Sequential Decision Making

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications
• Security and Privacy: Large-scale security measurements
• Search and Retrieval-Augmented AI: Web evaluation methodologies and metrics

Abstract

With the rapid growth of the low-altitude economy, the demand for cellular-enabled low-altitude wireless networks (LAWNs) is rising significantly. The three-dimensional mobility of unmanned aerial vehicles (UAVs) 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 UAV 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 UAV 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 SNR is greater than 0dB and the sensing pilot ratio is 20%, the proposed joint HO criterion reduces the average HO region length by 49.97% and improves the activation probability by 76.31%.

Problem

• Addresses frequent handovers in UAV cellular networks
• Improves handover reliability using ISAC sensing data
• Reduces handover region length and increases activation probability

Innovation

• Integrates ISAC sensing with RSRP for handover
• Tailors ISAC signal model for low-altitude scenarios
• Reduces handover region length by 49.97%