Low-altitude UAV swarm ISAC: new opportunities and challenges

Abstract

With the rapid development of the low-altitude economy, low-altitude unmanned aerial vehicle (UAV) swarms are emerging as important components of sixth-generation (6G) mobile communication networks, facilitating “full coverage” and “Internet of Intelligence.” Integrated sensing and communication (ISAC) deeply integrates sensing functionality into wireless communication networks by sharing wireless infrastructures and resources such as base stations, antennas, radio frequency chains, and signal waveforms, thereby significantly improving the performance of low-altitude UAV swarms. This paper reviews the research status of low-altitude UAV swarm ISAC systems, analyzes the new challenges arising from key features of UAV swarms, including low–slow–small characteristics, high density, large quantity, complex low-altitude environments, and high swarm coordination requirements, presents a vision for future deployment, and proposes the so-called “Ten Ones” performance metrics tailored to low-altitude UAV swarm ISAC. To realize these ambitious key performance indicators for future UAV swarm ISAC, several promising technologies are discussed, such as new array architectures, including extremely-large multiple-input multiple-output (XL-MIMO), sparse XL-MIMO, and reconfigurable antenna arrays, sparse time–frequency resource allocation, and channel knowledge maps. Furthermore, the potential of exploiting UAV swarms as airborne ISAC platforms is discussed. Finally, future research directions are outlined, offering a guideline for the design and development of low-altitude UAV swarm ISAC systems.

1. Introduction

With the low-altitude economy being identified as a major strategic emerging industry, low-altitude aircraft, particularly unmanned aerial vehicles (UAVs), have achieved remarkable progress and widespread applications (Zeng Y et al., 2019). However, with the continuous expansion of UAV applications and the increasing complexity of their operating environments, the limitations of a single UAV are becoming increasingly evident. UAV swarms are expected to become a critical component of the future low-altitude economy. A UAV swarm is a distributed group system composed of multiple UAVs that achieves task planning and collaborative cooperation via inter-UAV data transmission and sharing, thereby completing complex tasks that a single UAV cannot accomplish. UAV swarms can provide more powerful technical support in fields such as urban logistics, traffic control, emergency rescue, patrol and inspection, agricultural and forestry protection, geographical surveying and mapping, and military security (Alqudsi and Makaraci, 2025).

The 3rd Generation Partnership Project (3GPP) released the 5G New Radio (NR) technical specifications supporting UAVs in 3GPP TR 21.918, validating the feasibility of supporting UAVs through terrestrial cellular networks, and also pointing out the required enhancements to remote control and data transmission-related technical indicators. On one hand, among various available wireless technologies supporting low-altitude UAV applications, mobile communication networks are considered the most effective way to achieve large-scale UAV swarm deployment and beyond line-of-sight (LoS) UAV operations (Song et al., 2025). On the other hand, space–air–ground–sea integrated infrastructures constructed based on UAV development are expected to help sixth-generation (6G) mobile communication networks achieve the vision of “full coverage” and “Internet of Intelligence,” accelerating the deep integration of low-altitude networks and economy (Qi et al., 2024; Zhang RY et al., 2025).