Communication-infrastructure-enabled ISAC for low-altitude sensing.

As a core infrastructure of modern information society, cellular networks have long supported terrestrial communications and are now being extended to low-altitude connectivity with the growth of the low-altitude economy. However, the increasing number of aerial vehicles poses new challenges to airspace supervision and flight safety, creating a need for wide-area, continuous and accurate sensing. Conventional sensing devices, such as dedicated radars and cameras, can provide target information but suffer from high deployment cost, electromagnetic interference, and complex coordination. By exploiting the similarities between communication and radar systems in electromagnetic propagation, hardware and signal processing, integrated sensing and communication offers a promising way to reuse communication infrastructure for low-altitude sensing. In this Review, key engineering issues in communication-infrastructure-enabled low-altitude sensing are discussed, including base station deployment, sensing mode design, synchronization and waveform design. Enabling techniques for target detection, localization, tracking and recognition are further summarized, with emphasis on communication-adapted signal processing, networked sensing, and multimodal fusion. Experimental demonstrations and future directions in weather monitoring, data security and privacy protection are also discussed.