A Review of Low-Altitude Communication Technologies in the Context of Integrating the Low-Altitude Economy and Rail Transit

With the rapid growth of the low-altitude economy and the advancement of rail transit, low-altitude communication technology has become a vital link between aerial vehicles and rail systems. This paper reviews its applications and challenges in integrating these domains, focusing on three key areas: network architecture, signal processing, and security assurance. At the architectural level, cellular networks, Space-Air-Ground Integrated Networks (SAGIN), and communication-sensing-computing integrated platforms are emerging as research hotspots, though issues of coverage, resource management, and collaborative optimization persist. For signal processing, techniques such as multipath fading mitigation, channel estimation, interference suppression, and spectrum efficiency enhancement—augmented by innovations like waveform design, intelligent reflecting surfaces, and OFDM—are critical to improving system reliability. In terms of security, robust measures against jamming, hijacking, and eavesdropping remain essential. The integration of artificial intelligence and quantum communication is expected to further strengthen security, accelerating the convergence of the low-altitude economy and rail transit.