Toward AFDM-Based Scalable and Secure Internet of Things for Low-Altitude Economy Networks

The low-altitude economy (LAE) network is emerging as a transformative paradigm that integrates advanced communication infrastructures to support diverse aerial economic activities. However, physical-layer communications in LAE networks face critical challenges, including (i) achieving robust transmission over high-mobility scenarios, (ii) supporting massive connectivity for aerial and ground Internet of Things (IoT) devices, and (iii) increasing security threats due to the broadcast and openness of aerial channels. To address these challenges, this paper investigates the Affine frequency division multiplexing (AFDM)-based waveform for reliable, scalable, and secure LAE networks. Leveraging chirp-based multicarrier modulation, AFDM provides strong resilience to Doppler impairments, supports massive access for aerial and IoT devices, and enables flexible physical-layer security and sensing capabilities. We first introduce the fundamental principles of AFDM and highlight its advantages for LAE networks, including enhanced robustness in high-mobility environments and inherent suitability for both physical-layer security (PLS) and sensing. Then, we present AFDM-based multiple access strategies to enable massive connectivity, followed by low-complexity transceiver designs tailored for power- and computation-constrained IoT devices. Finally, we explore PLS mechanisms customized for AFDM systems in LAE networks. This work may provide valuable insights into AFDM-based waveform design and implementation for future LAE communications.