Dynamic Channel Modeling of Fluid Antenna Systems in UAV Communications

As an emerging wireless communication technology, fluid antenna system (FAS) shows great potential for its reconfigurable radiation characteristics that can benefit air-to-ground (A2G) communications. In this letter, we propose a novel dynamic port-reconfigurable channel model for FAS-assisted unmanned aerial vehicle (UAV)-to-ground user (GU) A2G communications. Unlike conventional static antenna models, the proposed framework integrates the unique ability of FAS to dynamically activate and reconfigure antenna ports, enabling accurate simulation of FAS behaviors across diverse communication scenarios. Crucial performance indicators, such as modeling accuracy and channel capacity, are derived and investigated, revealing that the number of active ports and port spacing significantly impact both metrics. The dynamic characteristics of UAV is also shown to significantly affect the channel capacities, emphasizing the requirements for adaptive FAS configuration in A2G scenarios. These findings offer valuable insights for the design and analysis of FAS, particularly in dynamic environments like UAV communications.