Fast Fluid Antenna Multiple Access With Path Loss Consideration and Different Antenna Architecture

Fluid antennas located at the user device (UD) can exploit the natural multipath propagation and randomness of the desired data by adjusting its position spatially to find the point at which an interference null occurs. A fast fluid antenna multiple access (f-FAMA) system uses a large antenna array at the base station to transmit each user's signal from each antenna. The interference is then overcome by a single fluid antenna located at each receiving UD. Previous work has established a channel model for such a f-FAMA system with a technique that estimates the best port for the fluid antenna to receive the signal at every symbol instance. This paper proposes an improved version of the channel model by also taking into consideration the difference in path loss between different ports and also looks into how different fluid antenna architectures effect the performance of an f-FAMA system. Simulation results demonstrate the necessity of considering path loss variations, particularly in scenarios where there are substantial differences in distances from the transmitter to different ports. Additionally, among the three different antenna architectures considered, the performance of the wheel topology antenna is worse than the linear topology and circular topology antennas at shorter reference distances.