  The concept of reconfigurable fluid antennas (FA) is a potential and
promising solution to enhance the spectral efficiency of wireless communication
networks. Despite their many advantages, FA-enabled communications have
limitations as they require an enormous amount of spectral resources in order
to select the most desirable position of the radiating element from a large
number of prescribed locations. In this paper, we present an analytical
framework for the outage performance of large-scale FA-enabled communications,
where all user equipments (UEs) employ circular multi-FA array. In contrast to
existing studies, which assume perfect channel state information, the developed
framework accurately captures the channel estimation errors on the performance
of the considered network deployments. In particular, we focus on the limited
coherence interval scenario, where a novel sequential linear minimum
mean-squared error (LMMSE)-based channel estimation method is performed for
only a very small number of FA ports. Next, for the communication of each BS
with its associated UE, a low-complexity port-selection technique is employed,
where the port that provides the highest
signal-to-interference-plus-noise-ratio is selected among the ports that are
estimated to provide the strongest channel from each FA. By using stochastic
geometry tools, we derive both analytical and closed-form expressions for the
outage probability, highlighting the impact of channel estimation on the
performance of FA-based UEs. Our results reveal the trade-off imposed between
improving the network's performance and reducing the channel estimation
quality, indicating new insights for the design of FA-enabled communications.
