Fluid Antenna-Assisted Dirty Multiple Access Channels Over Composite Fading

This letter investigates the application of the emerging fluid antenna (FA) technology in multiuser communication systems when side information (SI) is known at the transmitters. We consider a
$K$
-user dirty multiple access channel (DMAC) with non-causally known SI at the transmitters, where
$K$
users send independent messages to a common receiver with a FA capable of changing its location depending on the channel condition. By connecting Jakes’ model to copula theory through Spearman’s
$\rho $
rank correlation coefficient, we accurately describe the spatial correlation between the FA channels, and derive a closed-form expression for the outage probability (OP) under Fisher-Snedecor
$\mathcal {F}$
fading. Results confirm that a FA-aided receiver can achieve better performance in multiuser communication: (
${i}$
) increasing the number of FA ports as well as FA size can significantly lower the OP; (ii) FA can support a large number of users using only one FA at the common receiver in a few wavelengths of space.