  This paper studies the deployment of multiple movable antennas (MAs) at the
base station (BS) for enhancing the multiuser communication performance. First,
we model the multiuser channel in the uplink to characterize the wireless
channel variation caused by MAs' movement at the BS. Then, an optimization
problem is formulated to maximize the minimum achievable rate among multiple
users for MA-aided uplink multiuser communications by jointly optimizing the
MAs' positions, their receive combining at the BS, and the transmit power of
users, under the constraints of finite moving region of MAs, minimum inter-MA
distance, and maximum transmit power of each user. To solve this challenging
non-convex optimization problem, a two-loop iterative algorithm is proposed by
leveraging the particle swarm optimization (PSO) method. Specifically, the
outer-loop updates the positions of a set of particles, where each particle's
position represents one realization of the antenna positioning vector (APV) of
all MAs. The inner-loop implements the fitness evaluation for each particle in
terms of the max-min achievable rate of multiple users with its corresponding
APV, where the receive combining matrix of the BS and the transmit power of
each user are optimized by applying the block coordinate descent (BCD)
technique. Simulation results show that the antenna position optimization for
MAs-aided BS can significantly improve the rate performance as compared to
conventional BS with fixed-position antennas (FPAs).
