  This paper investigates a multiple input single output (MISO) downlink
communication system in which users are equipped with fluid antennas (FAs).
First, we adopt a field-response based channel model to characterize the
downlink channel with respect to FAs' positions. Then, we aim to minimize the
total transmit power by jointly optimizing the FAs' positions and beamforming
matrix. To solve the resulting non-convex problem, we employ an alternating
optimization (AO) algorithm based on penalty method and successive convex
approximation (SCA) to obtain a sub-optimal solution. Numerical results
demonstrate that the FA-assisted communication system performs better than
conventional fixed position antennas system.
