Joint Beamforming and Position Optimization for Movable-Antenna and Movable-Element RIS-Aided Full-Duplex 6G MISO Systems

Abstract: Full-duplex communication substantially enhances spectral efficiency by enabling simultaneous transmission and reception on the same time-frequency resources. However, its practical deployment remains hindered by strong residual self-interference and inter-user interference, which severely degrade system performance. This work investigates a full-duplex MISO network that leverages movable-antenna base stations (MA-BS) and movable-element reconfigurable intelligent surfaces (ME-RIS) to overcome these limitations in next-generation 6G systems. Unlike conventional fixed-geometry architectures, the proposed framework jointly optimizes antenna and RIS element positions, together with RIS phase shifts, to strengthen desired links while suppressing interference. Our design objective is to maximize the system sum rate through the joint optimization of transmit and receive beamforming vectors, uplink transmit powers, RIS phase shifts, and the spatial locations of both the BS antennas and RIS elements. To solve this challenging nonconvex problem, an alternating optimization algorithm is developed, employing semidefinite relaxation for beamforming design and successive convex approximation for position optimization. Simulation results demonstrate that the proposed ME-RIS-assisted architecture with movable BS antennas offers substantial gains over conventional fixed-position full-duplex networks. These findings highlight the potential of integrating movable antennas with movable RIS elements as a key enabler for high-performance full-duplex operation in future 6G wireless systems.