Beamforming design has been extensively investigated in integrated sensing and communication (ISAC) systems. The use of movable antennas has proven effective in enhancing the design of beamforming. Although some studies have explored joint optimization of transmit beamforming matrices and antenna positions in bistatic scenarios, there is a gap in the literature regarding monostatic full-duplex (FD) systems. To fill this gap, we propose an algorithm that jointly optimizes the beamforming and antenna positions at both the transmitter and the receiver in a monostatic FD system. In an FD system, suppressing self-interference is crucial. This interference can be significantly reduced by carefully designing transmit and receive beamforming matrices. To further enhance the suppression, we derive a formulation of self-interference characterized by antenna position vectors. This enables the strategic positioning of movable antennas to further mitigate interference. Our approach optimizes the weighted sum of communication capacity and mutual information by simultaneously optimizing beamforming and antenna positions for both tranceivers. Specifically, we propose a coarse-to-fine grained search algorithm (CFGS) to find optimal antenna positions. Numerical results demonstrate that our proposed algorithm provides significant improvements for the MA system compared to conventional fixed-position antenna systems.

翻译：波束成形设计在集成感知与通信系统中已得到广泛研究。可移动天线的使用已被证明能有效增强波束成形设计。尽管已有研究探索了双基地场景下发射波束成形矩阵与天线位置的联合优化，但针对单基地全双工系统的相关文献尚存空白。为填补这一空白，我们提出一种算法，在单基地全双工系统中联合优化发射端与接收端的波束成形和天线位置。在全双工系统中，抑制自干扰至关重要。通过精心设计发射与接收波束成形矩阵，可显著降低此类干扰。为进一步增强抑制效果，我们推导了以天线位置向量表征的自干扰表达式。这使得可通过策略性地布置可移动天线来进一步减轻干扰。我们的方法通过同时优化收发两端的波束成形与天线位置，以最大化通信容量与互信息的加权和。具体而言，我们提出一种由粗到细的粒度搜索算法来寻找最优天线位置。数值结果表明，与传统固定位置天线系统相比，我们提出的算法为可移动天线系统带来了显著性能提升。