This study employs a uniform rectangular array (URA) sub-connected hybrid beamforming (SC-HBF) architecture to provide a novel self-interference (SI) suppression scheme in a full-duplex (FD) massive multiple-input multiple-output (mMIMO) system. Our primary objective is to mitigate the strong SI through the design of RF beamforming stages for uplink and downlink transmissions that utilize the spatial degrees of freedom provided due to the use of large array structures. We propose a non-constant modulus RF beamforming (NCM-BF-SIS) scheme that incorporates the gain controllers for both transmit (Tx) and receive (Rx) RF beamforming stages and optimizes the uplink and downlink beam directions jointly with gain controller coefficients. To solve this challenging non-convex optimization problem, we propose a swarm intelligence-based algorithmic solution that finds the optimal beam perturbations while also adjusting the Tx/Rx gain controllers to alleviate SI subject to the directivity degradation constraints for the beams. The data-driven analysis based on the measured SI channel in an anechoic chamber shows that the proposed NCM-BF-SIS scheme can suppress SI by around 80 dB in FD mMIMO systems.

翻译：本研究采用均匀矩形阵列（URA）子连接混合波束赋形（SC-HBF）架构，为全双工（FD）大规模多输入多输出（mMIMO）系统提出了一种新型自干扰（SI）抑制方案。我们的主要目标是通过设计利用大型阵列结构提供的空间自由度的上行链路和下行链路射频波束赋形阶段，来缓解强自干扰。我们提出了一种非恒定模数射频波束赋形（NCM-BF-SIS）方案，该方案在发射（Tx）和接收（Rx）射频波束赋形阶段整合了增益控制器，并联合优化了上行链路和下行链路波束方向与增益控制器系数。为了解决这一具有挑战性的非凸优化问题，我们提出了一种基于群体智能的算法解决方案，该方案在满足波束方向性退化约束的条件下，寻找最优波束扰动同时调整Tx/Rx增益控制器以减轻自干扰。基于消声室中实测自干扰信道的数据驱动分析表明，所提出的NCM-BF-SIS方案在全双工大规模MIMO系统中可实现约80 dB的自干扰抑制。