The in-band Full Duplex (FD) technology is lately gaining attention as an enabler for the emerging paradigm of Integrated Sensing and Communications (ISAC), which envisions seamless integration of sensing mechanisms for unconnected entities into next generation wireless networks. In this paper, we present an FD Multiple-Input Multiple-Output (MIMO) system with extremely large antenna arrays at its transceiver module, which is optimized, considering two emerging analog beamforming architectures, for simultaneous DownLink (DL) communications and monostatic-type sensing intended at the sub-THz frequencies, with the latter operation relying on received reflections of the transmitted information-bearing signals. A novel optimization framework for the joint design of the analog and digital transmit beamforming, analog receive combining, and the digital canceler for the self-interference signal is devised with the objective to maximize the achievable DL rate, while meeting a predefined threshold for the position error bound for the unknown three-dimensional parameters of a passive target. Capitalizing on the distinctive features of the beamforming architectures with fully-connected networks of phase shifters and partially-connected arrays of metamaterials, two ISAC designs are presented. Our simulation results showcase the superiority of both proposed designs over state-of-the-art schemes, highlighting the role of various system parameters in the trade-off between the communication and sensing functionalities.

翻译：带内全双工技术近来作为集成感知与通信这一新兴范式的使能技术受到关注，该范式旨在将针对非连接实体的感知机制无缝集成到下一代无线网络中。本文提出一种在收发器模块配备超大规模天线阵列的全双工多输入多输出系统，该系统基于两种新兴的模拟波束赋形架构进行优化设计，旨在亚赫兹频段同时实现下行链路通信与单站式感知，其中感知操作依赖于传输信息承载信号的接收反射。我们设计了一种新颖的联合优化框架，用于综合设计模拟与数字发射波束赋形、模拟接收合并以及自干扰信号的数字消除器，其目标是在满足无源目标未知三维参数的位置误差界限预定阈值的前提下，最大化可达到的下行链路速率。基于全连接移相器网络和部分连接超材料阵列这两种波束赋形架构的独特特性，本文提出了两种集成感知与通信设计方案。仿真结果表明，所提两种设计均优于现有先进方案，并揭示了各种系统参数在通信与感知功能权衡中的作用。