In the context of integrated sensing and communication (ISAC), a full-duplex (FD) transceiver can operate as a monostatic radar while maintaining communication capabilities. This paper investigates the design of precoders and combiners for a joint radar and communication (JRC) system at mmWave frequencies. The primary goals of the design are to minimize self-interference (SI) caused by FD operation, while guaranteeing certain performance in terms of some sensing and communication metrics, as well as taking into account the hardware limitations coming from a hybrid MIMO architecture. Specifically, we introduce a generalized eigenvalue-based precoder that takes into account downlink user rate, radar gain, and SI suppression. Since the hybrid analog/digital architecture degrades the SI suppression capability of the precoder, we further enhance SI suppression with the analog combiner. Our numerical results demonstrate that the proposed architecture achieves the required radar gain and SI mitigation while incurring a small loss in downlink spectral efficiency. Additionally, the numerical experiments also show that the use of orthogonal frequency division multiplexing (OFDM) for radar processing with the proposed beamforming architecture results in highly accurate range and velocity estimates for detected targets.

翻译：在集成感知与通信（ISAC）背景下，全双工（FD）收发器可作为单站雷达运行，同时保持通信能力。本文研究了毫米波频率下联合雷达与通信（JRC）系统的预编码器与合并器设计。设计的主要目标是最小化全双工操作引起的自干扰（SI），同时保证感知与通信指标方面的特定性能，并考虑混合MIMO架构带来的硬件限制。具体而言，我们提出了一种基于广义特征值的预编码器，该预编码器综合考量了下行用户速率、雷达增益和自干扰抑制。由于混合模拟/数字架构会削弱预编码器的自干扰抑制能力，我们进一步通过模拟合并器增强自干扰抑制。数值结果表明，所提架构在实现所需雷达增益和自干扰抑制的同时，仅导致下行频谱效率的轻微损失。此外，数值实验还表明，将正交频分复用（OFDM）用于雷达处理并结合所提波束赋形架构，可实现对检测目标的高精度距离与速度估计。