This paper considers a cell-free integrated sensing and communication (ISAC) MIMO system, where distributed MIMO access points are jointly serving the communication users and sensing the targets. For this setup, we first develop two baseline approaches that separately design the sensing and communication beamforming vectors, namely communication-prioritized sensing beamforming and sensing-prioritized communication beamforming. Then, we consider the joint sensing and communication (JSC) beamforming design and derive the optimal structure of these JSC beamforming vectors based on a max-min fairness formulation. The results show that the developed JSC beamforming is capable of achieving nearly the same communication signal-to-interference-plus-noise ratio (SINR) that of the communication-prioritized sensing beamforming solutions with almost the same sensing SNR of the sensing-prioritized communication beamforming approaches, yielding a promising strategy for cell-free ISAC MIMO systems.

翻译：本文研究了一种无蜂窝集成感知与通信（ISAC）MIMO系统，其中分布式MIMO接入点共同服务于通信用户并感知目标。针对这一场景，我们首先开发了两种分别设计感知和通信波束赋形向量的基线方法，即通信优先的感知波束赋形和感知优先的通信波束赋形。随后，我们考虑联合感知与通信（JSC）波束赋形设计，并基于最大最小公平性准则推导了这些JSC波束赋形向量的最优结构。结果表明，所提出的JSC波束赋形能够在实现与通信优先感知波束赋形方案几乎相同的通信信干噪比（SINR）的同时，保持与感知优先通信波束赋形方法近乎一致的感知信噪比，从而为无蜂窝ISAC MIMO系统提供了一种有前景的策略。