Integrated sensing and communication (ISAC) has recently merged as a promising technique to provide sensing services in future wireless networks. In the literature, numerous works have adopted a monostatic radar architecture to realize ISAC, i.e., employing the same base station (BS) to transmit the ISAC signal and receive the echo. Yet, the concurrent information transmission causes severe self-interference (SI) to the radar echo at the BS which cannot be effectively suppressed. To overcome this difficulty, in this paper, we propose a coordinated cellular network-supported multistatic radar architecture to implement ISAC. In particular, among all the coordinated BSs, we select a BS as the multistatic receiver to receive the sensing echo signal, while the other BSs act as the multistatic transmitters to collaborate with each other to facilitate cooperative ISAC. This allows us to spatially separate the ISAC signal transmission and radar echo reception, intrinsically circumventing the problem of SI. To this end, we jointly optimize the transmit and receive beamforming policy to minimize the sensing beam pattern mismatch error subject to both the communication and sensing quality-of-service requirements. The resulting non-convex optimization problem is tackled by a low-complexity alternating optimization-based suboptimal algorithm. Simulation results showed that the proposed scheme outperforms the two baseline schemes adopting conventional designs. Moreover, our results confirm that the proposed architecture is promising in achieving high-quality ISAC.

翻译：集成感知与通信（ISAC）近期作为未来无线网络中提供感知服务的一项有前景技术而兴起。现有文献中，众多研究采用单站雷达架构实现ISAC，即利用同一基站（BS）发射ISAC信号并接收回波。然而，同时进行的信息传输会在基站处对雷达回波造成严重的自干扰，且该干扰难以有效抑制。为克服这一难题，本文提出一种基于协调蜂窝网络的多站雷达架构来实现ISAC。具体而言，在所有协调基站中，我们选取一个基站作为多站接收机以接收感知回波信号，而其他基站作为多站发射机相互协作以支持协同ISAC。这使得我们在空间上分离了ISAC信号发射与雷达回波接收，从而从根本上规避了自干扰问题。为此，我们联合优化发射与接收波束赋形策略，在满足通信与感知服务质量约束的同时，最小化感知波束方向图失配误差。针对由此产生的非凸优化问题，我们提出一种基于交替优化的低复杂度次优算法。仿真结果表明，所提方案优于采用传统设计的两种基线方案。此外，研究结果证实，所提架构在实现高质量ISAC方面具有显著潜力。