Rotatable Array-Enabled Multi-BS Cooperative ISAC Transmit Beampattern Design
Kaiqian Qu, Haojin Li, Chen Sun, Wenqi Zhang, Shuaishuai Guo, Haijun Zhang
Abstract
In this work, we investigate a multiple base station (BS) cooperative integrated sensing and communications (MC-ISAC) system enabled by the rotatable array (RA), where each BS is equipped with a RA driven by a motor. This scheme enhances the efficient utilization of spatial resources with minimal hardware modifications, thereby significantly improving the performance of the ISAC system. Specifically, we jointly optimize the multi-BS array rotation angles and the multi-BS beamforming matrix, aiming to optimize the sensing beampattern matching while satisfying the communication performance requirements and power constraints. To solve this non-convex problem, we design an alternating optimization scheme that iteratively optimizes the rotation angles and beamforming by utilizing semidefinite relaxation (SDR) techniques and the quasi-Newton method. The numerical results show that the proposed RA-enabled multi-BS cooperative ISAC (RAMC-ISAC) beamforming method achieves a lower beampattern matching error under the same communication requirements.