Conference Paper

This paper proposes a low-complexity hybrid analog--digital (HAD) beamforming design for integrated sensing and communication (ISAC) systems based on a partially connected architecture. Building upon a communication-centric ISAC framework, the objective is to maximize the downlink communication sum-rate while explicitly satisfying sensing and transmit power constraints in a multi-user and multi-beam scenario. By exploiting the structural properties of partial connectivity, we develop a new and low-complexity algorithm for the design of the analog and digital precoders, whose computational complexity scales linearly with the number of transmit antennas. Numerical results demonstrate that, while a performance gap with respect to fully connected architectures is observed due to reduced beamforming flexibility, the proposed approach achieves a favorable trade-off between communication performance and complexity, offering substantial gains in computational efficiency and energy consumption, which are particularly attractive for large-scale and massive MIMO ISAC deployments.