Manifold optimization for hybrid beamforming in dual-function radar-communication system

We study hybrid beamforming design for millimeter wave dual-function radar-communication system, which simultaneously performs downlink communication and target detection. With two typical analog beamformer structures, we consider the hybrid beamforming design to minimize a weighted summation of radar and communication performance. Leveraging Riemannian optimization theory, a manifold alternating direction method of multipliers is developed for the fully-connected structure. While for the partially-connected structure, a low-complexity Riemannian product manifold trust region algorithm is proposed to approach a near-optimal solution. Numerical simulations are provided to demonstrate the effectiveness of the proposed methods.