Beamforming Design and Multi-User Scheduling in Transmissive RIS Enabled Distributed Cooperative ISAC Networks with RSMA

In this paper, we propose a transmissive reconfigurable intelligent surface (TRIS)-empowered distributed cooperative integrated sensing and communication (ISAC) network, which enhances the coverage and wireless environment understanding through the joint design of cooperative users (CUEs) and destination users (DUEs). Rate-splitting multiple access (RSMA) is implemented at the base station (BS), where the common stream is decoded and recoded by the CUEs and forwarded to the DUEs, while the private stream meets the CUEs’ own communication requirements. We construct an optimization problem with the objective of maximizing the minimum Radar mutual information (RMI), and jointly optimize the BS beamforming matrix, the CUE beamforming matrixs, common stream rate, and user scheduling vectors. To address the challenges of the nonconvex optimization problem, the consensus alternating direction multiplier framework (ADMM) is utilized to decouple the variables, and the subproblems are solved independently through iterative optimization until overall convergence is achieved. Numerical results validate the superiority of the proposed scheme in terms of improving communication sum-rate and RMI, and greatly reduce the algorithm complexity.