  Cooperative rate splitting (CRS), built upon rate splitting multiple access
(RSMA) and opportunistic user relaying, has been recognized as a promising
transmission strategy to enhance the user fairness and spectral efficiency in
multiantenna broadcast channels. To further boost its performance, the
interplay of CRS and reconfigurable intelligent surface (RIS) is investigated
in this work. Specifically, a novel RIS-aided CRS transmission framework is
proposed and the corresponding resource allocation problem to maximize the
minimum rate among users is investigated. An alternative optimization algorithm
is then proposed to optimize the transmit beamforming, common rate allocation,
and RIS phases, iteratively. Numerical results show that the proposed RIS-aided
CRS transmission framework significantly improves the spectral efficiency
compared with its non-cooperative counterpart and other schemes without RIS.
