  Future sixth generation (6G) wireless communication networks face the need to
similarly meet unprecedented quality of service (QoS) demands while also
providing a larger energy efficiency (EE) to minimize their carbon footprint.
Moreover, due to the diverseness of network participants, mixed criticality QoS
levels are assigned to the users of such networks. In this work, with a focus
on a cloud-radio access network (C-RAN), the fulfillment of desired QoS and
minimized transmit power use is optimized jointly within a rate-splitting
paradigm. Thereby, the optimization problem is non-convex. Hence, a
low-complexity algorithm is proposed based on fractional programming. Numerical
results validate that there is a trade-off between the QoS fulfillment and
power minimization. Moreover, the energy efficiency of the proposed
rate-splitting algorithm is larger than in comparative schemes, especially with
mixed criticality.
