  Rate-Splitting Multiple Access (RSMA) is a robust multiple access scheme for
multi-antenna wireless networks. In this work, we study the performance of RSMA
in downlink overloaded networks, where the number of transmit antennas is
smaller than the number of users. We provide analysis and closed-form solutions
for optimal power and rate allocations that maximize max-min fairness when
low-complexity precoding schemes are employed. The derived closed-form
solutions are used to propose a low-complexity RSMA system design for precoder
selection and resource allocation for arbitrary number of users and antennas
under perfect and imperfect Channel State Information at the Transmitter
(CSIT). We compare the performance of the proposed design with benchmark
designs based on Space Division Multiple Access (SDMA) with and without user
scheduling. By numerical results, we show that the proposed low-complexity RSMA
design achieves a significantly higher rate compared to the SDMA-based
benchmark designs under perfect and imperfect CSIT.
