  We consider the problem of power allocation in Rate-Splitting Multiple Access
(RSMA) systems, where messages are split into common and private messages. The
common and private streams are jointly transmitted to allow efficient use of
the bandwidth, and decoded by Successive Interference Cancellation (SIC) at the
receiver. However, the power allocation between streams significantly affects
the overall performance. In this letter, we address this problem. We develop a
novel algorithm, dubbed Power Allocation in RSMA systems using Genetic
Algorithm (PARGA), to allocate the power between streams in RSMA systems in
order to maximize the user sum-rate. Simulation results demonstrate the high
efficiency of PARGA compared to existing methods.
