  We introduce an energy-efficient downlink rate splitting multiple access
(RSMA) scheme, employing a simple matched filter (MF) for precoding. We
consider a transmitter equipped with multiple antennas, serving several
single-antenna users at the same frequency-time resource, each with distinct
message requests. Within the conventional 1-layer RSMA framework, requested
messages undergo splitting into common and private streams, which are then
precoded separately before transmission. In contrast, we propose a novel
strategy where only an MF is employed to precode both the common and private
streams in RSMA, promising significantly improved energy efficiency and reduced
complexity. We demonstrate that this MF-precoded RSMA achieves the same
delivery performance as conventional RSMA, where the common stream is
beamformed using maximal ratio transmission (MRT) and the private streams are
precoded by MF. Taking into account imperfect channel state information at the
transmitter, we proceed to analyze the delivery performance of the MF-precoded
RSMA. We derive the ergodic rates for decoding the common and private streams
at a target user respectively in the massive MIMO regime. Finally, numerical
simulations validate the accuracy of our analytical models, as well as
demonstrate the advantages over conventional RSMA.
