  Users' desire for enhanced performance drive the inevitable technological
progress on vertical applications in wireless communication systems. To meet
these demands, researchers vigorously investigate potential 6G and beyond
technologies and solutions. Reconfigurable intelligent surfaces (RISs) have
risen in popularity and attracted the attention of academia as well as industry
and seem to be a promising candidate for 6G technology. RISs are reflective
metamaterials with many configurable elements consisting of pin diodes that
have the ability to manipulate the impinging signals' properties, hence,
enabling some sort of virtual control over the wireless channel. In this paper,
we propose a novel over-the-air index modulation (IM) scheme through the use of
a hybrid RIS with active and passive partitions to convey additional IM bits
over-the-air. In addition we propose another modified scheme that allows the
transmission for even more IM bits but at the expense of certain trade-offs.
First, we present the system model for both of the proposed schemes.
Furthermore, comprehensive computer simulation results are provided and
discussed presenting the superior bit error rate (BER) performance and
additional benefits of the proposed systems compared to similar benchmarks.
