  The upper mid-band frequencies (i.e., 7-24,GHz) are regarded as the golden
bands for the sixth-generation (6G) wireless communication systems, combining
good coverage, much new spectrum, and many antennas in compact form factors.
The first 6G networks will most likely use this band. There is much prior work
on channel modeling, coexistence, and possible implementation scenarios in
these bands. On the other hand, the use of reconfigurable intelligent surfaces
(RISs) has not yet been examined in these bands, even if this transformative
technology has generally garnered considerable attention in recent years for
its ability to enhance spectral efficiency, coverage, and reliability of
wireless channels. There are significant frequency-specific challenges related
to RIS deployment, use cases, number of required elements, channel estimation,
and control. These are previously unaddressed for the upper mid-band. In this
paper, we aim to bridge this gap by exploring various use cases, including
RIS-assisted fixed wireless access (FWA), enhanced capacity in mobile
communications, and increased reliability at the cell edge. We identify the
conditions under which RIS can provide major benefits and optimal strategies
for deploying RIS to enhance the performance of 6G upper mid-band communication
systems.
