  One technology that has the potential to improve wireless communications in
years to come is integrated sensing and communication (ISAC). In this study, we
take advantage of reconfigurable intelligent surface's (RIS) potential
advantages to achieve ISAC while using the same frequency and resources.
Specifically, by using the reflecting elements, the RIS dynamically modifies
the radio waves' strength or phase in order to change the environment for radio
transmission and increase the ISAC systems' transmission rate. We investigate a
single cell downlink communication situation with RIS assistance. Combining the
ISAC base station's (BS) beamforming with RIS's discrete phase shift
optimization, while guaranteeing the sensing signal, The aim of optimizing the
sum rate is specified. We take advantage of alternating maximization to find
practical solutions with dividing the challenge into two minor issues. The
first power allocation subproblem is non-convex that CVX solves by converting
it to convex. A local search strategy is used to solve the second subproblem of
phase shift optimization. According to the results of the simulation, using RIS
with adjusted phase shifts can significantly enhance the ISAC system's
performance.
