  In this paper, we explore the integration of two revolutionary technologies,
reconfigurable intelligent surfaces (RISs) and orthogonal time frequency space
(OTFS) modulation, to enhance high-speed wireless communications. We introduce
a novel phase shift design algorithm for RIS-assisted OTFS, optimizing energy
reception and channel gain in dynamic environments. The study evaluates the
proposed approach in a downlink scenario, demonstrating significant performance
improvements compared to benchmark schemes in the literature, particularly in
terms of bit error rate (BER). Our results showcase the potential of RIS to
enhance the system's performance. Specifically, our proposed phase shift design
technique outperforms the benchmark solutions by over 4 dB. Furthermore, even
greater gains can be obtained as the number of RIS elements increases.
