  The Future wireless communication systems face the challenging task of
simultaneously providing high quality of service (QoS) and broadband data
transmission, while also minimizing power consumption, latency, and system
complexity. Although Orthogonal Frequency Division Multiplexing OFDM has been
widely adopted in 4G and 5G systems, it struggles to cope with the significant
delay and Doppler spread in high mobility scenarios. To address these
challenges, a novel waveform called Orthogonal Time Frequency Space OTFS has
emerged, aiming to outperform OFDM by closely aligning signals with the channel
behaviour. In this paper, we propose a switching strategy that empowers
operators to select the most appropriate waveform based on the estimated speed
of the mobile user. This strategy enables the base station to dynamically
choose the waveform that best suits the mobile users speed. Additionally, we
suggest integrating an Integrated Sensing and Communication radar for accurate
Doppler estimation, providing precise information to aid in waveform selection.
By leveraging the switching strategy and harnessing the Doppler estimation
capabilities of an ISAC radar, our proposed approach aims to enhance the
performance of wireless communication systems in scenarios of high mobility.
Considering the complexity of waveform processing, we introduce an optimized
hybrid system that combines OTFS and OFDM, resulting in reduced complexity
while still retaining performance benefits. This hybrid system presents a
promising solution for improving the performance of wireless communication
systems in scenarios with a high mobility. The simulation results validate the
effectiveness of our approach, demonstrating its potential advantages for
future wireless communication systems. The effectiveness of the proposed
approach is validated by simulation results as it will be shown.
