###### Abstract
Performance Improvement: OTFS modulation is particularly well suited to environments with severe multipath fading. By transforming the received signals from the time-delay domain to the DD domain, OTFS modulation can effectively separate multipath components. This transformation enhances the system's ability to combat fading and improves communication performance. 2. Resilience to Time Variability: OTFS modulation is designed to handle time-varying channels, making it robust in scenarios where the channel conditions change rapidly. This is crucial in dynamic environments, such as those encountered in vehicular communication or mobile communication, where the channel characteristics can vary over short time intervals. 2. Interference Rejection 1. Spatial Separation: The DD domain representation in OTFSs provides a form of spatial separation for different signals. This can aid in the rejection of interference, as signals from different directions in the DD domain can be more easily distinguished. 2. Improved Detection in Noisy Environments: The ability of OTFS modulation to focus on distinct DD signatures allows for improved detection in the presence of interference and noise. The framework's capacity to isolate signals in the DD domain contributes to enhanced interference rejection capabilities. The OTFS modulation framework shows promise in addressing challenges posed by varying environmental conditions, including interference and fluctuating signal strengths. Its unique approach of focusing on the DD domain provides advantages in multipath fading scenarios and dynamic channel conditions, making it a candidate for applications requiring reliable communication in challenging environments. In contrast to conventional approaches that operate in the time-frequency (TF) domain, the OTFS modulation strategy conveys information symbols (ISs) across the two-dimensional (2D) DD domain, as explained in [14; 18; 19; 20; 21; 22]. In this domain, wireless channel paths with distinct DD shifts represent resolvable paths. Significant benefits are associated with employing the DD domain for channel characterization. In communication scenarios featuring pronounced mobility, the DD domain channel typically exhibits sparsity and quasi-static behavior in contrast to the highly dynamic properties in the TF domain, as emphasized in references [23; 24; 25; 26]. Additionally, the OTFS boasts a reduced PAPR [27; 25; 28; 29; 30], simplifying implementation through more efficient power amplifiers, unlike its OFDM counterpart. In traditional OFDM systems, a high PAPR requires power amplifiers to operate with a larger dynamic range, leading to increased power requirements and impacting the overall energy efficiency of the system. OTFS modulation utilizes a unique signal representation in the DD domain, which may impact the PAPR characteristics differently compared to traditional OFDM. The energy efficiency of the OTFS modulation framework may be influenced by the computational complexity of its signal processing algorithms. Adaptive techniques for power control and modulation parameters may be employed to manage power levels dynamically, contributing to energy efficiency. Notably, the DD shifts, which correspondingly infer the velocity and range of targets, are pivotal, making OTFS modulation a logical selection for achieving ISAR (inverse synthetic aperture radar) objectives. Recent scholarly endeavors have examined radar sensing using the OTFS framework, as evidenced in [31; 32]. A maximum likelihood (ML) algorithm for estimating R and V in the OTFS is introduced by the authors in [31]. The results demonstrate that the OTFS signal has superior communication effectiveness compared to OFDM while preserving the radar estimation performance limit. Furthermore, Ref. [32] proposed a matched-filter (MF) algorithm to estimate the R and V parameters, leveraging the structure of the OTFS effective channel (EC). The findings indicate that OTFS-based speed estimations of targets outperform those of OFDM.