Design of OTFS Signals with Pulse Shaping and Window Function for OTFS-Based Radar

TL;DR

This paper introduces a novel OTFS radar signal design using a flexible generalized window function based on RRC, improving delay-Doppler estimation accuracy through enhanced pulse shaping and interpolation techniques.

Contribution

It proposes a generalized RRC window for OTFS signals, relaxing traditional constraints, and combines it with interpolation methods to improve fractional parameter estimation in radar.

Findings

Enhanced ambiguity function concentration in delay-Doppler domain

Superior fractional delay and Doppler shift estimation accuracy

Flexible window design allows negative and >1 values

Abstract

We propose a pulse radar system that employs a generalized window function derived from the root raised cosine (RRC), which relaxes the conventional constraint that the window values are within the range [0, 1]. The proposed window allows both negative values and values exceeding 1, enabling greater flexibility in signal design. The system transmits orthogonal time frequency space (OTFS) signals intermittently, establishing a flexible input-output relationship that captures both fractional delays and Doppler shifts. By combining the generalized RRC window with a rectangular pulse, the resulting pilot signal achieves a sharp concentration in the ambiguity function over both the delay and Doppler domains. To enhance the estimation accuracy of fractional parameters, we apply frequency-domain interpolation based on the autocorrelation of the RRC window, which outperforms conventional linear interpolation by preserving the signal structure more effectively.