Zak-OTFS for Identification of Linear Time-Varying Systems

Fuente: arXiv
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Hauptverfasser: Nisar, Danish, Mohammed, Saif Khan, Hadani, Ronny, Chockalingam, Ananthanarayanan, Calderbank, Robert
Format: Preprint
Veröffentlicht: 2025
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author Nisar, Danish
Mohammed, Saif Khan
Hadani, Ronny
Chockalingam, Ananthanarayanan
Calderbank, Robert
author_facet Nisar, Danish
Mohammed, Saif Khan
Hadani, Ronny
Chockalingam, Ananthanarayanan
Calderbank, Robert
contents Linear time-varying (LTV) systems model radar scenes where each reflector/target applies a delay, Doppler shift and complex amplitude scaling to a transmitted waveform. The receiver processes the received signal using the transmitted signal as a reference. The self-ambiguity function of the transmitted signal captures the cross-correlation of delay and Doppler shifts of the transmitted waveform. It acts as a blur that limits resolution, at the receiver, of the delay and Doppler shifts of targets in close proximity. This paper considers resolution of multiple targets and compares performance of traditional chirp waveforms with the Zak-OTFS waveform. The self-ambiguity function of a chirp is a line in the delay-Doppler domain, whereas the self-ambiguity function of the Zak-OTFS waveform is a lattice. The advantage of lattices over lines is better localization, and we show lattices provide superior noise-free estimation of the range and velocity of multiple targets. When the delay spread of the radar scene is less than the delay period of the Zak-OTFS modulation, and the Doppler spread is less than the Doppler period, we describe how to localize targets by calculating cross-ambiguities in the delay-Doppler domain. We show that the signal processing complexity of our approach is superior to the traditional approach of computing cross-ambiguities in the continuous time / frequency domain.
format Preprint
id arxiv_https___arxiv_org_abs_2503_18900
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Zak-OTFS for Identification of Linear Time-Varying Systems
Nisar, Danish
Mohammed, Saif Khan
Hadani, Ronny
Chockalingam, Ananthanarayanan
Calderbank, Robert
Signal Processing
Information Theory
Linear time-varying (LTV) systems model radar scenes where each reflector/target applies a delay, Doppler shift and complex amplitude scaling to a transmitted waveform. The receiver processes the received signal using the transmitted signal as a reference. The self-ambiguity function of the transmitted signal captures the cross-correlation of delay and Doppler shifts of the transmitted waveform. It acts as a blur that limits resolution, at the receiver, of the delay and Doppler shifts of targets in close proximity. This paper considers resolution of multiple targets and compares performance of traditional chirp waveforms with the Zak-OTFS waveform. The self-ambiguity function of a chirp is a line in the delay-Doppler domain, whereas the self-ambiguity function of the Zak-OTFS waveform is a lattice. The advantage of lattices over lines is better localization, and we show lattices provide superior noise-free estimation of the range and velocity of multiple targets. When the delay spread of the radar scene is less than the delay period of the Zak-OTFS modulation, and the Doppler spread is less than the Doppler period, we describe how to localize targets by calculating cross-ambiguities in the delay-Doppler domain. We show that the signal processing complexity of our approach is superior to the traditional approach of computing cross-ambiguities in the continuous time / frequency domain.
title Zak-OTFS for Identification of Linear Time-Varying Systems
topic Signal Processing
Information Theory
url https://arxiv.org/abs/2503.18900