Low Overhead and Scalable Time-Frequency Pilots Design for MIMO OTFS Channel Estimation

Fuente: arXiv
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Autori principali: Wang, Kailong, Petropulu, Athina
Natura: Preprint
Pubblicazione: 2025
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author Wang, Kailong
Petropulu, Athina
author_facet Wang, Kailong
Petropulu, Athina
contents Orthogonal Time Frequency Space (OTFS) modulation has recently garnered attention for its robustness in high-mobility wireless communication environments. In OTFS, the data symbols are mapped to the Doppler-Delay (DD) domain. In this paper, we address low-overhead, scalable pilot-aided estimation of channel state information (CSI) for MIMO OTFS systems. Existing channel estimation techniques either require non-overlapping DD domain pilots with guard regions across multiple antennas, thus sacrificing significant communication rate as the number of transmit antennas increases, or allow pilots to overlap between antennas and rely on high-complexity methods to mitigate pilot pollution. We propose a novel pilot placement approach that embeds pilots within the time-frequency (TF) frame of each OTFS burst, along with a new use of TF and DD guard bins to preserve waveform orthogonality on the TF pilot bins and data integrity in the DD domain, respectively. The proposed pilot placement enables low-complexity coarse estimation of the channel parameters. Moreover, the pilot orthogonality allows the construction of a virtual array (VA), enabling the formulation of a sparse signal recovery (SSR) problem in which the coarse estimates are used to build a low-dimensional dictionary matrix. The SSR solution then yields high-resolution estimates of the channel parameters. Simulation results show that the proposed approach achieves good performance with very low overhead and is robust to pilot pollution. Importantly, the required overhead is independent of the number of transmit antennas, ensuring scalability to large MIMO arrays. The proposed approach accounts for practical rectangular transmit pulse shaping and receiver matched filtering, as well as fractional Doppler effects.
format Preprint
id arxiv_https___arxiv_org_abs_2511_08504
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Low Overhead and Scalable Time-Frequency Pilots Design for MIMO OTFS Channel Estimation
Wang, Kailong
Petropulu, Athina
Signal Processing
Orthogonal Time Frequency Space (OTFS) modulation has recently garnered attention for its robustness in high-mobility wireless communication environments. In OTFS, the data symbols are mapped to the Doppler-Delay (DD) domain. In this paper, we address low-overhead, scalable pilot-aided estimation of channel state information (CSI) for MIMO OTFS systems. Existing channel estimation techniques either require non-overlapping DD domain pilots with guard regions across multiple antennas, thus sacrificing significant communication rate as the number of transmit antennas increases, or allow pilots to overlap between antennas and rely on high-complexity methods to mitigate pilot pollution. We propose a novel pilot placement approach that embeds pilots within the time-frequency (TF) frame of each OTFS burst, along with a new use of TF and DD guard bins to preserve waveform orthogonality on the TF pilot bins and data integrity in the DD domain, respectively. The proposed pilot placement enables low-complexity coarse estimation of the channel parameters. Moreover, the pilot orthogonality allows the construction of a virtual array (VA), enabling the formulation of a sparse signal recovery (SSR) problem in which the coarse estimates are used to build a low-dimensional dictionary matrix. The SSR solution then yields high-resolution estimates of the channel parameters. Simulation results show that the proposed approach achieves good performance with very low overhead and is robust to pilot pollution. Importantly, the required overhead is independent of the number of transmit antennas, ensuring scalability to large MIMO arrays. The proposed approach accounts for practical rectangular transmit pulse shaping and receiver matched filtering, as well as fractional Doppler effects.
title Low Overhead and Scalable Time-Frequency Pilots Design for MIMO OTFS Channel Estimation
topic Signal Processing
url https://arxiv.org/abs/2511.08504