A Design Framework that Unifies 6G Modulation Schemes for Double Selectivity

Fuente: arXiv
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Main Authors: Mehrotra, Nishant, Mattu, Sandesh Rao, Calderbank, Robert
Format: Preprint
Published: 2025
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author Mehrotra, Nishant
Mattu, Sandesh Rao
Calderbank, Robert
author_facet Mehrotra, Nishant
Mattu, Sandesh Rao
Calderbank, Robert
contents There is significant recent interest in designing new modulation schemes for doubly-selective channels with large delay and Doppler spreads, where legacy modulation schemes based on time-frequency signal representations underperform. Multiple modulation schemes, e.g., in the delay-Doppler, chirp, time-sequency, and other domains, have been proposed in the literature for this purpose, with varying implementation details. In this letter, we establish that all previously proposed modulation schemes for doubly-selective signaling are instances of a single family of complex Hadamard-modulated pulse trains. When the delay and Doppler spread of the doubly-selective channel is limited to a certain support, all modulation schemes in this waveform family offer equivalent, full diversity achieving performance with no symbol fading and low channel estimation overhead. The existence of this waveform family also enables flexible, multi-waveform co-existence -- allowing a common transceiver architecture to generate multiple waveforms in the family, that may each be flexibly allocated to different users and services.
format Preprint
id arxiv_https___arxiv_org_abs_2511_09418
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Design Framework that Unifies 6G Modulation Schemes for Double Selectivity
Mehrotra, Nishant
Mattu, Sandesh Rao
Calderbank, Robert
Signal Processing
Information Theory
There is significant recent interest in designing new modulation schemes for doubly-selective channels with large delay and Doppler spreads, where legacy modulation schemes based on time-frequency signal representations underperform. Multiple modulation schemes, e.g., in the delay-Doppler, chirp, time-sequency, and other domains, have been proposed in the literature for this purpose, with varying implementation details. In this letter, we establish that all previously proposed modulation schemes for doubly-selective signaling are instances of a single family of complex Hadamard-modulated pulse trains. When the delay and Doppler spread of the doubly-selective channel is limited to a certain support, all modulation schemes in this waveform family offer equivalent, full diversity achieving performance with no symbol fading and low channel estimation overhead. The existence of this waveform family also enables flexible, multi-waveform co-existence -- allowing a common transceiver architecture to generate multiple waveforms in the family, that may each be flexibly allocated to different users and services.
title A Design Framework that Unifies 6G Modulation Schemes for Double Selectivity
topic Signal Processing
Information Theory
url https://arxiv.org/abs/2511.09418