CIS-BWE: Chaos-Informed Speech Bandwidth Extension

Tarikul Islam Tamiti, Tonmoy Das, Nursadul Mamun, Anomadarshi Barua


Abstract
We design CIS-BWE, a novel adversarial Bandwidth Extension (BWE) framework that introduces two chaos-informed discriminators - Multi-Resolution Lyapunov Discriminator (MRLD) and Multi-Scale Detrended Fractal Analysis Discriminator (MSDFA) - for capturing the deterministic chaos from speech. MRLD exploits Lyapunov exponents to capture nonlinear chaotic fluctuations. MSDFA exploits detrended fluctuation analysis to quantify fractal-like, long-range temporal chaotic correlations. To the best of our knowledge, MRLD and MSDFA are included here for the first time with a complex-valued adversarial network to explore the chaotic study of speech reconstruction. We also introduce a novel complex-valued and dual-stream generator, which uses our newly proposed ConformerNeXt as a core block with Lattice interactions, acting as a gating mechanism by enabling controlled mixing of information across streams. We extensively optimize our design across five resolutions and use depth-wise separable convolutions to make our model lightweight yet powerful. Our CIS-BWE is tested with a de facto English and French dataset for clean and noisy speech for generalization. It achieves better performance across a total of nine subjective and objective evaluation metrics with a 40x reduction in discriminator size and overall 0.5x fewer parameters, establishing a new baseline in the BWE task.
Anthology ID:
2026.acl-long.1925
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
41509–41529
Language:
URL:
https://aclanthology.org/2026.acl-long.1925/
DOI:
10.18653/v1/2026.acl-long.1925
Bibkey:
Cite (ACL):
Tarikul Islam Tamiti, Tonmoy Das, Nursadul Mamun, and Anomadarshi Barua. 2026. CIS-BWE: Chaos-Informed Speech Bandwidth Extension. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 41509–41529, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
CIS-BWE: Chaos-Informed Speech Bandwidth Extension (Tamiti et al., ACL 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.acl-long.1925.pdf
Checklist:
 2026.acl-long.1925.checklist.pdf