Author Identifier
Muhammad Haziq: https://orcid.org/0009-0006-7406-8149
Date of Award
2025
Document Type
Thesis
Publisher
Edith Cowan University
Degree Name
Master of Engineering Science
School
School of Engineering
First Supervisor
Quoc Viet Phung
Second Supervisor
Stefan Lachowicz
Abstract
Underwater acoustic channels are highly time-varying and suffer from Doppler distortions and frequency-selective fades, which degrade the performance of the OFDM receiver. Therefore, this research enhances the transmission capability of OFDM by addressing two core issues: Doppler distortions and frequency-selective fades. The proposed study mitigates the Doppler shift at the subcarrier level using the cross-ambiguity function and employs an AI-based channel predictor that forecasts instantaneous channel gains for dynamic subcarrier power allocation. By integrating subcarrier-level CAF Doppler correction with predictive, adaptive power allocation, this research aims to improve spectral efficiency maximize per-subcarrier SNR, and increase the data rate in UWAC systems.
Simulation results confrm that the proposed CAF Doppler mitigation restores orthogonality and reduces ICI by over 3 dB. Furthermore, the CNN-based predictor delivers channel-state estimates with a normalized MSE below 1 × 10−2 , and the capped water-filling algorithm achieves a roughly 20% reduction in BER as compared to conventional OFDM with equal power allocation. This approach relies on standard pilot subcarriers and a lightweight CNN, making it compatible with existing OFDM frameworks.
Access Note
Access to this thesis is embargoed until 31st October 2026
DOI
10.25958/s1rq-0f83
Recommended Citation
Haziq, M. (2025). A study on the Doppler effect influence on subcarrier power allocation for a UWAC OFDM system. Edith Cowan University. https://doi.org/10.25958/s1rq-0f83