Machine Learning for Underwater Optical Wireless Communication Systems: A Comprehensive Survey
Abstract
Underwater Optical Wireless Communication (UOWC) has emerged as a promising technology for high-speed underwater data transmission, offering significantly higher bandwidth and lower latency compared to acoustic and Radio Frequency (RF) technologies. However, the underwater medium introduces severe impairments that degrade link performance and limit communication range. The growing complexity of these challenges has increased research interest in Machine Learning (ML) and Deep Learning (DL) approaches, which offer powerful tools for channel modeling, signal processing, and system adaptation in ways that conventional analytical methods struggle to achieve. This survey provides a comprehensive review of ML methods applied across the full UOWC system pipeline, covering channel modeling, transmitter design, receiver detection and equalization, link alignment, and emerging applications, including wireless power transfer, semantic communication, object detection, optical sensing, and localization. Finally, we discuss open challenges and future research directions to motivate further work in this rapidly growing field.
Figures & tables
| Abbreviation | Definition | Abbreviation | Definition |
|---|---|---|---|
| AE | Autoencoder | MLP | Multilayer Perceptron |
| ANN | Artificial Neural Network | NN | Neural Network |
| APD | Avalanche Photodiode | OAM | Orbital Angular Momentum |
| APT | Acquisition, Pointing, and Tracking | OFDM | Orthogonal Frequency Division Multiplexing |
| AUV | Autonomous Underwater Vehicle | OOK | On-Off Keying |
| BER | Bit Error Rate | OWC | Optical Wireless Communication |
| Pipeline stage | Reference | ML family | Data source | Evaluation |
| Channel modeling & estimation | Zhao et al. [ 28 ] | CNN (AlexNet) | Experimental QAM constellation diagrams | Experiment |
| Al-Amodi et al. [ 29 ] | CNN | Simulated received signal samples | Simulation | |
| Shashikanth et al. [ 30 ] | CNN - LSTM | Bubble turbulence (15 classes) | Experiment | |
| Lu et al. [ 31 ] | CNN + DNN | Harbor, clear, and mixed water channels | Simulation and experiment | |
| Jia et al. [ 32 ] | SRCNN + DnCNN | Experimental OFDM FD- UOWC channels | Experiment | |
| Bo et al. [ 33 ] | CNN - AE hybrid | EGG turbulence model | Simulation |
| Pipeline stage | Reference | ML family | Data source | Evaluation |
| Link alignment & adaptive control | Jia et al. [ 67 ] | YOLOv8s + RTMPose-t | ULDB image dataset | Experiment |
| Lu et al. [ 68 ] | CNN | MIMO UOWC | Simulation and experiment | |
| Tanaka et al. [ 69 ] | CNN | Twin-beam images (2.4 m tank) | Experiment | |
| Ishida et al. [ 70 ] | LSTM + DQN | Wave displacement data | Simulation | |
| Romdhane & Kaddoum [ 71 ] | Q-learning + SARSA | 4 water types | Simulation | |
| Shin et al. [ 72 ] | TPTA- DRL (3 agents) | USV trajectory data | Simulation |
| Parameter | Acoustic | RF | UOWC |
|---|---|---|---|
| Data Rate | kbps | Mbps | Gbps |
| Distance | Up to km | 10 m | 10–100 m |
| Latency | High | Moderate | Low |
| Frequency Band | 10–15 kHz | 30–300 Hz (ELF) / MHz range (buoyant) | – Hz |
| Key Limitation | Low data rate, high latency | Severe seawater attenuation | Limited range, misalignment sensitive |
| Reference | Model | Dataset | CR | Reported PSNR | Reported SSIM |
| [ 48 ] | ResNet + LSTM | EUVP | 1/16 | 26.92% improvement | 51.90% improvement |
| [ 49 ] | Swin Transformer | EUVP, UIEB, RUIE | – | 2.09 dB gain (BD-PSNR) | 0.0864 gain (BD-SSIM) |
| [ 51 ] | Swin Transformer | EUVP, UIEB, RUIE | 1/6 | 25.462 dB | 0.9417 |
| [ 50 ] | VAE | EUVP, UIEB, LSUI | 1/48 | 22.57 dB | 0.609 |
| [ 52 ] | ConvSC | UFO-120 | 1/16 | 25.8 dB | 8.7 dB MS-SSIM |
| [ 53 ] | RQ - VAE | EUVP | – | 28.89 dB | – |
| Reference | Method | Signal Format | Main Result | Evaluation |
|---|---|---|---|---|
| [ 59 ] | Shallow DNN | oversampled OOK | Joint equalization and decoding; 2.3 dB and 1.1 dB received-power gains over threshold detection and maximum likelihood estimation. | Experimental |
| [ 62 ] | BGRU | 64- APSK | Maximum Q-factor improvement of 2.4 dB and a transmission rate of 3.19 Gbps. | 1.2-m experimental link |
| [ 64 ] | DeepESN | PAM 4 and QAM - OFDM | Outperformed recursive LS equalization and trained only the output weights using SVD . | 40.5-m experimental link |
| [ 60 ] | TCN-LSTM-AM | PAM and QPSK - OFDM | Achieved 97.99% accuracy; the source reports a BER -performance improvement of up to 71.4% at 130 m relative to its reference results. | Simulation |
| [ 61 ] | CNN | Multiplexed OAM | Directly decoded intensity maps and outperformed the Gerchberg–Saxton algorithm under moderate and strong turbulence. | Numerical simulation |
| [ 66 ] | semiTNN | PAM 4 | Reached 4.26 Gbps using only 5–10% labeled data. | 14-m and 56-m experiments |
| UOWC Stage | Simulation | Experiment | Simulation and Experiment | Emulated UOWC | Total |
|---|---|---|---|---|---|
| Channel | 4 | 6 | 1 | 0 | 11 |
| Transmitter | 9 | 2 | 1 | 3 | 15 |
| Receiver | 6 | 7 | 1 | 0 | 14 |
| Link alignment | 6 | 3 | 3 | 0 | 12 |
| Emerging applications | 7 | 9 | 0 | 0 | 16 |
| Total | 32 | 27 | 6 | 3 | 68 |