Deep Learning Aided Signal Detection for SPAD-Based Underwater Optical Wireless Communications

Rui Jiang,Aidong Zhang,Hongjie Wang,Caiming Sun,Xinke Tang,Long Zhang

doi:10.1109/access.2020.2967461

Abstract

In underwater optical wireless communication (UOWC) systems, using single photon avalanche photondiode (SPAD) as the detector can improve the transmission distance. However, the signal detection for SPAD-based systems is greatly challenged by the complex optical channel characteristics and SPAD nonlinear distortion. To address this issue, a novel deep learning aided signal detection scheme is proposed in this paper. By exploiting the physical mechanism and prior expert knowledge of the signal processing, a two-connected multilayer perception (MLP) network is integrated into the receiver. The first subnetwork is regarded as a channel compensation block while the second one works as a demodulator. With sophisticated numerical optical channel model and SPAD non-Poisson model, large amounts of training data are utilized to train the proposed model offline. Afterwards, the online data are recovered with the trained network. Simulation results verify that significant bit error ratio (BER) improvement can be achieved with the proposed scheme.

Highlights

With the application of technologies such as massive multi-input multi-output transmission, millimeter-wave communication and non-orthogonal multiple access scheme, 5G mobile communication has significantly increased the system capacity and supported massive connections [1]
Besides Underwater optical wireless communication (UOWC), underwater acoustic communication and radio frequency (RF) communication can be used for underwater wireless communication
The remainder of this paper is organized as follows: In Section II, we describe the characteristics of the UOWC systems, including the inherent optical property, the underwater optical channel and the single photon avalanche photondiode (SPAD) nonlinear detection

Summary

INTRODUCTION

With the application of technologies such as massive multi-input multi-output transmission, millimeter-wave (mm-mave) communication and non-orthogonal multiple access scheme, 5G mobile communication has significantly increased the system capacity and supported massive connections [1]. R. Jiang et al.: Deep Learning Aided Signal Detection for SPAD-Based UOWC radio wave can pass through the air-water interface, the underwater communication and terrestrial communication can be switched over smoothly [6]. Jiang et al.: Deep Learning Aided Signal Detection for SPAD-Based UOWC radio wave can pass through the air-water interface, the underwater communication and terrestrial communication can be switched over smoothly [6] The defect of this technology is that the distance is confined in the range of several meters due to the conductivity of the water. The expression of the Beer Law is simple to be used for optical link budget It is not accurate since the photons scattered out of the incident beam are not taken into account when calculating the radiance of the received light.

SPAD NONLINEAR DETECTION

SPAD BASED UOWC SYSTEM WITH DCO-OFDM MODULATION

OFFLINE TRAINING

PERFORMANCE EVALUATION

CONCLUSION