Workshop on Optical Wireless Communication (OWC)

Session WS6-1

Session 1

2:00 PM — 3:30 PM CST
Aug 9 Sun, 2:00 AM — 3:30 AM EDT

A Comprehensive Accuracy Analysis of Visible Light Positioning under Shot Noise

Xiaona Liu; Difan Zou; Nuo Huang; Sha Zhang

Visible light positioning (VLP) has received increasing attention recently due to its advantages of green energy, high accuracy, low cost and so on. And there exist a vast body of works focusing on proving the positioning accuracy limit of the VLP system based on Cramer-Rao lower bounds (CRLBs). However, most of them only consider thermal noise in their signal model but ignore other signal-dependent noises, which may be the dominant part in optical communication systems. Motivated by this, we study the positioning performance of VLP system in a more practical setting. More specifically, we prove the positioning accuracy limit under the consideration of both thermal noise and shot noise, and reveal how those two types of noises affect the positioning accuracy. In our numerical experiments, we show that shot noise cannot be neglected in the VLP system, especially in the high signal-noise-ratio (SNR) regime.

Dynamic Optical Wireless Communication Channel Characterization Through Air-Water Interface

Tianrui Lin; Chen Gong; Jianghua Luo; Zhengyuan Xu

In this paper, we consider an optical wireless communication system model whose channel consists of three parts: underwater channel, atmosphere channel and the interface between air and water. To better approximate the reality, besides the effect of random air-water interface, we consider the impact of ocean current which leads to misalignment between the transmitter and receiver. On the basis of this model, we explore the communication viability and simulate its link gain and time delay. Monte Carlo simulation results show that the dynamic air-water interface extends the communication opportunities, especially when there is no direct path between the underwater nodes and airborne base station.

Design of DBN based Demodulator in Underwater Wireless Optical Communications

Shuai Ma; Zhongdan Zhang; Hang Li; Jing Xu; Han Zhang; Sha Zhang; Shiyin Li

In this work, we present a machine learning based demodulation method for underwater wireless optical communication (UWOC) systems. Specifically, the demodulator is designed based on deep belief network (DBN) network. The DBN demodulator extracts features layer-by-layer through three restricted Boltzmann machines. To make the method more practical, we build a flexible end-to-end UWOC experimental platform to obtain a real data set of signals from ten different modulation methods. The extensive experiments are conducted and our results show that the DBN demodulator enjoys a better performance than other benchmarks.

Indoor Visible Light Communication Scheduling for IOT Scenarios with Short Blocklength

Shiyao Chang; Chen Gong; Nuo Huang; Zhengyuan Xu

We consider visible light communication (VLC) for Industrial Internet of Things (IOT), where multi-user area aggregation and distributed scheduling are adopted to improve network throughput and reduce user packet loss rate. For one thing, because of the massive connection, it faces huge computational complexity, and for another, when allocating limited resources, it is also necessary to consider the quality of service requirements. Based on the above requirements, we have proposed an approach of user area aggregation and maximizing the user sum throughput. In addition, we consider short packet transmission as the control message in Industry 4.0, and derive the achievable transmission rate of short packet. To solve the optimization problem, we adopt the Markov decision process (MDP). Simulation results show the performance gain over the conventional Round-robin method

Session Chair

Chen Gong

Session WS6-2

Session 2

4:00 PM — 5:30 PM CST
Aug 9 Sun, 4:00 AM — 5:30 AM EDT

Optimum Signal Shaping in Double-Sided Clipping DCO-OFDM

Shuo Li; Xintong Ling; Pengfei Ge; Jiaheng Wang; Xiqi Gao

Because of the nonnegative requirement for intensity modulation (IM) and the limited dynamic range of light-emitting diodes (LEDs), double-sided clipping is inevitable in direct-current-biased optical orthogonal frequency division multiplexing (DCO-OFDM) systems. Therefore, we should design proper signal shaping by finding a suitable bias and time-domain signal power to reduce the impact of clipping distortion. In this paper, we propose an optimal signal shaping scheme for double-sided clipping DCO-OFDM visible light communication (VLC) systems. We first model the double-sided clipping process, and formulate the signal shaping as an optimization problem in terms of the bias and time-domain signal power. We then analytically characterize the optimization problem and find the optimal signal shaping scheme. Based on the obtained optimal solution, we reveal several useful insights for practical DCO-OFDM design. The superiority and optimality of our proposed signal shaping scheme are verified by simulations.

Experimental Study on Wavefront Distortion Correction of 40-Elements Adaptive Optical System Based on SPGD Algorithm

Jun Li; Jianghua Luo; Zhenheng Xu; Xiuhua Yuan

We build an experimental system of adaptive optical (AO) system in a laboratory environment. When the light signal is transmitted through the turbulence chamber, the wavefront distortion is generated under the influence of atmospheric turbulence. We employ a deformable mirror (DM) to correct the wavefront distortion. The AO system adopts stochastic parallel gradient descent (SPGD) algorithm. Experimental results show that AO system is able to well correct the wavefront distortion.

Design and Implementation of a Rolling Shutter Based Image Sensor Communication System

Xixi Li; Weijie Liu; Zhengyuan Xu

Noticing the existing gap between two consecutive frames in a rolling shutter (RS) based image sensor communication system, we propose a method to obtain the frame gap time and the read-out time of the image sensor. Accordingly, we design and optimize the packet-reconstruction scheme in the presence of their adverse effects. We further suggest a beacon-jointed RS scheme with an novel header estimation strategy to reduce the extra cost for packet recovery and increase the transmission data rate. We present various experimental results to validate our design and method.

Optical rogue waves in the non-line-of-sight scattering and turbulence channels

Shangbin Li; Chen Gong; Boyang Huang; Difan Zou; Kun Wang; Zhengyuan Xu

The first significant evidences of optical rogue waves in the non-line-of-sight (NLOS) scattering and turbulence channels are observed. Some optical rogue waves can be well simulated by the soliton solutions of the nonlinear Schrodinger equation (NLSE).

Session Chair

Fang Yang

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