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Hongjia Wu

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3 records found

Co-Designing Smart Lighting and Communication for Visible Light Networks

Journal article (2020) - Hongjia Wu, Qing Wang, Jie Xiong, Marco Zuniga
Visible Light Communication (VLC) based on LEDs has been a hot topic investigated for over a decade. However, most of the research efforts assume the intensity of LED light is constant. This hypothesis is not true when Smart Lighting is introduced to VLC, which requires LEDs to adapt their brightness based on the intensity of natural ambient light. Smart lighting saves power consumption and improves user comfort. However, intensity adaptation severely affects the throughput performance of data communication. In this paper, we propose SmartVLC, a system that can maximize the throughput (benefit communication) while still maintaining the LEDs' illumination function (benefit smart lighting). A novel Adaptive Multiple Pulse Position Modulation (AMPPM) scheme is proposed to support fine-grained dimming levels to avoid flickering while maximizing the throughput under each dimming level. SmartVLC is implemented on off-the-shelf commodity hardware. Several real-life challenges in both hardware and software are addressed to make it a robust real-time system. Comprehensive experiments are carried out to evaluate the system performance under multifaceted scenarios. Experimental results demonstrate that SmartVLC supports a communication distance up to 3.6m, and improves the throughput achieved with two state-of-the-art approaches by 40 and 12 percent on average, respectively, without bringing any flickering to users. ...

When Smart Lighting Meets VLC

Conference paper (2017) - Hongjia Wu, Qing Wang, Jie Xiong, M.A. Zuñiga Zamalloa
Visible Light Communication (VLC) based on LEDs has been a hot topic investigated for over a decade. However, most of the research efforts in this area assume the intensity of the light emitted from LEDs is constant. This is not true any more when Smart Lighting is introduced to VLC in recent years, which requires the LEDs to adapt their brightness according to the intensity of the natural ambient light. Smart lighting saves power consumption and improves user comfort. However, intensity adaptation severely affects the throughput performance of the data communication. In this paper, we propose SmartVLC, a system that can maximize the throughput (benefit communication) while still maintaining the LEDs' illumination function (benefit smart lighting). A new adaptive multiple pulse position modulation scheme is proposed to support fine-grained dimming levels to avoid flickering and at the same time, maximize the throughput under each dimming level. SmartVLC is implemented on low-cost commodity hardware and several real-life challenges in both hardware and software are addressed to make SmartVLC a robust realtime system. Comprehensive experiments are carried out to evaluate the performance of SmartVLC under multifaceted scenarios. The results demonstrate that SmartVLC supports a communication distance up to 3.6m, and improves the throughput achieved with two state-of-the-art approaches by 40% and 12% on average, respectively, without bringing any flickering to users. ...

OpenVLC1.2 for Increased Data Rate With Embedded Systems

Conference paper (2017) - Ander Galisteo, Hongjia Wu, Qing Wang, Diego Juara, Marco Zuñiga , Domenico Giustiniano
We introduce the OpenVLC1.2 platform for research in Visible Light Communication (VLC) systems. The platform builds on top of previous versions, that has attracted dozens of users from the research community. We maintain its advantages such as the support for communication with TCP/IP layers, software-based and programmable MAC and PHY layers, and low-cost front-end. In this new version, we make an effort to increase data rate and its overall performance. OpenVLC1.2 is available to the research community. ...