Dense and Robust Visible Light Networking for Beyond 5G
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Visible light communication (VLC) has attracted significant attention over the past decade. In this talk, I will first present DenseVLC, a cell-free massive MIMO networking system enabled by densely distributed LED. DenseVLC forms different beam spots to serve multiple receivers simultaneously. Given a power budget for communication, we optimize the system throughput by adequately assigning the power budget among the distributed LEDs. Besides, we propose a novel synchronization method using non-line-of-sight VLC to synchronize all the transmitters that will form a beam spot to serve the same receiver. We implement DenseVLC with off-the-shelf devices, solve practical challenges in the system design, and evaluate it with extensive experiments in a system of 36 transmitters and four receivers in an area of 3 m x 3 m. Our results show that DenseVLC can improve the average system throughput by 45%, or improve the average power efficiency by 2.3x.
Next, I will show that VLC is not as secure as people thought: VLC can be sniffed through walls! The key principle behind this is that in VLC transmissions, a VLC transmitter not only emits visible light signals but also leaks out ‘side channel RF signals’. The leaked RF signals can be sniffed by a receiver to decode the VLC transmissions even the receiver is blocked (e.g., by walls) from the VLC transmitter. In our recent work, we establish a theoretical model to quantify the amplitude of the leaked RF signal and verify the model with comprehensive experiments. We design and implement a VLC sniffing system including receiver coil design, signal processing and frame decoding, spanning across hardware and software. Field studies show that with a cheap receiver design, our system can simultaneously sniff transmissions from multiple VLC transmitters 6.4 meters away with a 14 cm concrete wall in between, where the distance exceeds the communication range of most state-of-the-art VLC systems.
Qing Wang，世界顶尖理工大学之一荷兰代尔夫特理工大学的助理教授（工科在全球排名第15）。主要研究方向为面向物联网和Beyond 5G的可见光通信与组网。作为联合创始人，创建了全球首套开源的可见光通信系统科研平台OpenVLC。在ACM MobiCom、CoNEXT、SenSys、IEEE/ACM ToN、IEEE JSAC、TMC、TWC、INFOCOM等网络和通信领域著名会议和期刊上发表论文10余篇，为可见光通信在物联网等领域的科学研究和应用做出了突出贡献。