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1. Visible Light Communication Cyber-Physical Systems-on-Chip for Smart Cities

   Zijin, Pan; Tian, Lang; Cheng, Li; Mengfu, Di; Gang, Chen; Yehuda, Kalay; Ramdas, Pai; Albert, Wang (December 2019, Proc. 2nd IEEE International Conference on Information Communication and Signal Processing (ICSP))

   null (Ed.)

   This paper reviews recent developments of Light Emitting Diode (LED) based Visible Light Communication (VLC) technologies and related cyber-physical systems-on-chip (CPSoC) for smart city applications. Critical aspects of LED VLC cyber-physical systems are discussed. Designs of LEDbased VLC CPSoC Integrated Circuits (IC) are depicted. LED VLC technology, as a viable internet of things (IoT) solution, has the potential for various applications for smart cities including smart hospitals, smart homes, smart communities and smart traffics in near future. 

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2. A Study of Optical Tag Detection Using Rolling Shutter Based Visible Light Communications

   https://doi.org/10.1109/GLOBECOM38437.2019.9013449  

   Pan, Zijin; Lang, Tian; Li, Zening; Chen, Gang; Wang, Albert (December 2019, Proc. IEEE Global Communications Conference (GLOBECOM))

   null (Ed.)

   In this paper, we present an in-depth study of light emitting diode (LED) based indoor visible light communication positioning system using a smart phone camera with rolling shutter effect, aiming for smart and connected hospital applications. The LED transmits periodical signals with different frequencies as its optical tags. The camera exploits the rolling shutter effect to detect the fundamental frequency of optical signals. The roles of camera parameters determining the rolling effect are studied and a technique to measure the camera readout time per column is presented. Factors limiting the detectable optical frequency range is explained based on the discussion of rolling shutter mechanism. The Fourier spectrum based frequency resolution, which determines the tracking capacity, is analyzed. 

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3. Enabling Multiple Access in Visible Light Communication Using Liquid Crystal Displays: A Proof-of-Concept Study

   https://doi.org/10.3390/electronics9050826  

   Rahman, MD Rashed; Adedara, Kehinde; Ashok, Ashwin (May 2020, Electronics)

   null (Ed.)

   The directionality of optical signals provides an opportunity for efficient space reuse of optical links in visible light communication (VLC). Space reuse in VLC can enable multiple-access communication from multiple light emitting transmitters. Traditional VLC system design using photo-receptors requires at least one receiving photodetector element for each light emitter, thus constraining VLC to always require a light-emitter to light-receptor element pair. In this paper, we propose, design and evaluate a novel architecture for VLC that can enable multiple-access reception using a photoreceptor receiver that uses only a single photodiode. The novel design includes a liquid-crystal-display (LCD) based shutter system that can be automated to control and enable selective reception of light beams from multiple transmitters. We evaluate the feasibility of multiple access on a single photodiode from two light emitting diode (LED) transmitters and the performance of the communication link using bit-error-rate (BER) and packet-error-rate (PER) metrics. Our experiment and trace based evaluation through proof-of-concept implementation reveals the feasibility of multiple LED reception on a single photodiode. We further evaluate the system in controlled mobile settings to verify the adaptability of the receiver when the LED transmitter changes position. 

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4. Securing Smart Grid Enabled Home Area Networks with Retro-Reflective Visible Light Communication

   https://doi.org/10.3390/s23031245  

   Salas, Mathew; Shao, Sihua; Salustri, Adrian; Schroeck, Zachary; Zheng, Jun (February 2023, Sensors)

   Smart appliances’ run schedule and electric vehicles charging can be managed over a smart grid enabled home area network (HAN) to reduce electricity demand at critical times and add more plug-in electric vehicles to the grid, which eventually lower customers’ energy bills and reduce greenhouse gas emissions. Short range radio-based wireless communication technologies commonly adopted in a HAN are vulnerable to cyber attacks due to their wide interception range. In this work, a low-cost solution is proposed for securing the low-volume data exchange of sensitive tasks (e.g., key management and mutual authentication). Our approach utilizes the emerging concept of retro-reflector based visible light communication (Retro-VLC), where smart appliances, IoT sensors and other electric devices perform the sensitive data exchange with the HAN gateway via the secure Retro-VLC channel. To conduct the feasibility study, a multi-pixel Retro-VLC link is prototyped to enable quadrature amplitude modulation. The bit error rate of Retro-VLC is studied analytically, numerically and experimentally. A heterogeneous Retro-VLC + WLAN connection is implemented by socket programming. In addition, the working range, sniffing range, and key exchange latency are measured. The results validate the applicability of the Retro-VLC based solution. 

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5. MiShape: Accurate Human Silhouettes and Body Joints from Commodity Millimeter-Wave Devices

   https://doi.org/10.1145/3550300  

   Adhikari, Aakriti; Regmi, Hem; Sur, Sanjib; Nelakuditi, Srihari (September 2022, Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies)

   We propose MiShape, a millimeter-wave (mmWave) wireless signal based imaging system that generates high-resolution human silhouettes and predicts 3D locations of body joints. The system can capture human motions in real-time under low light and low-visibility conditions. Unlike existing vision-based motion capture systems, MiShape is privacy non-invasive and can generalize to a wide range of motion tracking applications at-home. To overcome the challenges with low-resolution, specularity, and aliasing in images from Commercial-Off-The-Shelf (COTS) mmWave systems, MiShape designs deep learning models based on conditional Generative Adversarial Networks and incorporates the rules of human biomechanics. We have customized MiShape for gait monitoring, but the model is well adaptive to any tracking applications with limited fine-tuning samples. We experimentally evaluate MiShape with real data collected from a COTS mmWave system for 10 volunteers, with diverse ages, gender, height, and somatotype, performing different poses. Our experimental results demonstrate that MiShape delivers high-resolution silhouettes and accurate body poses on par with an existing vision-based system, and unlocks the potential of mmWave systems, such as 5G home wireless routers, for privacy-noninvasive healthcare applications. 

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