Article
Engineering, Electrical & Electronic
Tilahun Zerihun Gutema, Harald Haas, Wasiu O. Popoola
Summary: This work investigates probabilistic shaping (PS) for optical wireless communications and its application to wavelength division multiplexing (WDM) based visible light communication (VLC). The performance of the proposed scheme is validated through experimental demonstration. The experimental setup employs lenses to collimate the light beam and optimizes system parameters of the WDM based VLC system, measures channel response, and allocates PS-based symbols to individual orthogonal frequency division multiplexing (OFDM) subcarriers. Under the considered channel conditions, PS achieves a near Shannon capacity transmission rate of 10.81 Gb/s, which is 25% higher than the widely used adaptive bit-power loading algorithm under the same channel conditions.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Chemistry, Analytical
Mohamad Hijazi, Shenjie Huang, Majid Safari
Summary: Visible light communication (VLC) is an emerging mode of wireless communication that supports both illumination and communication. In this paper, an adaptive SPAD receiver is proposed to enhance the sensitivity of VLC systems in low-light conditions. The receiver uses a variable optical attenuator (VOA) to adaptively control the SPAD's incident photon rate according to the received optical power.
Article
Computer Science, Information Systems
Faisal Khan, Fahim Umrani, Attiya Baqai, Muhammad Ijaz
Summary: This paper presents a novel SIM OFDM technique based on DS-PIM, which improves the conventional SIM OFDM by utilizing variable symbol size of DPIM and dynamic assignment of subcarriers.
Article
Computer Science, Information Systems
Itisha Nowrin, M. Rubaiyat Hossain Mondal, Rashed Islam, Joarder Kamruzzaman
Summary: This paper proposes a new hybrid optical OFDM form DPO-OFDM, which is power efficient and has a wide dimming range. Additionally, switching and machine learning algorithms are introduced to optimize performance.
Article
Optics
Ganesh Miriyala, V. V. Mani
Summary: This paper proposes a new modulation technique, LADO-OFDM, for VLC systems to mitigate mutual interference between signals, reduce computing complexity and latency. Simulation results show that the proposed scheme outperforms traditional ADO-OFDM in terms of BER performance.
Article
Engineering, Electrical & Electronic
Hima Bindu Valiveti, Budati Anil Kumar
Summary: The use of LiFi technology in high-speed vehicular networks improves indoor connectivity and eliminates the potential hazards of high radiated electromagnetic waves from WiFi. The effectiveness of using LiFi for video streaming is promising.
INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS
(2021)
Article
Engineering, Electrical & Electronic
Josep M. Fabrega, Raul Munoz, Laia Nadal, Carlos Manso, Michela Svaluto Moreolo, Ricard Vilalta, Ricardo Martinez, Francico Javier Vilchez, Diego Perez Galacho, Salvador Sales, Evangelos Grivas, Jaroslaw P. Turkiewicz, Simon Rommel, Idelfonso Tafur Monroy
Summary: An experiment showcasing a 5G digital fronthaul network utilizing multi-adaptive bandwidth/bitrate variable transceivers and an autonomic SDN control system for partially-disaggregated WDM/SDM. The SDN controller assigns optimal constellation based on per-subcarrier SNR to achieve EVM below 2.1%.
IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS
(2021)
Article
Optics
Lijuan Tang, Yinmei Wu, Zerui Cheng, Dongdong Teng, Lilin Liu
Summary: In this paper, integrated transmitter modules with 9 V high-voltage LED chips and built-in hardware pre-equalization circuits are designed and fabricated for WDM VLC system. The measured -3 dB electrical modulation bandwidths are obtained for purple, blue, green, and red channels, resulting in an aggregate bandwidth of about 3.37 GHz. The experiment shows that the maximum aggregate data rate for the offline VLC system exceeds 23.43 Gb/s and all wavelength channels have BERs below the pre-FEC limit of 7%.
OPTICS COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Yun-Han Chang, Yu-Ming Huang, Wahyu Hendra Gunawan, Guan-Hao Chang, Fang-Jyun Liou, Chi-Wai Chow, Hao-Chung Kuo, Yang Liu, Chien-Hung Yeh
Summary: This study demonstrates a record 4.343 Gbit/s green color micro-LED based visible-light communication technology. By growing the micro-LED on a semipolar orientation, a higher modulation bandwidth was achieved at a lower current density, leading to improved communication efficiency.
IEEE PHOTONICS JOURNAL
(2021)
Article
Optics
Peng Hao, Zhenchuan Wang, X. Steve Yao
Summary: We propose and demonstrate a Lidar beam-forming scheme using wavelength-division-multiplexing (WDM) and time-division-multiplexing (TDM), which eliminates the need for moving parts. The scheme achieves beam formation by demultiplexing lights with different wavelengths into N waveguides (WDM channels) and further switching them into M waveguides (TDM channels) to point in different directions. We have successfully demonstrated the scheme using 4 WDM channels and 1 x 4 optical fiber switches, together with time-of-flight (ToF) technique for distance measurement. This combined TDM and WDM scheme offers an attractive alternative to existing beam scanning methods.
OPTICS AND LASERS IN ENGINEERING
(2023)
Article
Telecommunications
Dil Nashin Anwar, Rizwana Ahmad, Anand Srivastava
Summary: This paper proposes a coexistence scheme for the Internet of Things (IoT) devices and LiFi users, considering their different requirements. The proposed scheme utilizes multiple techniques to achieve concurrent interference-free, low complexity, and reliable communication.
IEEE TRANSACTIONS ON GREEN COMMUNICATIONS AND NETWORKING
(2022)
Article
Computer Science, Information Systems
Mohammad Javad Zakavi, S. Alireza Nezamalhosseini, Lawrence R. Chen
Summary: This paper proposes a multiuser visible light communication (VLC) system using massive multiple-input multiple-output (mMIMO) orthogonal frequency-division multiplexing (OFDM) for achieving high data rates. By utilizing an array of LEDs to illuminate a room, user interference can be eliminated with simple linear signal processing, allowing more users to communicate simultaneously. The performance of three linear precoding methods in terms of spectral efficiency and downlink optical power is evaluated and compared.
Article
Optics
Syifaul Fuada, Erwin Setiawan, Trio Adiono, Wasiu O. Popoola
Summary: This paper presents a System-on-Chip (SoC) design for an Orthogonally Frequency Division Multiplexing (OFDM)-based Visible Light Communication (VLC) transceiver. The design includes a PHY layer implemented with OFDM modulation and an analog front-end (AFE). The SoC-based PHY layer is designed using a reuse methodology, and the IP cores are integrated using the AXI4 protocol standard. The proposed SoC architecture is tested with off-the-shelf components and field tests confirm the feasibility and performance of the design.
Article
Chemistry, Analytical
Wahyu Hendra Gunawan, Chi-Wai Chow, Yang Liu, Yun-Han Chang, Chien-Hung Yeh
Summary: This work presents a high-capacity visible light communication system that utilizes five dimensions in physics and achieves significant improvements in spectral efficiency and bandwidth utilization. The system is based on orthogonal frequency division multiplexing and non-orthogonal multiple access signals.
Article
Computer Science, Hardware & Architecture
Jianli Jin, Lifang Feng, Jianping Wang, Danyang Chen, Huimin Lu
Summary: This article introduces the architecture and multiplexing methods of visible light positioning systems, as well as the application of a new signature code. By discussing the decomposition of received signal strengths and the adaptive positioning mechanism, it demonstrates the potential superior performance in a large-scale IoT environment.
IEEE WIRELESS COMMUNICATIONS
(2021)
Article
Engineering, Electrical & Electronic
Anil Yesilkaya, Harald Haas
Summary: This article proposes an in-flight wireless communication method based on Light Fidelity (LiFi) technology, which provides seamless connection without RF interference in dense cabin environment by using reading lights as optical wireless access points. Modeling the in-flight LiFi links using Monte Carlo ray-tracing (MCRT) technique, the performance of on-board direct-current biased optical orthogonal frequency division multiplexing (DCO-OFDM) is evaluated.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Hossein Kazemi, Elham Sarbazi, Mohammad Dehghani Soltani, Taisir E. H. El-Gorashi, Jaafar M. H. Elmirghani, Richard V. Penty, Ian H. White, Majid Safari, Harald Haas
Summary: This paper systematically designs a MIMO optical wireless communication (OWC) link based on VCSEL arrays to support data rates in excess of 1 Tb/s for 6G indoor wireless networks. The proposed design combines DCO-OFDM and spatial multiplexing MIMO, and analyzes the impact of alignment errors on system performance, providing new guidelines for designing short-range Tb/s MIMO OWC systems.
IEEE TRANSACTIONS ON COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Tilahun Zerihun Gutema, Harald Haas, Wasiu O. Popoola
Summary: This work investigates probabilistic shaping (PS) for optical wireless communications and its application to wavelength division multiplexing (WDM) based visible light communication (VLC). The performance of the proposed scheme is validated through experimental demonstration. The experimental setup employs lenses to collimate the light beam and optimizes system parameters of the WDM based VLC system, measures channel response, and allocates PS-based symbols to individual orthogonal frequency division multiplexing (OFDM) subcarriers. Under the considered channel conditions, PS achieves a near Shannon capacity transmission rate of 10.81 Gb/s, which is 25% higher than the widely used adaptive bit-power loading algorithm under the same channel conditions.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Alain R. Ndjiongue, Telex M. N. Ngatched, Octavia A. Dobre, Harald Haas
Summary: This paper introduces the concept of using reconfigurable intelligent surfaces (RIS) to improve signal quality in optical wireless communication networks. By using digital RIS and applying digital signal processing techniques, the performance of optical communication systems can be enhanced. Additionally, the paper discusses the application of metamaterials with liquid crystals as the material for optical RIS.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
M. O. H. A. M. M. A. D. D. E. H. G. H. A. N. I. SOLTANI, E. L. H. A. M. SARBAZI, N. I. K. O. L. A. O. S. BAMIEDAKIS, P. R. I. Y. A. N. K. A. DE SOUZA, H. O. S. S. E. I. N. KAZEMI, J. A. A. F. A. R. M. H. ELMIRGHANI, I. A. N. H. WHITE, R. I. C. H. A. R. D. V. PENTY, H. A. R. A. L. D. HAAS, M. A. J. I. D. SAFARI
Summary: This article presents a comprehensive framework for eye safety analysis based on beam propagation, evaluating the received power of various laser sources and considering the impact of optical elements such as lenses, diffusers, and VCSEL arrays. The study investigates the effects of parameters including wavelength, exposure duration, and divergence angle on safety analysis.
PROCEEDINGS OF THE IEEE
(2022)
Article
Engineering, Electrical & Electronic
Chen Chen, Lin Zeng, Xin Zhong, Shu Fu, Zhihong Zeng, Min Liu, Harald Haas
Summary: In this paper, a novel two-dimensional generalized optical spatial modulation scheme is proposed for MIMO-OWC systems. Two different 2D GOSM mapping schemes are designed, and a deep learning-aided detection scheme is proposed to address the complexity and noise propagation issues. Simulation results demonstrate the superiority of the proposed scheme in high-speed and low-complexity MIMO-OWC systems.
IEEE PHOTONICS JOURNAL
(2022)
Article
Telecommunications
Iman Tavakkolnia, Cheng Chen, Yinzhou Tan, Harald Haas
Summary: A high-speed optical wireless-fiber solution is proposed, utilizing state-of-the-art modulation and multiplexing techniques, such as multicore fibers and coherent detection based on Kramer-Kronig receivers. Performance analysis shows that the proposed system outperforms an intensity modulation and direct detection system. The position of optical amplifiers affects the multiplexing gain and achievable data rate, considering the eye-safety constraint. Important challenges for practical deployment of the system are also discussed.
IEEE COMMUNICATIONS LETTERS
(2022)
Article
Telecommunications
Iman Tavakkolnia, Cheng Chen, Yinzhou Tan, Harald Haas
Summary: An optical communication link proposal is presented for high-speed point-to-point data transmission, which integrates fiber and optical wireless technologies. The use of Kramer-Kronig coherent detection ensures simplicity in component and implementation. By employing spatial multiplexing, multi-core fiber, and wavelength division multiplexing, the link effectively utilizes all available degrees of freedom. Consideration for various noise sources allows estimation of the link's signal-to-noise ratio. The impact of link loss and optical amplifier placement on achievable SNR is theoretically studied. Results reveal the possibility of achieving over 1 Tb/s per wavelength with a 4-core fiber and a simple optical wireless alignment system. The design has important applications in backhaul and intra-data center links.
IEEE COMMUNICATIONS LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Cheng-Xiang Wang, Zhen Lv, Xiqi Gao, Xiaohu You, Yang Hao, Harald Haas
Summary: This paper proposes a pervasive wireless channel modeling theory that can integrate important channel characteristics at different frequency bands and scenarios. It further applies the theory to a 3D space-time-frequency stochastic model for 6G wireless communication systems. The proposed model can accurately characterize channels for various frequency bands and scenarios.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Xiuming Zhu, Cheng-Xiang Wang, Jie Huang, Ming Chen, Harald Haas
Summary: This paper proposes a novel indoor visible light communication (VLC) channel model that captures unique channel characteristics and validates its accuracy and practicality through simulation and analysis. The proposed model plays an important supporting role in the design of future 6G VLC systems.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2022)
Article
Computer Science, Information Systems
Rui Feng, Cheng-Xiang Wang, Jie Huang, Xiqi Gao, Sana Salous, Harald Haas
Summary: This article emphasizes the importance of analyzing new massive MIMO channel characteristics and developing corresponding models for the Internet of Things (IoT). It provides a unified classification framework for different massive MIMO channel models and reviews recent advances in channel modeling. Furthermore, it elaborates and compares different nonpredictive massive MIMO channel models. Future challenges in massive MIMO channel modeling are also discussed.
IEEE INTERNET OF THINGS JOURNAL
(2022)
Article
Engineering, Electrical & Electronic
Mohammad Dehghani Soltani, Hossein Kazemi, Elham Sarbazi, Taisir E. H. El-Gorashi, Jaafar M. H. Elmirghani, Richard V. Penty, Ian H. White, Harald Haas, Majid Safari
Summary: In this paper, we propose a design of a compact high-speed and wide field of view (FOV) imaging receiver using an array of photodetectors and focusing lenses. By controlling the trade-offs between area-bandwidth and gain-FOV, we optimize the data rate achievable while maintaining a desired FOV.
IEEE TRANSACTIONS ON COMMUNICATIONS
(2023)
Article
Computer Science, Information Systems
Cheng-Xiang Wang, Xiaohu You, Xiqi Gao, Xiuming Zhu, Zixin Li, Chuan Zhang, Haiming Wang, Yongming Huang, Yunfei Chen, Harald Haas, John S. Thompson, Erik G. Larsson, Marco Di Renzo, Wen Tong, Peiying Zhu, Xuemin Shen, H. Vincent Poor, Lajos Hanzo
Summary: 5G has been commercially deployed, providing new services and improved user experiences to users, and offering novel opportunities to various industries. However, it still faces challenges, leading to research on 6G wireless communication systems by international organizations. This paper comprehensively presents the vision, technical requirements, and application scenarios of 6G, critically evaluates its network architecture and key technologies, introduces existing testbeds and advanced verification platforms, and identifies future research directions and open challenges.
IEEE COMMUNICATIONS SURVEYS AND TUTORIALS
(2023)
Article
Engineering, Electrical & Electronic
Tilahun Zerihun Gutema, Harald Haas, Wasiu O. Popoola
Summary: This work presents an analysis of symbol error performance in wireless communications using probabilistic shaping (PS) in both noise-limited and fading channels, specifically Rayleigh and log-normal fading channels. The results are validated through simulations and compared to uniformly distributed input symbols. The study shows that PS significantly reduces the required signal-to-noise ratio (SNR) compared to uniformly shaped symbols, across all channel conditions. For example, in a noise-limited channel, PS-based quadrature amplitude modulation (QAM) signals achieve SNR gains of 1.16 dB, 1.41 dB, and 1.52 dB compared to uniformly distributed QAM symbols at entropy rates of 4, 6, and 8 bit/symbol with a symbol error ratio (SER) of 1 x 10(-3).
IEEE OPEN JOURNAL OF THE COMMUNICATIONS SOCIETY
(2023)
Article
Engineering, Electrical & Electronic
Jordan Hill, Cheng Chen, Enyuan Xie, Jonathan J. D. Mckendry, Johannes Herrnsdorf, Erdan Gu, Harald Haas, Martin D. Dawson
Summary: We systematically investigate the performance of UV-C LEDs for optical wireless communication, focusing on the device size dependence. Smaller devices exhibit lower optical power but faster modulation speed. The study finds that a 60 μm diameter LED transmitter achieves the highest average SNR and SE, with a data transmission rate of up to 5.53 Gbps.
IEEE PHOTONICS JOURNAL
(2023)
