Recent Publications
2025
Eldeeb, Hossien B.; Qaraqe, Marwa; Muhaidat, Sami; Ghrayeb, Ali; Tavakkolnia, Iman; Haas, Harald
Shaping Connectivity: Channel Modeling and Performance Analysis of Reconfigurable Intelligent Surfaces for IoV Visible Light Communication Journal Article
In: IEEE Transactions on Vehicular Technology, vol. 74, no. 8, pp. 12529–12543, 2025, ISSN: 0018-9545, 1939-9359.
Links | BibTeX | Tags: LRDC, transport, vehicular communications
@article{eldeeb_shaping_2025b,
title = {Shaping Connectivity: Channel Modeling and Performance Analysis of Reconfigurable Intelligent Surfaces for IoV Visible Light Communication},
author = {Hossien B. Eldeeb and Marwa Qaraqe and Sami Muhaidat and Ali Ghrayeb and Iman Tavakkolnia and Harald Haas},
url = {https://ieeexplore.ieee.org/document/10938375/},
doi = {10.1109/TVT.2025.3554581},
issn = {0018-9545, 1939-9359},
year = {2025},
date = {2025-08-01},
urldate = {2025-08-27},
journal = {IEEE Transactions on Vehicular Technology},
volume = {74},
number = {8},
pages = {12529–12543},
keywords = {LRDC, transport, vehicular communications},
pubstate = {published},
tppubtype = {article}
}
King, Liam G.; Majlesein, Behnaz; Osahon, Isaac N. O.; Yoshida, Kou; Haas, Harald; Samuel, Ifor D. W.
Visible light communication using thermally activated delayed fluorescent OLEDs Journal Article
In: Device, pp. 100835, 2025, ISSN: 26669986.
Links | BibTeX | Tags: LRDC, OLEDs, visible-light communication (VLO)
@article{king_visible_2025,
title = {Visible light communication using thermally activated delayed fluorescent OLEDs},
author = {Liam G. King and Behnaz Majlesein and Isaac N. O. Osahon and Kou Yoshida and Harald Haas and Ifor D. W. Samuel},
url = {https://linkinghub.elsevier.com/retrieve/pii/S2666998625001486},
doi = {10.1016/j.device.2025.100835},
issn = {26669986},
year = {2025},
date = {2025-06-01},
urldate = {2025-08-27},
journal = {Device},
pages = {100835},
keywords = {LRDC, OLEDs, visible-light communication (VLO)},
pubstate = {published},
tppubtype = {article}
}
Yoshida, Kou; Majlesein, Behnaz; Chen, Cheng; Haas, Harald; Turnbull, Graham A.; Samuel, Ifor D. W.
High-speed organic light-emitting diodes based on dinaphthylperylene achieving 4-Gbps communication Journal Article
In: Advanced Photonics, vol. 7, no. 03, 2025, ISSN: 2577-5421.
Links | BibTeX | Tags: LRDC, OLEDs, visible-light communication (VLO)
@article{yoshida_high-speed_2025,
title = {High-speed organic light-emitting diodes based on dinaphthylperylene achieving 4-Gbps communication},
author = {Kou Yoshida and Behnaz Majlesein and Cheng Chen and Harald Haas and Graham A. Turnbull and Ifor D. W. Samuel},
url = {https://www.spiedigitallibrary.org/journals/advanced-photonics/volume-7/issue-03/036005/High-speed-organic-light-emitting-diodes-based-on-dinaphthylperylene-achieving/10.1117/1.AP.7.3.036005.full},
doi = {10.1117/1.AP.7.3.036005},
issn = {2577-5421},
year = {2025},
date = {2025-06-01},
urldate = {2025-08-27},
journal = {Advanced Photonics},
volume = {7},
number = {03},
keywords = {LRDC, OLEDs, visible-light communication (VLO)},
pubstate = {published},
tppubtype = {article}
}
Xu, Chao; Masouros, Christos; Sugiura, Shinya; Petropoulos, Periklis; Maunder, Robert G.; Yang, Lie-Liang; Haas, Harald; Hanzo, Lajos
Integrated Positioning and Communication Relying on Wireless Optical OFDM Journal Article
In: IEEE Journal on Selected Areas in Communications, vol. 43, no. 5, pp. 1721–1737, 2025, ISSN: 1558-0008, 0733-8716.
@article{xu_integrated_2025,
title = {Integrated Positioning and Communication Relying on Wireless Optical OFDM},
author = {Chao Xu and Christos Masouros and Shinya Sugiura and Periklis Petropoulos and Robert G. Maunder and Lie-Liang Yang and Harald Haas and Lajos Hanzo},
url = {https://ieeexplore.ieee.org/document/10900727/},
doi = {10.1109/JSAC.2025.3543532},
issn = {1558-0008, 0733-8716},
year = {2025},
date = {2025-05-01},
urldate = {2025-08-27},
journal = {IEEE Journal on Selected Areas in Communications},
volume = {43},
number = {5},
pages = {1721–1737},
keywords = {LRDC},
pubstate = {published},
tppubtype = {article}
}
Nacke, Richard; Pellegrino, Carmine; Lackner, David; Siefer, Gerald; Majlesein, Behnaz; Younus, Othman; Osahon, Isaac; Tavakkolnia, Iman; Bett, Andreas W.; Haas, Harald; Helmers, Henning
Application scenarios for simultaneous optical power and data transfer Proceedings Article
In: Jalali, Bahram (Ed.): Optical Power Delivery, pp. 20, SPIE, San Francisco, United States, 2025, ISBN: 9781510684669 9781510684676.
@inproceedings{nacke_application_2025,
title = {Application scenarios for simultaneous optical power and data transfer},
author = {Richard Nacke and Carmine Pellegrino and David Lackner and Gerald Siefer and Behnaz Majlesein and Othman Younus and Isaac Osahon and Iman Tavakkolnia and Andreas W. Bett and Harald Haas and Henning Helmers},
editor = {Bahram Jalali},
url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/13359/3042965/Application-scenarios-for-simultaneous-optical-power-and-data-transfer/10.1117/12.3042965.full},
doi = {10.1117/12.3042965},
isbn = {9781510684669 9781510684676},
year = {2025},
date = {2025-03-01},
urldate = {2025-08-27},
booktitle = {Optical Power Delivery},
pages = {20},
publisher = {SPIE},
address = {San Francisco, United States},
keywords = {LRDC},
pubstate = {published},
tppubtype = {inproceedings}
}
Du, Jia; Chen, Chen; Zeng, Zhihong; Wang, Dengke; Ye, Jia; Song, Jian; Haas, Harald
Flexible Waveform Design for RO-ISAC Based on OFDM-Embedded Maximum Length Sequence Journal Article
In: IEEE Wireless Communications Letters, pp. 1–1, 2025, ISSN: 2162-2337, 2162-2345.
@article{du_flexible_2025,
title = {Flexible Waveform Design for RO-ISAC Based on OFDM-Embedded Maximum Length Sequence},
author = {Jia Du and Chen Chen and Zhihong Zeng and Dengke Wang and Jia Ye and Jian Song and Harald Haas},
url = {https://ieeexplore.ieee.org/document/11098738/},
doi = {10.1109/LWC.2025.3593253},
issn = {2162-2337, 2162-2345},
year = {2025},
date = {2025-01-01},
urldate = {2025-08-27},
journal = {IEEE Wireless Communications Letters},
pages = {1–1},
keywords = {LRDC},
pubstate = {published},
tppubtype = {article}
}
Li, Qingchao; El-Hajjar, Mohammed; Cao, Kaijun; Xu, Chao; Haas, Harald; Hanzo, Lajos
Holographic Metasurface-Based Beamforming for Multi-Altitude LEO Satellite Networks Journal Article
In: IEEE Transactions on Wireless Communications, pp. 1–1, 2025, ISSN: 1558-2248.
Abstract | Links | BibTeX | Tags: Array signal processing, Computer architecture, Downlink, holographic metasurface, hybrid beamforming, inter-satellite interference, Low Earth Orbit (LEO) satellite communication, Metasurfaces, Precoding, Satellite broadcasting, stochastic geometry
@article{li_holographic_2025,
title = {Holographic Metasurface-Based Beamforming for Multi-Altitude LEO Satellite Networks},
author = {Qingchao Li and Mohammed El-Hajjar and Kaijun Cao and Chao Xu and Harald Haas and Lajos Hanzo},
url = {https://ieeexplore.ieee.org/abstract/document/10844052/?casa_token=5kb4rgy_qqAAAAAA:Qy4zV9IQ3FSfC6Cy7it5EvcxjQM2a675RSsbRiRKNPsADHjWFXZ0VHem5zJ_dVf5IBDhE6R2sg},
doi = {10.1109/TWC.2025.3527962},
issn = {1558-2248},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {IEEE Transactions on Wireless Communications},
pages = {1–1},
abstract = {Low Earth Orbit (LEO) satellite networks are capable of improving the global Internet service coverage. In this context, we propose a hybrid beamforming design for holographic metasurface based terrestrial users in multi-altitude LEO satellite networks. Firstly, the holographic beamformer is optimized by maximizing the downlink channel gain from the serving satellite to the terrestrial user. Then, the digital beamformer is designed by conceiving a minimum mean square error (MMSE) based detection algorithm for mitigating the interference arriving from other satellites. To dispense with excessive overhead of full channel state information (CSI) acquisition of all satellites, we propose a low-complexity MMSE beamforming algorithm that only relies on the distribution of the LEO satellite constellation harnessing stochastic geometry, which can achieve comparable throughput to that of the algorithm based on the full CSI in the case of a dense LEO satellite deployment. Furthermore, it outperforms the maximum ratio combining (MRC) algorithm, thanks to its inter-satellite interference mitigation capacity. The simulation results show that our proposed holographic metasurface based hybrid beamforming architecture is capable of outperforming the state-of-the-art antenna array architecture in terms of its throughput, given the same physical size of the transceivers. Moreover, we demonstrate that the beamforming performance attained can be substantially improved by taking into account the mutual coupling effect, imposed by the dense placement of the holographic metasurface elements.},
keywords = {Array signal processing, Computer architecture, Downlink, holographic metasurface, hybrid beamforming, inter-satellite interference, Low Earth Orbit (LEO) satellite communication, Metasurfaces, Precoding, Satellite broadcasting, stochastic geometry},
pubstate = {published},
tppubtype = {article}
}
Low Earth Orbit (LEO) satellite networks are capable of improving the global Internet service coverage. In this context, we propose a hybrid beamforming design for holographic metasurface based terrestrial users in multi-altitude LEO satellite networks. Firstly, the holographic beamformer is optimized by maximizing the downlink channel gain from the serving satellite to the terrestrial user. Then, the digital beamformer is designed by conceiving a minimum mean square error (MMSE) based detection algorithm for mitigating the interference arriving from other satellites. To dispense with excessive overhead of full channel state information (CSI) acquisition of all satellites, we propose a low-complexity MMSE beamforming algorithm that only relies on the distribution of the LEO satellite constellation harnessing stochastic geometry, which can achieve comparable throughput to that of the algorithm based on the full CSI in the case of a dense LEO satellite deployment. Furthermore, it outperforms the maximum ratio combining (MRC) algorithm, thanks to its inter-satellite interference mitigation capacity. The simulation results show that our proposed holographic metasurface based hybrid beamforming architecture is capable of outperforming the state-of-the-art antenna array architecture in terms of its throughput, given the same physical size of the transceivers. Moreover, we demonstrate that the beamforming performance attained can be substantially improved by taking into account the mutual coupling effect, imposed by the dense placement of the holographic metasurface elements.
Zeng, Zhihong; Chen, Chen; Wu, Xiping; Savović, Svetislav; Soltani, Mohammad Dehghani; Safari, Majid; Haas, Harald
Interference mitigation using optimised angle diversity receiver in LiFi cellular network Journal Article
In: Optics Communications, vol. 574, pp. 131125, 2025, ISSN: 00304018.
@article{zeng_interference_2025b,
title = {Interference mitigation using optimised angle diversity receiver in LiFi cellular network},
author = {Zhihong Zeng and Chen Chen and Xiping Wu and Svetislav Savović and Mohammad Dehghani Soltani and Majid Safari and Harald Haas},
url = {https://linkinghub.elsevier.com/retrieve/pii/S0030401824008629},
doi = {10.1016/j.optcom.2024.131125},
issn = {00304018},
year = {2025},
date = {2025-01-01},
urldate = {2024-10-30},
journal = {Optics Communications},
volume = {574},
pages = {131125},
keywords = {LRDC},
pubstate = {published},
tppubtype = {article}
}
2024
Safi, Hossein; Ihsan, Asim; Tavakkolnia, Iman; Haas, Harald
Optimizing Spatial Acquisition in Inter-Satellite FSO Links Under Beam jitter Miscellaneous
2024.
Abstract | Links | BibTeX | Tags: LRDC
@misc{safi_optimizing_2024b,
title = {Optimizing Spatial Acquisition in Inter-Satellite FSO Links Under Beam jitter},
author = {Hossein Safi and Asim Ihsan and Iman Tavakkolnia and Harald Haas},
url = {https://www.repository.cam.ac.uk/handle/1810/374012},
doi = {10.17863/CAM.112232},
year = {2024},
date = {2024-12-01},
urldate = {2024-10-30},
publisher = {Apollo - University of Cambridge Repository},
abstract = {The acquisition system is a key element in intersatellite free-space optics (FSO) links. Because satellite vibrations cause the scanning beam to jitter, making the acquisition process both challenging and time-consuming, minimizing acquisition time is crucial for the rapid establishment of an FSO link. In this paper, we present an optimization framework aimed at minimizing acquisition time while maintaining a predefined failure probability threshold. The optimization problem considers the total available power, the amount of overlap between the scanning beams (overlapping factor), and the beamwidth of the scanning beam. Additionally, we incorporate a weighting parameter to account for the varying power costs associated with adjusting the beamwidth and the overlapping factor. To solve this non-convex and NP-hard problem, we utilize an iterative successive convex approximation-based algorithm. When the cost of increasing laser power is high, the results show that as jitter variance increases, the optimal overlapping factor must also increase to maintain the acquisition success probability. Simultaneously, the beamwidth slightly decreases to adhere to power constraints. On the other hand, when the cost for increasing laser power is low, the optimal strategy involves maximizing the beamwidth and increasing the overlapping factor to mitigate jitter effects.},
keywords = {LRDC},
pubstate = {published},
tppubtype = {misc}
}
The acquisition system is a key element in intersatellite free-space optics (FSO) links. Because satellite vibrations cause the scanning beam to jitter, making the acquisition process both challenging and time-consuming, minimizing acquisition time is crucial for the rapid establishment of an FSO link. In this paper, we present an optimization framework aimed at minimizing acquisition time while maintaining a predefined failure probability threshold. The optimization problem considers the total available power, the amount of overlap between the scanning beams (overlapping factor), and the beamwidth of the scanning beam. Additionally, we incorporate a weighting parameter to account for the varying power costs associated with adjusting the beamwidth and the overlapping factor. To solve this non-convex and NP-hard problem, we utilize an iterative successive convex approximation-based algorithm. When the cost of increasing laser power is high, the results show that as jitter variance increases, the optimal overlapping factor must also increase to maintain the acquisition success probability. Simultaneously, the beamwidth slightly decreases to adhere to power constraints. On the other hand, when the cost for increasing laser power is low, the optimal strategy involves maximizing the beamwidth and increasing the overlapping factor to mitigate jitter effects.
Yuri, Jeon; Amlan, Basu; Tavakkolnia, Iman; Haas, Harald
Leveraging Time-domain Fingerprinting for Joint LiFi Position and Orientation Estimation Miscellaneous
2024.
Abstract | Links | BibTeX | Tags: LRDC
@misc{yuri_leveraging_2024b,
title = {Leveraging Time-domain Fingerprinting for Joint LiFi Position and Orientation Estimation},
author = {Jeon Yuri and Basu Amlan and Iman Tavakkolnia and Harald Haas},
url = {https://www.repository.cam.ac.uk/handle/1810/375328},
doi = {10.17863/CAM.113042},
year = {2024},
date = {2024-10-01},
urldate = {2024-10-30},
publisher = {Apollo - University of Cambridge Repository},
abstract = {To support performance requirements for smart services in 6G, user positioning is a crucial component. Indoor user position and orientation estimation based on Light Fidelity (LiFi) system is considered as a promising technology, due to its high precision, along with its ease of installation. The main bottleneck of user position and orientation estimation in LiFi is a non-linearity between the metrics, such as the received signal strength (RSS), position and orientation. A deep learning-based estimation methodology holds promise for addressing this issue, because it can learn complex propagation features dependent on user position and orientation. To fully capitalize on this advantage in the time-domain, we propose utilizing both time-series RSS and its received time, i.e. time-of-arrival (ToA) fingerprints, along with a novel neural network architecture named Deep RSS-ToA Fusion Network (DRTFNet). Simulation results demonstrate that the proposed DRTFNet achieves positioning accuracy of less than 3 cm and orientation accuracy of less than 3 degrees, outperforming both the basic Convolutional Neural Network (CNN) architecture using only RSS data and other baseline systems with more light sources.},
keywords = {LRDC},
pubstate = {published},
tppubtype = {misc}
}
To support performance requirements for smart services in 6G, user positioning is a crucial component. Indoor user position and orientation estimation based on Light Fidelity (LiFi) system is considered as a promising technology, due to its high precision, along with its ease of installation. The main bottleneck of user position and orientation estimation in LiFi is a non-linearity between the metrics, such as the received signal strength (RSS), position and orientation. A deep learning-based estimation methodology holds promise for addressing this issue, because it can learn complex propagation features dependent on user position and orientation. To fully capitalize on this advantage in the time-domain, we propose utilizing both time-series RSS and its received time, i.e. time-of-arrival (ToA) fingerprints, along with a novel neural network architecture named Deep RSS-ToA Fusion Network (DRTFNet). Simulation results demonstrate that the proposed DRTFNet achieves positioning accuracy of less than 3 cm and orientation accuracy of less than 3 degrees, outperforming both the basic Convolutional Neural Network (CNN) architecture using only RSS data and other baseline systems with more light sources.
Yoshida, Kou; Chen, Cheng; Haas, Harald; Turnbull, Graham A.; Samuel, Ifor D. W.
RGB‐Single‐Chip OLEDs for High‐Speed Visible‐Light Communication by Wavelength‐Division Multiplexing Journal Article
In: Advanced Science, pp. 2404576, 2024, ISSN: 2198-3844, 2198-3844.
Abstract | Links | BibTeX | Tags: LRDC
@article{yoshida_rgbsinglechip_2024b,
title = {RGB‐Single‐Chip OLEDs for High‐Speed Visible‐Light Communication by Wavelength‐Division Multiplexing},
author = {Kou Yoshida and Cheng Chen and Harald Haas and Graham A. Turnbull and Ifor D. W. Samuel},
url = {https://onlinelibrary.wiley.com/doi/10.1002/advs.202404576},
doi = {10.1002/advs.202404576},
issn = {2198-3844, 2198-3844},
year = {2024},
date = {2024-10-01},
urldate = {2024-10-30},
journal = {Advanced Science},
pages = {2404576},
abstract = {Abstract
Organic light‐emitting diodes (OLEDs) have been developed for high‐speed transmitters of visible‐light communication (VLC) but so far the possibility of direct fabrication of multiple colors on a single substrate has not been exploited for multi‐Gbps data transmission. Very fast red‐, green‐, and blue (RGB)‐emitting OLEDs are developed on a single substrate to realize high data transmission speed by wavelength division multiplexing (WDM). −6 dB electrical bandwidth of over 100 MHz is achieved for all colors by selecting fluorescent materials with nanosecond emission lifetimes and little overlap between their emission spectra and incorporating them into OLEDs designed for high‐speed operation. Optical microcavities in top‐emitting OLED structures are used to minimize spectral overlap. A record data transmission rate for an OLED transmitter system of 3.2 Gbps is demonstrated, by transmitting data with the 3 colors simultaneously and separating each data by dichroic mirrors. The results show that WDM with integrated RGB pixels is a useful way to increase the data transmission rate of a VLC system based on OLED transmitters, which has the potential to enable multi‐gigabit transmission by displays. The availability of high‐speed multiple‐color devices as developed here also expands applications of OLEDs for spectroscopy, sensing, and ranging.},
keywords = {LRDC},
pubstate = {published},
tppubtype = {article}
}
Abstract
Organic light‐emitting diodes (OLEDs) have been developed for high‐speed transmitters of visible‐light communication (VLC) but so far the possibility of direct fabrication of multiple colors on a single substrate has not been exploited for multi‐Gbps data transmission. Very fast red‐, green‐, and blue (RGB)‐emitting OLEDs are developed on a single substrate to realize high data transmission speed by wavelength division multiplexing (WDM). −6 dB electrical bandwidth of over 100 MHz is achieved for all colors by selecting fluorescent materials with nanosecond emission lifetimes and little overlap between their emission spectra and incorporating them into OLEDs designed for high‐speed operation. Optical microcavities in top‐emitting OLED structures are used to minimize spectral overlap. A record data transmission rate for an OLED transmitter system of 3.2 Gbps is demonstrated, by transmitting data with the 3 colors simultaneously and separating each data by dichroic mirrors. The results show that WDM with integrated RGB pixels is a useful way to increase the data transmission rate of a VLC system based on OLED transmitters, which has the potential to enable multi‐gigabit transmission by displays. The availability of high‐speed multiple‐color devices as developed here also expands applications of OLEDs for spectroscopy, sensing, and ranging.
Organic light‐emitting diodes (OLEDs) have been developed for high‐speed transmitters of visible‐light communication (VLC) but so far the possibility of direct fabrication of multiple colors on a single substrate has not been exploited for multi‐Gbps data transmission. Very fast red‐, green‐, and blue (RGB)‐emitting OLEDs are developed on a single substrate to realize high data transmission speed by wavelength division multiplexing (WDM). −6 dB electrical bandwidth of over 100 MHz is achieved for all colors by selecting fluorescent materials with nanosecond emission lifetimes and little overlap between their emission spectra and incorporating them into OLEDs designed for high‐speed operation. Optical microcavities in top‐emitting OLED structures are used to minimize spectral overlap. A record data transmission rate for an OLED transmitter system of 3.2 Gbps is demonstrated, by transmitting data with the 3 colors simultaneously and separating each data by dichroic mirrors. The results show that WDM with integrated RGB pixels is a useful way to increase the data transmission rate of a VLC system based on OLED transmitters, which has the potential to enable multi‐gigabit transmission by displays. The availability of high‐speed multiple‐color devices as developed here also expands applications of OLEDs for spectroscopy, sensing, and ranging.
Tang, Yuru; Chen, Chen; He, Cuiwei; Deng, Bohua; Liu, Min; Tang, Xinke; Fu, H. Y.; Haas, Harald
Joint In-Phase and Quadrature Non-Orthogonal Multiple Access for Multi-User VLC Journal Article
In: Journal of Lightwave Technology, vol. 42, no. 20, pp. 7219–7228, 2024, ISSN: 0733-8724, 1558-2213.
@article{tang_joint_2024b,
title = {Joint In-Phase and Quadrature Non-Orthogonal Multiple Access for Multi-User VLC},
author = {Yuru Tang and Chen Chen and Cuiwei He and Bohua Deng and Min Liu and Xinke Tang and H. Y. Fu and Harald Haas},
url = {https://ieeexplore.ieee.org/document/10557663/},
doi = {10.1109/JLT.2024.3414834},
issn = {0733-8724, 1558-2213},
year = {2024},
date = {2024-10-01},
urldate = {2024-10-30},
journal = {Journal of Lightwave Technology},
volume = {42},
number = {20},
pages = {7219–7228},
keywords = {LRDC},
pubstate = {published},
tppubtype = {article}
}
Liu, Mingqing; Kazemi, Hossein; Safari, Majid; Tavakkolnia, Iman; Haas, Harald
Energy Efficiency Comparison of THz and VCSEL-Based OWC for 6G Miscellaneous
2024.
Abstract | Links | BibTeX | Tags: LRDC
@misc{liu_energy_2024b,
title = {Energy Efficiency Comparison of THz and VCSEL-Based OWC for 6G},
author = {Mingqing Liu and Hossein Kazemi and Majid Safari and Iman Tavakkolnia and Harald Haas},
url = {https://www.repository.cam.ac.uk/handle/1810/375123},
doi = {10.17863/CAM.112916},
year = {2024},
date = {2024-10-01},
urldate = {2024-10-30},
publisher = {Apollo - University of Cambridge Repository},
abstract = {Both optical wireless communications (OWC) and Terahertz (THz) communication systems are regarded as enablers for the 6th-generation (6G) networks. Facing the 6G requirements of ultra-dense and high-rate networks, vertical-cavity surface-emitting laser (VCSEL)-based OWC is considered as a strong contender for providing high data rates with ultra-small cells. Hence, this work quantitatively compares VCSEL-based OWC and THz communication in terms of energy efficiency. We derive the energy efficiency model for realistic systems by including non-linearity power conversion of VCSEL and area-bandwidth tradeoff of the photodiode (PD) for OWC, and gain and power loss in cascaded THz systems, respectively. Then, we formulate the similarity of embedding optical lenses into VCSEL-based system and high-directivity antenna into THz system to achieve high channel gain, i.e., leading to a gain-coverage tradeoff for both systems. Taking account of this performance tradeoff in analyzing two systems' energy efficiency, we show numerically the superiority of the VCSEL-based system, while the THz system is more robust in long-range scenarios due to a more relaxed relationship between pointing error and transmission distances. This study provides design guidelines for selecting appropriate technologies tailored to various 6G application scenarios from an energy efficiency perspective.},
keywords = {LRDC},
pubstate = {published},
tppubtype = {misc}
}
Both optical wireless communications (OWC) and Terahertz (THz) communication systems are regarded as enablers for the 6th-generation (6G) networks. Facing the 6G requirements of ultra-dense and high-rate networks, vertical-cavity surface-emitting laser (VCSEL)-based OWC is considered as a strong contender for providing high data rates with ultra-small cells. Hence, this work quantitatively compares VCSEL-based OWC and THz communication in terms of energy efficiency. We derive the energy efficiency model for realistic systems by including non-linearity power conversion of VCSEL and area-bandwidth tradeoff of the photodiode (PD) for OWC, and gain and power loss in cascaded THz systems, respectively. Then, we formulate the similarity of embedding optical lenses into VCSEL-based system and high-directivity antenna into THz system to achieve high channel gain, i.e., leading to a gain-coverage tradeoff for both systems. Taking account of this performance tradeoff in analyzing two systems' energy efficiency, we show numerically the superiority of the VCSEL-based system, while the THz system is more robust in long-range scenarios due to a more relaxed relationship between pointing error and transmission distances. This study provides design guidelines for selecting appropriate technologies tailored to various 6G application scenarios from an energy efficiency perspective.
Osahon, Isaac N. O.; Kostakis, Ioannis; Powell, Denise; Meredith, Wyn; Missous, Mohamed; Haas, Harald; Tang, Jianming; Rajbhandari, Sujan
Neural Network Equalisation for High-Speed Eye-Safe Optical Wireless Communication with 850 nm SM-VCSELs Journal Article
In: Photonics, vol. 11, no. 8, pp. 772, 2024, ISSN: 2304-6732.
Abstract | Links | BibTeX | Tags: LRDC
@article{osahon_neural_2024b,
title = {Neural Network Equalisation for High-Speed Eye-Safe Optical Wireless Communication with 850 nm SM-VCSELs},
author = {Isaac N. O. Osahon and Ioannis Kostakis and Denise Powell and Wyn Meredith and Mohamed Missous and Harald Haas and Jianming Tang and Sujan Rajbhandari},
url = {https://www.mdpi.com/2304-6732/11/8/772},
doi = {10.3390/photonics11080772},
issn = {2304-6732},
year = {2024},
date = {2024-08-01},
urldate = {2024-10-30},
journal = {Photonics},
volume = {11},
number = {8},
pages = {772},
abstract = {In this paper, we experimentally illustrate the effectiveness of neural networks (NNs) as non-linear equalisers for multilevel pulse amplitude modulation (PAM-M) transmission over an optical wireless communication (OWC) link. In our study, we compare the bit-error-rate (BER) performances of two decision feedback equalisers (DFEs)—a multilayer-perceptron-based DFE (MLPDFE), which is the NN equaliser, and a transversal DFE (TRDFE)—under two degrees of non-linear distortion using an eye-safe 850 nm single-mode vertical-cavity surface-emitting laser (SM-VCSEL). Our results consistently show that the MLPDFE delivers superior performance in comparison to the TRDFE, particularly in scenarios involving high non-linear distortion and PAM constellations with eight or more levels. At a forward error correction (FEC) threshold BER of 0.0038, we achieve bit rates of textasciitilde28 Gbps, textasciitilde29 Gbps, textasciitilde22.5 Gbps, and textasciitilde5 Gbps using PAM schemes with 2, 4, 8, and 16 levels, respectively, with the MLPDFE. Comparably, the TRDFE yields bit rates of textasciitilde28 Gbps and textasciitilde29 Gbps with PAM-2 and PAM-4, respectively. Higher PAM levels with the TRDFE result in BERs greater than 0.0038 for bit rates above 2 Gbps. These results highlight the effectiveness of the MLPDFE in optimising the performance of SM-VCSEL-based OWC systems across different modulation schemes and non-linear distortion levels.},
keywords = {LRDC},
pubstate = {published},
tppubtype = {article}
}
In this paper, we experimentally illustrate the effectiveness of neural networks (NNs) as non-linear equalisers for multilevel pulse amplitude modulation (PAM-M) transmission over an optical wireless communication (OWC) link. In our study, we compare the bit-error-rate (BER) performances of two decision feedback equalisers (DFEs)—a multilayer-perceptron-based DFE (MLPDFE), which is the NN equaliser, and a transversal DFE (TRDFE)—under two degrees of non-linear distortion using an eye-safe 850 nm single-mode vertical-cavity surface-emitting laser (SM-VCSEL). Our results consistently show that the MLPDFE delivers superior performance in comparison to the TRDFE, particularly in scenarios involving high non-linear distortion and PAM constellations with eight or more levels. At a forward error correction (FEC) threshold BER of 0.0038, we achieve bit rates of textasciitilde28 Gbps, textasciitilde29 Gbps, textasciitilde22.5 Gbps, and textasciitilde5 Gbps using PAM schemes with 2, 4, 8, and 16 levels, respectively, with the MLPDFE. Comparably, the TRDFE yields bit rates of textasciitilde28 Gbps and textasciitilde29 Gbps with PAM-2 and PAM-4, respectively. Higher PAM levels with the TRDFE result in BERs greater than 0.0038 for bit rates above 2 Gbps. These results highlight the effectiveness of the MLPDFE in optimising the performance of SM-VCSEL-based OWC systems across different modulation schemes and non-linear distortion levels.
Cui, Yuanxin; Chen, Chen; Cai, Yueping; Zeng, Zhihong; Liu, Min; Ye, Jia; Shao, Sihua; Haas, Harald
Retroreflective optical ISAC using OFDM: channel modeling and performance analysis Journal Article
In: Optics Letters, vol. 49, no. 15, pp. 4214, 2024, ISSN: 0146-9592, 1539-4794.
Abstract | Links | BibTeX | Tags: LRDC
@article{cui_retroreflective_2024b,
title = {Retroreflective optical ISAC using OFDM: channel modeling and performance analysis},
author = {Yuanxin Cui and Chen Chen and Yueping Cai and Zhihong Zeng and Min Liu and Jia Ye and Sihua Shao and Harald Haas},
url = {https://opg.optica.org/abstract.cfm?URI=ol-49-15-4214},
doi = {10.1364/OL.528029},
issn = {0146-9592, 1539-4794},
year = {2024},
date = {2024-08-01},
urldate = {2024-10-30},
journal = {Optics Letters},
volume = {49},
number = {15},
pages = {4214},
abstract = {In this Letter, we propose and investigate a retroreflective optical
integrated sensing and communication (RO-ISAC) system using orthogonal
frequency division multiplexing (OFDM) and corner cube reflector
(CCR). To accurately model the reflected sensing channel of the
RO-ISAC system, both a point source model and an area source model are
proposed according to the two main types of light sources that are
widely used. Detailed theoretical and experimental results are
presented to verify the accuracy of the proposed channel models and
evaluate the communication and sensing performance of the considered
RO-ISAC system.},
keywords = {LRDC},
pubstate = {published},
tppubtype = {article}
}
In this Letter, we propose and investigate a retroreflective optical
integrated sensing and communication (RO-ISAC) system using orthogonal
frequency division multiplexing (OFDM) and corner cube reflector
(CCR). To accurately model the reflected sensing channel of the
RO-ISAC system, both a point source model and an area source model are
proposed according to the two main types of light sources that are
widely used. Detailed theoretical and experimental results are
presented to verify the accuracy of the proposed channel models and
evaluate the communication and sensing performance of the considered
RO-ISAC system.
integrated sensing and communication (RO-ISAC) system using orthogonal
frequency division multiplexing (OFDM) and corner cube reflector
(CCR). To accurately model the reflected sensing channel of the
RO-ISAC system, both a point source model and an area source model are
proposed according to the two main types of light sources that are
widely used. Detailed theoretical and experimental results are
presented to verify the accuracy of the proposed channel models and
evaluate the communication and sensing performance of the considered
RO-ISAC system.
Chen, Cheng; Das, Sovan; Videv, Stefan; Sparks, Adrian; Babadi, Sina; Krishnamoorthy, Aravindh; Lee, Changmin; Grieder, Daniel; Hartnett, Kathleen; Rudy, Paul; Raring, James; Najafi, Marzieh; Papanikolaou, Vasilis K.; Schober, Robert; Haas, Harald
100 Gbps Indoor Access and 4.8 Gbps Outdoor Point-to-Point LiFi Transmission Systems Using Laser-Based Light Sources Journal Article
In: Journal of Lightwave Technology, vol. 42, no. 12, pp. 4146–4157, 2024, ISSN: 0733-8724, 1558-2213.
Links | BibTeX | Tags: Journal, LRDC, REASON, TITAN, TOWS
@article{chen_100_2024b,
title = {100 Gbps Indoor Access and 4.8 Gbps Outdoor Point-to-Point LiFi Transmission Systems Using Laser-Based Light Sources},
author = {Cheng Chen and Sovan Das and Stefan Videv and Adrian Sparks and Sina Babadi and Aravindh Krishnamoorthy and Changmin Lee and Daniel Grieder and Kathleen Hartnett and Paul Rudy and James Raring and Marzieh Najafi and Vasilis K. Papanikolaou and Robert Schober and Harald Haas},
url = {https://ieeexplore.ieee.org/document/10529519/},
doi = {10.1109/JLT.2024.3400192},
issn = {0733-8724, 1558-2213},
year = {2024},
date = {2024-06-01},
urldate = {2024-08-20},
journal = {Journal of Lightwave Technology},
volume = {42},
number = {12},
pages = {4146–4157},
keywords = {Journal, LRDC, REASON, TITAN, TOWS},
pubstate = {published},
tppubtype = {article}
}
Safi, Hossein; Tavakkolnia, Iman; Haas, Harald
Deep Learning Based End-to-End Optical Wireless Communication Systems With Autoencoders Journal Article
In: IEEE Communications Letters, vol. 28, no. 6, pp. 1342–1346, 2024, ISSN: 1089-7798, 1558-2558, 2373-7891.
Links | BibTeX | Tags: GreenCom, Journal, LRDC, REASON
@article{safi_deep_2024b,
title = {Deep Learning Based End-to-End Optical Wireless Communication Systems With Autoencoders},
author = {Hossein Safi and Iman Tavakkolnia and Harald Haas},
url = {https://ieeexplore.ieee.org/document/10496138/},
doi = {10.1109/LCOMM.2024.3387286},
issn = {1089-7798, 1558-2558, 2373-7891},
year = {2024},
date = {2024-06-01},
urldate = {2024-08-20},
journal = {IEEE Communications Letters},
volume = {28},
number = {6},
pages = {1342–1346},
keywords = {GreenCom, Journal, LRDC, REASON},
pubstate = {published},
tppubtype = {article}
}
Zhong, Xin; Chen, Chen; Wen, Wanli; Liu, Min; Fu, H. Y.; Haas, Harald
Optimization of Surface Configuration in IRS-Aided MIMO-VLC: A BER Minimization Approach Journal Article
In: IEEE Photonics Journal, vol. 16, no. 3, pp. 1–12, 2024, ISSN: 1943-0655, 1943-0647.
@article{zhong_optimization_2024b,
title = {Optimization of Surface Configuration in IRS-Aided MIMO-VLC: A BER Minimization Approach},
author = {Xin Zhong and Chen Chen and Wanli Wen and Min Liu and H. Y. Fu and Harald Haas},
url = {https://ieeexplore.ieee.org/document/10517366/},
doi = {10.1109/JPHOT.2024.3395894},
issn = {1943-0655, 1943-0647},
year = {2024},
date = {2024-06-01},
urldate = {2024-10-30},
journal = {IEEE Photonics Journal},
volume = {16},
number = {3},
pages = {1–12},
keywords = {LRDC},
pubstate = {published},
tppubtype = {article}
}
Stewart, Will; Simeonidou, Dimitra; Richardson, David; Parmigiani, Francesca; Savory, Seb; Lord, Andrew; Haas, Harald
Editorial Foreword to the ECOC 2023 Special Issue Journal Article
In: Journal of Lightwave Technology, vol. 42, no. 11, pp. 3971–3971, 2024, ISSN: 0733-8724, 1558-2213.
@article{stewart_editorial_2024b,
title = {Editorial Foreword to the ECOC 2023 Special Issue},
author = {Will Stewart and Dimitra Simeonidou and David Richardson and Francesca Parmigiani and Seb Savory and Andrew Lord and Harald Haas},
url = {https://ieeexplore.ieee.org/document/10557578/},
doi = {10.1109/JLT.2024.3407988},
issn = {0733-8724, 1558-2213},
year = {2024},
date = {2024-06-01},
urldate = {2024-10-30},
journal = {Journal of Lightwave Technology},
volume = {42},
number = {11},
pages = {3971–3971},
keywords = {LRDC},
pubstate = {published},
tppubtype = {article}
}
Sperga, Janis; Islim, Mohamed Sufyan; Bian, Rui; Martena, Giovanni Luca; Haas, Harald
Photodiode Arrays Do Not Violate the Second Law of Thermodynamics: Photocurrent Bandwidth Trade-Off Proceedings Article
In: ICC 2024 - IEEE International Conference on Communications, pp. 2414–2419, IEEE, Denver, CO, USA, 2024, ISBN: 978-1-72819-054-9.
@inproceedings{sperga_photodiode_2024b,
title = {Photodiode Arrays Do Not Violate the Second Law of Thermodynamics: Photocurrent Bandwidth Trade-Off},
author = {Janis Sperga and Mohamed Sufyan Islim and Rui Bian and Giovanni Luca Martena and Harald Haas},
url = {https://ieeexplore.ieee.org/document/10622212/},
doi = {10.1109/ICC51166.2024.10622212},
isbn = {978-1-72819-054-9},
year = {2024},
date = {2024-06-01},
urldate = {2024-10-30},
booktitle = {ICC 2024 - IEEE International Conference on Communications},
pages = {2414–2419},
publisher = {IEEE},
address = {Denver, CO, USA},
keywords = {LRDC},
pubstate = {published},
tppubtype = {inproceedings}
}
Li, Juncheng; Huang, Yifan; Huang, Shenjie; Tavakkolnia, Iman; Haas, Harald; Safari, Majid
Integrated Communication and Positioning for IRS-Assisted LiFi Networks Proceedings Article
In: 2024 IEEE Wireless Communications and Networking Conference (WCNC), pp. 01–06, IEEE, Dubai, United Arab Emirates, 2024, ISBN: 9798350303582.
Links | BibTeX | Tags: Conference, LRDC, TOWS
@inproceedings{li_integrated_2024b,
title = {Integrated Communication and Positioning for IRS-Assisted LiFi Networks},
author = {Juncheng Li and Yifan Huang and Shenjie Huang and Iman Tavakkolnia and Harald Haas and Majid Safari},
url = {https://ieeexplore.ieee.org/document/10570819/},
doi = {10.1109/WCNC57260.2024.10570819},
isbn = {9798350303582},
year = {2024},
date = {2024-04-01},
urldate = {2024-08-20},
booktitle = {2024 IEEE Wireless Communications and Networking Conference (WCNC)},
pages = {01–06},
publisher = {IEEE},
address = {Dubai, United Arab Emirates},
keywords = {Conference, LRDC, TOWS},
pubstate = {published},
tppubtype = {inproceedings}
}
Qidan, Ahmad Adnan; Soltani, Mohammad Dehghani; Ali, Wajahat; Chen, Rui; Huang, Shenjie; Yosuf, Barzan; Mohamed, Sanaa; Singh, Ravinder; Liu, Yi; Kazemi, Hossein; Sarbazi, Elham; Berde, Bela; Chiaroni, Dominique; Bechadergue, Bastien; Abdeldayem, Fathi; Soni, Hardik; Tabu, Jose; Perrufel, Micheline; Serafimovski, Nikola; El-Gorashi, Taisir E. H.; Crisp, Michael; Penty, Richard; White, Ian H.; Haas, Harald; Safari, Majid; Elmirghani, Jaafar
Indoor Laser-Based Wireless Communications Book Section
In: Ding, Jupeng; Song, Jian; Mu, Penghua; Jia, Kejun (Ed.): Free Space Optics Technologies in B5G and 6G Era - Recent Advances, New Perspectives and Applications, IntechOpen, 2024, ISBN: 978-0-85466-389-7 978-0-85466-388-0.
Abstract | Links | BibTeX | Tags: LRDC
@incollection{ding_indoor_2024b,
title = {Indoor Laser-Based Wireless Communications},
author = {Ahmad Adnan Qidan and Mohammad Dehghani Soltani and Wajahat Ali and Rui Chen and Shenjie Huang and Barzan Yosuf and Sanaa Mohamed and Ravinder Singh and Yi Liu and Hossein Kazemi and Elham Sarbazi and Bela Berde and Dominique Chiaroni and Bastien Bechadergue and Fathi Abdeldayem and Hardik Soni and Jose Tabu and Micheline Perrufel and Nikola Serafimovski and Taisir E.H. El-Gorashi and Michael Crisp and Richard Penty and Ian H. White and Harald Haas and Majid Safari and Jaafar Elmirghani},
editor = {Jupeng Ding and Jian Song and Penghua Mu and Kejun Jia},
url = {https://www.intechopen.com/chapters/1167044},
doi = {10.5772/intechopen.1004064},
isbn = {978-0-85466-389-7 978-0-85466-388-0},
year = {2024},
date = {2024-03-01},
urldate = {2024-10-30},
booktitle = {Free Space Optics Technologies in B5G and 6G Era - Recent Advances, New Perspectives and Applications},
publisher = {IntechOpen},
abstract = {Optical wireless communication (OWC) is a strong candidate in the sixth generation (6G) of wireless communications as it can support data transmission at high communication speeds, low power consumption, high security, and high reliability. Near-infrared lasers, specifically vertical cavity surface emitting lasers (VCSELs), exhibit larger modulation bandwidth compared to light-emitting diodes (LEDs), and can provide aggregate data rates ranging up to Terabit per second (Tbps). This chapter proposes innovative optical transmitter and receiver designs for indoor laser-based wireless communications, aiming to provide seamless coverage in high-speed multi-user scenarios. The proposed optical transmitter is based on a 5 × 5 VCSEL array where each VCSEL can provide 10 Gigabit per second (Gbps) in a uniform coverage area of 20 cm x 20 cm, achieving a total of 250 Gbps in an area of 1 m2 at 3 m transmission distance. Moreover, two wide-FOV receiver designs that employ photodetector (PD) arrays in along with imaging or non-imaging optics are introduced to support such an ultra-high-speed optical link. The new design of OWC requires potential techniques to address various networking challenges, including cell formation, interference management, resource allocation, and backhauling. To this end, potential solutions for these challenges are discussed to help establish an end-to-end OWC infrastructure for practical deployment.},
keywords = {LRDC},
pubstate = {published},
tppubtype = {incollection}
}
Optical wireless communication (OWC) is a strong candidate in the sixth generation (6G) of wireless communications as it can support data transmission at high communication speeds, low power consumption, high security, and high reliability. Near-infrared lasers, specifically vertical cavity surface emitting lasers (VCSELs), exhibit larger modulation bandwidth compared to light-emitting diodes (LEDs), and can provide aggregate data rates ranging up to Terabit per second (Tbps). This chapter proposes innovative optical transmitter and receiver designs for indoor laser-based wireless communications, aiming to provide seamless coverage in high-speed multi-user scenarios. The proposed optical transmitter is based on a 5 × 5 VCSEL array where each VCSEL can provide 10 Gigabit per second (Gbps) in a uniform coverage area of 20 cm x 20 cm, achieving a total of 250 Gbps in an area of 1 m2 at 3 m transmission distance. Moreover, two wide-FOV receiver designs that employ photodetector (PD) arrays in along with imaging or non-imaging optics are introduced to support such an ultra-high-speed optical link. The new design of OWC requires potential techniques to address various networking challenges, including cell formation, interference management, resource allocation, and backhauling. To this end, potential solutions for these challenges are discussed to help establish an end-to-end OWC infrastructure for practical deployment.
Fonseca, Dayrene Frometa; Guzman, Borja Genoves; Martena, Giovanni Luca; Bian, Rui; Haas, Harald; Giustiniano, Domenico
Prediction-model-assisted reinforcement learning algorithm for handover decision-making in hybrid LiFi and WiFi networks Journal Article
In: Journal of Optical Communications and Networking, vol. 16, no. 2, pp. 159, 2024, ISSN: 1943-0620, 1943-0639.
Abstract | Links | BibTeX | Tags: LRDC
@article{frometa_fonseca_prediction-model-assisted_2024b,
title = {Prediction-model-assisted reinforcement learning algorithm for handover decision-making in hybrid LiFi and WiFi networks},
author = {Dayrene Frometa Fonseca and Borja Genoves Guzman and Giovanni Luca Martena and Rui Bian and Harald Haas and Domenico Giustiniano},
url = {https://opg.optica.org/abstract.cfm?URI=jocn-16-2-159},
doi = {10.1364/JOCN.495234},
issn = {1943-0620, 1943-0639},
year = {2024},
date = {2024-02-01},
urldate = {2024-10-30},
journal = {Journal of Optical Communications and Networking},
volume = {16},
number = {2},
pages = {159},
abstract = {The handover process in hybrid light fidelity (LiFi) and wireless fidelity (WiFi) networks (HLWNets) is very challenging due to the short area covered by LiFi access points and the coverage overlap between LiFi and WiFi networks, which introduce frequent horizontal and vertical handovers, respectively. Different handover schemes have been proposed to reduce the handover rate in HLWNets, among which handover skipping (HS) techniques stand out. However, existing solutions are still inefficient or require knowledge that is not available in practice, such as the exact user’s trajectory or the network topology. In this work, a novel machine learning-based handover scheme is proposed to overcome the limitations of previous HS works. Specifically, we have designed a classification model to predict the type of user’s trajectory and assist a reinforcement learning (RL) algorithm to make handover decisions that are automatically adapted to new network conditions. The proposed scheme is called RL-HO, and we compare its performance against the standard handover scheme of long-term evolution (STD-LTE) and the so-called smart handover (Smart HO) algorithm. We show that our proposed RL-HO scheme improves the network throughput by 146% and 59% compared to STD-LTE and Smart HO, respectively. We make our simulator code publicly available to the research community.},
keywords = {LRDC},
pubstate = {published},
tppubtype = {article}
}
The handover process in hybrid light fidelity (LiFi) and wireless fidelity (WiFi) networks (HLWNets) is very challenging due to the short area covered by LiFi access points and the coverage overlap between LiFi and WiFi networks, which introduce frequent horizontal and vertical handovers, respectively. Different handover schemes have been proposed to reduce the handover rate in HLWNets, among which handover skipping (HS) techniques stand out. However, existing solutions are still inefficient or require knowledge that is not available in practice, such as the exact user’s trajectory or the network topology. In this work, a novel machine learning-based handover scheme is proposed to overcome the limitations of previous HS works. Specifically, we have designed a classification model to predict the type of user’s trajectory and assist a reinforcement learning (RL) algorithm to make handover decisions that are automatically adapted to new network conditions. The proposed scheme is called RL-HO, and we compare its performance against the standard handover scheme of long-term evolution (STD-LTE) and the so-called smart handover (Smart HO) algorithm. We show that our proposed RL-HO scheme improves the network throughput by 146% and 59% compared to STD-LTE and Smart HO, respectively. We make our simulator code publicly available to the research community.
Deng, Bohua; Chen, Chen; Huang, Haoyu; Li, Yibin; Tang, Yuru; Wei, Zixian; Luo, Yang; Liu, Min; Haas, Harald; Fu, H. Y.
Three-Dimensional Transmission Based UOWC in Complex Underwater Environments Journal Article
In: Journal of Lightwave Technology, pp. 1–13, 2024, ISSN: 0733-8724, 1558-2213.
@article{deng_three-dimensional_2024,
title = {Three-Dimensional Transmission Based UOWC in Complex Underwater Environments},
author = {Bohua Deng and Chen Chen and Haoyu Huang and Yibin Li and Yuru Tang and Zixian Wei and Yang Luo and Min Liu and Harald Haas and H. Y. Fu},
url = {https://ieeexplore.ieee.org/document/10636089/},
doi = {10.1109/JLT.2024.3443351},
issn = {0733-8724, 1558-2213},
year = {2024},
date = {2024-01-01},
urldate = {2024-10-30},
journal = {Journal of Lightwave Technology},
pages = {1–13},
keywords = {LRDC},
pubstate = {published},
tppubtype = {article}
}
Katsaros, Konstantinos; Mavromatis, Ioannis; Antonakoglou, Kostantinos; Ghosh, Saptarshi; Kaleshi, Dritan; Mahmoodi, Toktam; Asgari, Hamid; Karousos, Anastasios; Tavakkolnia, Iman; Safi, Hossein; Hass, Harald; Vrontos, Constantinos; Emami, Amin; Parra-Ullauri, Juan Marcelo; Moazzeni, Shadi; Simeonidou, Dimitra
AI-Native Multi-Access Future Networks—The REASON Architecture Journal Article
In: IEEE Access, vol. 12, pp. 178586–178622, 2024, ISSN: 2169-3536.
Links | BibTeX | Tags: 6G, artificial intelligence (AI), LRDC, REASON
@article{katsaros_ai-native_2024,
title = {AI-Native Multi-Access Future Networks—The REASON Architecture},
author = {Konstantinos Katsaros and Ioannis Mavromatis and Kostantinos Antonakoglou and Saptarshi Ghosh and Dritan Kaleshi and Toktam Mahmoodi and Hamid Asgari and Anastasios Karousos and Iman Tavakkolnia and Hossein Safi and Harald Hass and Constantinos Vrontos and Amin Emami and Juan Marcelo Parra-Ullauri and Shadi Moazzeni and Dimitra Simeonidou},
url = {https://ieeexplore.ieee.org/document/10769448/},
doi = {10.1109/ACCESS.2024.3507186},
issn = {2169-3536},
year = {2024},
date = {2024-01-01},
urldate = {2025-08-27},
journal = {IEEE Access},
volume = {12},
pages = {178586–178622},
keywords = {6G, artificial intelligence (AI), LRDC, REASON},
pubstate = {published},
tppubtype = {article}
}
Li, Juncheng; Huang, Shenjie; Soltani, Mohammad Dehghani; Haas, Harald; Safari, Majid
Laser-Based Indoor Mobile Wireless Communication Aided by Stabilizers Journal Article
In: IEEE Open Journal of the Communications Society, pp. 1–1, 2024, ISSN: 2644-125X.
Links | BibTeX | Tags: Journal, LRDC, TOWS
@article{li_laser-based_2024b,
title = {Laser-Based Indoor Mobile Wireless Communication Aided by Stabilizers},
author = {Juncheng Li and Shenjie Huang and Mohammad Dehghani Soltani and Harald Haas and Majid Safari},
url = {https://ieeexplore.ieee.org/document/10579847/},
doi = {10.1109/OJCOMS.2024.3420102},
issn = {2644-125X},
year = {2024},
date = {2024-01-01},
urldate = {2024-08-20},
journal = {IEEE Open Journal of the Communications Society},
pages = {1–1},
keywords = {Journal, LRDC, TOWS},
pubstate = {published},
tppubtype = {article}
}
Huang, Yifan; Safari, Majid; Haas, Harald; Tavakkolnia, Iman
Optical Wireless 3-D-Positioning and Device Orientation Estimation Journal Article
In: IEEE Open Journal of the Communications Society, vol. 5, pp. 4519–4530, 2024, ISSN: 2644-125X.
Links | BibTeX | Tags: Journal, LRDC, REASON, TITAN, TOWS
@article{huang_optical_2024b,
title = {Optical Wireless 3-D-Positioning and Device Orientation Estimation},
author = {Yifan Huang and Majid Safari and Harald Haas and Iman Tavakkolnia},
url = {https://ieeexplore.ieee.org/document/10585312/},
doi = {10.1109/OJCOMS.2024.3423420},
issn = {2644-125X},
year = {2024},
date = {2024-01-01},
urldate = {2024-08-20},
journal = {IEEE Open Journal of the Communications Society},
volume = {5},
pages = {4519–4530},
keywords = {Journal, LRDC, REASON, TITAN, TOWS},
pubstate = {published},
tppubtype = {article}
}
Chen, Cheng; Huang, Shenjie; Tavakkolnia, Iman; Safari, Majid; Haas, Harald
Spatial and Wavelength Division Joint Multiplexing System Design for MIMO-OFDM Visible Light Communications Journal Article
In: IEEE Access, pp. 1–1, 2024, ISSN: 2169-3536.
Links | BibTeX | Tags: GreenCom, Journal, LRDC, META, TITAN
@article{chen_spatial_2024b,
title = {Spatial and Wavelength Division Joint Multiplexing System Design for MIMO-OFDM Visible Light Communications},
author = {Cheng Chen and Shenjie Huang and Iman Tavakkolnia and Majid Safari and Harald Haas},
url = {https://ieeexplore.ieee.org/document/10623642/},
doi = {10.1109/ACCESS.2024.3439407},
issn = {2169-3536},
year = {2024},
date = {2024-01-01},
urldate = {2024-08-20},
journal = {IEEE Access},
pages = {1–1},
keywords = {GreenCom, Journal, LRDC, META, TITAN},
pubstate = {published},
tppubtype = {article}
}
Zhong, Xin; Chen, Chen; Zhao, Yinan; Liu, Min; He, Cuiwei; Haas, Harald
Dual-mode spatial index modulation for MIMO-OWC Journal Article
In: Optics Letters, vol. 49, no. 2, pp. 334, 2024, ISSN: 0146-9592, 1539-4794.
Abstract | Links | BibTeX | Tags: LRDC
@article{zhong_dual-mode_2024b,
title = {Dual-mode spatial index modulation for MIMO-OWC},
author = {Xin Zhong and Chen Chen and Yinan Zhao and Min Liu and Cuiwei He and Harald Haas},
url = {https://opg.optica.org/abstract.cfm?URI=ol-49-2-334},
doi = {10.1364/OL.509658},
issn = {0146-9592, 1539-4794},
year = {2024},
date = {2024-01-01},
urldate = {2024-10-30},
journal = {Optics Letters},
volume = {49},
number = {2},
pages = {334},
abstract = {In this Letter, we propose and demonstrate a dual-mode spatial index modulation (DM-SIM) scheme for spectral efficiency enhancement of band-limited multiple-input multiple-output optical wireless communication (MIMO-OWC) systems. By performing dual-mode index modulation in the spatial domain, DM-SIM can transmit both spatial and constellation symbols. Since constellation design plays a vital role in the proposed DM-SIM scheme, we further propose three dual-mode constellation design approaches including phase rotation, amplitude scaling and joint phase rotation and amplitude scaling. Moreover, we also designed a differential log-likelihood ratio (LLR) detector for the proposed DM-SIM scheme. Experimental results show that the joint phase rotation and amplitude scaling approach can achieve a remarkable 3.2 dB signal-to-noise ratio (SNR) gain compared with the phase rotation approach in a 2×2 MIMO-OWC system applying DM-SIM.},
keywords = {LRDC},
pubstate = {published},
tppubtype = {article}
}
In this Letter, we propose and demonstrate a dual-mode spatial index modulation (DM-SIM) scheme for spectral efficiency enhancement of band-limited multiple-input multiple-output optical wireless communication (MIMO-OWC) systems. By performing dual-mode index modulation in the spatial domain, DM-SIM can transmit both spatial and constellation symbols. Since constellation design plays a vital role in the proposed DM-SIM scheme, we further propose three dual-mode constellation design approaches including phase rotation, amplitude scaling and joint phase rotation and amplitude scaling. Moreover, we also designed a differential log-likelihood ratio (LLR) detector for the proposed DM-SIM scheme. Experimental results show that the joint phase rotation and amplitude scaling approach can achieve a remarkable 3.2 dB signal-to-noise ratio (SNR) gain compared with the phase rotation approach in a 2×2 MIMO-OWC system applying DM-SIM.
Safi, Hossein; Dabiri, Mohammad Taghi; Cheng, Julian; Tavakkolnia, Iman; Haas, Harald
CubeSat-Enabled Free-Space Optics: Joint Data Communication and Fine Beam Tracking Miscellaneous
2024, (Version Number: 1).
Abstract | Links | BibTeX | Tags: electronic engineering, FOS: Computer and information sciences, FOS: Electrical engineering, information engineering, Information Theory (cs.IT), LRDC, Signal Processing (eess.SP)
@misc{safi_cubesat-enabled_2024-1,
title = {CubeSat-Enabled Free-Space Optics: Joint Data Communication and Fine Beam Tracking},
author = {Hossein Safi and Mohammad Taghi Dabiri and Julian Cheng and Iman Tavakkolnia and Harald Haas},
url = {https://arxiv.org/abs/2406.18598},
doi = {10.48550/ARXIV.2406.18598},
year = {2024},
date = {2024-01-01},
urldate = {2024-10-30},
publisher = {arXiv},
abstract = {The integration of CubeSats with Free Space Optical (FSO) links accelerates a major advancement in high-throughput, low-Earth orbit communication systems. However, CubeSats face challenges such as size, weight, and power (SWaP) limitations, as well as vibrations that cause fluctuations in the angle-of-arrival (AoA) of the optical beam at the receiver. These practical challenges make establishing CubeSat-assisted FSO links complicated. To mitigate AoA fluctuations, we expand the receiver's field of view and track the location of the focused beam spot using an array of avalanche photodiodes at the receiver. Initially, we model the optical channel between the transmitter and the detector array. Furthermore, to reduce the computational load of maximum likelihood sequence detection, which is infeasible for CubeSats due to SWaP constraints, we propose a sub-optimal blind sequence data detection approach that relies on the generalized likelihood ratio test (GLRT) criterion. We also utilize combining methods such as equal gain combining (EGC) and maximal ratio combining (MRC) for data detection, benchmarking their performance against the GLRT-based method. Numerical results demonstrate that the proposed low-complexity GLRT-based method outperforms the combining methods, achieving performance close to that of the ideal receiver.},
note = {Version Number: 1},
keywords = {electronic engineering, FOS: Computer and information sciences, FOS: Electrical engineering, information engineering, Information Theory (cs.IT), LRDC, Signal Processing (eess.SP)},
pubstate = {published},
tppubtype = {misc}
}
The integration of CubeSats with Free Space Optical (FSO) links accelerates a major advancement in high-throughput, low-Earth orbit communication systems. However, CubeSats face challenges such as size, weight, and power (SWaP) limitations, as well as vibrations that cause fluctuations in the angle-of-arrival (AoA) of the optical beam at the receiver. These practical challenges make establishing CubeSat-assisted FSO links complicated. To mitigate AoA fluctuations, we expand the receiver's field of view and track the location of the focused beam spot using an array of avalanche photodiodes at the receiver. Initially, we model the optical channel between the transmitter and the detector array. Furthermore, to reduce the computational load of maximum likelihood sequence detection, which is infeasible for CubeSats due to SWaP constraints, we propose a sub-optimal blind sequence data detection approach that relies on the generalized likelihood ratio test (GLRT) criterion. We also utilize combining methods such as equal gain combining (EGC) and maximal ratio combining (MRC) for data detection, benchmarking their performance against the GLRT-based method. Numerical results demonstrate that the proposed low-complexity GLRT-based method outperforms the combining methods, achieving performance close to that of the ideal receiver.
Kazemi, Hossein; Sarbazi, Elham; Crisp, Michael; El-Gorashi, Taisir E. H.; Elmirghani, Jaafar M. H.; Penty, Richard V.; White, Ian H.; Safari, Majid; Haas, Harald
A Novel Terabit Grid-of-Beam Optical Wireless Multi-User Access Network With Beam Clustering Miscellaneous
2024, (Version Number: 1).
Abstract | Links | BibTeX | Tags: electronic engineering, FOS: Electrical engineering, information engineering, LRDC, Signal Processing (eess.SP)
@misc{kazemi_novel_2024b,
title = {A Novel Terabit Grid-of-Beam Optical Wireless Multi-User Access Network With Beam Clustering},
author = {Hossein Kazemi and Elham Sarbazi and Michael Crisp and Taisir E. H. El-Gorashi and Jaafar M. H. Elmirghani and Richard V. Penty and Ian H. White and Majid Safari and Harald Haas},
url = {https://arxiv.org/abs/2404.04443},
doi = {10.48550/ARXIV.2404.04443},
year = {2024},
date = {2024-01-01},
urldate = {2024-10-30},
publisher = {arXiv},
abstract = {In this paper, we put forward a proof of concept for sixth generation (6G) Terabit infrared (IR) laser-based indoor optical wireless networks. We propose a novel double-tier access point (AP) architecture based on an array of arrays of vertical cavity surface emitting lasers (VCSELs) to provide a seamless grid-of-beam coverage with multi-Gb/s per beam. We present systematic design and thorough analytical modeling of the AP architecture, which are then applied to downlink system modeling using non-imaging angle diversity receivers (ADRs). We propose static beam clustering with coordinated multi-beam joint transmission (CoMB-JT) for network interference management and devise various clustering strategies to address inter-beam interference (IBI) and inter-cluster interference (ICI). Non-orthogonal multiple access (NOMA) and orthogonal frequency division multiple access (OFDMA) schemes are also adopted to handle intra-cluster interference, and the resulting signal-to-interference-plus-noise ratio (SINR) and achievable data rate are derived. The network performance is studied in terms of spatial distributions and statistics of the downlink SINR and data rate through extensive computer simulations. The results demonstrate that data rates up to 15 Gb/s are achieved within the coverage area and a properly devised clustering strikes a balance between the sum rate and fairness depending on the number of users.},
note = {Version Number: 1},
keywords = {electronic engineering, FOS: Electrical engineering, information engineering, LRDC, Signal Processing (eess.SP)},
pubstate = {published},
tppubtype = {misc}
}
In this paper, we put forward a proof of concept for sixth generation (6G) Terabit infrared (IR) laser-based indoor optical wireless networks. We propose a novel double-tier access point (AP) architecture based on an array of arrays of vertical cavity surface emitting lasers (VCSELs) to provide a seamless grid-of-beam coverage with multi-Gb/s per beam. We present systematic design and thorough analytical modeling of the AP architecture, which are then applied to downlink system modeling using non-imaging angle diversity receivers (ADRs). We propose static beam clustering with coordinated multi-beam joint transmission (CoMB-JT) for network interference management and devise various clustering strategies to address inter-beam interference (IBI) and inter-cluster interference (ICI). Non-orthogonal multiple access (NOMA) and orthogonal frequency division multiple access (OFDMA) schemes are also adopted to handle intra-cluster interference, and the resulting signal-to-interference-plus-noise ratio (SINR) and achievable data rate are derived. The network performance is studied in terms of spatial distributions and statistics of the downlink SINR and data rate through extensive computer simulations. The results demonstrate that data rates up to 15 Gb/s are achieved within the coverage area and a properly devised clustering strikes a balance between the sum rate and fairness depending on the number of users.
Eltokhey, Mahmoud Wafik; Bashir, Muhammad Salman; Younus, Othman Isam; Ghassemlooy, Zabih; Haas, Harald; Karagiannidis, George; Teli, Shivani Rajendra; Zvanovec, Stanislav; Khalighi, Mohammad-Ali; Zhang, Zhenyu Charlus; Hranilovic, Steve; Brandt-Pearce, Maïté; Linnartz, Jean-Paul; Trichili, Abderrahmen; Chun, Hyunchae; O'Brien, Dominic; Uysal, Murat; Alouini, Mohamed-Slim
Optical Wireless Communications: Illuminating the Path for Cooper's Law Miscellaneous
2024.
@misc{eltokhey_optical_2024b,
title = {Optical Wireless Communications: Illuminating the Path for Cooper's Law},
author = {Mahmoud Wafik Eltokhey and Muhammad Salman Bashir and Othman Isam Younus and Zabih Ghassemlooy and Harald Haas and George Karagiannidis and Shivani Rajendra Teli and Stanislav Zvanovec and Mohammad-Ali Khalighi and Zhenyu Charlus Zhang and Steve Hranilovic and Maïté Brandt-Pearce and Jean-Paul Linnartz and Abderrahmen Trichili and Hyunchae Chun and Dominic O'Brien and Murat Uysal and Mohamed-Slim Alouini},
url = {https://www.techrxiv.org/users/708396/articles/700309-optical-wireless-communications-illuminating-the-path-for-cooper-s-law?commit=aa24e95eedcf894f24fdf42272b0d651fbc6991b},
doi = {10.36227/techrxiv.170620142.21301431/v1},
year = {2024},
date = {2024-01-01},
urldate = {2024-10-30},
publisher = {Preprints},
keywords = {LRDC},
pubstate = {published},
tppubtype = {misc}
}
0000
Does 5G Have a Bright Future? Light Based Communications for Wireless Solutions textbar IEEE Communications Society Miscellaneous
0000.
Abstract | Links | BibTeX | Tags:
@misc{noauthor_does_nodate,
title = {Does 5G Have a Bright Future? Light Based Communications for Wireless Solutions textbar IEEE Communications Society},
url = {https://www.comsoc.org/publications/ctn/does-5g-have-bright-future-light-based-communications-wireless-solutions},
urldate = {2025-02-24},
abstract = {This month the good people of PureLiFi are giving us an update on the state of light based wireless communications and exactly where they are in developing a commercial product. How big will LiFi be in ultra dense networking?},
keywords = {},
pubstate = {published},
tppubtype = {misc}
}
This month the good people of PureLiFi are giving us an update on the state of light based wireless communications and exactly where they are in developing a commercial product. How big will LiFi be in ultra dense networking?