- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Underwater optical wireless sensor networks using resource allocation
摘要： Optical wireless communications is an energy efficient and cost-effective solution for high speed and high secure wireless connections. In this paper, we propose an underwater optical wireless sensor network using multiple input multiple output technique and power allocation algorithm for supporting multiple users with the impacts of underwater channel uncertainty interferences. In proposed power allocation algorithm, all the LED nodes in are coordinated and controlled by a central controller; each LED node supports all the users within its field of view. To separate users, optical code division multiple access is used; cyclic optical orthogonal code working as CDMA code is employed. At the receiver, a minimal mean squared error (MMSE) filter is uniquely designed for each user. The MMSE filters and the assigned power can be jointly optimized to improve the overall throughput and signal to noise ratio. Since the system performance may be impacted by the underwater channel uncertainty, the proposed power allocation can use the predicted channel uncertainty variance to reduce the interference of the channel uncertainty and improve the signal to noise ratio. Compared to the equal power allocation algorithm, the proposed algorithm can support longer transmission distance, higher bit rate and lower bit error rate.
关键词： Multiple access interference,Underwater communications,Wireless sensor networks,Channel uncertainty,MIMO system,CDMA,Optical wireless communications,Resource allocation
更新于2025-09-23 15:23:52
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An optical wireless communication system deploying active high-pass pre-emphasis circuit for high speed application
摘要： This article presents a high-speed optical wireless communication link with a newly proposed pre-emphasis circuit to increase transmission performance at higher data rates. The effectiveness of the pre-emphasis circuit has been verified through testing on an optical wireless link implemented with existing laser communications components in our laboratory operating at 1550 nm. When the proposed pre-emphasis circuit is included in the optical wireless link, we achieved bit-error-rate (BER) power penalty improvements of 1.6, 2.2, and 1.0 dB at 155 Mbps, 622 Mbps, and 1.244 Gbps, respectively at the BER of 2 × 10?3 compared with the optical wireless communication links without pre-emphasis circuit. For the lower BER of 10?9, BER power penalty improvements of 2.2, 3.7, 0.7 dB at 155 Mbps, 622 Mbps, and 1.244 Gbps are observed, which show the effectiveness of our proposed pre-emphasis circuit in optical wireless communications link.
关键词： pre-emphasis,optical communications,optical wireless communications,free space optical communications,optical wireless link
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Conference on Internet of Things and Intelligence System (IOTAIS) - BALI, Indonesia (2018.11.1-2018.11.3)] 2018 IEEE International Conference on Internet of Things and Intelligence System (IOTAIS) - Optical Internet of Things within 5G: Applications and Challenges
摘要： The fifth generation (5G) telecommunications standards are being developed to meet the growing demands for high-speed wireless networks (i.e., few tens of Gigabits per second). The 5G standard stems largely from an increasing number of users and plethora of different devices, collectively referred to as smart devices, connecting to a network as part of Internet-of-Things (IoT). A few potential technologies have emerged for 5G such as millimeter waves, massive multiple-input multiple-output, and small cell communications. Although these technologies would satisfy the requirements of 5G, there is a complementary alternative wireless technology of optical wireless communications (OWC), which is being considered. As part of OWC, visible light communications (VLC) and optical camera communications (OCC) are the most attractive options for 5G networks and beyond. VLC with huge frequency spectrum integrated with IoT can open up a wide range of indoor and outdoor applications as part of future smart environments. This paper provides an overview of the all-optical IoT (OIoT) focusing on VLC and OCC based potential applications and challenges as part of 5G standards.
关键词： light emitting diodes (LEDs),visible light communications (VLC),Internet of things (IoT),Optical wireless communications (OWC),optical camera communications (OCC)
更新于2025-09-23 15:22:29
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[IEEE 2018 26th International Conference on Software, Telecommunications and Computer Networks (SoftCOM) - Split (2018.9.13-2018.9.15)] 2018 26th International Conference on Software, Telecommunications and Computer Networks (SoftCOM) - Car to X Communication with Optical Wireless as Support and Alternative to RF-Technologies for Roads and Future Transportation
摘要： Among the different types of lasers and light sources for Communications, new components are becoming more and more important also for Optical Wireless and Optical Sensing applications. In this contribution, combinations of Optical- and RF-Wave Propagation are illustrated, considering also new technologies of lasers and fibre lasers. The presentation includes Optical Wireless Communication (OWC, well known as Free Space Optics (FSO)) as hybrid transmission methods with telecommunication technologies (like WIFI, RF- and Satellite Communications) and also Sensing Technologies (like LiDAR and radar combinations). Important characteristics of physical layer including useful Modulations, Forward Error Correction Coding for single light source are considered. Furthermore, different cases for enhancing the SNR in daytime condition are discussed. The contribution deals with possible fields of application for optical wireless in conjunction with automated driving.
关键词： Car to X Communication,Optical Wireless Communications,light sources,hybrid networks
更新于2025-09-23 15:22:29
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IEEE Access Special Section Editorial: Optical Wireless Technologies for 5G Communications and Beyond
摘要： Wide bandwidth and dense spatial reuse are of extreme importance for future wireless communication networks, including 5G and beyond. In particular, these properties are important to enable future wireless networks to cope with the explosive increase in the demand for high data-rate communications. Optical wireless communications (OWC) is a promising technology for achieving this goal due to the abundant reusable license-free optical spectrum. This potential of OWC attracted significant global attention both from communications and optoelectronics viewpoints, and continues to do so.
关键词： 5G,beam-steering,mixed FSO/fiber backhauling,OFDM,MIMO,Optical wireless communications,vehicle-to-vehicle communications,free-space optics,vehicle-to-infrastructure communications,network-layer aspects,visible-light communications
更新于2025-09-23 15:21:21
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Indoor Visible Light Communications, Networking, and Applications
摘要： Light-emitting diodes (LEDs) are changing indoor wireless communications. Visible light communications (VLC) that use LEDs as transmitters is an emerging research area and has significant commercial potential. The light emitted from LEDs can simultaneously carry information and provide illumination. Due to the intrinsic characteristics of light, VLC is more secure, more power efficient, and can provide higher network data transmission rates than radio frequency (RF) communications. This paper describes state-of-the-art VLC systems including transmitters, receivers, and channel models. Modulation and networking algorithms for physical layer and cross-layer designs are discussed. These algorithms are designed considering practical constraints, such as the bandlimited channel, illumination requirements, and transmitted power limitations. Indoor localization algorithms are proposed, with a particular focus on fingerprinting. In addition, this paper introduces practical applications of VLC in many fields such as national defense, healthcare, robotics, and vehicle-to-vehicle communications. The paper concludes with a discussion of the challenges, opportunities, and future of VLC.
关键词： Visible light communications,modulation,optical wireless communications,visible light positioning,LEDs,networking
更新于2025-09-23 15:19:57
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Gallium nitride micro-light-emitting diode structured light sources for multi-modal optical wireless communications systems
摘要： Gallium nitride-based light-emitting diodes (LEDs) have revolutionized the lighting industry with their efficient generation of blue and green light. While broad-area (square millimetre) devices have become the dominant LED lighting technology, fabricating LEDs into micro-scale pixels (micro-LEDs) yields further advantages for optical wireless communications (OWC), and for the development of smart-lighting applications such as tracking and imaging. The smaller active areas of micro-LEDs result in high current density operation, providing high modulation bandwidths and increased optical power density. Fabricating micro-LEDs in array formats allows device layouts to be tailored for target applications and provides additional degrees of freedom for OWC systems. Temporal and spatial control is crucial to use the full potential of these micro-scale sources, and is achieved by bonding to pitch-matched complementary metal-oxide-semiconductor control electronics. These compact, integrated chips operate as digital-to-light converters, providing optical signals from digital inputs. Applying the devices as projection systems allows structured light patterns to be used for tracking and self-location, while simultaneously providing space-division multiple access communication links. The high-speed nature of micro-LED array devices, combined with spatial and temporal control, allows many modes of operation for OWC providing complex functionality with chip-scale devices.
关键词： Gallium nitride,structured light,light-emitting diodes,optical wireless communications
更新于2025-09-23 15:19:57
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Automatic Compensation for Defects of Laser Reflective Patterns in Optics-Based Auto-Focusing Microscopes
摘要： This paper summarizes recent work on the use of optical wireless links as a robust outdoor backhaul solution for small radio cells, such as WiFi, LTE and 5G, over distances between 20 and 200 m. Results of a 5-month outdoor field trial in Berlin, Germany, indicate that the visibility range was never below 180 m, with more than 1 km in 99% of all times during this period. Rate-adaptive transmission proved to improve the availability remarkably in the occasional presence of fog or sunlight. A mathematical model of the backhaul link including these impairments is presented and implemented to obtain an optimized link design. A prototype was realized, accordingly, using low-cost optoelectronic components and a 1 Gb/s baseband chipset. Gross data rates of 800, 500, and 225 Mb/s have been achieved in real-time operation over 20, 100, and 215 m outdoor link distance, respectively, with 2 ms latency at 95% load. Finally, we discuss further evolution towards 5G mobile networks.
关键词： Fronthaul,LTE,small cells,5G,Backhaul,LED,optical wireless communications
更新于2025-09-23 15:19:57
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Proof-of-Principle Experiment of a 20-kW-Average-Power Ka-Band Gyro-Traveling Wave Tube With a Cut-Off Waveguide Section
摘要： This paper summarizes recent work on the use of optical wireless links as a robust outdoor backhaul solution for small radio cells, such as WiFi, LTE and 5G, over distances between 20 and 200 m. Results of a 5-month outdoor field trial in Berlin, Germany, indicate that the visibility range was never below 180 m, with more than 1 km in 99% of all times during this period. Rate-adaptive transmission proved to improve the availability remarkably in the occasional presence of fog or sunlight. A mathematical model of the backhaul link including these impairments is presented and implemented to obtain an optimized link design. A prototype was realized, accordingly, using low-cost optoelectronic components and a 1 Gb/s baseband chipset. Gross data rates of 800, 500, and 225 Mb/s have been achieved in real-time operation over 20, 100, and 215 m outdoor link distance, respectively, with 2 ms latency at 95% load. Finally, we discuss further evolution towards 5G mobile networks.
关键词： Backhaul,optical wireless communications,small cells,Fronthaul,LTE,LED,5G
更新于2025-09-23 15:19:57
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Signal Quality Assessment for Transdermal Optical Wireless Communications under Pointing Errors
摘要： In this paper, we assess the signal quality of the out-body to in-body optical communication link, which can be used as a fundamental enabler of novel biomedical appliances, such as medical implants, as well as biological and chemical components monitoring. In particular, we present a mathematical understanding of the transdermal system, which takes into account the optical channel characteristics, the integrated area limitations of the in-body unit, the transceivers’ pointing errors and the particularities of the optical units. Moreover, to accommodate the propagation characteristics, we present a novel simplified, but accurate, transdermal path-gain model. Finally, we extract low-complexity closed-form expressions for the instantaneous and average signal to noise ratio of the transdermal optical link (TOL). Numerical and simulation results are provided for several insightful scenarios and reveal that pointing errors can significantly affect the reliability and effectiveness of the TOL; hence, it should be taken into account in the analysis and design of such systems.
关键词： optical wireless communications,pointing errors,transdermal optical wireless links
更新于2025-09-19 17:15:36