This paper studies a cooperative relay transmission system within the framework of Multiple-Input Multiple-Output Radio Frequency/Underwater Optical Wireless Communication(MIMO-RF/UOWC),aiming to establish sea-based h...This paper studies a cooperative relay transmission system within the framework of Multiple-Input Multiple-Output Radio Frequency/Underwater Optical Wireless Communication(MIMO-RF/UOWC),aiming to establish sea-based heterogeneous networks.In this setup,the RF links obey κ-μ fading,while the UOWC links undergo the generalized Gamma fading with the pointing error impairments.The relay operates under an Amplify-and-Forward(AF)protocol.Additionally,the attenuation caused by the Absorption and Scattering(AaS)is considered in UOWC links.The work yields precise results for the Average Channel Capacity(ACC),Outage Probability(OP),and average Bit Error Rate(BER).Furthermore,to reveal deeper insights,bounds on the ACC and asymptotic results for the OP and average BER are derived.The findings highlight the superior performance of MIMO-RF/UOWC AF systems compared to Single-Input-Single-Output(SISO)-RF/UOWC AF systems.Various factors affecting the Diversity Gain(DG)of the MIMO-RF/UOWC AF system include the number of antennas/apertures,fading parameters of both links,and pointing error parameters.Moreover,while an increase in the AaS effect can result in significant attenuation,it does not determine the achievable DG of the proposed MIMO-RF/UOWC AF relaying system.展开更多
In the intensity modulation and direct detection （IM/DD） multiple-input multiple-output （MIMO） optical wireless communication systems, a direct-current-biased adaptive modulation scheme is proposed to guarantee th...In the intensity modulation and direct detection （IM/DD） multiple-input multiple-output （MIMO） optical wireless communication systems, a direct-current-biased adaptive modulation scheme is proposed to guarantee the nonnegative property of transmitted signals, and the MIMO channel is converted to a parallel channel by using a singular value decomposition. Besides, a QR decomposition and successive interference cancellation based adaptive modulation scheme is proposed, and the MIMO channel can be simplified to a parallel channel under the bit error ratio （BER） target constraint. The power is optimally allocated to each sub-channel to maximize the data rate. Simulation results show that the proposed adaptive modulation schemes can effectively improve the transmission rate of the systems under the BER target and constant optical power constraints. The proposed adaptive modulation schemes make use of the multiplexing gain of the MIMO techniques, and can further improve the spectrum efficiency of optical wireless systems.展开更多
The Optical Wireless Communication(OWC)offers the high capacity of optical fiber communication with the flexibility of wireless communication.Since it works in the optical region of the ElectroMagnetic(EM)spectrum,it ...The Optical Wireless Communication(OWC)offers the high capacity of optical fiber communication with the flexibility of wireless communication.Since it works in the optical region of the ElectroMagnetic(EM)spectrum,it guarantees safety and security which are critical in radio and microwave frequency communication.The principal objective of this paper is to analyze the indoor OWC systems on these guaranteed features,and safety and security are jointly denoted by the term green.The high obstacle impermeability of optical signals and their directivity strengthen the security of indoor OWC data transmission.The confidentiality and authenticity of optical wireless data can also be preserved with the Quantum Key Distribution(QKD).This paper provides a technological overview and a review of literature about the OWC system that helps to identify the challenges in the path of a ubiquitous deployment of green wireless communication systems.Significant advancements in the sources and detectors are discussed together with the coding,modulation and multiplexing techniques for making highly robust OWC links.The ubiquitous deployment of green OWC necessitates the development of optical transmitters and receivers,performance enhancement techniques,incorporation of uplink and energy harvesting abilities,and safety and security enhancement techniques.Hence,a special emphasis is placed on these aspects and their challenges towards the green implementation.Furthermore,the paper explores some significant indoor applications based on the OWC that have great impacts on the Next Generation Networks(NGN)and the Internet of Things(IoT).展开更多
The optical spectrum can serve as a good spectrum resource for wideband wireless communications. The advantages of optical wireless communications （OWC） mainly lie in two aspects： the potential large transmission b...The optical spectrum can serve as a good spectrum resource for wideband wireless communications. The advantages of optical wireless communications （OWC） mainly lie in two aspects： the potential large transmission bandwidth due to the high-frequency carrier, and thecommunication security due to no radio-frequency radiation. Thus OWC can be applied in the seenarios where the radio silence is required or the radio frequency radiation may cause explosions, for example in the battle field or some special ar- eas in the storehouses.展开更多
A new optical wireless network based on white LED lights in home area is proposed. It is a duplex channel communication system utilizing signal emitters of white LED lights in the downlink and infrared devices in the ...A new optical wireless network based on white LED lights in home area is proposed. It is a duplex channel communication system utilizing signal emitters of white LED lights in the downlink and infrared devices in the uplink. Strategies for the system construction are given. Performance for users＇ mobile access of different kinds of optical concentrators is investigated. Indoor channel band-width is analyzed considering white LED light distribution, wall reflection, and receivers field of view （FOV）. Various modulation methods are discussed. A demo point-to-point system for surfing the net is constructed using a new line code of 4B6B which is developed to stabilize the optical output, and a peak data rate of 1 Mbps is achieved. This system is built into the lighting infrastructure, therefore decreasing the cost and offering a solution for wireless access in places which are sensitive to radio frequency like hospitals.展开更多
Optical wireless communications have been widely studied during the past decade in short-range applications, such as indoor highspeed wireless networks and interconnects in data centers and high-performance computing....Optical wireless communications have been widely studied during the past decade in short-range applications, such as indoor highspeed wireless networks and interconnects in data centers and high-performance computing. In this paper, recent developments in high-speed short-range optical wireless communications are reviewed, including visible light communications （VLCs）, infrared indoor communication systems, and reconfigurable optical interconnects. The general architecture of indoor high-speed optical wireless communications is described, and the advantages and limitations of both visible and infrared based solutions are discussed. The concept of reconfigurable optical interconnects is presented, and key results are summarized. In addition, the challenges and potential future directions of short-range optical wireless communications are discussed.展开更多
Subcarrier intensity modulation with direet detection is a modulatiou/detection technique tbr optical wireless communication systems, where a pre-modulated and properly biased radio frequency signal is modulated on th...Subcarrier intensity modulation with direet detection is a modulatiou/detection technique tbr optical wireless communication systems, where a pre-modulated and properly biased radio frequency signal is modulated on the intensity of the optical carrier. The most important benefits of subcarrier intensity modulation are as follows： 1） it does not provide irreducible error floor like the conventional on-off keying intensity modulation with a fixed detection threshold; 2） it provides improved spectral efficiency and supports higher order modulation schemes; and 3） it has much less implementation complexity compared to coherent optical wireless communications with heterodyne or homodyne detection. In this paper, we present an up-to-date review of subcarrier intensity modulated optical wireless communication systems. We survey the error rate and outage performance of subcarrier intensity modulations in the atmospheric turbulence channels considering different modulation and coding schemes. We also explore different contemporary atmospheric turbulence fading mitigation solutions that can be employed for subcarrier intensity modulation. These solutions include diversity combining, adaptive transmission, relay assisted transmission, multiple-subcarrier intensity modulations, and optical orthogonal frequency division multiplexing. Moreover, we review the performance of subcarrier intensity modulations due to the pointing error and synchronization error.展开更多
In this paper, we investigate the effect of water attenuation on an underwater optical wireless communication based on LOS model. We take into account parameters including the chlorophyll concentration and also discus...In this paper, we investigate the effect of water attenuation on an underwater optical wireless communication based on LOS model. We take into account parameters including the chlorophyll concentration and also discuss the choice of suitable wavelength for underwater optical wireless communication. Using analytical expressions and calculating the Jerlov water type attenuation, the received signal power is studied. The characteristics of bit error rate for four kinds of optical modulation techniques （OOK, 2FSK, 2DPSK, and L-PPM） are analyzed. The results show that the performance of OOK and 2DPSK are more suitable for underwater optical wireless communication. On the other hand, the wavelength 450 nm is better compared with the wavelength 600 nm.展开更多
Optical wireless communication, which serves as an important alternative to the radio-frequency communication, shows great potential to a lot of applications, such as indoor communication, secure communication, and ba...Optical wireless communication, which serves as an important alternative to the radio-frequency communication, shows great potential to a lot of applications, such as indoor communication, secure communication, and battlefield communication. It has attracted increasing research interests from both academia and industrial fields. Moreover, optical wireless communication has been applied to the indoor communication and positioning system. The upcoming special issue of ZTE Communication will focus on the cutting-edge research and application on the communication system and related signal processing in optical wireless communication. The expected publication date will be in Mar. 2016. It includes （but not limited to） the following research directions：展开更多
Optical wireless communications(OWCs)have seen rapid progress in recent decades.Cylindrical vector beam shaping has been proven as a promising way to further improve the performance and realize multiple functions for ...Optical wireless communications(OWCs)have seen rapid progress in recent decades.Cylindrical vector beam shaping has been proven as a promising way to further improve the performance and realize multiple functions for OWCs.In this paper,we provide a review of recent progress in two popular cylindrical vector beam shaping techniques,namely,few-mode-and orbital angular momentum(OAM)-based beam shaping and their corresponding digital signal processing technologies including impairment mitigation and advanced coding for OWCs.展开更多
This study examines paramagnetic liquids for optical beam steering in optical wireless communication(OWC)systems.By employing magnetic actuation,effective optical beam control was achieved for both free-space optics(F...This study examines paramagnetic liquids for optical beam steering in optical wireless communication(OWC)systems.By employing magnetic actuation,effective optical beam control was achieved for both free-space optics(FSO)and underwater wireless optical communication(UWOC).Experimental findings revealed that dysprosium nitrate provided the highest beam steering angles of 5.99°in the±X direction and 5.73°in the±Y direction.Additionally,power loss analysis indicated minimal absorption and scattering for dysprosium nitrate and gadolinium nitrate.The system achieved high-speed data rates of 2.1 Gbps for FSO and 1.9 Gbps for UWOC systems,showcasing the promise of this technology.展开更多
As the global population ages,the demand for implantable medical electronic devices for physiological monitoring and functional support continues to grow.In such systems,wireless data exchange is essential for device ...As the global population ages,the demand for implantable medical electronic devices for physiological monitoring and functional support continues to grow.In such systems,wireless data exchange is essential for device control and real-time physiological data acquisition.While coil-based methods are widely used,the method may pose challenges such as electromagnetic interference,or unwanted induced currents in diverse clinical environments.Here,we introduce a soft,flexible optical wireless communication system capable of reliable,real-time data exchange through biological tissues without the need for antenna coils.Microscale light-emitting diodes(LEDs)and photodetector(PD),microfabricated and integrated into flexible platforms,enable wireless data transmission via light modulation through biological skin,in a relatively small form factor.In vivo experiments validate wireless bi-directional data transfer with integrated physiological sensors,demonstrating on-demand,real-time monitoring of signals such as electrocardiogram and body temperature.This approach offers a promising pathway toward safer,miniaturized wireless implantable electronics.展开更多
In this paper,a quadrature phase shift keying(QPSK)phase-recovery algorithm is presented for coherent intersatellite optical wireless communication(Is OWC).From a theoretical perspective,we explain the process of the ...In this paper,a quadrature phase shift keying(QPSK)phase-recovery algorithm is presented for coherent intersatellite optical wireless communication(Is OWC).From a theoretical perspective,we explain the process of the multiplier-free algorithm.Through simulations,we analyze key parameters and provide guidance on their optimal selection.Additionally,the proposed algorithm maintains stable phase tracking at bit energy to noise power spectral density(Eb/N0)as low as 4 d B.In an ob2b transmission test,our algorithm achieved a sensitivity of-49 d Bm@5 Gbps QPSK[hard-decision forward-errorcorrection(HD-FEC)limit].Compared to the Viterbi and Viterbi phase-recovery(V&V)algorithm,its receiving sensitivity is improved by 1 d B,resulting in a link distance extension of 1100 km.Our multiplier-free and robust algorithm meets the requirements of Is OWC systems and shows promise for future applications.展开更多
The Underwater Communication Link(UCL)is a crucial component of Underwater Wireless Optical Communication(UWOC)systems,requiring optimised design to mitigate the high power attenuation inherent in seawater.To ensure t...The Underwater Communication Link(UCL)is a crucial component of Underwater Wireless Optical Communication(UWOC)systems,requiring optimised design to mitigate the high power attenuation inherent in seawater.To ensure the reliability of an optimal UCL design,it is essential to account for the three primary scattering regimes:forward scattering(FSC),backward scattering(BSC),and isotropic scattering(ISC)in seawater channels.This study introduces a new photon-tracking model based on a discrete equation,facilitating Monte Carlo Simulation(MCS)to evaluate how different scattering regimes influence received photon distribution.Three distinct Scattering Regime Contribution Weight(SRCW)probability sets were employed,each representing different UCL operational configurations dominated by specific scattering regimes.The proposed modeling approach enables a comprehensive assessment of the temporal characteristics of received optical pulses,channel loss,and time spread-ultimately defining the optimal UCL design parameters.The key findings of this study include:(1)Enhancing the FSC regime dominance leads to a quasi-light waveguide effect over link spans and small Fields of View(FOV)<25°,significantly improving channel performance in Harbor seawater compared to Coastal seawater.(2)A well-designed UCL with a small FOV(<25°)can minimise channel loss and time spread,ensuring high capacity and efficient performance in both Coastal and Harbor seawaters.(3)When BSC and ISC contributions exceed FSC dominance,the received optical pulse undergoes significant temporal broadening,particularly for larger FOV angles(>25°)and extended link spans.(4)The developed novel MCS-based discrete equation provides a simple yet robust model for simulating photon propagation in both homogeneous and inhomogeneous underwater channels.These insights contribute to developing more efficient and reliable UCL designs with military standards by enhancing UWOC system performance over a longer linkspan for a given limited optical power across various underwater environments.展开更多
We experimentally demonstrated optical wireless power transfer(OWPT)using a near-infrared laser diode(LD)as the optical power transmitter.We considered a photovoltaic(PV)cell and a photodiode(PD)as the optical power r...We experimentally demonstrated optical wireless power transfer(OWPT)using a near-infrared laser diode(LD)as the optical power transmitter.We considered a photovoltaic(PV)cell and a photodiode(PD)as the optical power receivers.We investigated the characteristics of the LD,PD,and PV cell in order to determine the optimum operating condition from the viewpoint of transfer efficiency.We also experimentally demonstrated a whole system optimization process to maximize the DC-to-DC transfer efficiency of the OWPT.Our experimental results showed that the optimization process can improve the OWPT efficiency by up to 48%.展开更多
In underwater optical wireless communication(UOWC),a channel is characterized by abundant scattering/absorption effects and optical turbulence.Most previous studies on UOWC have been limited to scattering/absorption e...In underwater optical wireless communication(UOWC),a channel is characterized by abundant scattering/absorption effects and optical turbulence.Most previous studies on UOWC have been limited to scattering/absorption effects.However,experiments in the literature indicate that underwater optical turbulence(UOT)can cause severe degradation of UOWC performance.In this paper,we characterize an UOWC channel with both scattering/absorption and UOT taken into consideration,and a spatial diversity receiver scheme,say a singleinput–multiple-output(SIMO) scheme,based on a light-emitting-diode(LED) source and multiple detectors is proposed to mitigate deep fading.The Monte Carlo based statistical simulation method is introduced to evaluate the bit-error-rate performance of the system.It is shown that spatial diversity can effectively reduce channel fading and remarkably extend communication range.展开更多
Ground-breaking optical wireless power transfer(OWPT)techniques have gained significant attention from both academia and industry in recent decades.Powering remote systems through laser diodes(LDs)to either operate de...Ground-breaking optical wireless power transfer(OWPT)techniques have gained significant attention from both academia and industry in recent decades.Powering remote systems through laser diodes(LDs)to either operate devices or recharge batteries offers several benefits.Remote LDs can remove the burden of carrying extra batteries and can reduce mission time by removing battery swap-time and charging.Apart from its appealing benefits,laser power transfer(LPT)is still a challenging task due to its low transfer efficiency.In this paper,we discuss the necessity and feasibility of OWPT and discuss several projects,working principle,system design,and components.In addition,we show that OWPT is an essential element to supply power to Internet-of-Things(IoT)terminals.We also highlight the impacts of dynamic OWPT.We outline several OWPT techniques including optical beamforming,distributed laser charging(DLC),adaptive-DLC(ADLC),simultaneous lightwave information and power transfer(SLIPT),Thing-to-Thing(T2T)OWPT,and high intensity laser power beaming(HILPB).We also deal with laser selection,hazard analysis,and received photovoltaic(PV)cell selection for OWPT systems.Finally,we discuss a range of open challenges and counter measures.We believe that this review will be helpful in integrating research and eliminating technical uncertainties,thereby promoting progress and innovation in the development of OWPT technologies.展开更多
With the rapid deployment of Next-Generation Networks(NGN),the research community has initiated discussions on an entirely new suite of optical enabling techniques.To pave the way for the development of future wireles...With the rapid deployment of Next-Generation Networks(NGN),the research community has initiated discussions on an entirely new suite of optical enabling techniques.To pave the way for the development of future wireless networks,this article aims to unify the existing infrared,visible light,and ultraviolet subbands while also exploring the potential of the Petahertz(PHz)band to support extremely bandwidth-thirsfy telepresence style applications.Our focus is on the emerging Petahertz Communication(PetaCom)framework,scenario-dependent propagation channels,modulation schemes,system performance,multiple access techniques,and networking.We conclude with a range of PetaCom challenges and open research issues.展开更多
We experimentally demonstrate an underwater optical wireless power transfer （OWPT） using a laser diode （LD） as a power transmitter. We investigate the characteristics of a solar cell and a photodiode （PD） as a p...We experimentally demonstrate an underwater optical wireless power transfer （OWPT） using a laser diode （LD） as a power transmitter. We investigate the characteristics of a solar cell and a photodiode （PD） as a power receiver. We optimize the LD, the PD, and the solar cell to achieve the maximum transfer efficiency. The maxi- mum transfer efficiency of the back-to-back OWPT is measured as 4.3% with the PD receiver. Subsequently, we demonstrate the OWPT in tap and sea water. Our result shows an attenuation of 3 dB/m in sea water.展开更多
Intelligent Transport Systems(ITS)are crucial for safety,efficiency,and reduced congestion in transportation.They require efficient,secure,high-speed communication.Radio Frequency(RF)technologies like Fifth Generation...Intelligent Transport Systems(ITS)are crucial for safety,efficiency,and reduced congestion in transportation.They require efficient,secure,high-speed communication.Radio Frequency(RF)technologies like Fifth Generation(5G),Beyond 5G(B5G),and Sixth Generation(6G)are promising,but spectrum scarcity mandates coexistence with Optical Wireless Communication(OWC)networks,which offer high data rates and security,forming a strong foundation for hybrid RF/OWC applications in ITS.In this paper,we delve into the application of Machine Learning(ML)to enhance data communications within OWC systems in ITS.We commence by conducting an in-depth examination of the data communication prerequisites and the associated challenges within the ITS domain.Subsequently,we elucidate the compelling rationale behind the convergence of heterogeneous RF technologies with OWC for data communications in ITS scenarios.Our investigation then pivots towards elucidating the indispensable role played by ML in optimizing data communications via OWC within ITS.To provide a comprehensive perspective,we systematically evaluate and compare a spectrum of ML methodologies employed in OWC ITS data communications.As a culmination of our study,we proffer a set of valuable recommendations and illuminate promising avenues for future research endeavors that warrant further exploration within this critical intersection of ML,OWC,and ITS data communications.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 62301272the Natural Science Research Start-up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications under Grants NY223023 and NY223027.
文摘This paper studies a cooperative relay transmission system within the framework of Multiple-Input Multiple-Output Radio Frequency/Underwater Optical Wireless Communication(MIMO-RF/UOWC),aiming to establish sea-based heterogeneous networks.In this setup,the RF links obey κ-μ fading,while the UOWC links undergo the generalized Gamma fading with the pointing error impairments.The relay operates under an Amplify-and-Forward(AF)protocol.Additionally,the attenuation caused by the Absorption and Scattering(AaS)is considered in UOWC links.The work yields precise results for the Average Channel Capacity(ACC),Outage Probability(OP),and average Bit Error Rate(BER).Furthermore,to reveal deeper insights,bounds on the ACC and asymptotic results for the OP and average BER are derived.The findings highlight the superior performance of MIMO-RF/UOWC AF systems compared to Single-Input-Single-Output(SISO)-RF/UOWC AF systems.Various factors affecting the Diversity Gain(DG)of the MIMO-RF/UOWC AF system include the number of antennas/apertures,fading parameters of both links,and pointing error parameters.Moreover,while an increase in the AaS effect can result in significant attenuation,it does not determine the achievable DG of the proposed MIMO-RF/UOWC AF relaying system.
基金The National High Technology Research and Development Program of China(863 Program)(No.2013AA013601)the National Science and Technology M ajor Project of China(No.2015ZX03004009)
文摘In the intensity modulation and direct detection （IM/DD） multiple-input multiple-output （MIMO） optical wireless communication systems, a direct-current-biased adaptive modulation scheme is proposed to guarantee the nonnegative property of transmitted signals, and the MIMO channel is converted to a parallel channel by using a singular value decomposition. Besides, a QR decomposition and successive interference cancellation based adaptive modulation scheme is proposed, and the MIMO channel can be simplified to a parallel channel under the bit error ratio （BER） target constraint. The power is optimally allocated to each sub-channel to maximize the data rate. Simulation results show that the proposed adaptive modulation schemes can effectively improve the transmission rate of the systems under the BER target and constant optical power constraints. The proposed adaptive modulation schemes make use of the multiplexing gain of the MIMO techniques, and can further improve the spectrum efficiency of optical wireless systems.
基金This publication is an outcome of the R&D work undertaken project under the Visvesvaraya PhD Scheme(Grant No.Ph.D-MLA/4(16))of Ministry of Electronics&Information Technology,Government of India,being implemented by Digital India Corporation.
文摘The Optical Wireless Communication(OWC)offers the high capacity of optical fiber communication with the flexibility of wireless communication.Since it works in the optical region of the ElectroMagnetic(EM)spectrum,it guarantees safety and security which are critical in radio and microwave frequency communication.The principal objective of this paper is to analyze the indoor OWC systems on these guaranteed features,and safety and security are jointly denoted by the term green.The high obstacle impermeability of optical signals and their directivity strengthen the security of indoor OWC data transmission.The confidentiality and authenticity of optical wireless data can also be preserved with the Quantum Key Distribution(QKD).This paper provides a technological overview and a review of literature about the OWC system that helps to identify the challenges in the path of a ubiquitous deployment of green wireless communication systems.Significant advancements in the sources and detectors are discussed together with the coding,modulation and multiplexing techniques for making highly robust OWC links.The ubiquitous deployment of green OWC necessitates the development of optical transmitters and receivers,performance enhancement techniques,incorporation of uplink and energy harvesting abilities,and safety and security enhancement techniques.Hence,a special emphasis is placed on these aspects and their challenges towards the green implementation.Furthermore,the paper explores some significant indoor applications based on the OWC that have great impacts on the Next Generation Networks(NGN)and the Internet of Things(IoT).
文摘The optical spectrum can serve as a good spectrum resource for wideband wireless communications. The advantages of optical wireless communications （OWC） mainly lie in two aspects： the potential large transmission bandwidth due to the high-frequency carrier, and thecommunication security due to no radio-frequency radiation. Thus OWC can be applied in the seenarios where the radio silence is required or the radio frequency radiation may cause explosions, for example in the battle field or some special ar- eas in the storehouses.
文摘A new optical wireless network based on white LED lights in home area is proposed. It is a duplex channel communication system utilizing signal emitters of white LED lights in the downlink and infrared devices in the uplink. Strategies for the system construction are given. Performance for users＇ mobile access of different kinds of optical concentrators is investigated. Indoor channel band-width is analyzed considering white LED light distribution, wall reflection, and receivers field of view （FOV）. Various modulation methods are discussed. A demo point-to-point system for surfing the net is constructed using a new line code of 4B6B which is developed to stabilize the optical output, and a peak data rate of 1 Mbps is achieved. This system is built into the lighting infrastructure, therefore decreasing the cost and offering a solution for wireless access in places which are sensitive to radio frequency like hospitals.
基金supported under Australian Research Council’s Discovery Early Career Researcher Award(DECRA)funding scheme(project number DE150100924)The University of Melbourne’s Early Career Researcher(ECR)funding scheme(project number 602702)the Victoria Fellowship(D2015/35025)
文摘Optical wireless communications have been widely studied during the past decade in short-range applications, such as indoor highspeed wireless networks and interconnects in data centers and high-performance computing. In this paper, recent developments in high-speed short-range optical wireless communications are reviewed, including visible light communications （VLCs）, infrared indoor communication systems, and reconfigurable optical interconnects. The general architecture of indoor high-speed optical wireless communications is described, and the advantages and limitations of both visible and infrared based solutions are discussed. The concept of reconfigurable optical interconnects is presented, and key results are summarized. In addition, the challenges and potential future directions of short-range optical wireless communications are discussed.
文摘Subcarrier intensity modulation with direet detection is a modulatiou/detection technique tbr optical wireless communication systems, where a pre-modulated and properly biased radio frequency signal is modulated on the intensity of the optical carrier. The most important benefits of subcarrier intensity modulation are as follows： 1） it does not provide irreducible error floor like the conventional on-off keying intensity modulation with a fixed detection threshold; 2） it provides improved spectral efficiency and supports higher order modulation schemes; and 3） it has much less implementation complexity compared to coherent optical wireless communications with heterodyne or homodyne detection. In this paper, we present an up-to-date review of subcarrier intensity modulated optical wireless communication systems. We survey the error rate and outage performance of subcarrier intensity modulations in the atmospheric turbulence channels considering different modulation and coding schemes. We also explore different contemporary atmospheric turbulence fading mitigation solutions that can be employed for subcarrier intensity modulation. These solutions include diversity combining, adaptive transmission, relay assisted transmission, multiple-subcarrier intensity modulations, and optical orthogonal frequency division multiplexing. Moreover, we review the performance of subcarrier intensity modulations due to the pointing error and synchronization error.
文摘In this paper, we investigate the effect of water attenuation on an underwater optical wireless communication based on LOS model. We take into account parameters including the chlorophyll concentration and also discuss the choice of suitable wavelength for underwater optical wireless communication. Using analytical expressions and calculating the Jerlov water type attenuation, the received signal power is studied. The characteristics of bit error rate for four kinds of optical modulation techniques （OOK, 2FSK, 2DPSK, and L-PPM） are analyzed. The results show that the performance of OOK and 2DPSK are more suitable for underwater optical wireless communication. On the other hand, the wavelength 450 nm is better compared with the wavelength 600 nm.
文摘Optical wireless communication, which serves as an important alternative to the radio-frequency communication, shows great potential to a lot of applications, such as indoor communication, secure communication, and battlefield communication. It has attracted increasing research interests from both academia and industrial fields. Moreover, optical wireless communication has been applied to the indoor communication and positioning system. The upcoming special issue of ZTE Communication will focus on the cutting-edge research and application on the communication system and related signal processing in optical wireless communication. The expected publication date will be in Mar. 2016. It includes （but not limited to） the following research directions：
基金supported by the National Natural Science Foundation of China(No.12304325)the Natural Science Foundation of Shandong Province(No.ZR2024QF247)the Taishan Scholar Project of Shandong Province(No.tsqnz20231209)。
文摘Optical wireless communications(OWCs)have seen rapid progress in recent decades.Cylindrical vector beam shaping has been proven as a promising way to further improve the performance and realize multiple functions for OWCs.In this paper,we provide a review of recent progress in two popular cylindrical vector beam shaping techniques,namely,few-mode-and orbital angular momentum(OAM)-based beam shaping and their corresponding digital signal processing technologies including impairment mitigation and advanced coding for OWCs.
基金supported by the Key Research and Development Program of Hainan Province(No.ZDYF2023GXJS016)the National Key Research and Development Program of China(No.2022YFC2808200)。
文摘This study examines paramagnetic liquids for optical beam steering in optical wireless communication(OWC)systems.By employing magnetic actuation,effective optical beam control was achieved for both free-space optics(FSO)and underwater wireless optical communication(UWOC).Experimental findings revealed that dysprosium nitrate provided the highest beam steering angles of 5.99°in the±X direction and 5.73°in the±Y direction.Additionally,power loss analysis indicated minimal absorption and scattering for dysprosium nitrate and gadolinium nitrate.The system achieved high-speed data rates of 2.1 Gbps for FSO and 1.9 Gbps for UWOC systems,showcasing the promise of this technology.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(Ministry of Science and ICT,MIST)(No.RS-2023-00277831)partially supported by the GISTMIT Research Collaboration grant funded by the GIST。
文摘As the global population ages,the demand for implantable medical electronic devices for physiological monitoring and functional support continues to grow.In such systems,wireless data exchange is essential for device control and real-time physiological data acquisition.While coil-based methods are widely used,the method may pose challenges such as electromagnetic interference,or unwanted induced currents in diverse clinical environments.Here,we introduce a soft,flexible optical wireless communication system capable of reliable,real-time data exchange through biological tissues without the need for antenna coils.Microscale light-emitting diodes(LEDs)and photodetector(PD),microfabricated and integrated into flexible platforms,enable wireless data transmission via light modulation through biological skin,in a relatively small form factor.In vivo experiments validate wireless bi-directional data transfer with integrated physiological sensors,demonstrating on-demand,real-time monitoring of signals such as electrocardiogram and body temperature.This approach offers a promising pathway toward safer,miniaturized wireless implantable electronics.
文摘In this paper,a quadrature phase shift keying(QPSK)phase-recovery algorithm is presented for coherent intersatellite optical wireless communication(Is OWC).From a theoretical perspective,we explain the process of the multiplier-free algorithm.Through simulations,we analyze key parameters and provide guidance on their optimal selection.Additionally,the proposed algorithm maintains stable phase tracking at bit energy to noise power spectral density(Eb/N0)as low as 4 d B.In an ob2b transmission test,our algorithm achieved a sensitivity of-49 d Bm@5 Gbps QPSK[hard-decision forward-errorcorrection(HD-FEC)limit].Compared to the Viterbi and Viterbi phase-recovery(V&V)algorithm,its receiving sensitivity is improved by 1 d B,resulting in a link distance extension of 1100 km.Our multiplier-free and robust algorithm meets the requirements of Is OWC systems and shows promise for future applications.
基金The Deanship of Scientific Research(DSR)at King Abdulaziz University(KAU),Jeddah,Saudi Arabia,has funded this project under Grant No.(KEP-PhD:72-130-1443).
文摘The Underwater Communication Link(UCL)is a crucial component of Underwater Wireless Optical Communication(UWOC)systems,requiring optimised design to mitigate the high power attenuation inherent in seawater.To ensure the reliability of an optimal UCL design,it is essential to account for the three primary scattering regimes:forward scattering(FSC),backward scattering(BSC),and isotropic scattering(ISC)in seawater channels.This study introduces a new photon-tracking model based on a discrete equation,facilitating Monte Carlo Simulation(MCS)to evaluate how different scattering regimes influence received photon distribution.Three distinct Scattering Regime Contribution Weight(SRCW)probability sets were employed,each representing different UCL operational configurations dominated by specific scattering regimes.The proposed modeling approach enables a comprehensive assessment of the temporal characteristics of received optical pulses,channel loss,and time spread-ultimately defining the optimal UCL design parameters.The key findings of this study include:(1)Enhancing the FSC regime dominance leads to a quasi-light waveguide effect over link spans and small Fields of View(FOV)<25°,significantly improving channel performance in Harbor seawater compared to Coastal seawater.(2)A well-designed UCL with a small FOV(<25°)can minimise channel loss and time spread,ensuring high capacity and efficient performance in both Coastal and Harbor seawaters.(3)When BSC and ISC contributions exceed FSC dominance,the received optical pulse undergoes significant temporal broadening,particularly for larger FOV angles(>25°)and extended link spans.(4)The developed novel MCS-based discrete equation provides a simple yet robust model for simulating photon propagation in both homogeneous and inhomogeneous underwater channels.These insights contribute to developing more efficient and reliable UCL designs with military standards by enhancing UWOC system performance over a longer linkspan for a given limited optical power across various underwater environments.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.NRF-2019RIFIA1045956)supported by Kyungsung University Research Grants in 2019。
文摘We experimentally demonstrated optical wireless power transfer(OWPT)using a near-infrared laser diode(LD)as the optical power transmitter.We considered a photovoltaic(PV)cell and a photodiode(PD)as the optical power receivers.We investigated the characteristics of the LD,PD,and PV cell in order to determine the optimum operating condition from the viewpoint of transfer efficiency.We also experimentally demonstrated a whole system optimization process to maximize the DC-to-DC transfer efficiency of the OWPT.Our experimental results showed that the optimization process can improve the OWPT efficiency by up to 48%.
基金supported by the National Key Basic Research Program of China (Grant No.2013CB329201)the National Natural Science Foundation of China (Grant Nos.61171066 and 61471332)the State Key Laboratory of Robotics
文摘In underwater optical wireless communication(UOWC),a channel is characterized by abundant scattering/absorption effects and optical turbulence.Most previous studies on UOWC have been limited to scattering/absorption effects.However,experiments in the literature indicate that underwater optical turbulence(UOT)can cause severe degradation of UOWC performance.In this paper,we characterize an UOWC channel with both scattering/absorption and UOT taken into consideration,and a spatial diversity receiver scheme,say a singleinput–multiple-output(SIMO) scheme,based on a light-emitting-diode(LED) source and multiple detectors is proposed to mitigate deep fading.The Monte Carlo based statistical simulation method is introduced to evaluate the bit-error-rate performance of the system.It is shown that spatial diversity can effectively reduce channel fading and remarkably extend communication range.
文摘Ground-breaking optical wireless power transfer(OWPT)techniques have gained significant attention from both academia and industry in recent decades.Powering remote systems through laser diodes(LDs)to either operate devices or recharge batteries offers several benefits.Remote LDs can remove the burden of carrying extra batteries and can reduce mission time by removing battery swap-time and charging.Apart from its appealing benefits,laser power transfer(LPT)is still a challenging task due to its low transfer efficiency.In this paper,we discuss the necessity and feasibility of OWPT and discuss several projects,working principle,system design,and components.In addition,we show that OWPT is an essential element to supply power to Internet-of-Things(IoT)terminals.We also highlight the impacts of dynamic OWPT.We outline several OWPT techniques including optical beamforming,distributed laser charging(DLC),adaptive-DLC(ADLC),simultaneous lightwave information and power transfer(SLIPT),Thing-to-Thing(T2T)OWPT,and high intensity laser power beaming(HILPB).We also deal with laser selection,hazard analysis,and received photovoltaic(PV)cell selection for OWPT systems.Finally,we discuss a range of open challenges and counter measures.We believe that this review will be helpful in integrating research and eliminating technical uncertainties,thereby promoting progress and innovation in the development of OWPT technologies.
基金supported by the Key Program of the National Natural Science Foundation of China(No.61631018),Key Research Program of Frontier Sciences of CAS(No.QYZDY-SSW-JSC003)Strategic Priority Research Program of CAS(No.XDA22000000).L.Hanzo would like to acknowledge the financial support of the Engineering and Physical Sciences Research Council projects EP/P034284/1 and EP/P003990/1(COALESCE)as well as of the European Research Council’s Advanced Fellow Grant QuantCom(Grant No.789028).
文摘With the rapid deployment of Next-Generation Networks(NGN),the research community has initiated discussions on an entirely new suite of optical enabling techniques.To pave the way for the development of future wireless networks,this article aims to unify the existing infrared,visible light,and ultraviolet subbands while also exploring the potential of the Petahertz(PHz)band to support extremely bandwidth-thirsfy telepresence style applications.Our focus is on the emerging Petahertz Communication(PetaCom)framework,scenario-dependent propagation channels,modulation schemes,system performance,multiple access techniques,and networking.We conclude with a range of PetaCom challenges and open research issues.
基金supported by the Kyungsung University Research Grants in 2017
文摘We experimentally demonstrate an underwater optical wireless power transfer （OWPT） using a laser diode （LD） as a power transmitter. We investigate the characteristics of a solar cell and a photodiode （PD） as a power receiver. We optimize the LD, the PD, and the solar cell to achieve the maximum transfer efficiency. The maxi- mum transfer efficiency of the back-to-back OWPT is measured as 4.3% with the PD receiver. Subsequently, we demonstrate the OWPT in tap and sea water. Our result shows an attenuation of 3 dB/m in sea water.
文摘Intelligent Transport Systems(ITS)are crucial for safety,efficiency,and reduced congestion in transportation.They require efficient,secure,high-speed communication.Radio Frequency(RF)technologies like Fifth Generation(5G),Beyond 5G(B5G),and Sixth Generation(6G)are promising,but spectrum scarcity mandates coexistence with Optical Wireless Communication(OWC)networks,which offer high data rates and security,forming a strong foundation for hybrid RF/OWC applications in ITS.In this paper,we delve into the application of Machine Learning(ML)to enhance data communications within OWC systems in ITS.We commence by conducting an in-depth examination of the data communication prerequisites and the associated challenges within the ITS domain.Subsequently,we elucidate the compelling rationale behind the convergence of heterogeneous RF technologies with OWC for data communications in ITS scenarios.Our investigation then pivots towards elucidating the indispensable role played by ML in optimizing data communications via OWC within ITS.To provide a comprehensive perspective,we systematically evaluate and compare a spectrum of ML methodologies employed in OWC ITS data communications.As a culmination of our study,we proffer a set of valuable recommendations and illuminate promising avenues for future research endeavors that warrant further exploration within this critical intersection of ML,OWC,and ITS data communications.
