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
针对在水下无线光通信(Underwater Wireless Optical Communication,UWOC)中使用直流偏置光正交频分复用(Direct Current Optical-Orthogonal Frequency Division Multiplexing,DCOOFDM)技术导致的峰均比(Peak-to-Average Power Ratio,P...针对在水下无线光通信(Underwater Wireless Optical Communication,UWOC)中使用直流偏置光正交频分复用(Direct Current Optical-Orthogonal Frequency Division Multiplexing,DCOOFDM)技术导致的峰均比(Peak-to-Average Power Ratio,PAPR)过高的问题,基于部分传输序列(Partial Transmit Sequence,PTS)方法,使用粒子群优化-遗传因子算法(Partial Swarm Optimization-Genetic Algorithm,PSO-GA)联合算法寻找最佳相位因子,以降低PAPR。仿真结果表明,使用联合算法寻找最佳相位因子,在互补累积分布函数(Complementary Cumulative Distribution Function,CCDF)为10-4时,可以使得系统的峰均比降低约3 dB。相较于传统PTS算法与限幅算法,PSO-GA算法在保证PAPR性能改善的前提下,没有牺牲误码率性能。展开更多
The performance of underwater wireless optical communication(UWOC)system is degraded due to the influence of seawater transmission path loss,ocean turbulence effect,and pointing error during the transmission of optica...The performance of underwater wireless optical communication(UWOC)system is degraded due to the influence of seawater transmission path loss,ocean turbulence effect,and pointing error during the transmission of optical signals.In order to solve this problem,an orthogonal frequency division multiplexing(OFDM)UWOC system composite channel model based on wavelength diversity was established,and the analytical expressions for the outage probability and the average symbol error rate(SER)of the system were derived.The system performance of wavelength diversity UWOC is investigated under different pointing errors,number of subcarriers,and maximum ratio combining(MRC)and equal gain combining(EGC)schemes.The results show that the performance of the UWOC system using the wavelength diversity technique is significantly improved.Compared with the no-diversity system,a diversity order of 3 reduces the outage probability from 10-3to the order of 10-8and the average SER from 10-2to 10-7.A smaller pointing error reduces the outage probability of the system.Additionally,a larger ratio of beam width to receiver aperture also decreases the outage probability.Increasing the number of subcarriers will increase the system's average symbol error rate.展开更多
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.
文摘针对在水下无线光通信(Underwater Wireless Optical Communication,UWOC)中使用直流偏置光正交频分复用(Direct Current Optical-Orthogonal Frequency Division Multiplexing,DCOOFDM)技术导致的峰均比(Peak-to-Average Power Ratio,PAPR)过高的问题,基于部分传输序列(Partial Transmit Sequence,PTS)方法,使用粒子群优化-遗传因子算法(Partial Swarm Optimization-Genetic Algorithm,PSO-GA)联合算法寻找最佳相位因子,以降低PAPR。仿真结果表明,使用联合算法寻找最佳相位因子,在互补累积分布函数(Complementary Cumulative Distribution Function,CCDF)为10-4时,可以使得系统的峰均比降低约3 dB。相较于传统PTS算法与限幅算法,PSO-GA算法在保证PAPR性能改善的前提下,没有牺牲误码率性能。
基金supported by the Equipment Pre Research Joint Fund Funded Project by the Ministry of Education of China(8091B032130)。
文摘The performance of underwater wireless optical communication(UWOC)system is degraded due to the influence of seawater transmission path loss,ocean turbulence effect,and pointing error during the transmission of optical signals.In order to solve this problem,an orthogonal frequency division multiplexing(OFDM)UWOC system composite channel model based on wavelength diversity was established,and the analytical expressions for the outage probability and the average symbol error rate(SER)of the system were derived.The system performance of wavelength diversity UWOC is investigated under different pointing errors,number of subcarriers,and maximum ratio combining(MRC)and equal gain combining(EGC)schemes.The results show that the performance of the UWOC system using the wavelength diversity technique is significantly improved.Compared with the no-diversity system,a diversity order of 3 reduces the outage probability from 10-3to the order of 10-8and the average SER from 10-2to 10-7.A smaller pointing error reduces the outage probability of the system.Additionally,a larger ratio of beam width to receiver aperture also decreases the outage probability.Increasing the number of subcarriers will increase the system's average symbol error rate.
