<div style="text-align:justify;"> In the channel estimation for ultraviolet communication, the single scattering power is usually used to approximate the received total power. This approximation error ...<div style="text-align:justify;"> In the channel estimation for ultraviolet communication, the single scattering power is usually used to approximate the received total power. This approximation error is affected by the transceiver configuration. Here, we employ the proportion of received single scattering power in received total power to indicate the approximation error of the single scattering model in different configurations. This is useful for reducing the approximation error by selecting a more appropriate transceiver configuration. </div>展开更多
With rapid advances of solar blind ultraviolet LED and ultraviolet detecting technology in recent years, ultraviolet communication gradually becomes a research hotspot due to its inherent advantages: low solar backgro...With rapid advances of solar blind ultraviolet LED and ultraviolet detecting technology in recent years, ultraviolet communication gradually becomes a research hotspot due to its inherent advantages: low solar background noise, non-line-of-sight(NLOS) and good secrecy. The strong scattering characteristics in atmospheric render ultraviolet waveband the ideal choice for achieving NLOS optical communication. This paper reviews the research history and status of ultraviolet communication both in China and abroad, and especially introduces three main issues of ultraviolet communication: channel model, system analysis and design, light sources and detectors. For each aspect, current open issues and prospective research directions are analyzed.展开更多
Lens-free on-chip microscopy with RGB LEDs(LFOCM-RGB)provides a portable,cost-effective,and high-throughput imaging tool for resource-limited environments.However,the weak coherence of LEDs limits the high-resolution ...Lens-free on-chip microscopy with RGB LEDs(LFOCM-RGB)provides a portable,cost-effective,and high-throughput imaging tool for resource-limited environments.However,the weak coherence of LEDs limits the high-resolution imaging,and the luminous surfaces of the LED chips on the RGB LED do not overlap,making the coherence-enhanced executions tend to undermine the portable and cost-effective implementation.Here,we propose a specially designed pinhole array to enhance coherence in a portable and cost-effective implementation.It modulates the three-color beams from the RGB LED separately so that the three-color beams effectively overlap on the sample plane while reducing the effective light-emitting area for better spatial coherence.The separate modulation of the spatial coherence allows the temporal coherence to be modulated separately by single spectral filters rather than by expensive triple spectral filters.Based on the pinhole array,the LFOCM-RGB simply and effectively realizes the high-resolution imaging in a portable and cost-effective implementation,offering much flexibility for various applications in resource-limited environments.展开更多
In this Let ter,a single scattering turbulence model in a narrow beam case for ultraviolet(UV)communication is proposed based on the division of the effective scattering volume.This model takes the variation of atmosp...In this Let ter,a single scattering turbulence model in a narrow beam case for ultraviolet(UV)communication is proposed based on the division of the effective scattering volume.This model takes the variation of atmospheric scattering,absorption,and turbulence in different paths into account.Meanwhile,the applicable transceiver configurations of this model are provided by analyzing path loss error caused by the single scattering assumption in the UV channel.Furthermore,we investigate the effect of turbulence on the probability density function of the arriving power in both coplanar and non-coplanar scenarios.The averaging effect of multipath propagation on the arriving power's fluctuations is presented.Then,the bit-error-rate performance is also studied.This work provides an efficient way for UV turbulence channel estimation.展开更多
文摘<div style="text-align:justify;"> In the channel estimation for ultraviolet communication, the single scattering power is usually used to approximate the received total power. This approximation error is affected by the transceiver configuration. Here, we employ the proportion of received single scattering power in received total power to indicate the approximation error of the single scattering model in different configurations. This is useful for reducing the approximation error by selecting a more appropriate transceiver configuration. </div>
基金supported by the National High-tech R&D Program of China grant 2015AA043302the Basic research project of Shenzhen grant JCYJ20140417115840236
文摘With rapid advances of solar blind ultraviolet LED and ultraviolet detecting technology in recent years, ultraviolet communication gradually becomes a research hotspot due to its inherent advantages: low solar background noise, non-line-of-sight(NLOS) and good secrecy. The strong scattering characteristics in atmospheric render ultraviolet waveband the ideal choice for achieving NLOS optical communication. This paper reviews the research history and status of ultraviolet communication both in China and abroad, and especially introduces three main issues of ultraviolet communication: channel model, system analysis and design, light sources and detectors. For each aspect, current open issues and prospective research directions are analyzed.
基金supported by the Shenzhen Key Basic Program(No.JCYJ20200109143031287)the Shenzhen General Basic Program(No.WDZC20220816110140002)。
文摘Lens-free on-chip microscopy with RGB LEDs(LFOCM-RGB)provides a portable,cost-effective,and high-throughput imaging tool for resource-limited environments.However,the weak coherence of LEDs limits the high-resolution imaging,and the luminous surfaces of the LED chips on the RGB LED do not overlap,making the coherence-enhanced executions tend to undermine the portable and cost-effective implementation.Here,we propose a specially designed pinhole array to enhance coherence in a portable and cost-effective implementation.It modulates the three-color beams from the RGB LED separately so that the three-color beams effectively overlap on the sample plane while reducing the effective light-emitting area for better spatial coherence.The separate modulation of the spatial coherence allows the temporal coherence to be modulated separately by single spectral filters rather than by expensive triple spectral filters.Based on the pinhole array,the LFOCM-RGB simply and effectively realizes the high-resolution imaging in a portable and cost-effective implementation,offering much flexibility for various applications in resource-limited environments.
基金the Basic Research Program of Shenzhen(No.JCYJ20170412171744267)。
文摘In this Let ter,a single scattering turbulence model in a narrow beam case for ultraviolet(UV)communication is proposed based on the division of the effective scattering volume.This model takes the variation of atmospheric scattering,absorption,and turbulence in different paths into account.Meanwhile,the applicable transceiver configurations of this model are provided by analyzing path loss error caused by the single scattering assumption in the UV channel.Furthermore,we investigate the effect of turbulence on the probability density function of the arriving power in both coplanar and non-coplanar scenarios.The averaging effect of multipath propagation on the arriving power's fluctuations is presented.Then,the bit-error-rate performance is also studied.This work provides an efficient way for UV turbulence channel estimation.
