无线供电通信网络(Wireless-powered Communication Network,WPCN)不仅可以实现远程无线充电而且能够提供无线通信服务,因此受到了学术界和工业界的广泛关注。然而,低效率的能量收集和信息传输会限制WPCN的性能,并且在WPCN中的双重远近...无线供电通信网络(Wireless-powered Communication Network,WPCN)不仅可以实现远程无线充电而且能够提供无线通信服务,因此受到了学术界和工业界的广泛关注。然而,低效率的能量收集和信息传输会限制WPCN的性能,并且在WPCN中的双重远近效应会导致物联网设备收集的能量与消耗的能量之间的不平衡。为了解决这些问题,提出基于能量回收的主动智能反射面(Intelligent Reflecting Surface,IRS)辅助WPCN波束成形算法,其中物联网设备既能从功率站端收集能量,还能从其他物联网设备的上行信息传输中回收能量。考虑能量收集、吞吐量、时间分配,以及功率站和主动IRS的最大功率等约束,基于能量回收机制,建立了系统总吞吐量最大化的资源分配模型;然后,提出一种基于内层近似和双线性变换的交替优化算法进行求解。仿真结果表明,在相应的参数配置下,能量回收机制的应用能够提升约8.13%的吞吐量,而主动IRS的应用能够提升约61.1%的吞吐量。展开更多
The concept of emissivity has been with the scientific and engineering world since Planck formulated his blackbody radiation law more than a century ago.Nevertheless,emissivity is an elusive concept even for ex⁃perts....The concept of emissivity has been with the scientific and engineering world since Planck formulated his blackbody radiation law more than a century ago.Nevertheless,emissivity is an elusive concept even for ex⁃perts.It is a vague and fuzzy concept for the wider community of engineers.The importance of remote sensing of temperature by measuring IR radiation has been recognized in a wide range of industrial,medical,and environ⁃mental uses.One of the major sources of errors in IR radiometry is the emissivity of the surface being measured.In real experiments,emissivity may be influenced by many factors:surface texture,spectral properties,oxida⁃tion,and aging of surfaces.While commercial blackbodies are prevalent,the much-needed grey bodies with a known emissivity,are unavailable.This study describes how to achieve a calibrated and stable emissivity with a blackbody,a perforated screen,and a reliable and linear novel IR thermal sensor,18 dubbed TMOS.The Digital TMOS is now a low-cost commercial product,it requires low power,and it has a small form factor.The method⁃ology is based on two-color measurements,with two different optical filters,with selected wavelengths conform⁃ing to the grey body definition of the use case under study.With a photochemically etched perforated screen,the effective emissivity of the screen is simply the hole density area of the surface area that emits according to the blackbody temperature radiation.The concept is illustrated with ray tracing simulations,which demonstrate the approach.Measured results are reported.展开更多
文摘无线供电通信网络(Wireless-powered Communication Network,WPCN)不仅可以实现远程无线充电而且能够提供无线通信服务,因此受到了学术界和工业界的广泛关注。然而,低效率的能量收集和信息传输会限制WPCN的性能,并且在WPCN中的双重远近效应会导致物联网设备收集的能量与消耗的能量之间的不平衡。为了解决这些问题,提出基于能量回收的主动智能反射面(Intelligent Reflecting Surface,IRS)辅助WPCN波束成形算法,其中物联网设备既能从功率站端收集能量,还能从其他物联网设备的上行信息传输中回收能量。考虑能量收集、吞吐量、时间分配,以及功率站和主动IRS的最大功率等约束,基于能量回收机制,建立了系统总吞吐量最大化的资源分配模型;然后,提出一种基于内层近似和双线性变换的交替优化算法进行求解。仿真结果表明,在相应的参数配置下,能量回收机制的应用能够提升约8.13%的吞吐量,而主动IRS的应用能够提升约61.1%的吞吐量。
文摘The concept of emissivity has been with the scientific and engineering world since Planck formulated his blackbody radiation law more than a century ago.Nevertheless,emissivity is an elusive concept even for ex⁃perts.It is a vague and fuzzy concept for the wider community of engineers.The importance of remote sensing of temperature by measuring IR radiation has been recognized in a wide range of industrial,medical,and environ⁃mental uses.One of the major sources of errors in IR radiometry is the emissivity of the surface being measured.In real experiments,emissivity may be influenced by many factors:surface texture,spectral properties,oxida⁃tion,and aging of surfaces.While commercial blackbodies are prevalent,the much-needed grey bodies with a known emissivity,are unavailable.This study describes how to achieve a calibrated and stable emissivity with a blackbody,a perforated screen,and a reliable and linear novel IR thermal sensor,18 dubbed TMOS.The Digital TMOS is now a low-cost commercial product,it requires low power,and it has a small form factor.The method⁃ology is based on two-color measurements,with two different optical filters,with selected wavelengths conform⁃ing to the grey body definition of the use case under study.With a photochemically etched perforated screen,the effective emissivity of the screen is simply the hole density area of the surface area that emits according to the blackbody temperature radiation.The concept is illustrated with ray tracing simulations,which demonstrate the approach.Measured results are reported.
