- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - AMI Data Quality and Collection Method Considerations for Improving the Accuracy of Distribution Models
摘要： In the 5G system, we foresee the use of LOS-dominated mm-wave radio links to moving users being subject to slow fading resulting from the users’ random locations and orientations. We refer to this as a random-LOS channel. MIMO processing algorithms will be used in 5G to improve performance in slow fading, similar to how they are used in Rayleigh fading. To this end, we study the probability of detection in the random-LOS channel when there are dual-polarized antennas on both sides of the link. We introduce two polarization de?ciencies: the polarization non-orthogonality and the amplitude imbalance between the ports of a two-port antenna. The MIMO ef?ciency is evaluated as a function of these de?ciencies. In the analysis, we consider the MRC algorithm for one bitstream, and the ZF and SVD algorithms for two bitstreams. We also present two analytical formulas for the MIMO ef?ciency that can be used to determine performance. We use the formulas on two ideally orthogonal dipoles, and show by means of coverage plots how much the 1- and 2-bitstream performances degrade due to the polarization de?ciencies in off-boresight directions.
关键词： antenna measurements,line-of-sight,polarization-MIMO,Antenna theory
更新于2025-09-23 15:21:01
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Low-Complexity Multiuser Receiver for Massive Hybrid Array mmWave Communications
摘要： In this paper, we study the low complexity reception of multiuser signals in uplink millimeter wave (mmWave) communications using a partially connected hybrid antenna array. Exploiting the mmWave channel property, we propose a low-complexity user-directed multiuser receiver with three novel schemes for allocating subarrays to users. This receiver only requires the knowledge of angles-of-arrival (AoAs) for dominating paths and a small amount of equivalent channel information instead of perfect channel state information. For comparison, we also derive a successive interference cancellation based solution as a performance benchmark. We design two types of reference signals with the channel estimation method to enable efficient and simple estimation for AoA and equivalent baseband channel. Also, we provide analytical results for the performance of AoA estimation, using the lower bounds of mean square errors in line-of-sight dominated mmWave channels. Simulation results validate that the proposed channel estimation method is effective when employed in combination with a zero-forcing equalizer.
关键词： mmWave communications,subarray,angle-of-arrival estimation,Hybrid antenna array,line-of-sight
更新于2025-09-19 17:15:36
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Computational periscopy with an ordinary digital camera
摘要： Computing the amounts of light arriving from different directions enables a diffusely reflecting surface to play the part of a mirror in a periscope—that is, perform non-line-of-sight imaging around an obstruction. Because computational periscopy has so far depended on light-travel distances being proportional to the times of flight, it has mostly been performed with expensive, specialized ultrafast optical systems1–12. Here we introduce a two-dimensional computational periscopy technique that requires only a single photograph captured with an ordinary digital camera. Our technique recovers the position of an opaque object and the scene behind (but not completely obscured by) the object, when both the object and scene are outside the line of sight of the camera, without requiring controlled or time-varying illumination. Such recovery is based on the visible penumbra of the opaque object having a linear dependence on the hidden scene that can be modelled through ray optics. Non-line-of-sight imaging using inexpensive, ubiquitous equipment may have considerable value in monitoring hazardous environments, navigation and detecting hidden adversaries.
关键词： penumbra,ray optics,digital camera,non-line-of-sight imaging,computational periscopy
更新于2025-09-19 17:15:36
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Atomic Vapor Confined in a Nanoscale Geometry: From Mesoscopic to Collective Effects
摘要： Simulation data from a ray-tracing tool applied in specific urban environments in the 28-GHz band suggest that the utilization of arbitrary base station (BS) angles in a directional search procedure may not be of maximum benefit for users located in non-line-of-sight positions, because certain angles restrict the radio frequency illumination to a lower maximum power than from others. An appropriate selection of BS angles offers a potential power level benefit of greater than 2 dB in a defined number of consecutive measurements; however, this performance improvement appears to be conditioned by the severity of the existing street canyon propagation and the probability of the angle used. A simple ray tracing method is proposed to approximately identify the most effective BS angles that avoid power emissions in directions largely blocked by nearby buildings. The results indicate that prior site-specific information may be helpful, particularly for systems using analog beamforming.
关键词： Angle of arrival,millimeter wave,user equipment,ray tracing,non-line-of-sight,base station,radio frequency,beam direction
更新于2025-09-19 17:13:59
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Single-input Multiple-output Multi-carrier Wireless Indoor Direction Finding in a Compact Multipath Scenario Using 2.4 GHz ISM Band2
摘要： Super-resolution direction of arrival (DoA) estimation of impinging signals from a line of sight (LOS) source and multiple point scatterers at the 2.4 GHz ISM band is considered within a compact area. The channel is partially frequency ?at in the interested range and all the impinging signals due to the point scatterers are correlated, which introduces the necessity of algorithms for decorrelation of signals. This paper introduces a frequency domain decorrelation scheme for the DoA estimation of a LOS source and point scatterers, which constraints a particular structure on the receiver antenna. The limitation in terms of resolution is demonstrated with respect to the coherence bandwidth of the channel for distinct cases of point scatterer locations with respect to the LOS source.
关键词： coherence bandwidth,line of sight (LOS),2.4 GHz ISM band,direction of arrival (DoA),frequency domain decorrelation
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 2nd International Conference on Renewable Energy and Power Engineering (REPE) - Toronto, ON, Canada (2019.11.2-2019.11.4)] 2019 IEEE 2nd International Conference on Renewable Energy and Power Engineering (REPE) - Perovskite solar cells-A futuristic approach
摘要： Simulation data from a ray-tracing tool applied in specific urban environments in the 28-GHz band suggest that the utilization of arbitrary base station (BS) angles in a directional search procedure may not be of maximum benefit for users located in non-line-of-sight positions, because certain angles restrict the radio frequency illumination to a lower maximum power than from others. An appropriate selection of BS angles offers a potential power level benefit of greater than 2 dB in a defined number of consecutive measurements; however, this performance improvement appears to be conditioned by the severity of the existing street canyon propagation and the probability of the angle used. A simple ray tracing method is proposed to approximately identify the most effective BS angles that avoid power emissions in directions largely blocked by nearby buildings. The results indicate that prior site-specific information may be helpful, particularly for systems using analog beamforming.
关键词： Angle of arrival,millimeter wave,user equipment,ray tracing,non-line-of-sight,base station,radio frequency,beam direction
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Rear Heterojunction GaAs Solar Cells With Strain-Balanced GaInAs/GaAsP Quantum Wells
摘要： Simulation data from a ray-tracing tool applied in specific urban environments in the 28-GHz band suggest that the utilization of arbitrary base station (BS) angles in a directional search procedure may not be of maximum benefit for users located in non-line-of-sight positions, because certain angles restrict the radio frequency illumination to a lower maximum power than from others. An appropriate selection of BS angles offers a potential power level benefit of greater than 2 dB in a defined number of consecutive measurements; however, this performance improvement appears to be conditioned by the severity of the existing street canyon propagation and the probability of the angle used. A simple ray tracing method is proposed to approximately identify the most effective BS angles that avoid power emissions in directions largely blocked by nearby buildings. The results indicate that prior site-specific information may be helpful, particularly for systems using analog beamforming.
关键词： Angle of arrival,user equipment,radio frequency,non-line-of-sight,beam direction,base station,millimeter wave,ray tracing
更新于2025-09-19 17:13:59
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A Review on Practical Considerations and Solutions in Underwater Wireless Optical Communication
摘要： Underwater wireless optical communication (UWOC) has attracted increasing interest in various underwater activities because of its order-of-magnitude higher bandwidth compared to acoustic and radio-frequency technologies. Testbeds and pre-aligned UWOC links were constructed for physical layer evaluation, which verified that UWOC systems can operate at tens of gigabits per second or close to a hundred meters of distance. This holds promise for realizing a globally connected Internet of Underwater Things (IoUT). However, due to the fundamental complexity of the ocean water environment, there are considerable practical challenges in establishing reliable UWOC links. Thus, in addition to providing an exhaustive overview of recent advances in UWOC, this paper addresses various underwater challenges and offers insights into the solutions for these challenges. In particular, oceanic turbulence, which induces scintillation and misalignment in underwater links, is one key factor in degrading UWOC performance. Novel solutions are proposed to ease the requirements on pointing, acquisition, and tracking (PAT) for establishing robustness in UWOC links. The solutions include light-scattering-based non-line-of-sight (NLOS) PAT-relieving communication modality as well as scintillating-fiber-based photoreceiver and large-photovoltaic cells as the optical signal detectors. Naturally, the dual-function photovoltaic–photodetector device readily offers a means of energy harvesting for powering up future IoUT sensors.
关键词： non-line-of-sight,Underwater wireless optical communication,energy harvesting,turbulence,fiber detector
更新于2025-09-16 10:30:52
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[IEEE 2019 XIth International Scientific and Practical Conference on Electronics and Information Technologies (ELIT) - Lviv, Ukraine (2019.9.16-2019.9.18)] 2019 XIth International Scientific and Practical Conference on Electronics and Information Technologies (ELIT) - Computational-Measurement System a??Nanoplasmonicsa??. Part 2: Structure of Microservices
摘要： Ray tracing simulation results indicate that a high-resolution database is not needed to exploit user position knowledge in the 28-GHz band, even in the case of inexact information. A proposed antenna alignment algorithm (using maximum position errors and database resolutions of 10 and 4 m, respectively) that takes advantage of the propagation characteristics knowledge of database points located around the reported location is applied. The results show that the distance between the points can be increased up to 2 m with no considerable negative impact on performance. Simulations also indicate that this outcome is sustained when the maximum power level received at the user equipment varies. The algorithm provides the benefit of a higher initial power delivery and fewer steps, as long as the exact geographical position of the user is within the circular area containing the considered database points. The performance is similar to or better than that of a modified classical hierarchical procedure.
关键词： Base station (BS),database (DB),non-line of sight (NLOS),millimeter wave (mmW),ray tracing (RT),user equipment (UE),signal-to-noise ratio (SNR)
更新于2025-09-16 10:30:52
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Optical Fiber Communications (Principles and Applications) || Wireless Optics
摘要： The wireless optics holds great potential for fixed wireless communications as well as for other wireless applications. In spite of all other technology developments, wireless optics has promised an economical alternative to last mile connection solution in the wireless domain. The concept of wireless optics was originally developed over few decades ago by the military. An optical wireless technology, also known as free space optics (FSO) technology, provides broadband data communication links between line-of-sight (point-to-point) locations.
关键词： FSO,wireless optics,free space optics,broadband,line-of-sight
更新于2025-09-12 10:27:22