- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2018 IEEE 8th International Conference Nanomaterials: Application & Properties (NAP) - Zatoka, Ukraine (2018.9.9-2018.9.14)] 2018 IEEE 8th International Conference Nanomaterials: Application & Properties (NAP) - Optical and Thermal Analysis of PVB Encapsulant Polymer Functionalized with Luminescent Organic Dye as Emerging Material for Photovoltaic Application
摘要： Wireless sensor networks (WSNs) can utilize the unlicensed industrial, scienti?c, and medical (ISM) band to communicate the sensed data. The ISM band has been already saturated due to the overlaid deployment of WSNs. To solve this problem, WSNs have been powered up by cognitive radio (CR) capability. By using CR capability, WSNs can utilize the spectrum holes opportunistically. The sensor nodes, which need large bandwidth to transmit their sensed data from source to destination require some scheme, which should be able to provide them a wide band channel whenever required. Channel bonding (CB) is a technique through which multiple contiguous channels can be combined to form a single wide band channel. By using CB technique, CR-based WSN nodes attempt to ?nd and combine contiguous channels to avail larger bandwidth. In this paper, we show that by increasing the number of channels, the probability of ?nding contiguous channels decreases. Moreover, we then propose a primary-radio (PR) user-activity-aware CB algorithm and compare it with three state-of-the-art schemes: SWA, KNOWS, and AGILE. It has been demonstrated through extensive NS-2 simulations that intelligent CB decisions can reduce harmful interference to PR nodes. We ?nd that CB in CR sensor networks attempts to provide greater bandwidth and utilizes the spectrum effectively.
关键词： cognitive radio,dynamic spectrum access,wireless sensor networks,Channel bonding
更新于2025-09-23 15:21:01
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[IEEE 2019 International Semiconductor Conference (CAS) - Sinaia, Romania (2019.10.9-2019.10.11)] 2019 International Semiconductor Conference (CAS) - Broadband Y-type Divider in Ku-band Using Substrate Integrated Waveguide
摘要： Clipping is one of the simplest peak-to-average power ratio reduction schemes for orthogonal frequency division multiplexing (OFDM). Deliberately clipping the transmission signal degrades system performance, and clipping mitigation is required at the receiver for information restoration. In this paper, we acknowledge the sparse nature of the clipping signal and propose a low-complexity Bayesian clipping estimation scheme. The proposed scheme utilizes a priori information about the sparsity rate and noise variance for enhanced recovery. At the same time, the proposed scheme is robust against inaccurate estimates of the clipping signal statistics. The undistorted phase property of the clipped signal, as well as the clipping likelihood, is utilized for enhanced reconstruction. Furthermore, motivated by the nature of modern OFDM-based communication systems, we extend our clipping reconstruction approach to multiple antenna receivers and multi-user OFDM. We also address the problem of channel estimation from pilots contaminated by the clipping distortion. Numerical findings are presented that depict favorable results for the proposed scheme compared to the established sparse reconstruction schemes.
关键词： Clipping,Bayesian sparse signal estimation,OFDM,PAPR reduction,multi-user communication,channel estimation
更新于2025-09-23 15:21:01
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Sherman-Morrison Formula Aided Adaptive Channel Estimation for Underwater Visible Light Communication With Fractionally-sampled OFDM
摘要： In this paper, we investigate the channel estimation (CE) problem in an underwater visible light communication (UVLC) system invoking fractionally-sampled optical orthogonal frequency division multiplexing (FS-OOFDM). In practical UVLC scenarios, the communication links inevitably suffer from many stochastic channel effects including multi-path dispersion, scattering, turbulence, etc., and/or from the mobility of the transceiver, therefore resulting in a time-varying, location-dependent non-stationary propagation environment. Naturally, compared with the indoor visible light communication (VLC) scenario with a typical assumption being the time-flat channel models, it becomes a notable challenge for designing a low-complexity adaptive CE in the much more complicated UVLC scenarios. To solve this problem, we derive a class of Bayesian CE algorithms referred to as the Sherman-Morrison formula (SMF) based CE (SMF-CE), by exploiting the property of rank-one structure of the second-order channel statistics in the delay domain. Furthermore, an adaptive version of SMF-CE (ASMF-CE) can be obtained through updating the imperfect a priori knowledge of the channel and the noise’s statistics. Simulation results demonstrate the superior performances of the proposed algorithms in comparison to existing methods, while maintaining a reduced computational complexity in comparison to the conventional linear minimum mean square error (LMMSE) scheme.
关键词： Sherman-Morrison formula (SMF),Channel estimation (CE),underwater visible light communication (UVLC),fractional sampling (FS),optical orthogonal frequency division multiplexing (OOFDM)
更新于2025-09-23 15:21:01
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[IEEE 2019 Joint Conference of the IEEE International Frequency Control Symposium anEuropean Frequency and Time Forum (EFTF/IFC) - Orlando, FL, USA (2019.4.14-2019.4.18)] 2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum (EFTF/IFC) - Support Transducer Enabled Single Resonator Channel Select Filter
摘要： In this work, we report a piezoelectric channel select filter design using a single resonator which utilizes Thin Piezo on Substrate (TPoS) transducer uniquely positioned so as to drive the central bulk Single Crystal Silicon (SCS) into resonance. Here, the support transducers operate in a combined length extension and an in-plane shear mode. A short connector between transducers and central SCS is used to create a frequency split to realize the filter. The device is fabricated using MEMSCAP Inc. AlN-on-silicon platform. A differential drive and single port sense method was employed to realize the narrow bandwidth (NBW) filter with a reduced feedthrough level. As a result, we demonstrate a 20.62 MHz TPoS MEMS filter with an extremely flat passband and a tiny bandwidth of 18 kHz (0.087% BW), a 4dB Insertion Loss with a 39dB Stop Band Rejection and less than 0.1dB passband ripple.
关键词： Channel select filter,differential,piezoelectric,narrow bandwidth,TPoS,support transducer
更新于2025-09-23 15:21:01
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - Pulsed RF Power Measurements of Laterally Scaled Ga <sub/>2</sub> O <sub/>3</sub> FETs
摘要： This paper tackles the problem of minimum-energy cooperative transmission in wireless networks under the assumption of limited channel state information at the transmitters. It is assumed that only the average statistics of the fading channels are known to the transmitters. The objective here is to jointly optimize the set of relays and the transmission powers for both the broadcasting and cooperative transmission phases while satisfying probabilistic signal-to-noise ratio (SNR) constraints at the relays and at the destination node. Increasing the broadcasting power expands the set of potential relays and decreases the required power for cooperative transmission. Hence, there is a compromise in the selection of the power values, which is addressed in this work using a chance-constrained optimization framework. A closed-form approximate solution is also presented, which provides a low-complexity transmission scheme for energy-harvesting wireless networks. Simulations are presented to demonstrate the efficacy of the proposed approach and the approximate solution.
关键词： optimization,imperfect channel state information,Cooperative communications,relay networks
更新于2025-09-23 15:21:01
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - Numerical Investigation of Topological Edge States in a GaAs-Based Three-Dimensional Chiral Photonic Crystal
摘要： Massive expansion of wireless body area networks (WBANs) in the field of health monitoring applications has given rise to the generation of huge amount of biomedical data. Ensuring privacy and security of this very personal data serves as a major hurdle in the development of these systems. An effective and energy friendly authentication algorithm is, therefore, a necessary requirement for current WBANs. Conventional authentication algorithms are often implemented on higher levels of the Open System Interconnection model and require advanced software or major hardware upgradation. This paper investigates the implementation of a physical layer security algorithm as an alternative. The algorithm is based on the behavior fingerprint developed using the wireless channel characteristics. The usability of the algorithm is established through experimental results, which show that this authentication method is not only effective, but also very suitable for the energy-, resource-, and interface-limited WBAN medical applications.
关键词： Wireless body area networks,physical layer security,wireless channel characteristics,authentication
更新于2025-09-23 15:21:01
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - Growth of InGaAs solar cells on InP(001) miscut substrates using solid-source molecular beam epitaxy
摘要： In this paper, we present a new motor imagery classification method in the context of electroencephalography (EEG)-based brain–computer interface (BCI). This method uses a signal-dependent orthogonal transform, referred to as linear prediction singular value decomposition (LP-SVD), for feature extraction. The transform defines the mapping as the left singular vectors of the LP coefficient filter impulse response matrix. Using a logistic tree-based model classifier; the extracted features are classified into one of four motor imagery movements. The proposed approach was first benchmarked against two related state-of-the-art feature extraction approaches, namely, discrete cosine transform (DCT) and adaptive autoregressive (AAR)-based methods. By achieving an accuracy of 67.35%, the LP-SVD approach outperformed the other approaches by large margins (25% compared with DCT and 6 % compared with AAR-based methods). To further improve the discriminatory capability of the extracted features and reduce the computational complexity, we enlarged the extracted feature subset by incorporating two extra features, namely, Q- and the Hotelling’s T 2 statistics of the transformed EEG and introduced a new EEG channel selection method. The performance of the EEG classification based on the expanded feature set and channel selection method was compared with that of a number of the state-of-the-art classification methods previously reported with the BCI IIIa competition data set. Our method came second with an average accuracy of 81.38%.
关键词： feature extraction,linear prediction,Brain-computer interface,orthogonal transform,channel selection
更新于2025-09-23 15:21:01
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[IEEE 2019 Research, Invention, and Innovation Congress (RI2C) - Bangkok, Thailand (2019.12.11-2019.12.13)] 2019 Research, Invention, and Innovation Congress (RI2C) - Progress in a Development of a Laser-Based Weed Control System
摘要： In this correspondence, we investigate the performance of a multi-cell multiple-input multiple-output downlink (DL) system aided by base station (BS) cooperation, relay cooperation, and polarization-multiplexing (PM). Triply-polarized antennas that are employed at the BSs, relays, and mobile stations (MSs) to conceive PM serve as an replacement for multiple uni-polarized antennas that in?ict space limitation. In a multi-user multi-cell relay-aided scenario, MSs and relays con?ict multi-user interference (MUI) as well as inter-cell or co-channel interference (CCI). Furthermore, the MSs experience intra-relay interference and inter-relay interference. In this paper, both the MUI and CCI at the relays are completely removed by the combined preprocessing operated at the BS. Similarly, the intra-relay and inter-relay interference are eliminated with the aid of the joint preprocessing operated at the relays. Speci?cally, in this contribution, the performance of the considered system is investigated when the channel state information (CSI) required at the BSs to implement the joint preprocessing suffers from feedback and back-haul delays. In our contribution, feedback channels that convey the CSI to the BSs endure noise and fading as well. Our simulation study demonstrates that the use of triply polarized antennas in combination with joint preprocessing at the BSs and relays can be regarded as an ef?cient technique for the cooperative multi-cell DL system to deal with the space constraints and the aforementioned interferences. Furthermore, the considered preprocessing results in superior symbol-error-rate performance compared with other preprocessing approaches.
关键词： inter-relay interference,interference,Co-channel,MIMO,multi-user interference,intra-relay interference,polarization-multiplexing,noisy feedback
更新于2025-09-23 15:21:01
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Parameters extraction of photovoltaic models using triple-phase teaching-learning-based optimization
摘要： Hybrid analog/digital multiple-input multiple-output architectures were recently proposed as an alternative for fully digital-precoding in millimeter wave wireless communication systems. This is motivated by the possible reduction in the number of RF chains and analog-to-digital converters. In these architectures, the analog processing network is usually based on variable phase shifters. In this paper, we propose hybrid architectures based on switching networks to reduce the complexity and the power consumption of the structures based on phase shifters. We define a power consumption model and use it to evaluate the energy efficiency of both structures. To estimate the complete MIMO channel, we propose an open-loop compressive channel estimation technique that is independent of the hardware used in the analog processing stage. We analyze the performance of the new estimation algorithm for hybrid architectures based on phase shifters and switches. Using the estimate, we develop two algorithms for the design of the hybrid combiner based on switches and analyze the achieved spectral efficiency. Finally, we study the tradeoffs between power consumption, hardware complexity, and spectral efficiency for hybrid architectures based on phase shifting networks and switching networks. Numerical results show that architectures based on switches obtain equal or better channel estimation performance to that obtained using phase shifters, while reducing hardware complexity and power consumption. For equal power consumption, all the hybrid architectures provide similar spectral efficiencies.
关键词： switches,precoding,Millimeter wave,hybrid architecture,channel estimation
更新于2025-09-23 15:21:01
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Control of Multiple Filamentation of Femtosecond Laser Pulses in Air
摘要： The results are presented of experiments on controlling the characteristics of the multiple filamentation domain of femtosecond laser pulses along atmospheric paths via variations in the initial spatial focusing, beam radius, and pulse energy, as well as the optical field structure at the initial beam aperture.
关键词： filamentation,femtosecond pulse,bimorph deformable mirror,laser radiation,postfilamentation light channel,self-focusing
更新于2025-09-23 15:21:01