摘要 :
In this paper, real frequency design equations of narrowband impedance matching network with complex terminations are derived; which are used to design L, Pi and T type of networks. In the approach, there is no need to have termin...
展开
In this paper, real frequency design equations of narrowband impedance matching network with complex terminations are derived; which are used to design L, Pi and T type of networks. In the approach, there is no need to have termination models with component values, it is enough to have measurement values of termination impedances. A few examples are solved to exhibit the have measurement values of termination impedances. A few examples are solved to exhibit the merits and application of the derived equations.
收起
摘要 :
In recent years, major natural disasters and public safety accidents have frequently occurred worldwide. In order to deal with various disasters and accidents using rapidly deployable, reliable, efficient, and stable emergency com...
展开
In recent years, major natural disasters and public safety accidents have frequently occurred worldwide. In order to deal with various disasters and accidents using rapidly deployable, reliable, efficient, and stable emergency communication networks, all countries in the world are strengthening and improving emergency communication network construction and related technology research. Motivated by these situations, in this paper, we provide a state-of-the-art survey of the current situation and development of emergency communication networks. In this detailed investigation, our primary focus is the extensive discussion of emergency communication network technology, including satellite networks, ad hoc networks, cellular networks, and wireless private networks. Then, we explore and analyze the networks currently applied in emergency rescue, such as the 370M narrowband private network, broadband cluster network, and 5G constellation plan. We propose a broadband-narrowband integrated emergency communication network to provide an effective solution for visual dispatch of emergency rescue services. The main findings derived from the comprehensive survey on the emergency communication network are then summarized, and possible research challenges are noted. Lastly, we complete this survey by shedding new light on future directions for the emergency communication network. In the future, the emergency network will develop in the direction of intelligence, integration, popularization, and lower cost, and space-air-ground-sea integrated networks. This survey provides a reference basis for the construction of networks to mitigate major natural disasters and public safety accidents.
收起
摘要 :
Using narrowband wireless On-Body Area Network (BAN) channel measurements (50 million data points) in diverse environments with multiple subjects, we examine the stationarity of the channel. Wide-Sense Stationarity (WSS) tests and...
展开
Using narrowband wireless On-Body Area Network (BAN) channel measurements (50 million data points) in diverse environments with multiple subjects, we examine the stationarity of the channel. Wide-Sense Stationarity (WSS) tests and power spectral estimates show that the channel has a 50% probability of stationarity at 500 ms and the probability rapidly diminishes thereafter. We show that non-stationarity is inherent to on-body BANs and not an artifact of experimental setup.
收起
摘要 :
Purpose - In the literature, while designing broadband matching networks, transducer power gain (TPG) is used to measure the transferred power. Generally, in TPG expressions, load and back-end impedances of the matching network ar...
展开
Purpose - In the literature, while designing broadband matching networks, transducer power gain (TPG) is used to measure the transferred power. Generally, in TPG expressions, load and back-end impedances of the matching network are used. This study aims to derive a new quality factor-based TPG expression.Design/methodology/approach - In deriving the new expression, narrowband L type-matching network design approach is used and the new expression in terms of back-end quality factor, load quality factor and output port quality factor is obtained. Then, a broadband-matching network design approach using the derived TPG expression is proposed. Findings - Two broadband double-matching networks are designed by using the proposed design approach using the derived TPG expression. Performances of the designed-matching networks are compared with the performances of the matching networks designed by means of simplified real frequency technique which is a well-known technique in the literature, and it is shown that they are nearly the same. Originality/value - In broadband-matching problems, generally an impedance-based TPG expression is used, and it must be satisfied by the designed broadband-matching networks. But, in the literature, there is no quality factor-based TPG expression that can be used in broadband-matching problems. So, this gap in the literature has been filled by this paper.
收起
摘要 :
This paper proposes a narrowband interference (NBI) suppression algorithm for Direct Sequence-Code Division Multiple Access systems. The NBI is considered from heterogeneous networks, and predicted based on its cyclostationary cha...
展开
This paper proposes a narrowband interference (NBI) suppression algorithm for Direct Sequence-Code Division Multiple Access systems. The NBI is considered from heterogeneous networks, and predicted based on its cyclostationary characteristic using a nonlinear feed-forward neural network predictor which eliminates the nonlinearity of the spread spectrum (SS) signal in the NBI prediction. To further improve the suppression performance, this paper exploits the structure of the spreading code, and proposes an iterative code-aided algorithm to jointly estimate the NBI and the SS signal. Simulation results reveal that the proposed algorithm largely outperforms the conventional linear prediction filtering and linear-conjugate linear polyperiodically time-varying filtering methods in both the signal to interference plus noise ratio improvement and the bit error rates, when it operates in NBI-contaminated environments.
收起
摘要 :
Ultra wideband (UWB) is the most preferred candidate for body area networks (BAN). The higher data rate and lower multipath fading makes it highly suitable for the design of BAN. However, narrowband interference (NBI) may signific...
展开
Ultra wideband (UWB) is the most preferred candidate for body area networks (BAN). The higher data rate and lower multipath fading makes it highly suitable for the design of BAN. However, narrowband interference (NBI) may significantly degrade the performance of UWB. The paper presents an effective method of NBI mitigation for UWB BAN. The method uses modified Hermite pulse (MHP) in lieu of Gaussian and other pulse shapes. The spectral characteristics of the MHP make them immune to interference. The performance has been tested in various body postures in the CM4 channel model of the BAN, and further validated by transmitting medical signals like electrocardiography and MRI. The results show that MHP pulse is highly immune to NBI.
收起
摘要 :
The detection process of partial discharge (PD) ultra-high frequency (UHF) signal is easily affected by white noise and periodic narrowband noise, which hinder the fault diagnosis of high-voltage electrical appliances. In order to...
展开
The detection process of partial discharge (PD) ultra-high frequency (UHF) signal is easily affected by white noise and periodic narrowband noise, which hinder the fault diagnosis of high-voltage electrical appliances. In order to extract PD UHF signal and suppress noise effectively, this paper provides a new method to detect PD UHF signal by EDSSV and low rank RBF neural network. Firstly, the singular value decomposition (SVD) is performed on the mixed noises of PD signal. Secondly, the peak index of energy difference spectrum of singular value (EDSSV) is selected as optimal singular value threshold, and then the periodic narrowband noise is eliminated by reconstructing the effective rank order. Finally, radial basis function (RBF) neural network is used to approximate the denoised PD signal, and Gaussian window filter is used to extract the PD signal. To verify the performance of the proposed method, we compared it with other three algorithms in simulation and field detection, including adaptive singular value decomposition (ASVD), singular value decomposition based on S-transform and MTFM (S-SVD) and EMD-WT algorithms. Particularly, four evaluation indices are designed for the detection data, which consider both the noise suppression and feature preservation. The results demonstrate the validity of the proposed method with higher signal-to-noise ratio and less waveform distortion.
收起
摘要 :
In this letter, we present a lightweight yet accurate scheme for mobile devices, called WidthSense, that identifies available Wi-Fi systems by using a collocated heterogeneous wireless personal area network (WPAN) radio such as Bl...
展开
In this letter, we present a lightweight yet accurate scheme for mobile devices, called WidthSense, that identifies available Wi-Fi systems by using a collocated heterogeneous wireless personal area network (WPAN) radio such as Bluetooth or ZigBee. Motivated by the observation that Wi-Fi signals in a 2.4 GHz ISM band can be sensed by a WPAN radio over the frequency range of the corresponding Wi-Fi channel, Width- Sense exploits the temporally correlated fluctuations in multiple narrowband WPAN-channels. To this end, we employ a distance-based similarity as a measurement of dependence between WPAN channels. We implement a prototype of WidthSense using a Bluetooth-compliant wireless transceiver, and demonstrate its efficiency. Experimental results show that WidthSense achieves high detection accuracy with a short delay (−500 ms).
收起
摘要 :
We present a new fast polling algorithm (FPA) in a wireless mesh network (WMN) for Narrowband Internet of Things systems using multi-hop WMNs. We focus on wireless networks with stationary IoT remote telemetry units (IoT RTU), suc...
展开
We present a new fast polling algorithm (FPA) in a wireless mesh network (WMN) for Narrowband Internet of Things systems using multi-hop WMNs. We focus on wireless networks with stationary IoT remote telemetry units (IoT RTU), such as wireless network monitoring. The goal of the new FPA is to minimize the time required for supervisory control and data acquisition center to poll all RTUs one by one and to receive their responses using random network coding. We study the performance of the proposed FPA by applying it in a WMN composing of 3 and 50 RTUs with a sub-carrier spacing of 6.25 kHz, 12.5 kHz, 25 kHz, and 50 kHz. This paper also provides a comparative study of existing polling cycle mechanisms; we find that our FPA significantly outperforms previously proposed polling-cycle mechanisms with improvements typically exceeding 70%.
收起
摘要 :
This paper presents a deep learning
approach for the inverse-design of metal-insulator-metal
metasurfaces for hyperspectral imaging applications.
Deep neural networks are able to compensate for the
complex interactions between...
展开
This paper presents a deep learning
approach for the inverse-design of metal-insulator-metal
metasurfaces for hyperspectral imaging applications.
Deep neural networks are able to compensate for the
complex interactions between electromagnetic waves and
metastructures to efficiently produce design solutions
that would be difficult to obtain using other methods.
Since electromagnetic spectra are sequential in nature,
recurrent neural networks are especially suited for
relating such spectra to structural parameters.
收起
原文获取