Results 61 to 70 of about 22,442 (264)

Wideband Spectrum Sensing Based on Bidirectional Decision of Normalized Spectrum for Cognitive Radio Networks

open access: yesIEEE Access, 2019
Cognitive radio (CR) is considered to be an effective approach to eliminate the dilemma of spectrum shortage. To meet the ever-increasing demands of instant and accurate spectrum sensing in CR with wideband and multi-frequency-slots, a novel wideband ...
Peihan Qi, Yi Du, Danyang Wang, Zan Li
doaj   +1 more source

AI-Enabled Compressive Spectrum Classification for Wideband Radios

open access: yesTechnologies, 2023
Cognitive radio is a promising technology that emerged as a potential solution to the spectrum shortage problem by enabling opportunistic spectrum access.
Tassadaq Nawaz   +1 more
doaj   +1 more source

Wideband Sequential Spectrum Sensing with Varying Thresholds [PDF]

open access: yes2010 IEEE Global Telecommunications Conference GLOBECOM 2010, 2010
In this contribution, time varying threshold sequential detectors are employed for energy detection-based spectrum sensing in low- SNR regimes. Sequential detection is proven to be faster (on average) than any other multi-sample detector for a set of given probabilities of detection and false-alarm.
Kasra Haghighi   +2 more
openaire   +1 more source

Three‐dimensional Antimony Sulfide Based Flat Optics

open access: yesAdvanced Functional Materials, EarlyView.
This work presents the development of a grayscale electron beam lithography (g‐EBL) method for fabricating antimony trisulfide (Sb2S3) nanostructures with customizable 3D profiles. The refractive index of g‐EBL patterned Sb2S3 is determined based on the synergy of genetic algorithm and transfer matrix method.
Wei Wang   +18 more
wiley   +1 more source

Compressive Identification of Active OFDM Subcarriers in Presence of Timing Offset

open access: yes, 2015
In this paper we study the problem of identifying active subcarriers in an OFDM signal from compressive measurements sampled at sub-Nyquist rate. The problem is of importance in Cognitive Radio systems when secondary users (SUs) are looking for available
Cabric, Danijela   +2 more
core   +1 more source

Spectrally Tunable 2D Material‐Based Infrared Photodetectors for Intelligent Optoelectronics

open access: yesAdvanced Functional Materials, EarlyView.
Intelligent optoelectronics through spectral engineering of 2D material‐based infrared photodetectors. Abstract The evolution of intelligent optoelectronic systems is driven by artificial intelligence (AI). However, their practical realization hinges on the ability to dynamically capture and process optical signals across a broad infrared (IR) spectrum.
Junheon Ha   +18 more
wiley   +1 more source

Sub-Nyquist Sampling: Bridging Theory and Practice [PDF]

open access: yes, 2011
Sampling theory encompasses all aspects related to the conversion of continuous-time signals to discrete streams of numbers. The famous Shannon-Nyquist theorem has become a landmark in the development of digital signal processing. In modern applications,
Eldar, Yonina C., Mishali, Moshe
core   +1 more source

Multilayer Soft Photonic Arrays Inspired by Cephalopod Skin for High‐Density, Independent, and Multimodal Actuation

open access: yesAdvanced Functional Materials, EarlyView.
A vertically stacked, DEA‐driven photonic array inspired by cephalopod skin, featuring highly crystalline colloidal crystal gels with vivid color, low FWHM and scalability is presented. The multilayer design removes lateral pixel interference, achieving near‐100% fill factor with fully independent RGB actuation.
Maga Kim   +11 more
wiley   +1 more source

Viscoelasticity‐Induced Controllable Periodic Meso‐Textures of Liquid Crystal Polymers in Additive Manufacturing

open access: yesAdvanced Functional Materials, EarlyView.
Viscoelasticity‐driven instabilities are harnessed to create tunable, periodic textures in 3D‐printed liquid crystalline polymers. This study illustrates how processing parameters control these spontaneous meso‐scale patterns. These unique structural architectures unlock new possibilities for functional devices, ranging from photonic components to ...
Miaomiao Zou   +17 more
wiley   +1 more source

Compressive Wideband Spectrum Sensing for Fixed Frequency Spectrum Allocation

open access: yes, 2010
Too high sampling rate is the bottleneck to wideband spectrum sensing for cognitive radio (CR). As the survey shows that the sensed signal has a sparse representation in frequency domain in the mass, compressed sensing (CS) can be used to transfer the sampling burden to the digital signal processor. An analog to information converter (AIC) can randomly
Liu, Yipeng, Wan, Qun
openaire   +2 more sources

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