S. Kundu

Cooperative spectrum sensing with censoring of cognitive radios in Rayleigh fading under majority logic fusion

In this paper, the performance of cooperative spectrum sensing (CSS) has been assessed in presence of Rayleigh fading. A cognitive radio (CR) senses the primary users (PUs) using an energy detector (ED) in sensing channel (S-channel). If a CR is selected to transmit its local decisions to a fusion centre (FC), it does so using a reporting (R)-channel with binary phase shift keying (BPSK) signaling. In the present work, we consider censoring of CRs based on a characterization of Rayleigh faded R-channels. In other words, CRs, whose estimated R-channel fading coefficient towards the FC exceeds a predefined threshold, are allowed to transmit. Majority logic fusion is considered at the FC to estimate the performance in terms of average missed detection and total error probabilities for various values of censoring threshold, number of CRs, false alarm probabilities, average S-channel and R-channel SNRs, under both perfect and imperfect channel estimations.

Cation dependent charge transport in linear dicarboxylate based isotypical 1D coordination polymers

Two new mixed-ligand one-dimensional coordination polymers (1D CPs) [Cd(adc)(4-phpy)2(H2O)2], (1) and [Zn(adc)(4-phpy)2(H2O)2], (2) (H2adc = acetylenedicarboxylic acid and 4-phpy = 4-phenylpyridine) have been synthesized and well characterized by elemental analysis, infrared spectroscopy, single crystal X-ray diffraction, powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA). Both compounds 1 and 2 are isostructural and fabricate 3D supramolecular networks by the combination of hydrogen bonding and C–H⋯π interactions. Interestingly, these two materials exhibit electrical conductivity and reveal Schottky barrier diode behavior. To shed light on the charge transport mechanism of the compounds, the mobility, transit time, diffusion length and density of states at a quasi Fermi level have been derived. The analysis indicates that compound 1 has higher mobility (9.15 × 10−7 m2 V−1 s−1) and diffusion length (1.116 μm) in comparison to compound 2 (mobility and diffusion length are 5.44 × 10−7 m2 V−1 s−1 and 1.050 μm respectively). Compound 1, with the larger cation and shorter H-bonding distance, shows higher electrical conductivity, which is 2.55 times greater than compound 2.

Performance of MRC fusion-based cooperative spectrum sensing with censoring of cognitive radios in rayleigh fading channels

In this paper, the performance of a cooperative spectrum sensing (CSS) is evaluated, considering maximal ratio combining (MRC) fusion in the presence of Rayleigh fading. A cognitive radio (CR) senses the primary users (PUs) using an energy detector (ED) in the sensing channel (S-channel). If a CR is selected to transmit its local decisions to a fusion centre (FC), it does so using a reporting (R)-channel with binary phase shift keying (BPSK) signaling. In the present work, we consider censoring of CRs based on a characterization of Rayleigh faded R-channels. In other words, CRs, whose estimated R-channel fading coefficients towards the FC exceed a predefined threshold (censoring threshold), are allowed to transmit. MRC fusion is considered at the FC to estimate the performance in terms of average missed detection and total error probabilities for various values of (i) the censoring threshold, (ii) the number of CRs, (iii) the average S-channel and R-channel signal-to-noise ratios (SNRs), under both perfect and imperfect channel estimations. The performance of CSS system with MRC fusion is also compared, for various values of the network parameters, with the performance with majority logic fusion.

Synthesis and structural characterization of a Cu(II)-based 1D coordination polymer and its application in Schottky devices

A new Cu(II) based one-dimensional coordination polymer (1D CP), [Cu(fum)(4-phpy)2(H2O)] (1) (H2fum = fumaric acid and 4-phpy = 4-phenyl pyridine), has been synthesized and well characterized using elemental analysis, infrared spectra, single crystal X-ray diffraction (SCXRD) techniques, powder X-ray diffraction (PXRD) patterns, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). In the solid state structure, 1D chains are self-assembled through strong intermolecular hydrogen bonding to give a 2D sheet structure. These 2D sheets are further accumulated to fabricate 3D supramolecular aggregates via weak CH⋯π interactions. The band gap measurement which is equivalent to the HOMO–LUMO gap calculated by density functional theory (DFT) computations confirms the semiconducting properties of the material. To gain insight into the charge transport mechanism of the compound, its mobility, lifetime and diffusion length have been estimated. The analysis indicates that compound 1 may be applied in active electronic devices. Finally, a metal–CP junction Schottky barrier diode has been successfully fabricated and studied in detail.

Experimental investigation ofT=1analog states ofAl26andMg26

The even-even nucleus

Fission fragment mass distributions from Po210 and At213

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Study of 26Mg through 1p pick-up reaction 27Al(d,3He)

Mg has been studied through the reaction

Cooperative spectrum sensing with censoring of cognitive radios with majority logic fusion in Hoyt fading

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Halogen···Halogen Interactions in the Supramolecular Assembly of 2D Coordination Polymers and the CO2 Sorption Behavior

Al(d,

Fragment emission mechanism in the S32+C12 reaction

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