Secrecy energy efficiency optimization for multiuser massive MIMO wiretap systems with transmit antenna selection

Massive multiple-input-multiple-output (Massive MIMO) significantly improves the capacity of wireless communication systems. However, large-scale antennas bring high hardware costs, and security is a vital issue in Massive MIMO networks. To deal with the above problems, antenna selection (AS) and artificial noise (AN) are introduced to reduce energy consumption and improve system security performance, respectively. In this paper, we optimize secrecy energy efficiency (SEE) in a downlink multi-user multi-antenna scenario, where a multi-antenna eavesdropper attempts to eavesdrop the information from the base station (BS) to the multi-antenna legitimate receivers. An optimization problem is formulated to maximize the SEE by jointly optimizing the transmit beamforming vectors, the artificial noise vector and the antenna selection matrix at the BS. The formulated problem is a nonconvex mixed integer fractional programming problem. To solve the problem, a successive convex approximation (SCA)-based joint antenna selection and artificial noise (JASAN) algorithm is proposed. After a series of relaxation and equivalent transformations, the nonconvex problem is approximated to a convex problem, and the solution is obtained after several iterations. Simulation results show that the proposed algorithm has good convergence behavior, and the joint optimization of antenna selection and artificial noise can effectively improve the SEE while ensuring the achievable secrecy rate.     

Book Reviews

Room temperature glass containing copper nitrate was produced using the microemulsion-gel method. Ultraviolet-visible spectroscopy and x-ray diffraction spectra were used to demonstrate the presence of copper nitrate in the gel samples. The samples were examined using optical microscopy, with and without polarized filters, and scanning electron microscopy with energy dispersive x-ray analysis, before and after the extraction of the surfactant with an organic solvent. The results indicated that copper nitrate was present throughout the silicate network formed and was associated with the microemulsion components, i.e., the interstitial liquid, remaining in the bulk material.     

Triphenylphosphane Oxide Complexes of Lanthanide Nitrates: Polymorphs and Photophysics

A series of mer‐[Ln(NO₃)₃(Ph₃PO)₃] complexes were prepared from Ln(NO₃)₃ · xH₂O and Ph₃PO in chloroform (Ln = La, Nd, Sm, Eu, Gd, Tb, Dy, and Er). The La and Nd complexes were 0.25 CHCl₃ solvates, whereas the others were solvent‐free. The identical reaction using Yb(NO₃)₃ · xH₂O produced the unique salt trans‐[Yb(NO₃)₂(Ph₃PO)₄][Yb(NO₃)₄(Ph₃PO)] · Et₂O. All nitrate ions in all complexes are η²‐chelating. A comparison of the various [Ln(NO₃)₃(Ph₃PO)₃] structures, including those in the literature, reveals at least four common polymorphs, each of which is represented by isomorphic structures of multiple Ln ions. Luminescence of mer‐[Ln(NO₃)₃(Ph₃PO)₃] (Ln = Y, La, Nd, Sm, Eu, Gd, Tb, and Dy), trans‐[Yb(NO₃)₂(Ph₃PO)₄][Yb(NO₃)₄(Ph₃PO)] and Ph₃PO assignments are reported. Latva's empirical rule allows for the antenna effect, in which energy is transferred from the triplet state of the Ph₃PO ligand, to occur only for Tb³⁺. Excitation via Ph₃PO results in strong green luminescence for Tb³⁺ having twice the intensity as that which results from direct excitation of the f‐f transitions.     

A novel design using meshed-planar fan-electromagnetic bandgap (MP-FEBG) structure for ultra-wideband (UWB) antenna

A concept to combine the plane fan antenna with the meshed-planar electromagnetic bandgap (MP-EBG) structure is proposed; and then, based on the theory, a novel ultra-wideband (UWB) antenna with double-deck meshed-planar fan-electromagnetic bandgap (MP-FEBG) is designed. The structure of the sector is beneficial to the increase of the antenna bandwidth. The double layer structure can greatly reduce the size of the antenna, and the aperture structure can easily adjust antenna's performance. The antenna is compact in size, suitable for UWB applications. An antenna model was established on the substrate of FR4 and at least 79.1% dimension of the antenna was reduced by the traditional UWB antenna in the related documents. The simulation results show that the antenna can achieve a wide bandwidth from 3.20 to 15.78 GHz with return loss less than −10 dB and exhibit stable antenna gain. Furthermore, the measurement result is in better consistence with the simulation result.     

Evaluation of nano-slot antenna for mid-infrared detectors

To improve the response performance of superconducting infrared detectors, we propose using a photonic antenna with a micro-detector in conjunction with a nano-structure. In this paper, we report evaluation results that show the basic characteristics of a photonic antenna in the mid-infrared region. The antenna consists of a nano-slot antenna and a thin-film load resistance placed in the center of the antenna. The antennas were designed for operation at approximately several tens of THz by using an electromagnetic simulator. Through measurements of the spectral reflectance characteristics, clear absorptions caused by the antenna properties were observed at approximately 50 THz, and high polarization dependencies were also observed. The results of the simulation qualitatively agreed with the results of the experiment. The effective area of the antenna was also evaluated and was found to be approximately 3.5 μm² at 54 THz.     

NIR-luminescence from ternary lanthanide [Ho, Pr and Tm] complexes with 1-(2-naphthyl)-4,4,4-trifluoro-1,3-butanedionate

The ligand 1-(2-naphthyl)-4,4,4-trifluoro-1,3-butanedionate (Htfnd) has been employed to synthesize six novel ternary-lanthanide complexes in which the synergic ligands were 1,10-phenanthroline-5,6-dione (dione) and 4,5-diazafluoren-9-one (dafone), respectively. Two series of complexes Ln(tfnd)₃dione and Ln(tfnd)₃dafone (Ln=Ho, Pr, Tm) were obtained. These complexes were characterized by elemental analysis, Fourier Transform Infrared spectra and diffused reflectance. After ligand-mediated excitation, Ln(tfnd)₃dione and Ln(tfnd)₃dafone all show the characteristic NIR luminescence of the corresponding Ln³⁺ ions (Ln=Ho, Pr, Tm). This can be attributed to the efficient energy transfer from ligands to central Ln³⁺ ions, via an antenna effect. The indirect energy transfer in the complexes has been investigated and the differences in the luminescence intensity between Ln(tfnd)₃dione and Ln(tfnd)₃dafone were discussed in detail. The excellent luminescent performances enable these NIR-luminescent complexes to have potential applications in optical amplification operating at 1300 or 1500 nm.     

Tris(porphyrinyl-oxinato)Ga Complexes as a Photosynthetic Antenna Miniature

Two oxinylporphyrins, 5-(8-hydroxy-5-quinolinyl)-10,15,20-( p -tolyl)- porphyrin ( 1 ) and 5,15-bis(8-hydroxy-5-quinolinyl)-10,20-bis( n -heptyl)-porphyrin ( 2 ), were prepared and coordinated with Ga(III) to afford tris(oxinato) complex 3 and poly(oxinato) complex 4 , respectively. The structure of 3 was analyzed by variable temperature NMR study with referring to tris(8-hydroxy-5-quinolinyl)Ga(III) complex 5 to be in a meridional form. Oxinato ligands of 3 and 5 were exchanged with one another, with keeping the meridional structure. UV-Vis and fluorescence spectra of tris(oxinato)complex 3 and poly(oxinato)complex 4 were compared with each monomeric compound 1 and 2 . The absorption spectra showed only a slight broadening of the Soret band, suggesting trivial electronic and excitonic interactions. The fluorescence intensity was increased significantly compared with each monomeric compound 1 and 2 . At the same time, efficient excitation energy transfer among three porphyrins has been observed.     

Antenna Performance of a Directly Dug Corrugated Feedhorn for the 150-GHz Band

We have developed a 150 GHz band corrugated feed horn. These corrugated feed horns have been established by a new machining method, which involves digging corrugations through a metal material. We were able to realize E plane and H plane symmetry, low side lobe level, and low cross-polarization level. Measured co-polarization beam patterns above − 35 dB were consistent with the simulated patterns within a designed frequency range. The peak levels of cross-polarization beam patterns were less than − 30 dB. And, the performances were uniform in several horns. In the present paper, we describe the corrugated horn produced by this methods.     

HL-2A装置LHCD天线波谱测量与数值计算

用网络分析仪对HL-2A装置LHCD天线阵列子波导间的相位差,子波导间的相对功率和各主波导的电压驻波比等参数进行了测量。用测量值代入程序计算得到的波谱与理论计算的结果进行比较,表明天线发射的波谱与数值计算基本一致,能满足将要在HL-2A进行的LHCD实验。     

Signal Level Simulation Modeling for Antenna Array of Aperture Synthesis Radiometer Based on the Equivalent Complex Baseband Representations

This paper presents a signal-level simulation model for simulating the process that antenna array of Aperture Synthesis Radiometer (ASR) collecting thermal radiation and transforming thermal radiation signal into radio frequency (RF) signal. By using the equivalent complex baseband signals to represent the practical thermal radiation and RF signals, simulation efficiency is improved significantly. The statistic characteristics of simulation results are found to match the corresponding theoretical analysis well. Results of an imaging simulation experiment show that this model can be employed in ASR system-level simulator design.