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Wang D.-Y.,North China University of Technology | Duan T.,Northern Institute of Electronic Equipment of China
Journal of China Universities of Posts and Telecommunications | Year: 2014

This paper proposes a method of blind multi-user detection algorithm based on signal sub-space estimation under the fading channels in the present of impulse noise. This algorithm adapts recursive least square (RLS) filter that can estimate the coefficients using only the signature waveform. In addition, to strengthen the ability of resisting the impulse noise, a new suppressive factor is induced, which can suppress the amplitude of the impulse, and improve the ability of convergence speed. Simulation results show that new RLS algorithm is more robust against consecutive impulse noise and have better convergence ability than conventional RLS. In addition, Compared to the least mean square (LMS) detector, the new robust RLS sub-space based method has better multi-address-inference (MAI) suppressing performance, especially, when channel degrades. © 2014 The Journal of China Universities of Posts and Telecommunications. Source


Xue Q.,Qingdao University | Du H.,Qingdao University | Gao X.,Qingdao University | Wang Y.,Harbin Institute of Technology | And 9 more authors.
Journal of Alloys and Compounds | Year: 2014

MnO2-doped barium strontium titanate-MgO (BST/MgO) composites were sintered by the solid-state reaction method. The effect of MnO 2-doping on the microstructure and microwave dielectric properties of the BST/MgO composites was investigated. The MgO grains were found to be surrounded by Mn-rich oxides, which hindered the incorporation of Mg 2+ into the lattice of BST. As a result, enhanced comprehensive microwave dielectric performances, such as the reduction of dielectric loss and leakage current about 0.78 nA/cm2, and an increase of electric field tunability of dielectric constant about 13.8% at 5 kV/mm were obtained in MnO2-doped BST/MgO ceramics. © 2014 Elsevier B.V. All rights reserved. Source


Wang D.-Y.,North China University of Technology | Duan T.,Northern Institute of Electronic Equipment of China | Zhang Y.-J.,University of International Relations
Journal of China Universities of Posts and Telecommunications | Year: 2012

In this paper, we studied the channel estimation problem for the orthogonal frequency division multiplexing (OFDM) system when the statistics of the multi-path fading channel is not known or partial known. A channel estimation approach based on polynomial approximation of the channel response is proposed. The pilot symbols are periodically inserted the channel responses for entire OFDM data sequence for exploiting channel correlation in both time and frequency domain, which is obtained from a time-variant frequency-selective Rayleigh fading channel model. Simulation shows that the method is robust to different channel statistics. Moreover, a window dimension adaptation algorithm is proposed to adapt the channel estimator to the channel statistics which further improves the robustness of the system. © 2012 The Journal of China Universities of Posts and Telecommunications. Source


Li X.-L.,National University of Defense Technology | Wang H.-M.,National University of Defense Technology | Guo C.-G.,China Electronic Systems Engineering Corporation | Ding B.,National University of Defense Technology | And 3 more authors.
Journal of Zhejiang University: Science C | Year: 2012

Network virtualization is recognized as an effective way to overcome the ossification of the Internet. However, the virtual network mapping problem (VNMP) is a critical challenge, focusing on how to map the virtual networks to the substrate network with efficient utilization of infrastructure resources. The problem can be divided into two phases: node mapping phase and link mapping phase. In the node mapping phase, the existing algorithms usually map those virtual nodes with a complete greedy strategy, without considering the topology among these virtual nodes, resulting in too long substrate paths (with multiple hops). Addressing this problem, we propose a topology awareness mapping algorithm, which considers the topology among these virtual nodes. In the link mapping phase, the new algorithm adopts the κ-shortest path algorithm. Simulation results show that the new algorithm greatly increases the long-term average revenue, the acceptance ratio, and the long-term revenue-to-cost ratio (R/C). © 2012 Zhejiang University and Springer-Verlag Berlin Heidelberg. Source


Wang Y.,Harbin Institute of Technology | Liu Y.,Harbin Institute of Technology | Liu Y.,Northern Institute of Electronic Equipment of China | Liu C.,Northern Institute of Electronic Equipment of China | And 4 more authors.
IEEE Photonics Journal | Year: 2015

Huygens' equivalent principle suggests that surface electric currents can be combined with magnetic currents to tailor electromagnetic (EM) wavefronts. Usually, the passive strategy is evolved into the concepts of sheet admittance and impedance. This paper attempts to resume the concepts of passive electric and magnetic currents and propose a novel design strategy for the transmitted phase of reflectionless metasurfaces with complete 2 \pi phase coverage. Split meander lines, plus spiral rings, are carefully adjusted to accommodate complex equivalent currents for generating the required transmitted phase. Both experimental and theoretical results verify that metacells proposed in this paper can be integrated to control the EM wave flexibly and efficiently. Furthermore, the concepts of combined passive electric and magnetic currents can be easily extended to design optical antennas and other plasmonic devices. © 2009-2012 IEEE. Source

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