Browsing by Author "Liu, Jia-Wei"

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A Low Complexity Interference Suppression Scheme for High Mobility STBC-OFDM Systems
(2012)
Sheu, Chorng-Ren
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Liu, Jia-Wei
;
Huang, Chuan-Yuan
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Huang, Chia-Chi
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電信工程研究所
A novel low complexity scheme based on received data symbol pair reordering and optimal selection, is proposed for space time block coded (STBC) OFDM systems to suppress co-channel interference (CCI) and inter-carrier interference (ICI) caused by time-varying channels. The proposed scheme reorders the conventional received data symbol pairs to produce extra received data symbol pairs. Then, the STBC decoding is performed on all the received data symbol pairs, and the STBC decoding output signals are used to obtain multiple combined signals. Finally, the optimal combined signal with minimum interference is selected to suppress CCI and ICI, and the system performance will be improved as long as the channels are mutually uncorrelated. Our computer simulation results verify that the proposed low complexity scheme achieves good performance for high mobility 2x2 STBC-OFDM systems in the ITU Vehicular A (VA) channels.
Effects of superconducting film on the defect mode in dielectric photonic crystal heterostructure
(2013-03-01)
Hu, Chung-An
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Liu, Jia-Wei
;
Wu, Chien-Jang
;
Yang, Tzong-Jer
;
Yang, Su-Lin
Effects of superconducting thin film on the defect mode in a dielectric photonic crystal heterostructure (PCH) are theoretically investigated. The considered structure is (12)S-N(21)(N), in which both layers 1 and 2 are dielectrics, layer S is a high-temperature superconducting layer, and N is the stack number. The defect mode is analyzed based on the transmission spectrum calculated by using the transfer matrix method. It is found that, in the normal incidence, the defect mode existing in the host PCH of (12)(N)(21)(N) will be blue-shifted as the thickness of layer S increases. In addition, the defect mode is also blue-shifted for both TE and TM modes in the case of oblique incidence. The embedded superconducting thin film plays the role of tuning agent for the defect mode of PCH. As a result, the proposed structure can be designed as a tunable narrowband transmission filter which could be of technical use in the optoelectronic applications. (c) 2013 Elsevier Ltd. All rights reserved.