Browsing by Author "Hsieh, YL"

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A channel effect prediction-based power control scheme using PRNN/ERLS for uplinks in DS-CDMA cellular mobile systems
(2006-01-01)
Chen, YS
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Chang, CJ
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Hsieh, YL
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交大名義發表
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National Chiao Tung University
This paper proposes a channel effect prediction-based power control scheme using pipeline recurrent neural network (PRNN)/extended recursive least squares (ERLS) for uplinks in direct sequence code division multiple access (DS-CDMA) cellular mobile systems. Conventional signal-to-interference (SIR) prediction-based power control schemes may incur prediction mistakes caused by the adjustment of transmission power. The proposed power control scheme purely tracks the variation of channel effect and, thus, can be immune to any power adjustment. Furthermore, it adopts the PRNN with ERLS for predicting the channel effect. Simulation results show that the channel effect prediction-based power control scheme using PRNN/ERLS achieves a 40% higher system capacity and a lower outage probability than the conventional SIR prediction-based power control scheme using grey prediction method (IEEE Trans. Veh. Technol., Vol. 49, No. 6, p. 2081, 2000).
A power control scheme with link gain prediction using PRNN/ERLS for DS-CDMA cellular mobile systems
(2003)
Hsieh, YL
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Chang, CJ
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Chen, YS
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電信工程研究所
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Institute of Communications Engineering
In this paper, a link gain prediction-based power control scheme is designed for DS-CDMA cellular mobile systems. The link gain prediction can help to remove the interference of the power control adjustment itself. The pipeline recurrent neural network (PRNN) with extended recursive least square (ERLS) is adopted for the prediction. This PRNN/ERLS predictor possesses infinite memory of past signals so that it can capture precisely the signal correlation and improve the delay compensation of power control. Simulation results show that the link gain prediction-based power control scheme using PRNN/ERLS has lower outage probability than the received SIR prediction-based power control scheme using grey prediction method [5] and improves the system capacity by an amount of 41.6%.
Characteristics of stable emission GaN-based resonant-cavity light-emitting diodes
(2004-01-19)
Lin, CF
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Yao, HH
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Lu, JW
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Hsieh, YL
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Kuo, HC
The resonant-cavity light-emitting diode (RC-LED) structure was grown by MOCVD. The structure of RC-LED consisted of a 3lambda InGaN/GaN MQW LED cavity between the top TiO2/SiO2 DBR (81.7%, reflectance) and the bottom AlN/GaN DBR (90.4%) stack. A stable 410 nm emission peak and a low thermally induced red-shift effect (0.12 nm/kA/cm(2)) were measured by varying the injection current density. The light output power of the full RC-LED device was three times higher than the RC-LED without top TiO2/SiO2 DBR layers under 600 A/cm(2) inject current density. The narrow line width of 7.4 nm, emission peak localization at 410 nm, and three times higher output power were caused by the resonance effect in this vertical cavity structure. (C) 2003 Published by Elsevier B.V.
Fault Hamiltonicity and fault Hamiltonian connectivity of the (n, k)-star graphs
(2003-12-01)
Hsu, HC
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Hsieh, YL
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Tan, JJM
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Hsu, LH
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資訊工程學系
In this paper, we consider the fault Hamiltonicity, and the fault Hamiltonian connectivity of the (n, k)-star graph S-n,S-k. Assume that F subset of V(S-n,S-k) boolean OR E(S-n,S-k). For n - k greater than or equal to 2, we prove that S-n,S-k - F is Hamiltonian if F less than or equal to n - 3 and S-n,S-k - F is Hamiltonian connected if F less than or equal to n - 4. For n - k = 1, S-n,S-n-1 is isomorphic to the n-star graph S-n which is known to be Hamiltonian if and only if n > 2 and Hamiltonian connected if and only if n = 2. Moreover, all the bounds are tight. (C) 2003 Wiley Periodicals, Inc.
Light-output enhancement in a nitride-based light-emitting diode with 22 degrees undercut sidewalls
(2005-01-01)
Kao, CC
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Kuo, HC
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Huang, HW
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Chu, JT
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Peng, YC
We successfully fabricated nitride-based light-emitting diodes (LEDs) with similar to 22degrees undercut sidewalls. The similar to 22degrees etching undercut sidewalls were achieved by controllable inductively coupled plasma reactive ion etching. With a 20-mA current injection, the output powers of the LED with similar to 22degrees undercut sidewalls and standard LED were 5.1 and 3 mW, respectively-a factor of 1.7 times enhancement. It was found that such undercut sidewalls could enhance the probability of escaping the photons outside from the LED in the near horizontal and in-plane directions. This simple and controllable method is beneficial to fabricate brighter LEDs.