Browsing by Author "Liu, Yen-Liang"

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40 Gb/s on-off keying downstream and 10 Gb/s on-off keying remodulated upstream signals in long-reach access network with multivideo services
(2011-12-01)
Yeh, Chien-Hung
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Chow, Chi-Wai
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Liu, Yen-Liang
;
Pan, Ci-Ling
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光電工程學系
In this demonstration, we propose and investigate a long reach passive optical network (PON) using four wavelength-multiplexed signals with both on-off keying modulations for 40 Gb/s downlink traffic in 100 km fiber transmission without dispersion compensation. In the exchange node, we can use four channels with video services broadcasting to each optical network unit (ONU) for the uplink signal remodulation. Hence, four wavelength-multiplexed video signals also can be used to inject into the corresponding reflective semiconductor optical amplifiers in each ONU for uplink signal remodulation to achieve a 4 x 2.5 Gb/s data rate. In addition, under the 32 split ratio PON system, the power penalties of nearly 6.7 and 1 dB could be measured at the bit error rate of 10(-9) for the downlink and uplink traffic, respectively. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3662395]
Adaptive filtering for white-light LED visible light communication
(2017-01)
Hsu, Chin-Wei
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Chen, Guan-Hong
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Wei, Liang-Yu
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Chow, Chi-Wai
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Lu, I-Cheng
White-light phosphor-based light-emitting diode (LED) can be used to provide lighting and visible light communication (VLC) simultaneously. However, the long relaxation time of phosphor can reduce the modulation bandwidth and limit the VLC data rate. Recent VLC works focus on improving the LED modulation bandwidths. Here, we propose and demonstrate the use of adaptive Volterra filtering (AVF) to increase the data rate of a white-light LED VLC system. The detailed algorithm and implementation of the AVF for the VLC system have been discussed. Using our proposed electrical frontend circuit and the proposed AVF, a significant data rate enhancement to 700.68 Mbit/s is achieved after 1-m free-space transmission using a single white-light phosphor-based LED. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
Adaptive filtering for white-light LED visible light communication
(2017-01-01)
Hsu, Chin-Wei
;
Chen, Guan-Hong
;
Wei, Liang-Yu
;
Chow, Chi-Wai
;
Lu, I-Cheng
White-light phosphor-based light-emitting diode (LED) can be used to provide lighting and visible light communication (VLC) simultaneously. However, the long relaxation time of phosphor can reduce the modulation bandwidth and limit the VLC data rate. Recent VLC works focus on improving the LED modulation bandwidths. Here, we propose and demonstrate the use of adaptive Volterra filtering (AVF) to increase the data rate of a white-light LED VLC system. The detailed algorithm and implementation of the AVF for the VLC system have been discussed. Using our proposed electrical frontend circuit and the proposed AVF, a significant data rate enhancement to 700.68 Mbit/s is achieved after 1-m free-space transmission using a single white-light phosphor-based LED. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
Demonstration of High Speed Imaging 3x3 MIMO-OFDM Visible Light Communication System
(2016-01-01)
Hsu, Chin-Wei
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Lu, I-Cheng
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Liu, Yen-Liang
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Yeh, Chien-Hung
;
Chow, Chi-Wai
We experimentally demonstrate the 3x3 imaging multiple-input multiple-output (MIMO) visible light communication (VLC) system, using orthogonal frequency division multiplexing (OFDM) modulation and bit-loading, a total data rate > 800-Mbit/s over 1-m transmission is achieved without using blue-filter.
High Speed Imaging 3 x 3 MIMO Phosphor White-Light LED Based Visible Light Communication System
(2016-12-01)
Hsu, Chin-Wei
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Chow, Chi-Wai
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Lu, I-Cheng
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Liu, Yen-Liang
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Yeh, Chien-Hung
The phosphor light-emitting diode (LED) has been widely used not only for indoor illumination but for the optical transmitter (Tx) as well in visible light communication (VLC). However, the transmission data rate is significantly limited by the modulation bandwidth of LED because of the low-speed response of phosphor. In order to enhance the data rate of the VLC system, we demonstrate a 3 x 3 imaging multiple-input multiple-output (MIMO) VLC system. Besides, the pre-equalizer circuit is used to extend the bandwidth of the LED Tx. Orthogonal frequency division multiplexing (OFDM) with bit-loading algorithm is used. By using the proposed scheme, the original 1 MHz bandwidth commercially available phosphor white light LED can achieve 1 Gbps data rate over 1-m free-space transmission distance.
High-Speed 2x2 MIMO-OFDM Visible Light Communication Employing Phosphorescent LED
(2016)
Lu, I-Cheng
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Liu, Yen-Liang
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Lai, Chih-Han
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光電工程學系
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Department of Photonics
We experimentally demonstrated a 2x2 multiple-input multiple-output (MIMO) visible light communication (VLC) system using commercial phosphorescent white light emitting diodes (LEDs) and low-cost PIN photodiodes (PDs). Additionally, a pre-equalizer was used to extend the available modulation bandwidth up to 100 MHz. Using spectral-efficient orthogonal frequency division multiplexing (OFDM) modulation with bit-loading algorithm, we successfully achieved high-speed VLC transmission at > 1 Gbit/s over a free-space link of 0.6 m.
Investigation of phosphor-LED lamp for real-time half-duplex wireless VLC system
(2016-06)
Yeh, Chien-Hung
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Chow, Chi-Wai
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Chen, Hsing-Yu
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Liu, Yen-Liang
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Hsu, Dar-Zu
In this investigation, a 71.3 to 148.4 Mbit s(-1) white phosphor-LED visible light communication (VLC) system is proposed and demonstrated under the practical transmission length of 140 to 210 cm. Here, a commercial white-light LED lamp with five cascaded phosphor-LED chips is utilized for illumination and communication simultaneously. In the measurement, we utilize the optical orthogonal frequency division multiplexing quadrature amplitude modulation (OFDM-QAM) with bit-loading algorithm and propose an optimal bias-tee circuit design to improve the modulation bandwidth from 1 MHz to 27 MHz. Moreover, a blue optical filter is not used on the client side. Finally, to realize and demonstrate the real-time transmission performance in the proposed LED VLC system, a commercial OFDM-based digital signal processor (DSP) chip is utilized on the LED lighting side and client side, respectively. Hence, the proposed real-time half-duplex VLC transmission could achieve the 70 Mbit s(-1) downstream and upstream data throughputs, under a practical transmission length of 200 cm.
Investigation of Using Injection-Locked Fabry-Perot Laser Diode With 10% Front-Facet Reflectivity for Short-Reach to Long-Reach Upstream PON Access
(2013-06-01)
Chen, Hsing-Yu
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Yeh, Chien-Hung
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Chow, Chi-Wai
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Sung, Jiun-Yu
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Liu, Yen-Liang
In this paper, we propose and investigate an injection-locked Fabry-Perot laser diode (FP-LD) with 10% front-facet reflectivity by using orthogonal frequency-division multiplexing-quadrature amplitude modulation (OFDM-QAM) in each optical network unit (ONU) for colorless operation in the carrier-distributed passive optical network (PON). Here, the 10-Gb/s 16-QAM OFDM upstream traffic can be generated via a 2.5-GHz-bandwidth injection-locked FP-LD for the short-reach (SR)-to-long-reach (LR) transmission. In this measurement, the CW injection power of -12 dBm for an injection-locked FP-LD is required to achieve 100-km single-mode fiber (SMF) transmission. Hence, error-free transmissions of 20-, 50-, 75-, and 100-km fiber lengths are achieved with the power penalties of 0.33, 0.86, 1.20, and 1.76 dB at the bit error rate (BER) of 3: 8 x 10(-3), respectively, for upstream traffic. Moreover, the relationship of CW injection power and signal-to-noise ratio (SNR) of each OFDM subcarrier in the injection-locked FP-LD has also been analyzed.
Performance of Long-Reach Passive Access Networks Using Injection-Locked Fabry-Perot Laser Diodes With Finite Front-Facet Reflectivities
(2013-06-15)
Yeh, Chien-Hung
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Chow, Chi-Wai
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Wu, Yu-Fu
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Huang, Sung-Ping
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Liu, Yen-Liang
In this study, we use the injection-locked Fabry-Perot laser diodes (FP-LDs) with front-facet reflectivities of 10% and 35% respectively, as colorless optical networking unit (ONU) in long-reach passive optical networks (LR-PONs). Here, the injection-locked FP-LD is directly modulated at 2.5 Gbit/s on-off keying (OOK) and 10 Gbit/s orthogonal-frequency-division-multiplexing (OFDM) modulations for upstream traffic transmission over 60 km of single-mode fiber (SMF). Different operating parameters for the injection-locked FP-LD to achieve higher data rate transmission are reported.
Real-time white-light phosphor-LED visible light communication (VLC) with compact size
(2013-11-04)
Yeh, Chien-Hung
;
Liu, Yen-Liang
;
Chow, Chi-Wai
;
光電工程學系
;
Department of Photonics
In this demonstration, we first demonstrate a real-time phosphor-LED visible light communication (VLC) system with 37 Mbit/s total throughput under a 1.5 m free space transmission length. The transmitter and receiver modules are compact size. Utilizing our proposed pre-equalization technology, the similar to 1 MHz bandwidth of phosphor LED could be extended to similar to 12 MHz without using blue filter. Thus, the increase in bandwidth would enhance the traffic data rate for VLC transmission. The maximum bit-rate achieved by the VLC system is 37 Mbit/s, and a video transmission at 28.419 Mbit/s is demonstrated using the proposed VLC system. In addition, the relationships of received power and signal performance are discussed and analyzed. (C) 2013 Optical Society of America
The role of the sub-thalamic nucleus in the preparation of volitional movement termination in Parkinson's disease
(2012-01-01)
Hsu, Yi-Ting
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Lai, Hsin-Yi
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Chang, Yao-Chuan
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Chiou, Shang-Ming
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Lu, Ming-Kuei
The sub-thalamic nucleus (STN) is relevant to the preparation of movement ignition but its role in movement termination is uncertain. Fourteen patients with Parkinson's disease (PD) received local field potentials (LFPs) recording at the left STN on the fourth day after deep brain stimulation surgery. They performed phasic and tonic movements of the right wrist extensor. Movement onset (Mon) and movement offset (Moff) of the electromyographic activities were used as triggers to determine an eight-second LFPs epoch for time-frequency analysis. Movement-related power changes were assessed by repeated measures analysis of variance with within-subject factors of Event (Mon and Moff), Period (ten time periods for phasic movement and six time periods for tonic movement), and Frequency (alpha, low-beta, and high-beta). There was significant triple interaction in both the phasic and tonic movements. By post-hoc analysis, high-beta event-related desynchronization (ERD) appeared earlier (3 s prior to Mon) than those of low-beta and alpha for the Mon phasic movement. There was no alpha ERD for the Mon tonic movement. Alpha, low-beta, and high-beta ERD all appeared about 1 s prior to the Moff tonic movement. The current findings suggest that STN participates in the preparation of volitional movement termination but via a different mechanism from that in movement initiation. Unlike asynchronous ERD frequency bands present in movement initiation, a simultaneous ERD across wide frequency bands in STN may play a pivotal role in terminating volitional movement. (C) 2011 Elsevier Inc. All rights reserved.
Theory and Technology for Standard WiMAX Over Fiber in High Speed Train Systems
(2010-08-15)
Yeh, Chien-Hung
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Chow, Chi-Wai
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Liu, Yen-Liang
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Wen, Sz-Kai
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Chen, Shi-Yang
In this investigation, we propose and investigate the standard WiMAX access in high speed railway (HSR) using radio over fiber (RoF) link. We also discuss the theory of mobile WiMAX at a target speed of 300 km/hr in simulation. We also analyze the effect of the Doppler frequency shift over HSR. The effective transmission fiber length in the WiMAX-RoF system was limited due to the time-division-duplex (TDD) protocol in the practical WiMAX. Thus, we also demonstrate the transmission limitation and performance of the standard WiMAX access in RoF link. The performances of throughput and packet loss at different fiber lengths are also investigated and discussed. Furthermore, a WiMAX-RoF field trial is also demonstrated based on a simple two RAUs RoF architecture. It was tested and measured in the SongShan tunnel of the Taiwan high speed railway (THSR).
Utilization of multi-band OFDM modulation to increase traffic rate of phosphor-LED wireless
(2015-01-26)
Yeh, Chien-Hung
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Chen, Hsing-Yu
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Chow, Chi-Wai
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Liu, Yen-Liang
;
光電工程學系
To increase the traffic rate in phosphor-LED visible light communication (VLC), a multi-band orthogonal frequency division multiplexed (OFDM) modulation is first proposed and demonstrated. In the measurement, we do not utilize optical blue filter to increase modulation bandwidth of phosphor-LED in the VLC system. In this proposed scheme, different bands of OFDM signals are applied to different LED chips in a LED lamp, this can avoid the power fading and nonlinearity issue by applying the same OFDM signal to all the LED chips in a LED lamp. Here, the maximum increase percentages of traffic rates are 41.1%, 17.8% and 17.8% under received illuminations of 200, 500 and 1000 Lux, respectively, when the proposed three-band OFDM modulation is used in the VLC system. In addition, the analysis and verification by experiments are also performed. (C) 2015 Optical Society of America