Research on Timing Synchronization Method for DC-Biased Optical OFDM Communication System

2013 ◽  
Vol 441 ◽  
pp. 911-914 ◽  
Author(s):  
Yong Wang ◽  
Yan Ling Jing
Keyword(s):  
Communication System ◽  
Direct Detection ◽  
Intensity Modulation ◽  
Timing Synchronization ◽  
Ofdm System ◽  
Synchronization Method ◽  
System Use ◽  
Optical Ofdm ◽  
Simulation Results

The timing synchronization methods for dc-biased optical OFDM system are different from wireless OFDM system because dc-biased optical OFDM system use intensity modulation/direct detection. Existing synchronization methods cant be used directly in dc-biased optical OFDM system. Therefore, the new timing synchronization method for dc-biased optical OFDM system is presented. The simulation results show that this timing synchronization method increasingly improves the estimated accuracy of dc-biased optical OFDM system.

An Improved Frame Synchronization for Optical OFDM Systems

2012 ◽  
Vol 571 ◽  
pp. 646-650
Author(s):  
Meng Liang ◽  
Rong Lu ◽  
Yuan Bo Wang ◽  
Jia Min Gong
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Direct Detection ◽  
Dispersion Compensation ◽  
Critical Factor ◽  
Timing Synchronization ◽  
Frame Synchronization ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Transmission Distance ◽  
Optical Ofdm

Orthogonal frequency division multiplexing (OFDM) is applied to optical communication widely because of its robustness against channel dispersion and high spectral efficiency. But the synchronization between transmitter and receiver is a critical factor for system performances. This paper proposes an improved frame timing synchronization algorithm for optical OFDM system to keep synchronization by delay time compensation. The simulation of 40 Gb/s single-side-band (SSB) direct-detection optical OFDM system is setup and investigated. The curve of timing metric and the constellation of four-quadrature amplitude modulation (QAM) are given in the paper. And the transmission distance using the proposed method is compared with Park method. The simulation results show that the improved frame synchronization method promote the performances of optical OFDM system greatly. The distance can be 1600 km without dispersion compensation under the bit error ratio of 10-4.

A Pilot-Correlated PMD Monitoring Scheme for Direct Detection Optical OFDM System

2015 ◽  
Vol 33 (13) ◽  
pp. 2884-2891 ◽  
Author(s):  
Tianwai Bo ◽  
Shuang Gao ◽  
Kam-Hon Tse ◽  
Chun-Kit Chan
Keyword(s):  
Direct Detection ◽  
Ofdm System ◽  
Monitoring Scheme ◽  
Optical Ofdm

An enhanced fine timing synchronization method for diagonal pilot OFDM system

ICTC 2011 ◽  
2011 ◽  
Author(s):  
Il Muk Choi ◽  
Kyung Hoon Won ◽  
Hyung-Jin Choi ◽  
Young Gun Ji
Keyword(s):  
Timing Synchronization ◽  
Ofdm System ◽  
Synchronization Method

scholarly journals Optical Back-Propagation for Nonlinear Compensation in OFDM-Based Long Range-Passive Optical Networks

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Ngo Thi Thu Trang ◽  
Nguyen Duc Nhan ◽  
Bui Trung Hieu
Keyword(s):  
Optical Networks ◽  
Long Range ◽  
Direct Detection ◽  
Back Propagation ◽  
Fourier Method ◽  
High Rate ◽  
Passive Optical Networks ◽  
Ofdm System ◽  
Nonlinear Compensation ◽  
Optical Ofdm

In direct-detection optical OFDM system, the nonlinear impairment is the key factor that limits the system performance. The back-propagation techniques in digital and optical domains have been proposed to compensate the nonlinear effects, however they can be unsuitable for long-range passive optical networks (LR-PONs) due to their implementation at receiver. In this study, we propose an optical back propagation (OBP) approach for compensation of the nonlinear and dispersion distortions in direct-detection optical OFDM system. The proposed OBP using split-step Fourier method is implemented at transmitter that is suitable for high-rate OFDM-based LR-PONs applications. In this OBP, the fiber Bragg grating (FBG) is used as a step for dispersion compensation and the high-nonlinear fiber (HNLF) with a short length is used as a step for nonlinear compensation. The performance improvement based on our proposed approach has been demonstrated via Monte-Carlo simulations of the 100 Gbit/s direct-detection optical OFDM system with 80 km of standard single mode fiber link. The influence of optical conjugation process and launching conditions has been investigated. The obtained results show that the proposed OBP can improve remarkably the performance of system with the launched power range from -2 dBm to 6 dBm.

scholarly journals Theoretical and Experimental Investigation of Direct Detection Optical OFDM Systems with Clipping and Normalization

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Jiang Wu ◽  
Zhongpeng Wang
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Direct Detection ◽  
Single Mode ◽  
Superior Performance ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Transmission Scheme ◽  
Awgn Channel ◽  
Ofdm Signal ◽  
Optical Ofdm

A data clipping and normalization technique is employed to improve the performance of the overall direct detection optical orthogonal frequency division multiplexing (DCO-OFDM) system. A detailed analysis of clipping distortion introduced by digital clipping and normalization is provided. The normalization operation amplifies the clipped data signal to the maximum input amplitude of a digital-to-analog converter (DAC). Based on the analysis, a BER formula of the proposed scheme is derived over the AWGN channel and single fiber channel. Performance of an optical clipped OFDM with normalization is assessed through numerical simulations and Monte Claro simulation over the AWGN channel. Theoretical analysis and simulation results both show that the clipping and normalization scheme can greatly improve the BER of an optical OFDM. In particular, BER performance of the proposed transmission scheme was measured in a practical OFDM transmission platform. The measured experimental results show that the clipped and amplified OFDM signal exhibits superior performance in comparison with the conventional OFDM signal. The received sensitivity at a BER of 10−3 for a 4 Gsamples/s (2.6667 Gbits/s) clipped and normalized OFDM signal with clipping ratio of 4 after 100 km standard single-mode fiber (SMF) transmission was improved by 4.3 dB when compared with the conventional OFDM system. The measured results also showed that the clipped OFDM signal exhibits superior performance in comparison with the conventional OFDM signal. Therefore, a clipping and normalization at the transmitter is most effective, and a substantial performance improvement can be obtained by a simple normalization after clipping.

PAPR Reduction for O-OFDM UOWC System

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Jurong Bai ◽  
Hang Dai ◽  
Feng Zhao ◽  
Yi Yang ◽  
Yanben Wang
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Direct Detection ◽  
Optical Transition ◽  
Average Power ◽  
Maximum Amplitude ◽  
Ofdm System ◽  
Wireless Optical Communication ◽  
Speed Up ◽  
Optical Ofdm ◽  
Papr Performance

AbstractIn this paper, a combination of Tone Reservation-Signal to Clipping noise Ratio (TR-SCR) and Companding schemes is proposed for underwater wireless optical communication (UOWC), in order to solve the problem of high peak-to-average power ratio (PAPR) of underwater Optical-Orthogonal Frequency Division Multiplexing (O-OFDM) system. Two optical modulation schemes, namely Direct Current-biased Optical OFDM (DCO-OFDM) and Asymmetrically Clipped Optical OFDM (ACO-OFDM), are adopted separately to achieve intensity modulation/direct detection over the seawater channel, with a distance of 100 meters of wireless optical transition to obtain the system bit error rate (BER). In the TR-SCR scheme, only the maximum amplitude signal is selected to reduce the complexity of the algorithm. The LSA method is introduced in the TR-SCR scheme for iteratively updating the signal to speed up the convergence. Finally, with the combination of the Companding scheme, the PAPR performance is significantly improved. The PAPR of the underwater optical OFDM system is reduced to 3.85 dB with its BER still satisfying the UOWC system requirements.

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