Performance Analysis of Digital Modulation for Coherent Detection of OFDM Scheme on Radio over Fiber System

Radio over fiber (RoF) system with the coherent detection offers high linearity for the transparent transport of high-frequency microwave signals, and better receiver sensitivity compared with intensity-modulated direct detection systems. The purpose of this paper is to analyze the performance of digital modulation for coherent detection of orthogonal frequency division multiplexing (OFDM) scheme on RoF system at 10 Gbps up to 100 km fiber length. The results show that coherent detection of OFDM-RoF system with 16 quadrature amplitude modulation (16-QAM) has the value of  bit error rate (BER) and the symbol error rate (SER) is very low and its constellation is better compared with other modulation formats (4-QAM, quadrature phase shift keying (QPSK), 8-PSK and 16-PSK), which BER 16-QAM is 0.053 and SER is 15.7%. The results also show that BER value of 4-QAM and QPSK relatively similar to fiber length variations. In general, an increasing value of the BER and SER for each modulation format are almost equal to the fiber length of 60-70 km (Region I and II). However, there is a significant increase in the value of BER in fiber length of 80-100 km (Region III. A and III. B) for the modulation of 4-QAM, QPSK, 8-PSK, and 16-PSK

Dithering Analysis in an Orthogonal Frequency Division Multiplexing-Radio over Fiber Link

Nonlinearity is one major problem broadband communication faced on utilizing the high capacity of optical fibers. That is due to scattering  phenomenon, which results in the deviations of wavelengths and energies. The dithering method is applied in the attempt to reduce those scatterings. In this paper, we propose the performance of a dithering technique based new system OFDM-RoF using two modulator scheme and coherent detection to alleviate the characteristics nonlinearity applied on the system. The dithering technique inputs signal externally to the signal processing systems to eliminate the effects of nonlinearity. Here, we report the performance of a dithering technique based on the OFDM-RoF, the results our experiment showed that the applied dithering with 16 QAM modulation can make the system more reliable and increases  the power level 1.55% with 193.1 THz, 2% with  100 THz and 1.99% ~ 200 THz, the best condition are with fd < fc. However, all condition close proximity in the parameters OLP (optical launch power), BER and SER measurement. The result demonstrated a high efficiency and good power in which the OLP operated 6.396 dBm / 4.361 E-3 W~fd 200 THz, 3.578 dBm / 2.279 E-3 W~fd 193.1 THz and 6.420 dBm / 4.3384 E-3 W~100 THz. The best BER value is achieved at 0.33 and SER 0.78 at 5 km~fd 100 THz, 0.33 and 0.768 for 10 km~fd 193.1 THz, 0.478 and 0.92 for 50 km~fd 193.1 THz

Dithering analysis in an orthogonal frequency division multiplexing-radio over fiber link

Nonlinearity is one major problem broadband communication faced on utilizing the high capacity of optical fibers. That is due to scattering phenomenon, which results in the deviations of wavelengths and energies. The dithering method is applied in the attempt to reduce those scatterings. In this paper, we propose the performance of a dithering technique based new system OFDM-RoF using two modulator scheme and coherent detection to alleviate the characteristics nonlinearity applied on the system. The dithering technique inputs signal externally to the signal processing systems to eliminate the effects of nonlinearity. Here, we report the performance of a dithering technique based on the OFDM-RoF, the results our experiment showed that the applied dithering with 16 QAM modulation can make the system more reliable and increases the power level 1.55% with 193.1 THz, 2% with 100 THz and 1.99% ~ 200 THz, the best condition are with fd fc. However, all condition close proximity in the parameters OLP (optical launch power), BER and SER measurement. The result demonstrated a high efficiency and good power in which the OLP operated 6.396 dBm/4.361 E-3 W~fd 200 THz, 3.578 dBm/2.279 E-3 W~fd 193.1 THz and 6.420 dBm/4.3384 E-3 W~100 THz. The best BER value is achieved at 0.33 and SER 0.78 at 5 km~fd 100 THz, 0.33 and 0.768 for 10 km~fd 193.1 THz, 0.478 and 0.92 for 50 km~fd 193.1 THz

Dithering analysis in an orthogonal frequency division multiplexing-radio over fiber link

Nonlinearity is one major problem broadband communication faced on utilizing the high capacity of optical fibers. That is due to scattering phenomenon, which results in the deviations of wavelengths and energies. The dithering method is applied in the attempt to reduce those scatterings. In this paper, we propose the performance of a dithering technique based new system OFDM-RoF using two modulator scheme and coherent detection to alleviate the characteristics nonlinearity applied on the system. The dithering technique inputs signal externally to the signal processing systems to eliminate the effects of nonlinearity. Here, we report the performance of a dithering technique based on the OFDM-RoF, the results our experiment showed that the applied dithering with 16 QAM modulation can make the system more reliable and increases the power level 1.55% with 193.1 THz, 2% with 100 THz and 1.99% ~ 200 THz, the best condition are with fd fc. However, all condition close proximity in the parameters OLP (optical launch power), BER and SER measurement. The result demonstrated a high efficiency and good power in which the OLP operated 6.396 dBm/4.361 E-3 W~fd 200 THz, 3.578 dBm/2.279 E-3 W~fd 193.1 THz and 6.420 dBm/4.3384 E-3 W~100 THz. The best BER value is achieved at 0.33 and SER 0.78 at 5 km~fd 100 THz, 0.33 and 0.768 for 10 km~fd 193.1 THz, 0.478 and 0.92 for 50 km~fd 193.1 THz

A Robust Optimization Approach for Designing FTTx Networks Integrating Free Space Optics under Weather Uncertainty

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