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[IEEE 2018 International Conference on Advanced Science and Engineering (ICOASE) - Duhok (2018.10.9-2018.10.11)] 2018 International Conference on Advanced Science and Engineering (ICOASE) - An ICI Reduction Based on PAPR Clipping in Coherent Optical OFDM System
摘要： The Inter-Carrier Interference (ICI) compensation for Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM) system has been studied in this paper. The purpose behind is to investigate the presence of ICI due to the impact of Laser Phase Noise (LPN) and Fiber Non-Linearity (FNL). Thereby, we propose a simple clipping scheme which represents an effective distortion algorithm to decrease the Peak to Average Power Ratio (PAPR) for 4QAM system. The method exhibits a significant process on ICI cancellation in CO-OFDM system. The OFDM signal is basically transmitted along 550km distance rated at 10Gbps single mode fiber for the coherent optical mode. The new findings show that the receiver sensitivity is highly improved below 10-3 FEC for laser power 5dBm; and archives about 1dBm to 2.4dBm when laser power becomes 8dBm at a typical clipping ratio of 0.6. In particular, the system exhibits a good performance over a 385km transmission distance in comparison to the conventional CO-OFDM. As a result, the proposed clipping shows that the system can enhance its the performance by reducing ICI in the CO-OFDM system; in addition to present a high robustness in BER metric against FNL by a clear reduction in PAPR.
关键词： Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM),Inter-Carrier Interference (ICI),Peak to Average Power Ratio (PAPR),Fiber Nonlinearity (FNL),Bit Error Rate (BER),Laser Phase Noise (LPN)
更新于2025-09-23 15:22:29
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[IEEE 2018 Second International Conference on Electronics, Communication and Aerospace Technology (ICECA) - Coimbatore (2018.3.29-2018.3.31)] 2018 Second International Conference on Electronics, Communication and Aerospace Technology (ICECA) - FSO Link Performance Analysis with Different Modulation Techniques under Atmospheric Turbulence
摘要： Free space optics (FSO) has achieved prominence in extremely large bandwidth, unlicensed spectrum and low power secure transmission in the field of wireless communication. Despite the advantages, it is deeply impacted due to atmospheric turbulence and fog weather conditions. This paper considers different modulation schemes under the presence of atmospheric turbulence and fog conditions. The desired expression of bit error rate (BER) is obtained by modeling the turbulence as gamma-gamma distributed channel and under this channel condition, 16-PPM has provided better performance than other schemes. BER is considered for the channel performance evaluation. This analysis can help to adopt a modulation technique according to the channel condition.
关键词： Bit error rate (BER),gamma-gamma distribution,atmospheric turbulence,Free space optics (FSO),Meijer’s G function
更新于2025-09-23 15:21:21
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Evaluation of Chirped Fiber Bragg Grating with APD on Designed Optical Fiber Communication Link
摘要： Application of fiber Bragg grating (FBG) in optical communication is an evolving field. In this research paper, various types of chirped FBG’s (CFBG) have been used with avalanche photodiode (APD) on the designed optical fiber communication (OFC) link. Data rate of 20 Gbps and return-to-zero modulation format has been kept as fixed parameters. The designed link has been evaluated for varying fiber lengths (100, 200, 300, 400 and 500 km), various type of CFBG’s (linear, quadratic, square root and cubic root) with Gaussian apodization function, varying grating lengths (10, 20, 30, 40 and 50 mm) and operating temperatures (5°C, 10°C, 15°C, 20°C, 25°C, 30°C). The designed OFC link has also been evaluated for APD with and without CFBG. The performance evaluation matrix parameters selected are Q-factor, bit error rate and eye diagram. The OFC link employing CFBG with APD has been found to be superior. In compensating chromatic dispersion, optimum results have been observed for linear CFBG with Gaussian apodization function in comparison to other types of CFBG with 50 mm grating length for the maximum transmission distance.
关键词： bit error rate (BER),Optical fiber communication (OFC),eye diagram,chirped fiber Bragg grating (CFBG),vertical cavity surface emitting laser (VCSEL),avalanche photodiode (APD),Q-factor
更新于2025-09-23 15:19:57
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Free Space Optical Communication (System Design, Modeling, Characterization and Dealing with Turbulence) || 6. Quality metrics and reliability analysis of ground-to-ground free space laser communication in different weather conditions together with beam steering system
摘要： Over the past two decades Free Space Optical Communication (FSOC) has become more and more interesting as an adjunct or alternative to Radio Frequency (RF) communication. Optical wave propagation in an FSOC channel is severely affected by turbulent atmospheric parameters and they lead to the degradation of the data transmission quality and reliability. Among the various atmospheric effects, beam wandering is the main cause for major power loss and cannot be solved without incorporation of a Beam Wandering Compensation (BWC) control system. Therefore, a closed form treatment describing beam wandering effect mitigation is required. Simplex FSOC data transmission (data rate is 155 Mbps) transmitter-receiver experimental setups are established for the data link range of 0.5 km at an altitude of 15.25 m at the college campus. A near IR 850 nm optical source is used for data transmission. The more accurate values of atmospheric attenuation (Atten) and turbulence strength (C2n) are obtained using the new models developed according to local weather data. The transmittance of the FSOC channel is calculated using the estimated atmospheric attenuation. The methods of measuring the Q-factor and Bit Error Rate (BER) by postprocessing the received signal are described and used to validate the performance of the FSOC system. The improvements on received signal strength and centroid stability by incorporating the BWC control system are analyzed with various communication key parameters in the very weak to very strong atmospheric turbulence conditions. The average BER at a value of 9.82 ? 10?9 is maintained with the Q-factor value of ≈ 6 in almost all atmospheric turbulence conditions with compensating beam wandering effects, i.e. pointing error losses. Evidence of the suitability and effectiveness of the developed controller in terms of received power (Pr), transmittance (T), eye diagram, Q-factor, Signal to Noise Ratio (SNR), BER, link margin and decoding decision threshold values are comprehensively analyzed through experimental results and reported in this chapter.
关键词： atmospheric turbulence,Beam Wandering Compensation (BWC),Q-factor,Signal to Noise Ratio (SNR),Bit Error Rate (BER),Free Space Optical Communication (FSOC)
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE 90th Vehicular Technology Conference (VTC2019-Fall) - Honolulu, HI, USA (2019.9.22-2019.9.25)] 2019 IEEE 90th Vehicular Technology Conference (VTC2019-Fall) - Performance of Free Space Optical Communication System under Jamming Attack and Its Mitigation over Non-Gaussian Noise Channel
摘要： In free space optical (FSO) communication, jamming can cause inaccuracy in the received information. In this paper, we investigate the impact of jamming over atmospheric turbulence (AT) fading channels. To describe the AT, negative exponential fading channel models are considered. The effect of jamming is studied over a single-input single-output (SISO) FSO link. We introduce a theoretical framework to acquire a closed-form expression of the average bit error rate (ABER) under jamming–leading to an additive non-Gaussian noise channel. It is observed by thorough analysis that a 2 × 1 FSO system performs better than SISO FSO system in presence of jamming signal. It is realized that under jamming the performance of FSO link is dependent on different AT conditions. Furthermore, increasing number of transmit apertures allows FSO system to significantly overcome the effect of jamming, in order to obtain an improved ABER.
关键词： Additive non-Gaussian noise,exponential fading,signal-to-jamming ratio (SJR),bit error rate (BER),free space optical (FSO) communication,jamming,Gamma-Gamma fading
更新于2025-09-12 10:27:22
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[Lecture Notes in Electrical Engineering] Recent Trends in Communication, Computing, and Electronics Volume 524 (Select Proceedings of IC3E 2018) || Performance Optimization of Carving Signal RZ-DQPSK Modulation Scheme
摘要： This paper depicts a modi?ed return-to-zero differential quadrature phase shift keying (RZ-DQPSK) modulation scheme. A simulative analysis has been performed for an optimization of the proposed scheme. The analysis has also been extended for two different types of commercial ?bers; standard single-mode ?ber (SSMF) and true wave-reduced slope (TW-RS) ?ber to report the similar qualitative performance characteristics. For the sake of better understanding of the proposed modi?ed carving signal RZ-DQPSK scheme, optical spectrum and eye pattern plots are also investigated.
关键词： Bit error rate (BER),Quality factor,True wave-reduced slope ?ber (TW-RS),Eye pattern,Return-to-zero differential quadrature phase shift keying (RZ-DQPSK)
更新于2025-09-09 09:28:46
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Comparison of Modulation Techniques for Underwater Optical Wireless Communication Employing APD Receivers
摘要： In this study, we theoretically analyze the performance of an underwater optical wireless communications system using different modulation techniques and an avalanche photodiode APD receiver over underwater environment channels. Based on the LOS geometrical model and combined with signal to noise ratio model for Si and Ge APD and BER; then the impact of the distance of transmission and power of the transmitter and Jerlov water type are analyzed. The characteristics of bit error rate BER for different optical modulation techniques are studied. Simulation results indicate that the performance of H-QAM is more suited for an underwater optical wireless communication. On the other hand, the suitability of avalanche photodiodes under these modulation techniques is discussed, because the photodiode Si APD has more advantages compared with Ge APD when used in an underwater optical communication.
关键词： Avalanche photodiode APD,modulation,underwater optical communication,bit error rate BER
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE 7th Global Conference on Consumer Electronics (GCCE) - Nara, Japan (2018.10.9-2018.10.12)] 2018 IEEE 7th Global Conference on Consumer Electronics (GCCE) - BER Performance Impaired by Transmission Time Offset between Users in Optical Wireless CSK/ACDMA System Using DMPOMs
摘要： An optical-wireless code-shift-keying (CSK) system utilizing dual modified pseudo orthogonal M-sequence sets (DMPOMs) has been proposed by authors. DMPOM is generated by merging modified pseudo orthogonal M-sequence sets (outer-code), bi-orthogonal code and orthogonal M-sequences (inner-code). In this paper, bit error rate (BER) of the optical-wireless CSK/asynchronous CDMA is investigated in 2-user communication. Consequently, for the realization of the CSK/CDMA, it is effective to utilize the inner codes generated by different feedback taps.
关键词： optical-wireless,bit error rate (BER),code-shift-keying (CSK),dual modified pseudo orthogonal M-sequence sets (DMPOMs),asynchronous CDMA (ACDMA)
更新于2025-09-04 15:30:14