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[Communications in Computer and Information Science] Futuristic Trends in Network and Communication Technologies Volume 958 (First International Conference, FTNCT 2018, Solan, India, February 9–10, 2018, Revised Selected Papers) || Future Perspectives in Elastic Optical Networks
摘要： The new generation Elastic Optical Networks (EONs) based on Orthogonal Frequency Division Multiplexing (OFDM) can accommodate exponentially increasing heterogeneous data traffic efficiently and economically. In EONs, the optimum channel spacing between various subcarriers is very crucial for its efficient performance. The use of Sub-Carrier Multiplexing (SCM) in EONs is visualized as an evolving field. This paper present the evaluation of SCM based EONs for both mathematical and simulative model. The designed SCM-EON network is analytically evaluated for its performance with different modulation techniques (Direct Modulation and External Modulation). The performance of system is also evaluated for amplification using Semiconductor Optical Amplifier (SOA) and Erbium Doped Fiber Amplifier (EDFA). Simulative results show that Optical Phase Modulation (OPM) along with EDFA offers enhanced performance for the proposed model. It has also been observed that OPM is a better technique for SCM and hence it can be deduced that the combination will boost EONs efficiency in handling network resources.
关键词： SCM,Elastic Optical Networks,OFDM,EDFA,OPM,Bandwidth variable-wavelength cross-connects (BV-WXC),Quadrature Amplitude Modulation (QAM),Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM),Mach-Zehnder modulator (MZM)
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Information and Communication Technology Convergence (ICTC) - Jeju (2018.10.17-2018.10.19)] 2018 International Conference on Information and Communication Technology Convergence (ICTC) - Performance of SIM/S-QAM FSO Systems with Phase Errors in Gamma-Gamma Turbulence Channels
摘要： In this paper, we study the performance of subcarrier intensity modulation (SIM) squared quadrature-amplitude modulation (S-QAM) free-space optical (FSO) communication systems considering the atmospheric turbulence-induced phase error in fading channel. The atmospheric fading channel is modeled by Gamma-Gamma distribution while the Tikhonov model is used for the turbulence-induced phase error. The numerical results quantitatively show the impact of atmospheric turbulence parameters to the performance of FSO systems in terms of average symbol-error probability (ASEP) and the power penalty. Besides, the theoretical results are validated through Monte Carlo simulation to confirm our analysis.
关键词： Free-space optics (FSO),Phase error.,Atmospheric Turbulence,Fading Channel,Squared quadrature-amplitude modulation (QAM)
更新于2025-09-23 15:22:29
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Open Innovation Using Satellite Imagery for Initial Site Assessment of Solar Photovoltaic Projects
摘要： Two novel blind equalization techniques for odd bit rectangular quadrature amplitude modulation (RQAM) signaling are proposed in this paper, namely, rectangular contour algorithm (RRECT CA) and improved rectangular contour algorithm (IRCA). The proposed RRECT CA algorithm minimizes the dispersion of constant with respect to a rectangular-shaped zero error contour. The algorithm exploits the geometry of the RQAM to correct phase error within 180?, thus enhancing the convergence rate while minimizing the equalizer mis-adjustments. On the other hand, the proposed IRCA algorithm employs the estimated output from the decision device into the cost function, thus guiding the equalizer output to reside on multiple zero error rectangular shaped moduli. This method of feeding back the slicer output further reduces the mis-adjustment between the transmitted constellation and the new cost function in an ef?cient manner, which leads to faster convergence and better intersymbol interference suppression. The proposed algorithms can also work for the square QAM by mere change of only two constellation dependent constants, thus facilitating the implementation in hardware to enable transmission of both even and odd number of bits per symbol based constellations. Steady-state error analysis, MSE, and residual ISI comparison through the simulation results con?rm the good performance of the proposed algorithms. Furthermore, the convergence characteristics of the proposed IRCA scheme establish the supremacy of IRCA over RRECTCA, which is its parent algorithm.
关键词： rectangular QAM,quadrature amplitude modulation (QAM),Blind equalization,cross QAM,inter symbol interference (ISI),mean square error (MSE)
更新于2025-09-19 17:13:59
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Performance Analysis and Constellation Optimization of Star-QAM-Aided Differential Faster-than-Nyquist Signaling
摘要： In this letter, motivated by the recent differential faster-than-Nyquist (DFTN) signaling concept, we propose an improved 16-point double-ring star quadrature amplitude modulation (QAM)-aided DFTN signaling transmission, which allows us to attain a higher bandwidth ef?ciency as well as a simple receiver based on noncoherent detection. We derive an analytical error-rate bound for the proposed star-QAM DFTN signaling in an uncoded scenario. The derived bound is used for optimizing the star-QAM constellation for our DFTN signaling in terms of error-rate performance in an uncoded scenario. Our simulation results demonstrate that the proposed star-QAM DFTN scheme outperforms its conventional phase-shift-keying-based DFTN counterpart.
关键词： noncoherent detection,bandwidth efficiency,Differential faster-than-Nyquist (DFTN) signaling,star quadrature amplitude modulation (QAM),error-rate performance
更新于2025-09-10 09:29:36
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34-GBd Linear Transimpedance Amplifier for 200-Gb/s DP-16-QAM Optical Coherent Receivers
摘要： High spectral ef?ciency offered by the coherent optical communication links makes them attractive for the next-generation optical communication links. Using advanced modulation schemes such as dual-polarization quadrature-amplitude modulation (DP-QAM) data rates beyond 200 Gb/s can be achieved. A key component of such links is the wide-bandwidth and high-linearity coherent optical receiver. In this paper, we present a fully differential (FD) optical receiver architecture consisting of a variable-gain transimpedance ampli?er (VG-TIA) followed by a VG ampli?er (VGA). The proposed optical receiver employs a dual-feedback automatic gain control (AGC) loop that controls both the front-end VG-TIA and the following VGA to achieve both low-noise and high-linearity operation. A new photodiode (PD) dc current cancellation scheme is developed and implemented for the full differential front-end TIA. A prototype dual-TIA chip is fabricated in a 0.13-μm SiGe BiCMOS process. The presented TIA achieves 20-pA/√Hz input-referred noise (IRN) density, 27-GHz, 3-dB bandwidth, and 1.5% total harmonic distortion (THD) at 1-mApp input PD current and 500-mVpp output voltage swing. This enables the 34-GBd operation with the bit error rate (BER) of 10?10 and 5.4 × 10?4 using DP-QPSK and DP-16-QAM formats at optical signal-to-noise ratios (OSNRs) of 25 and 30 dB, respectively, demonstrating the 100- and 200-Gb/s single wavelength optical coherent receiver operation. The dual-TIA chip occupies an area of 1.4 mm × 1.6 mm and consumes 313 mW per channel at 34 GBd from a 3.3-V supply.
关键词： dual-polarization (DP)-QPSK,Automatic gain control (AGC),coherent optical communication link,coherent optical receiver,silicon photonics,Linear transimpedance ampli?er (TIA),SiGe,DP-16-quadrature-amplitude modulation (QAM)
更新于2025-09-04 15:30:14