Impairment assessment of orthogonal frequency division multiplexing over dispersion-managed links in backbone and backhaul networks
01 Apr 2016-Optical Engineering (International Society for Optics and Photonics)-Vol. 55, Iss: 4, pp 046105-046105
TL;DR: A comprehensive analytical model for impairments in OFDM-based fiber links is developed and it is suggested that OFDM would perform better for uncompensated links than the compensated links due to the negligible FWM effects and there is a need for flexible compensation.
Abstract: The past decade has seen the phenomenal usage of orthogonal frequency division multiplexing (OFDM) in the wired as well as wireless communication domains, and it is also proposed in the literature as a future proof technique for the implementation of flexible resource allocation in cognitive optical networks. Fiber impairment assessment and adaptive compensation becomes critical in such implementations. A comprehensive analytical model for impairments in OFDM-based fiber links is developed. The proposed model includes the combined impact of laser phase fluctuations, fiber dispersion, self phase modulation, cross phase modulation, four-wave mixing, the nonlinear phase noise due to the interaction of amplified spontaneous emission with fiber nonlinearities, and the photodetector noises. The bit error rate expression for the proposed model is derived based on error vector magnitude estimation. The performance analysis of the proposed model is presented and compared for dispersion compensated and uncompensated backbone/backhaul links. The results suggest that OFDM would perform better for uncompensated links than the compensated links due to the negligible FWM effects and there is a need for flexible compensation. The proposed model can be employed in cognitive optical networks for accurate assessment of fiber-related impairments.
Citations
More filters
TL;DR: The result shows that AFIM algorithm enhances the system capacity by more than 6-folds at an outage probability of 0.5 and reduces the outage probability to 0.6 at the capacity range of 20 Gbps.
Abstract: An adaptive impairments assessment is necessary to evaluate the impact of various linear and nonlinear effects in future generation cognitive optical transport links. In this paper, an Adaptive Fiber Impairment Mitigation (AFIM) algorithm is proposed to identify a suitable mitigation scheme for the cognitive environment. The AFIM algorithm will assess fiber impairments and adaptively select a suitable mitigation scheme with minimum complexity based on the present network conditions and user performance target. The performance of AFIM algorithm is compared with Fixed Fiber Impairment Mitigation approach in terms of outage probability and outage capacity analysis. An Orthogonal Frequency Division Multiplexing based Mode Division Multiplexing system with Few Mode Fiber (FMF) is suggested as a solution to increase the nonlinearity threshold limit of the system. The $$\hbox {L}_2$$
-by-3 nonlinear transform based Peak to Average Power Ratio reduction technique is implemented to mitigate fiber nonlinear effects in FMF based backbone and backhaul links. The performance analysis of the FMF system has been evaluated and compared with that of Single Mode Fiber system. The proposed analytical model and mitigation schemes are integrated with the AFIM algorithm to realize the cognitive optical network. Further, the result shows that AFIM algorithm enhances the system capacity by more than 6-folds at an outage probability of 0.5 and reduces the outage probability to 0.6 at the capacity range of 20 Gbps.
2 citations
TL;DR: The results of the proposed model suggest that DD-OFDM would perform better for lower linewidth in dispersion uncompensated (DUC) links and it has no impact on the dispersion compensated (DC) links for BB networks.
Abstract:
Orthogonal frequency division multiplexing (OFDM) is a special form of multicarrier (MC) modulation technique which is adopted in 4G mobile communication systems. The combination of OFDM with passive optical network (PON) architecture is highly desirable for design of flexible and energy efficient backhaul and backbone networks for 5G systems. An intensive mathematical model for linewidth analysis in OFDM based backhaul (BH) and backbone (BB) systems is proposed. The proposed mathematical model includes fiber dispersion, fiber nonlinear effects, amplified spontaneous emission (ASE) noise, transmitter and receiver noises. The impact of laser linewidth in the developed analytical model is analysed in terms phase rotation term (PRT) and inter-carrier interference (ICI) power. Further, the BER performance of the DD-OFDM system as a function of laser linewidth is also presented. The results of the analytical model solved using MATLAB is compared with virtual photonics integrated (VPI) based simulation results. The results of our proposed model suggest that DD-OFDM would perform better for lower linewidth in dispersion uncompensated (DUC) links and it has no impact on the dispersion compensated (DC) links for BB networks. In BH networks, the system performs better for lower linewidth in both DUC and DC links.
References
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TL;DR: It is shown that filter bank multicarrier (FBMC) could be a more effective solution to the shortcomings of orthogonal frequency division multiplexing in certain applications and in other applications.
Abstract: As of today, orthogonal frequency division multiplexing (OFDM) has been the dominant technology for broadband multicarrier communications. However, in certain applications such as cognitive radios and uplink of multiuser multicarrier systems, where a subset of subcarriers is allocated to each user, OFDM may be an undesirable solution. In this article, we address the shortcomings of OFDM in these and other applications and show that filter bank multicarrier (FBMC) could be a more effective solution. Although FBMC methods have been studied by a number of researchers, and some even before the invention of OFDM, only recently has FBMC been seriously considered by a few standard committees.
1,304 citations
Additional excerpts
...(4) and (5), the complex field ŨlðNaLaÞ can be elaborated as(13) EQ-TARGET;temp:intralink-;e006;63;120ŨlðNaLaÞ 1⁄4 ðul þ n 0 l Þ expðiφDSX;l þ iδφSX;lÞ: (6)...
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...(4) and (5) except for the modified complex field ŨlðNaLaÞ....
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01 Dec 2006
TL;DR: The error vector magnitude (EVM) bit error rate (BER) and signal to noise ratio (SNR) and the fact that with such relationship it would be possible to predict or in cases substitute EVM in places of BER or even SNR is presented.
Abstract: In this paper, we relate the error vector magnitude (EVM) bit error rate (BER) and signal to noise ratio (SNR). We also present the fact that with such relationship it would be possible to predict or in cases substitute EVM in places of BER or even SNR. In doing so, we first define EVM with normalization so that the definition stands for multi-modulation systems, viz. binary phas shift keying (BPSK), quadrature phase shift keying (QPSK) etc. We also compare among the different performance metrics and show that EVM can be equivalently useful as signal to noise ratio and bit error rate. The relationships are based on stream based communication systems. A few Monte Carlo simulations are carried out to illustrate the performance of EVM based on these relationships.
621 citations
"Impairment assessment of orthogonal..." refers background in this paper
...EQ-TARGET;temp:intralink-;e022;326;225 l 1⁄4 HlXlΓl þHlXlΨlð0Þ þHmXmΨmðl −mÞ; (22) where Xl and Hl are the transmitted data and channel response, respectively....
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...(22), Ψlð0Þ denotes PRT on the l’th subcarrier and the power of PRT is represented as...
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...(22), Ψmðl −mÞ denotes ICI and it can be expressed as...
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TL;DR: The results show that derived equations can be used to reliably estimate SNR values using EVM measurements that are made based on detected data symbols, which can be quite useful for measurement devices such as vector signal analyzers (VSA), where EVm measurements are readily available.
Abstract: Error vector magnitude (EVM) is one of the widely accepted figure of merits used to evaluate the quality of communication systems In the literature, EVM has been related to signal-to-noise ratio (SNR) for data-aided receivers, where preamble sequences or pilots are used to measure the EVM, or under the assumption of high SNR values In this paper, this relation is examined for nondata-aided receivers and is shown to perform poorly, especially for low SNR values or high modulation orders The EVM for nondata-aided receivers is then evaluated and its value is related to the SNR for quadrature amplitude modulation (QAM) and pulse amplitude modulation (PAM) signals over additive white Gaussian noise (AWGN) channels and Rayleigh fading channels, and for systems with IQ imbalances The results show that derived equations can be used to reliably estimate SNR values using EVM measurements that are made based on detected data symbols Thus, presented work can be quite useful for measurement devices such as vector signal analyzers (VSA), where EVM measurements are readily available
196 citations
TL;DR: The orthogonal frequency division multiplexing (OFDM) technique in long-haul next generation optical communication links is analyzed and compared with the well-established single-carrier (SC) data transmission using high-level modulation formats and coherent detection.
Abstract: We analyze the orthogonal frequency division multiplexing (OFDM) technique in long-haul next generation optical communication links and compare it with the well-established single-carrier (SC) data transmission using high-level modulation formats and coherent detection. The analysis of the two alternative solutions is carried out in the 100 Gbps scenario, which is commonly considered to be the next upgrade of existing optical links, with special emphasis on quaternary phase-shift keying (QPSK) modulations. The comparison between OFDM and SC takes into account the main linear and nonlinear impairments of the optical channel, e.g., group velocity dispersion (GVD), polarization mode dispersion (PMD), self-phase modulation (SPM), cross-phase modulation (XPM), and four-wave mixing (FWM), as well as the phase noise due to transmit and receive lasers, their relative frequency offset, other synchronization aspects, the overall complexity, the power and spectral efficiency, and the technological constraints.
90 citations
Additional excerpts
...For CO-OFDM system, the transmitted signal can be represented as(18) EQ-TARGET;temp:intralink-;e003;63;564sðtÞ 1⁄4 eðj2πfL1tþφL1Þ · sBðtÞ; (3)...
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TL;DR: A new concept of cognitive optical networks utilizing intelligent software as well as flexible optics is discussed, capable of provisioning adaptive bandwidth services at wavelength and sub-wavelength levels, making future optical networks more cognitive and reconfigurable.
Abstract: To support efficient delivery of packet and circuit services simultaneously in future optical networks, software will play more and more important roles, not only in control and management plane, but also in transport plane. This article discusses a new concept of cognitive optical networks utilizing intelligent software (e.g., digital signal processing in the optical transport plane and GMPLS in the optical control plane) as well as flexible optics (e.g., colorless, directionless, contentionless, gridless ROADM, and optical OFDM). The software-defined CON architecture with advanced capabilities such as quality of transmission awareness and client service awareness is capable of provisioning adaptive bandwidth services at wavelength and sub-wavelength levels, making future optical networks more cognitive and reconfigurable.
77 citations
Additional excerpts
...EQ-TARGET;temp:intralink-;e001;326;230 sðtÞ 1⁄4 ej2πf0t þ αej2πðf0þΔfÞt · sBðtÞ; (1)...
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