We demonstrate two mode division multiplexing transmission systems through few-mode fiber by using two degenerate LP11 modes in high speed and low cost optical interconnection scenarios. Two novel MIMO equalizers base...
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We demonstrate two mode division multiplexing transmission systems through few-mode fiber by using two degenerate LP11 modes in high speed and low cost optical interconnection scenarios. Two novel MIMO equalizers based on machine learning are proposed and utilized to eliminate the impairments. In the ultra-low cost optical interconnection, the linear equalizer based on the elastic net can effectively reduce the bit error rate to the hard-decision forward error correction threshold with an extremely fast convergence speed. With the help of the nonlinear equalizer based on the neural network, high speed short-reach transmission has been achieved. By multiplexing two degenerate modes with the bit rate of 100 Gb/s/??????, 2 ? 100 Gb/s transmission of 30 G-class 1550 nm optical devices has been realized. Without the optical amplifier, the receiver sensitivity could be around-11 dBm in 2 ? 50 Gb/s transmission. This provides potential solutions for the future evolution of short-reach optical links.
Conventional space-time trellis code cannot be directly applied to the intensitymodulation/directdetection atmospheric optical transmission systems due to the complex and negative signal problem. An asymmetrically c...
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ISBN:
(数字)9781510627710
ISBN:
(纸本)9781510627710
Conventional space-time trellis code cannot be directly applied to the intensitymodulation/directdetection atmospheric optical transmission systems due to the complex and negative signal problem. An asymmetrically clipped space-time trellis code scheme is proposed, which combines the Hermitian symmetry of the inverse fast Fourier transform and the N/4 points to N points signal mapping to make the processed bipolar signal sequence satisfies the odd harmonic symmetry. The conversion of complex signal to positive real signal can then be achieved by clipping the bipolar signal sequence. Monte Carlo method is utilized to verify the feasibility of the proposed scheme. The results show that the proposed method can effectively resist the atmosphere scintillation.
Orthogonal frequency division multiplexing (OFDM) is attracting increasing attention in optical communication systems, thanks to its inherent benefits such as high spectral efficiency and resistance to frequency-selec...
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Orthogonal frequency division multiplexing (OFDM) is attracting increasing attention in optical communication systems, thanks to its inherent benefits such as high spectral efficiency and resistance to frequency-selective channels. In this paper, a novel energy and spectrally efficient scheme called asymmetrically clipped absolute value optical OFDM (AAO-OFDM) is proposed for intensity-modulated direct-detection systems. In AAO-OFDM, absolute value optical OFDM (AVO-OFDM) signals on the even subcarriers and asymmetrically clipped optical OFDM (ACOOFDM) signals on the odd subcarriers are combined for simultaneous transmission, which employs all the subcarriers requiring no dc biases. For AVO-OFDM scheme, the frequency symbols are first modulated on the even subcarriers, which are then fed into an inverse fast Fourier transform block. Afterward, the absolute values of the bipolar time-domain signals are taken to guarantee non-negativity, while their signs aremapped to the complex-valued symbols and modulated on the odd subcarriers. Since there remain unused odd subcarriers, other useful symbols can be modulated on them, which leads to the conventional ACO-OFDM scheme. At the receiver, the ACO-OFDM symbols on the odd subcarriers are demodulated first, which are reconstructed and removed from the received signals. Afterward, the remaining signals are utilized to detect the AVO-OFDM symbols with the aid of the demodulated sign symbols on the odd subcarriers. Theoretical analysis and simulation results show that AAO-OFDM has lower peak-to-average power ratio than other optical OFDM schemes, which makes it less sensitive to the nonlinearity of the optical devices. Furthermore, it achieves better bit error rate performance compared to its counterparts for the same spectral efficiency.
In this paper, we propose a novel hybrid peak-to-average power ratio (PAPR) reduction approach combining multi-band Jacket matrix spreading (MB-JS) with the clipping and filtering for the orthogonal frequency division...
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ISBN:
(纸本)9781538645024
In this paper, we propose a novel hybrid peak-to-average power ratio (PAPR) reduction approach combining multi-band Jacket matrix spreading (MB-JS) with the clipping and filtering for the orthogonal frequency division multiplexing (OFDM)-based optical communication systems. The PAPR performance of the proposed scheme is theoretical analyzed and the received signal-to-noise ratio (SNR) for each split sub-band are calculated. The 50 m step-index (SI) polymer optical fiber (POF) transmission based on offline processing is adopted as a special case to evaluate the system performance and then make comparisons with some other well known PAPR reduction techniques. With the help of this methodology, at least 2.57 dB PAPR reduction is obtained and 4 dBm power savings is achieved when compared to the original OFDM transmission. It is demonstrated that the proposed scheme can offer better system performance and make a favorable trade-off among the PAPR reduction, bit error rate and computational complexity.
A computationally efficient IFFT implementation for asymmetrically clipped optical OFDM transmitter is proposed and implemented in a Field-Programmable Gate Array. The overall computational complexity is reduced by 68...
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ISBN:
(纸本)9781509062935
A computationally efficient IFFT implementation for asymmetrically clipped optical OFDM transmitter is proposed and implemented in a Field-Programmable Gate Array. The overall computational complexity is reduced by 68% in a real-time transmitter.
In this paper, we propose a modified clipping noise cancellation scheme using compressed sensing (CS) technique with observation interference mitigation for direct current biased optical (DCO) orthogonal frequency div...
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ISBN:
(纸本)9781538620625
In this paper, we propose a modified clipping noise cancellation scheme using compressed sensing (CS) technique with observation interference mitigation for direct current biased optical (DCO) orthogonal frequency division multiplexing (OFDM) systems. The interference components in potential observations are theoretically analyzed and approximately estimated by exploiting the statistical model of the clipped DCO-OFDM signal. Then, the modified CS scheme eliminates the estimated interference from the potential observations, which can minimize the contamination influence of channel noise on CS recovery algorithm. In addition, a strategy jointly considering the compressed ratio and the decision noise is presented to generate the measurement matrix, which can sample the reliable data tones as final observations. With this scheme, the clipping noise in time domain can be effectively corrected and the bit error rate (BER) performance of the system is significantly improved. Simulation results demonstrate that the proposed scheme can perform well even under severe clipping conditions.
In this paper,we propose an EADO-OFDM(Enhanced Asymmetrically Clipped DC Biased Optical Orthogonal Frequency Division Multiplexing)method for IM/DD(intensity-Modulated directdetection)optical systems,in which the AV-D...
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In this paper,we propose an EADO-OFDM(Enhanced Asymmetrically Clipped DC Biased Optical Orthogonal Frequency Division Multiplexing)method for IM/DD(intensity-Modulated directdetection)optical systems,in which the AV-DCO-OFDM(Absolute Valued DC Biased Optical OFDM)symbols on the even subcarriers and ACO-OFDM(Asymmetrically Clipped Optical OFDM)symbols on the odd subcarriers are combined for simultaneous ***,we discuss the PDF(Probability Density Function)and electrical SNR(Signal to Noise Ratio)of the symbols,which are utilized to estimate the BER(Bit Error Ratio)performance and overall performance of *** Monte Carlo simulation results have validated the theoretical analysis and have also confirmed the EADO-OFDM is attractive considering the following ***,EADO-OFDM is more energy efficient compared to the power-efficient DCO-OFDM(DC Biased Optical OFDM),since the required DC bias is smaller when appropriate constellation size combinations are *** addition,EADO-OFDM performs better than the conventional ADO-OFDM(Asymmetrically Clipped DC Biased Optical OFDM),because the absolute value operation causes no clipping distortion.
This article reports an analytical investigation, confirmed by numerical simulations, about the non-linear noise contribution in single-channel systems adopting generic modulation-detection formats in long links with ...
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This article reports an analytical investigation, confirmed by numerical simulations, about the non-linear noise contribution in single-channel systems adopting generic modulation-detection formats in long links with both managed and unmanaged dispersion compensation and its impact in system performance. This noise contribution is expressed in terms of a pulse non-linear interaction length and permits a simple calculation of the Q-factor. Results point out the dependence of this non-linear noise on the number of amplifiers spans, N, according to the adopted chromatic dispersion compensation scheme, the modulation-detection format, and the signal baud rate. It is also shown how the effects of polarization multiplexing can be taken into account and how this single-channel non-linear noise contribution can be used in a wavelength-division multiplexing (WDM) environment.
We evaluate the performance of three direct-detection orthogonal frequency-division multiplexing (OFDM) schemes in combating multipath distortion in indoor optical wireless links, comparing them to unipolar M-ary puls...
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We evaluate the performance of three direct-detection orthogonal frequency-division multiplexing (OFDM) schemes in combating multipath distortion in indoor optical wireless links, comparing them to unipolar M-ary pulse-amplitude modulation (M-PAM) with minimum mean-square error decision-feedback equalization (MMSE-DFE). The three OFDM techniques are DC-clipped OFDM and asymmetrically clipped optical OFDM (ACO-OFDM) and PAM-modulated discrete multitone (PAM-DMT). We describe an iterative procedure to achieve optimal power allocation for DC-OFDM. For each modulation method, we quantify the received electrical SNR required at a given bit rate on a given channel, considering an ensemble of 170 indoor wireless channels. When using the same symbol rate for all modulation methods, M-PAM with MMSE-DFE has better performance than any OFDM format over a range of spectral efficiencies, with the advantage of (M-PAM) increasing at high spectral efficiency. ACO-OFDM and PAM-DMT have practically identical performance at any spectral efficiency. They are the best OFDM formats at low spectral efficiency, whereas DC-OFDM is best at high spectral efficiency. When ACO-OFDM or PAM-DMT are allowed to use twice the symbol rate of M-PAM, these OFDM formats have better performance than M-PAM. When channel state information is unavailable at the transmitter, however, M-PAM significantly outperforms all OFDM formats. When using the same symbol rate for all modulation methods, M-PAM requires approximately three times more computational complexity per processor than all OFDM formats and 63% faster analog-to-digital converters, assuming oversampling ratios of 1.23 and 2 for ACO-OFDM and M-PAM, respectively. When OFDM uses twice the symbol rate of M-PAM, OFDM requires 23% faster analog-to-digital converters than M-PAM but OFDM requires approximately 40% less computational complexity than M-PAM per processor.
This article reports a numerical investigation on the transmission performance of multilevel systems operating in building links encompassing step-index plastic optical fibers. For such an aim, a simplified model for ...
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This article reports a numerical investigation on the transmission performance of multilevel systems operating in building links encompassing step-index plastic optical fibers. For such an aim, a simplified model for the multimode fiber propagation is introduced. A sub-carrier multiplexing technique is also simulated to demonstrate the distribution of broadcasting television channels by adopting such fibers. The reported results show that a unique building network based on step-index plastic optical fibers is suitable to carry both Ethernet and broadcast TV signals in all rooms.
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