Nonlinear Distortion Cancellation in Spatial Division Multiplexing System Based on RZ-Coded PCTWs Technique

Iraqi Journal of Computer Communication Control and System Engineering ◽

10.33103/uot.ijccce.20.2.6 ◽

2020 ◽

pp. 47-57

Keyword(s):

Phase Noise ◽

Analytical Model ◽

Amplitude Modulation ◽

System Performance ◽

Nonlinear Distortion ◽

Quadrature Amplitude Modulation ◽

Bit Rate ◽

Nonlinear Phase ◽

Transmission Distance ◽

Spatial Division Multiplexing

spatial division multiplexing (SDM) system has been considered as promising systems due to its ability to transport a higher bit rate for longer transmission distance. However, nonlinear phase noise (NPN (degrades SDM system performance. In this paper, we propose return-to-zero (RZ)-coded phase-conjugated twin waves (PCTWs) to improve the effectiveness of nonlinear distortion cancellation in the SDM system. In this approach, the PCTWs are modulated by m-array quadrature amplitude modulation (mQAM) then RZ encoded. After that, RZ-mQAM PCTWs are co-propagated over two fibres links. The received signals are superimposed to suppress the NPN. An analytical model that characterizes the performance of spatial-multiplexed (SM) RZ-coded PCTWs scheme is developed. Moreover, we numerically investigate the system performance with 4QAM format at 20Gsymbol/s rate. The results display that the performance is substantially better for the proposed scheme. Transmission reaches of both 4QAM PCTWs and RZ-4QAM PCTWs schemes are extended by 77.8% and 100%, respectively, in contrast with the 4QAM scheme.

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Impact of Fiber Nonlinearity on the Performance of Mode Division Multiplexing Systems

Iraqi Journal of Computer Communication Control and System Engineering ◽

10.33103/uot.ijccce.19.2.5 ◽

2019 ◽

pp. 41-49

Keyword(s):

Phase Noise ◽

Analytical Model ◽

Error Vector Magnitude ◽

Lower Phase ◽

Channel Power ◽

Fiber Nonlinearity ◽

Nonlinear Phase ◽

Transmission Distance ◽

Mode Division Multiplexing ◽

Symbol Rate

In this paper, an analytical model is developed to estimate a nonlinear phase noise (NPN) due to Kerr fiber nonlinearity and its interaction with amplifier noise in mode division multiplexing (MDM) systems. Our analysis uses generalized coupled multimode nonlinear Schrödinger equations (MM- NLSE) that describe the propagation of the mode superimposing in the optical fiber. The nonlinear phase noise versus channel power and transmission distance is evaluated by implementing our analytical model for LP01, LP11a, and LP11b spatial modes. Each mode carries a 4-QAM signal at a symbol rate of 20 Gsymbol/s. The results reveal that LP11 mode has a lower phase noise variance than LP01 mode over entire transmission distances. Finally, the error vector magnitude (EVM) versus channel power is quantified using an analytical model.

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Experimental Demonstration of Special-Shaped 32-Quadrature Amplitude Modulation Constellations for Visible Light Communications

Advances in Condensed Matter Physics ◽

10.1155/2018/7252795 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7

Author(s):

Xinyue Guo ◽

Shuangshuang Li ◽

Yang Guo

Keyword(s):

Visible Light ◽

Amplitude Modulation ◽

High Speed ◽

Light Emitting Diode ◽

Rapid Development ◽

Average Power ◽

Visible Light Communication ◽

Quadrature Amplitude Modulation ◽

Visible Light Communications ◽

Transmission Distance

With the rapid development of light-emitting diode, visible light communication (VLC) has become a candidate technology for the next generation of high-speed indoor wireless communication. In this paper, we investigate the performance of the 32-quadrature amplitude modulation (32-QAM) constellation shaping schemes for the first time, where two special circular constellations, named Circular (4, 11, 17) and Circular (1, 5, 11, 15), and a triangular constellation are proposed based on the Shannon’s criterion. Theoretical analysis indicates that the triangular constellation scheme has the largest minimum Euclidian distance while the Circular (4, 11, 17) scheme achieves the lowest peak-to-average power ratio (PAPR). Experimental results show that the bit error rate performance is finally decided by the value of PAPR in the VLC system due to the serious nonlinearity of the LED, where the Circular (4, 11, 17) scheme always performs best under the 7% preforward error correction threshold of 3.8 × 10−3 with 62.5Mb/s transmission data rate and 1-meter transmission distance.

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An Investigation of the Impacts of Phase Noise on Symbol Error Rate in Quadrature Amplitude Modulation Systems

FUOYE Journal of Engineering and Technology ◽

10.46792/fuoyejet.v3i1.121 ◽

2018 ◽

Vol 3 (1) ◽

Author(s):

Hilary U Ezea ◽

Kehinde Adebusuyi ◽

Temidayo Ofusori ◽

Rita U Ezea

Keyword(s):

Phase Noise ◽

Error Rate ◽

Amplitude Modulation ◽

Symbol Error Rate ◽

Quadrature Amplitude Modulation ◽

Soft Decision ◽

Matlab Simulation ◽

System Complexity ◽

Soft Decision Decoding ◽

The Impact

The existence of phase noise in virtually every digital communications system poses a serious challenge to system designers especially as system complexity increases. Communication system complexity could be attributed to the modulation techniques adopted and the circuitry employed in achieving such modulations. This work investigates the impact of phase noise on the Symbol Error Rate (SER) of the different Quadrature Amplitude Modulation (QAM) schemes. MATLAB simulation technique is adopted for the work and the results of the simulations show that as the phase noise is increased negatively, all the QAM schemes investigated show a reduction in SER and at a point, records a zero error. The value at which the schemes record this zero symbol error rate increases as the complexity of the scheme increases. So, higher order QAM schemes accommodate more symbol errors than the lower orders. The results also show that hard decision decoding has the worst performance index, irrespective of the QAM scheme, when compared with soft decision decoding.

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Numerical Investigation of the Equalization Enhanced Phase Noise Penalty for M-Quadrature Amplitude Modulation Formats in Short-Haul Few-Mode Fiber Transmission Systems with Time-Domain Equalization

Applied Sciences ◽

10.3390/app8112182 ◽

2018 ◽

Vol 8 (11) ◽

pp. 2182 ◽

Cited By ~ 1

Author(s):

José Delgado Mendinueta ◽

Werner Klaus ◽

Jun Sakaguchi ◽

Satoshi Shinada ◽

Hideaki Furukawa ◽

...

Keyword(s):

Phase Noise ◽

Optical Communication ◽

Amplitude Modulation ◽

Communication Systems ◽

Numerical Study ◽

Optical Signal ◽

Quadrature Amplitude Modulation ◽

Transmission Systems ◽

Modulation Formats ◽

Optical Communication Systems

The equalization enhanced phase noise (EEPN), caused by the interaction of the chromatic dispersion (CD) with the phase noise of the local oscillator (LO), has been extensively studied for single-mode optical communication systems. Few-mode fiber (FMF) transmission systems introduce a new channel impairment, the differential mode delay (DMD), which also creates EEPN and hence limits the maximum transmission distance of those systems. In this work, we numerically investigate the optical signal to noise ratio (OSNR) penalties caused by the EEPN in a 3-mode FMF transmission system at 25 GBd for quadrature phase-shift keying (QPSK), 16-quadrature amplitude modulation (QAM), 32-QAM and 64-QAM modulation formats when using the blind phase search (BPS) carrier phase recovery (CPR) algorithm, which has been demonstrated to be both robust and suitable for optical communication systems. Our numerical study assumes a short-span of FMF, modeled in the weakly-coupled regime, and includes two cases; the use of ideal mode-selective de/multiplexers at both ends of the FMF span (model A), and the use of ideal non-mode-selective de/multiplexers (model B). The results show that the EEPN has almost no effect in model A. However, EEPN produces a severe penalty in model B with the onset of the OSNR degradation starting for a DMD spread of the impulse response of about 100 symbols for all modulation formats investigated. The distribution ratio of the amount of phase noise between the transmitter and receiver lasers is also assessed for model B and we confirm that the degradation is mainly due to the phase noise of the LO.

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