Differential Phase Shift Keying Modulation Research Articles

Investigation of MDRZ and DPSK modulation schemes employed in DWDM systems for smart city 5G access networks

Wavelength division multiplexing (WDM) is one of the emerging technologies for data transmission in 5G access network assembly between the antenna unit (AU) and the distribution unit (DU). Here, in this work, we evaluate and analyze a dense wavelength division multiplexing (DWDM) — passive optical networks (PONs) employing erbium–ytterbium-doped fiber amplifier (EYDFA) [Formula: see text] Raman hybrid optical amplifier (HOA) using two modulation schemes — modified duobinary return to zero (MDRZ) and differential phase shift keying (DPSK) for alternate channels, where the channel count has been varied from 8 to 40. The system has been analyzed over the wavelength span of 1550–1558.8[Formula: see text]nm with a channel spacing, input power and data rate of 25[Formula: see text]GHz, 0[Formula: see text]dB and 40[Formula: see text]Gb/s, respectively. An average gain, gain ripple and optical signal-to-noise ratio (OSNR) of 20.87, 0.95 and 30[Formula: see text]dB, respectively have been observed in the case of HOA along with the achievement of Q-factor of up to 9 at the receiving end of the system. The DPSK-modulated channels result in higher values of gain and OSNR along with lower gain ripple as compared to MDRZ channels making the proposed system a good option for 5G access network applications.

Design of DWDM optical communication systems with different modulation formats using DCF and a repeater.

The dense wavelength division multiplexing (DWDM) technique has been used to provide a large capacity and low bandwidth loss for optical communication systems. In this paper, simulation designs by Optisystem15.0 of carrier-suppressed return to zero (CSRZ), differential phase shift keying (DPSK), and intensity modulation is proposed to determine which modulation format is more compatible with four and eight DWDM channels for transmitting an optical signal over 400km distance. For a long optical path, the dispersion compensation fiber (DCF) technique is proposed to eliminate dispersion effects and increase the possibility of transmitting multiple optical wavelengths over long single-mode fiber. Optical amplifiers are used to amplify the optical signal with a distorted signal and process the attenuation caused by the long transmission distance. In DCF network design, CSRZ offers the best performance because of the large quality factor (24.560) and high threshold power (15dBm), which make the system compatible with increased distance between the transmitter and receiver; next is intensity modulation with a 24.5604 quality factor and 13dBm threshold power value; DPSK comes in last with the worst performance, with a quality factor of 10 at 13dBm power due to non-linear effects, especially non-linear phase noise. In the repeater design, the DPSK modulation format has the best performance with a large quality factor of 20.7913 at a high threshold power of 14dBm for 150GHz spacing; this is because the repeater technique is compatible with reducing the non-linear effects of the DPSK format. CSRZ and intensity modulation have the same performance with a 12 quality factor at 4dBm power for intensity modulation and 3dBm power for CSRZ modulation.

A Novel Low-Complexity High-Order DPSK System With Constellation Reconstruction for FSO Communication

Free Space Optical (FSO) communication has been widely studied because of its advantages such as rich spectrum resource, high transmission capacity, high security, low power consumption and flexible installation. However, FSO link is sensitive to weather conditions and atmospheric turbulence, which poses a great challenge on signal transmission quality. Differential Phase Shift Keying (DPSK) modulation is well recognized as a promising technique to deal with the inter-symbol interference due to channel fading. Nevertheless, the existing system structure for high-order DPSK modulation technology is too complex to be used in practice for FSO system. Therefore, this letter proposes a simplified DPSK modulation scheme. In order to alleviate signal transmission performance degradation caused by simplification, a constellation remapping method is employed in the proposed scheme to achieve flexible signal transmission and improve the Bit Error Rate (BER) performance. It is demonstrated that compared with the traditional DPSK system, the proposed scheme significantly reduces the system complexity and has better BER performance under low to moderate atmospheric turbulence.

Mode and orthogonal frequency division multiplexing using a single AWG-based MUX/DeMUX

An arrayed waveguide grating (AWG) configuration can simultaneously perform the optical discrete Fourier transform and multiplex and demultiplex (MUX/DeMUX) two optical modes, to optically generate/process orthogonal frequency division multiplexing (OFDM) signals in future scalable, converged two-mode optical communication systems. We use a single AWG-based MUX/DeMUX, inter-mode and intra-optical-subcarrier symbol interleaving to mitigate the mode/subcarrier crosstalk. We analyze the performance of a 2-mode × 8 optical-subcarrier × 10 Gbit/s, on-off keying (OOK), differential phase shift keying (DPSK), and differential quadrature phase shift keying (DQPSK) mode division multiplexing (MDM)-OFDM system, that can be used in high-speed, large-capacity short-range optical link, using only passive all-optical signal processing. We numerically demonstrate that it possible to achieve error-free transmission for an 8 subcarrier × 10 Gbit/s × 2 mode system, using OOK and DPSK modulation and for a 4 subcarrier × 10 Gbit/s × 2 mode system, using DQPSK modulation, using intra-optical-subcarrier symbol interleaving.

Design and Evaluation Study of Performance of Optical Wireless Sensors Network for Achieving High Data Rate and Power Saving

<p class="0abstract"><strong>Abstract—</strong>One of the major global issues today is the growing requirements for high-speed data transmission, energy consumption, and the huge volume of data utilized by a variety of multimedia applications such as video streaming, monitoring systems, and gaming. In this research, an analysis is carried out to study the design and evaluation of performance underwater OWC systems (UOWC) through medium communication link ranges to overcome absorption and scattering and to meet the requirements of a wide variety of optical wireless applications. Two modulation schemes of technology have been proposed in the UOWC system which is Differential Phase Shift Keying (DPSK) modulation with Direct Detection (DD) and the DPSK modulation with Coherent Detection (CD), both of them used Optical Orthogonal Frequency Division Multiplexing (OFDM) based on different configurations of multi-input multi-output technology (MIMO). The mathematical model has been proposed to calculate optimal beacon period (BI) and listen to the interval (LI) for preventing overlapping time between the signals and the required power is reduced. By using different types of water the simulation results are displayed the best performance of the UOWC system from link rang and receiver sensitivity. The simulation result of BER is equal 10<sup>-5</sup>, BI equal to 85ms, and LI equal to 108ms.</p>

DPSK modulation and demodulation system based on a novel Mach-Zehnder interference structure

As the conventional fiber Mach-Zehnder (M−Z) interference structure being sensitive to temperature variation and mismatching of arm length in Differential Phase Shift Keying (DPSK) system, we proposed a modulation and demodulation system of DPSK based on novel M−Z interference structure. This novel M−Z interference structure has some advantages of higher temperature stability, better robustness and lower restriction of laser linewidth. A detailed discussion of the working principle is presented and demonstrated, the influences of the delay induced by arm mismatching and temperature variation on the Q factor of DPSK system are analyzed. Experimental results as well as simulations show that the delay length mismatching corresponding to descent point of 3dB increases from [0.925,1.124] to [0.536,1.31], which reduces the requirement for the length accuracy of the interference arm, and the demodulation effect of the novel structure is better under the same deviation. The Q factor of the system keeps fluctuation within a narrow range when the temperature variation in the range of 20°C–120°C, and the demodulation effect of the system is almost unaffected by the variation of ambient temperature.

High-speed fiber system capacity with bidirectional Er-Yb CDFs based on differential phase shift keying (DPSK) modulation technique

Abstract This paper simulates the bidirectional Er-Yb codoped fiber amplifiers (CDFs)-based DPSK modulation scheme for high speed fiber system capacity. The combination of Erbium-Ytterbium codoped fibers into a single fiber has been developed for the extension of the absorption bands for doped fibers. The signal gain variations versus pump wavelength variations have been demonstrated for various doped amplifiers with the proposed Er-Yb CDFs at amplifier length of 5 m. Also the signal gain variations versus pump wavelength variations have been illustrated for the proposed Er-Yb CDFs at 5 m amplifier length in different pumping configurations. The total optical power, max. Q factor, total electrical power, output optical signal/noise ratio, and signal gain variations versus fiber length variations have between simulated and clarified in the presence of bidirectional various lengths of Er-Yb CDFs.

Performance Optimization of DPSK and QPSK for Super Dense Wavelength Division Multiplexing System

This paper investigates the performances of differential phase shift keying (DPSK) and quadrature phase shift keying (QPSK) for 400 channels super dense system for the data rate of 160, 170, 180 and 200[Formula: see text]Gbps, respectively. Evaluation has also been investigated in terms of bit error rate (BER), quality factor and received output power with varying input power. Final analysis has reflected that DPSK modulation has shown the acceptable performance in terms of better communication with minor effect of nonlinearity and dispersion using RAMAN-EDFA hybrid optical amplifier (HOA) for the distance of 250[Formula: see text]km.

Iterative receiver for the triple differential PSK modulation in the time‐varying underwater acoustic communications

Due to the time-varying property of the underwater acoustic (UWA) channel, the significant Doppler spread will severely degrade the performance of direct-sequence spread-spectrum (DSSS) communications. The relative velocity variation between the transmitter and the receiver will cause both the phase rotation and the magnitude loss of correlation peak, during the long transmission of the DSSS packet. To solve this problem, the authors propose a novel transceiver design for the UWA DSSS communications. At the transmitter, the triple differential phase shift keying (D 3 PSK) modulation is adopted to overcome the phase rotation, whereas the phase noise will be amplified resulting in the signal-to-noise ratio (SNR) loss. At the receiver, the improved bit-interleaved coded modulation with iterative decoding algorithm for D 3 PSK is used to recover the SNR loss, in which the D 3 PSK demodulator is treated as the convolutional decoder, and the linear prediction is adopted to track the channel variation. Furthermore, an adaptive selection of local reference signal is also applied to recover the correlation loss. Theoretical simulation shows that the proposed transceiver can effectively mitigate the performance loss caused by the motion acceleration, and the performance gain is significant over the conventional.

Technologies for future wavelength division multiplexing passive optical networks

This study reviews key technologies of next generation wavelength division multiplexing passive optical networks (WDM-PONs). The authors have studied WDM-PONs with centralised lightwave source and direct detection, where a wavelength-reuse system is employed to transmit the uplink data by using a colourless transmitter at the optical network unit (ONU). WDM-PON system was demonstrated using a Fabry-Perot laser diode as a colourless transmitter at the ONU for differential phase-shift keying (DPSK) downlink signals and on-off keying uplink signals. The constant-amplitude feature of the DPSK modulation could retain a great extinction ratio of the downlink signal and decrease the noise to the uplink signal. The proposed scheme offers a promising solution for future PONs.

Performance Comparison of Free-Space Optical (FSO) Communication Link Under OOK, BPSK, DPSK, QPSK and 8-PSK Modulation Formats in the Presence of Strong Atmospheric Turbulence

Abstract Free-space optical (FSO) communication system provides several advantages over radio frequency (RF) system offering high bandwidth, low cost, small space requirements and more secure transmission which is free from Electromagnetic Interference (EMI). However, when the transmitted light signal passes through the atmosphere it experiences attenuation and fluctuations due to atmospheric turbulence. This paper analyzes the bit error rate (BER) performance of FSO communication systems under strong atmospheric turbulence for on-off keying (OOK), binary phase-shift keying (BPSK), differential phase shift keying (DPSK), quadrature phase shift keying (QPSK) and 8-phase shift keying (8-PSK) for link distances of 500, 1,000, 1,500 and 2,000 m. The probability density function (pdf) of the received irradiance is modelled using the gamma-gamma distribution model. It is found that the system exhibits the best BER performance and compensates the lowest power penalty at BER of 10 - 9 for BPSK modulation compared with other modulation techniques which makes BPSK more appropriate to be used with FSO turbulent system.

Underwater Wireless Optical Communication Based on DPSK Modulation and Silicon Photomultiplier

In this paper, a promising phase-modulated underwater wireless optical communication (UWOC) system with silicon photomultiplier (SiPM) based receiver is proposed for the first time and its feasibility has been experimentally demonstrated in a laboratory environment. The phase modulation enables the additional degree of freedom available for encoding of information in UWOC, given that previous state-of-the-art systems mainly employ intensity modulation (IM) schemes with direct detection (DD). In the proposed UWOC system, the information is encoded in the phase of light wave carrier based on differential phase-shift keying (DPSK). A highly sensitive receiver is built from SiPM, which is able to compensate the transmission loss and dramatically enhances the performance of the DPSK UWOC system. We experimentally show the feasibility of the proposed system at a data rate of 200 Mbps. For comparison, the commonly used avalanche photodiode (APD) based receiver is also tested. Comparing with the APD, the use of SiPM reduces the BERs by about two orders of magnitudes. The minimum required optical power for achieving a BER below the FEC threshold is about −40.2 dBm, which is about 11.6 dB lower than the case of APD.

Performance analysis of 80 channels hybrid optical time division dense multiplexing system with the support of different orthogonal modulation techniques

High spectral transmission capacity signals are the prime requirement of today’s dense communication system to enhance the quality of different users services, which have been analyzed and resolved with the support of 80 channels hybrid optical time division dense multiplexing system with different orthogonal modulation techniques (return to zero (RZ), differential quadrature phase shift keying (DQPSK), non-return-to-zero (NRZ), polarization shift keying (PoISK), and differential phase shift keying (DPSK)). Further, evaluation has also been proceeded to receive the best rating results in terms of bit error rate (BER) and quality factor (38 dB to 20 dB) with attainable rating power amplification from Erbium-Doped fiber amplifier (EDFA). Furthermore, final examine has recommended that orthogonal DPSK modulation is the best choice to attain the data rate of 1.80 Tbps from the recommended system for 200 km optical communication with acceptable rating from 10-24 to 10-10.

Performance Analysis of 20 Gbit/s–40 GHz MDM-Ro-FSO Link Incorporating DPSK Modulation Scheme

Abstract The congestion in the radio frequency spectrum has posed a serious challenge for mobile service providers. Radio-over-free space optics (Ro-FSO) technology has been considered as a front runner to deal with the problem of spectrum congestion and to provide future generation high-capacity wireless networks. This work proposes designing and numerical analysis of differential phase shift keying (DPSK) modulation-based 20 Gbit/s–40 GHz hybrid mode division multiplexing-radio-over-free space optics (MDM-Ro-FSO) link up to 40 km transmission range under clear weather. Quality Factor (Q Factor), log of bit error rate (BER), signal to noise ratio (SNR), and received power are the key metrics used to probe the proposed system performance. The impact of increasing divergence angle and different fog weather conditions on the proposed system performance is also numerically evaluated. Further, the decomposition analysis of different spatial modes at the receiving unit is carried out in this work.

Performance Comparison between DPSK and OQPSK modulation approaches in multi environments channels with Matlab Simulink models

Phase shift keying modulation approaches are widely used in the communication industry. Differential phase shift keying (DPSK) and Offset Quadrature phase shift keying (OQPSK) schemes are chosen to be investigated is multi environment channels, where both systems are designed using MATLAB Simulink and tested. Cross talk and unity of signals generated from DPSK and OQPSK are examined using Cross-correlation and auto-correlation, respectively. In this research a proposed system included improvement in bit error rate (BER) of both systems in the additive white Gaussian Noise (AWGN) channel, by using the convolutional and block codes, by increasing the ratio of energy in the specular component to the energy in the diffuse component (k) and the diversity order BER in the fading channels will be improved in both systems.

Performance Evaluation of OOK, DPSK and Duo-binary Modulation Format based Mixed-Line-Rate (MLR) Optical Network

With the steady increase in the heterogeneous Internet traffic, the optical wavelength division multiplexed (WDM) networks based on a mixed line rate (MLR) strategy have emerged as an efficient-solution. Also, with the migration from the legacy to the higher line rate(s), the advanced modulation format(s) (MF) is/are required. However, use of appropriate MF(s) for the higher line rate(s) still remains an open problem. In this article, we compare the performance of an On-Off Keying (OOK), Differential Phase Shift Keying (DPSK) and Duo-binary (DB) MF based MLR network in the presence of various physical layer impairment(s) (PLIs) for which, we propose a mathematical model based on various MFs. As a novelty, we validate the proposed theoretical model’s results by comparing them with the results obtained through simulations from OptSim, which has not been conducted in any existing study(s) thus far. Our simulation results show that the DB MF is perfectly suitable for high spectral-efficient MLR systems owing to its high resistance to various PLIs.

Performance Comparison of All-Optical Amplify-and-Forward Relaying FSO Communication Systems With OOK and DPSK Modulations

All-optical amplify-and-forward (OAF) relaying technique can amplify and filter the attenuated optical signal in optical domain, and thus is regarded as a simple way to extend the transmission distance of free-space optical (FSO) communication systems. At the relaying node, however, the incident background radiation and the amplified spontaneous emission noise of the deployed erbium-doped fiber amplifier will deteriorate the optical signal-to-noise, therefore causing the degradation of the system's bit error ratio (BER). In this paper, we perform simulations and experiments on FSO system with on-off keying (OOK) and differential phase-shift keying (DPSK) signals, focusing on the receiving sensitivity loss (RSL) of the OAF-assisted dual-hop system. Taking the BER level of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-7</sup> as the reference, we find that the DPSK system suffers more than 8 dB RSL at the data rate of 5 Gb/s in simulation, while the OOK system gets less than 1 dB RSL at the same data rate. In the following experiments, the obtained results exhibit that RSL of DPSK system is nearly 10 dB, which of OOK system is less than 1.5 dB, shown similarly property to the simulations.

Performance analysis on DPSK modulation using symbol repetition and interleaving

SummaryIt is well known that the differential phase shift keying (DPSK) transmission does not require a reference phase and reduces the computational complexity and power consumption of the receiver at the cost of the transmission reliability. To improve the reliability of transmission under such scenario, we use a symbol repetition scheme to the DPSK modulation, such as the IEEE 802.15.6 wireless body area network and the ITU‐T G.9903. However, the message symbol repetition with interleaving in conventional manner as in coherent modulation schemes may degrade the receiver performance because of the noise characteristic of the differential demodulation structure. In this work, we analyze the performance of repeated DPSK system with and without the interleaver and demonstrate which scenario is suitable for each modulation order. We propose a proper transmission setting, which achieves noticeable performance improvement at the receiver as well as enhances the energy efficiency of the communication system. Since it can be implemented with very small modification to existing systems, our results are highly applicable with negligible modification of the hardware structure and thus enable substantially low‐cost implementation in future communication systems including wireless body area network internet of things applications.

Frequency recovery techniques for TM/TC satellite modem in critical scenarios

SummaryReliability and effectiveness are essential features of satellite transceivers for telemetry and telecommand applications. Modem performance has a strong impact on the success of a satellite mission, in particular, during critical scenarios as the early operation phase, the disposal of a satellite at the end of its life, or the deep‐space missions. In these specific mission critical scenarios, fast and correct data reception is even more important than high channel capacity. An unknown and fast variable channel condition, which can be caused by uncertain spacecraft attitude and large Doppler shift with respect to the data rate, requires efficient and innovative receiver architecture. This paper introduces a complete digital implementation of a transceiver for TM/TC application in low Earth orbit mission that is perfectly compliant with aforementioned requirements. Particular attention is dedicated to the definition and selection of the most appropriate frequency recovery technique; 2 open‐loop techniques that are derived from ML optimal estimator are presented and compared. Additionally, the performance of the proposed receiver is extensively studied and compared with an incoherent technique that is based on the double differential PSK modulation and is known to be suitable for sat‐com in critical scenarios.

A WDM-PON with DPSK modulated downstream and OOK modulated upstream signals based on symmetric 10 Gbit/s wavelength reused bidirectional reflective SOA

We investigate a wavelength-division-multiplexing passive optical network (WDM-PON) with centralized lightwave and direct detection. The system is demonstrated for symmetric 10 Gbit/s differential phase-shift keying (DPSK) downstream signals and on-off keying (OOK) upstream signals, respectively. A wavelength reused scheme is employed to carry the upstream data by using a reflective semiconductor optical amplifier (RSOA) as an intensity modulator at the optical network unit (ONU). The constant-intensity property of the DPSK modulation format can keep high extinction ratio (ER) of downstream signal and reduce the crosstalk to the upstream signal. The bit error rate (BER) performance of our scheme shows that the proposed 10 Gbit/s symmetric WDM-PON can achieve error free transmission over 25-km-long fiber transmission with low power penalty.