Differential Phase Shift Keying Research Articles

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.

Short-Time Spot Communication Using COTS Stereo Speaker

In this paper, we construct the spot communication method using a stereo speaker. In our proposed method, one speaker transmits differential binary phase-shift keying (DBPSK) symbols for communication, and the other speaker transmits sine waves whose frequency is close to that of the DBPSK symbols for jamming. Inside the spot, the jamming signal is canceled by the orthogonality of the communication symbols and jamming signals. Outside the spot, the jamming signal inverts the differential phase of the communication symbols, which prevents normal DBPSK demodulation rendering the communication symbols concealed in the area. This enables correct demodulation only inside the spot. In the conventional method using a stereo speaker, the effect of the jamming signal is weak; thus, transmitting at least 11 symbols is required. In our proposed method, the effective jamming using the interference between sine waves of close frequencies enables spot communication by transmitting only 3 symbols. In the evaluation experiments, we generate the spot from -10 to 20 degrees in a real environment and measure the signals at 9 positions inside and outside the spot, from -40 to 40 degrees at 10 degree intervals. The measurements were conducted 100 times at each position. Through these experiments, we confirmed that demodulation errors occur only outside the spot. In the measurement results, some systematic errors of the differential phase were observed inside the spot, where theoretically this error should not occur. To discuss this error, we conducted additional experiments and revealed the causes.

Polarization multiplexing and hybrid modulation based bandwidth efficient NG-PON2 coexisting with GPON and XG-PON

Bandwidth efficiency is an important design parameter for next-generation passive optical network stage 2 (NG-PON2). In this paper, two optical line terminal (OLT) designs based on the polarization split state are proposed for NG-PON2. The first method doubles the data rate per wavelength by separate amplitude modulation of both polarization states, whereas, in the second method, differential phase-shift keying (DPSK) modulates another data stream on each amplitude-modulated state; this approach increases the data rate per wavelength fourfold. The proposed system provides NG-PON2 access while coexisting with a gigabit passive optical network (GPON) and 10 GPON (XG-PON). The proposed system design serves 1024 NG-PON2 opitcal network units (ONUs), 128 GPON ONUs, and 128 XG-PON ONUs. The transmission performance of the system is verified by evaluating the bit error rate (BER) for varied received power. An acceptable BER level of less than ${{1}}{{{0}}^{- 9}}$ is considered in this work.

Compensation-free high-dimensional free-space optical communication using turbulence-resilient vector beams

Free-space optical communication is a promising means to establish versatile, secure and high-bandwidth communication between mobile nodes for many critical applications. While the spatial modes of light offer a degree of freedom to increase the information capacity of an optical link, atmospheric turbulence can introduce severe distortion to the spatial modes and lead to data degradation. Here, we demonstrate experimentally a vector-beam-based, turbulence-resilient communication protocol, namely spatial polarization differential phase shift keying (SPDPSK), that can reliably transmit high-dimensional information through a turbulent channel without the need of any adaptive optics for beam compensation. In a proof-of-principle experiment with a controllable turbulence cell, we measure a channel capacity of 4.84 bits per pulse using 34 vector modes through a turbulent channel with a scintillation index of 1.09, and 4.02 bits per pulse using 18 vector modes through even stronger turbulence corresponding to a scintillation index of 1.54.

High modulated soliton power propagation interaction with optical fiber and optical wireless communication channels

<p><span id="docs-internal-guid-52da184f-7fff-738a-f0e7-e8dd779e097b"><span>This paper has presented high modulated soliton power transmission interaction with optical fiber and optical wireless communication channels at flow rate of 40 Gbps and 20 km link range. The proposed modulation schemes are continuous phase frequency shift keying (CPFSK), Quadrature amplitude modulation (QAM), differential phase shift keying (DPSK), frequency shift keying (FSK), pulse amplitude modulation (PAM), minimum shift keying (MSK), and optical quadrature phase shift keying (OQPSK). CPFSK has presented better performance than other proposed modulation schemes for both optical fiber and optical wireless communication channels. The enhancement of optical signal/noise ratio at fiber/wireless channel, received electrical power and signal/noise ratio at optical receiver with increase of bits per symbol for different proposed modulation schemes except for CPFSK scheme. Therefore it is evident that CPFSK modulation scheme is more efficient and better performance than other modulation schemes for different communication channels. The obtained results are simulated with optisystem program version 13. </span></span></p>

Performance of Electromagnetic Nanonetwork under relaying for plant monitoring

Recently, Nanonetworks has been envisioned as a predominant technology. Applications of whose ranges from environment to agriculture and biomedical to military, almost in every field of human life. It plays a vital role in crop monitoring for high-resolution agriculture and in detection of emitted volatile organic compounds. However, sensing range of an individual nanosensor is limited. Multi-hop, relay system can be used to enhance the transmission range of nanosensor based Nanonetworks. This manuscript presents various performance measure of an Electromagnetic Nanonetworks under Amplify-and-Forward (AF) relaying for plant monitoring. Specifically, proposes closed form expressions for Average Error Rate and Spectral Efficiency (SE) of Differential Binary Phase Shift Keying (DBPSK) and Differential Quadrature Phase Shift Keying (DQPSK) modulation schemes of Nanonetworks under dual AF relaying. It is worthful to mention that plant scenarios and hence fading model for different types of plant is different. Therefore, in analysis fading channel from source to relay (S-R) is taken as Fox’s H (FH) function which realizes different fading models, such as EGK, Fisher-Snedecor (FS) distribution and Alpha-Mu fading models, as its special cases to represent different plant scenarios. Whereas, fading model from relay to destination (R-D) is taken as Generalized-Gamma (GG). It is observed that an increase in the value of severity and/or shaping parameters decreases the average error rate. On the other hand, converse is true for the spectral efficiency. Analytical results show perfect agreement with simulation.

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 of differential phase shift keying maritime laser communication over log-normal distribution turbulence channel

Laser communication is essential part of maritime-terrestrial-air intelligent communication/sensor network. Among them, different modulation formats would play a unique role in specific applications. Based on Rytov theory, we discussed system performance of the maritime laser communication with repeated coding technology in several modulation schemes. The closed-form expression of average bit error rate (BER) from weak to moderate atmospheric turbulence described by log-normal distribution is given. Differential phase shift keying (DPSK) modulation, as a potential solution for future maritime laser communication, has attracted a lot of attention. We analyzed the effects of atmospheric turbulence parameters (visibility, refractive index structure coefficient, non-Kolmogorov spectral power-law exponent, turbulence inner scale) and DPSK system parameters (receiver aperture diameter, repeat time) on average BER in detail. Compared with the aperture-averaging effects, the system BER can be well suppressed through increasing repeat time. This work is anticipated to provide a theoretical reference for maritime laser communication systems.

Receiver Energy Efficiency and Transmission Latency Analysis of Outage-Constrained Differential PSK With a Finite Resolution ADC

We consider a power constrained downlink communication scenario where energy efficiency, reliability, and latency take precedence over rate, as in some Internet of Things (IoT) applications. To reduce its receiver power consumption and complexity, we assume that the IoT device has a single RF chain and investigate the finite-resolution analog-to-digital converter (ADC) operation with differential Phase Shift Keying (PSK) modulation. A lower ADC resolution leads to an exponential decrease in power consumption, while adopting differential PSK enables the use of a low-cost detector with no channel state information (CSI) or carrier phase recovery circuitry. Our main goal in this article is to compare, both analytically and numerically using representative IoT system design parameters, the receiver energy efficiency of the proposed differential PSK system with a coherent PSK system that uses estimated CSI under reliability and latency constraints in Rayleigh slow-fading and ADC quantization distortion conditions. To mitigate the ADC finite-resolution effects without requiring CSI at the receiver or transmitter, we propose and analyze a PSK differentially-modulated Alamouti space-time block transmission scheme with only two RF chains at the transmitter while still restricting the IoT device to have a single RF chain. Our results demonstrate that in the considered low-rate, and outage and latency-constrained scenario with stringent power consumption requirements, differentially-modulated Alamouti transmissions to a single RF-chain IoT device with a low-resolution ADC is an attractive choice in terms of receiver energy efficiency, reliability, and transmission latency.

On Multi-User Deep-Learning-Based Non-Coherent DPSK Multiple-Symbol Differential Detection in Massive MIMO Systems

In view of reducing the complexity of signal detection in massive multiple-input multiple-output (MIMO) receivers, the use of non-coherent detection is favored over usual coherent techniques that require complex channel estimation. In this paper, a deep-learning approach to implement non-coherent multiple-symbol detection for differential phase-shift keying (DPSK) multi-user massive MIMO systems is proposed. The proposed deep-learning implementation reduces the high computational complexity required in conventional DPSK detection techniques. Two deep-learning-based multiple-symbol differential detection receiver designs are proposed and compared with decision-feedback differential detection (DFDD), and conventional multiple-symbol differential detection (MSDD) for the same system parameters. Multiple-symbol differential sphere detection (MSDSD) is used to implement conventional MSDD. The results show that the proposed deep-learning-based multiple-symbol differential detection implementation outperforms decision-feedback differential detection and achieves an optimal performance compared to conventional multiple-symbol differential detection implemented by multiple-symbol differential sphere detection for single-user and multi-user scenarios.

New Accurate Approximation for Average Error Probability

This paper proposes new accurate approximations for average error probability (AEP) of a communication system employing either $M$ -phase-shift keying (PSK) or differential quaternary PSK with Gray coding (GC-DQPSK) modulation schemes over generalized fading channel. Firstly, new accurate approximations of error probability (EP) of both modulation schemes are derived over additive white Gaussian noise (AWGN) channel. Leveraging the trapezoidal integral method, a tight approximate expression of symbol error probability for $M$ -PSK modulation is presented, while new upper and lower bounds for Marcum $Q$ -function (MQF) of the first order, and subsequently those for bit error probability (BEP) under DQPSK scheme, are proposed. Next, these bounds are linearly combined to propose a highly refined and accurate BE P’s approximation. The key idea manifested in the decrease property of modified Bessel function $I_{v}$ , strongly related to MQF, with its argument $v$ . As an application, these approximations are used to tackle AEP’s approximation under $\kappa -\mu $ shadowed fading. Numerical results show the accuracy of the presented approximations compared to the exact ones.

Modulation format identification in fiber communications using single dynamical node-based photonic reservoir computing

We present a simple approach based on photonic reservoir computing (P-RC) for modulation format identification (MFI) in optical fiber communications. Here an optically injected semiconductor laser with self-delay feedback is trained with the representative features from the asynchronous amplitude histograms of modulation signals. Numerical simulations are conducted for three widely used modulation formats (on–off keying, differential phase-shift keying, and quadrature amplitude modulation) for various transmission situations where the optical signal-to-noise ratio varies from 12 to 26 dB, the chromatic dispersion varies from − 500 to 500 ps/nm, and the differential group delay varies from 0 to 20 ps. Under these situations, final simulation results demonstrate that this technique can efficiently identify all those modulation formats with an accuracy of > 95 % after optimizing the control parameters of the P-RC layer such as the injection strength, feedback strength, bias current, and frequency detuning. The proposed technique utilizes very simple devices and thus offers a resource-efficient alternative approach to MFI.

High wavelength-resolved state of polarization monitoring method based on stimulated Brillouin scattering effect

A state of polarization (SOP) monitoring method with high wavelength resolution, based on the stimulated Brillouin scattering (SBS) in optical fiber is presented. By scanning the wavelength of pump which stimulates SBS effect, the signal spectrum with high resolution of ~ 0.1 pm can be obtained. Then, through measuring the signal spectra under six specific polarization states of pump, the Stokes vectors of each wavelength component of signal are retrieved. The results show that a mean error which is 0.018 is achieved for the wavelength-resolved SOP monitoring of a 40-Gb/s nonreturn-to-zero differential quadrature phase-shift keying (NRZ-DQPSK) signal. This monitoring method provides effective capability for estimation of polarization mode dispersion (PMD).

Quasi-Independent Bidirectional Communication Methods for Simultaneous Wireless Power and Information Transmission

Simultaneous wireless power and information transmission (SWPIT) is essential for power regulation, load detection, and maximum efficiency tracking in wireless power transfer (WPT) systems. To eliminate the interaction between power and information transmission, this paper proposes a novel bidirectional communication method based on differential phase shift keying (DPSK). First, the steady-state and transient models of the series–series compensated WPT system are established to analyze the characteristics of power transmission and the behavior of shared power/information channel. Second, regarding the stability of power transmission, principles of the forward and backward communication that integrated with power modulation through the full-bridge inverter and the semi-bridgeless active rectifier are elaborated. Then, the demodulator and half-duplex communication protocol are designed. Finally, the simulation is carried out and the experimental prototype is established, which shows that the proposed DPSK method is effective and the transmission of power and information is quasi-independent. Owing to the integration of power and information transmission, the complexity, cost, and volume of the SWPIT system are reduced significantly.

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.

Design and Analysis of Replica Piecewise M-Ary DCSK Scheme for Power Line Communications With Asynchronous Impulsive Noise

Previous studies have shown that impulsive noise can weaken the performance of power line communication (PLC). Though DCSK can improve the performance in an order of magnitude comparing to the direct sequence differential phase shift keying (DS-DPSK), it is still a challenge to further improve the BER performance with signal redesign without the need of advanced and expensive extra noise suppression technologies. The paper introduces the model of asynchronous impulsive noise of Middleton class-A noise and corresponding multipath fading channels in PLC, and analyzes the bit error rate (BER) performance of the M-ary differential chaos shift keying (MDCSK) scheme over different channels. Furthermore, a new replica piecewise frame of MDCSK (RP-MDCSK) is proposed to resist the impulse noise. In the proposed scheme, one piecewise of signals is transmitted first. Then, it replicates pw times, which serves as the reference signal transmitted in the first half symbol period. The information-bearing signal combines the reference signal with its Hilbert transform in the second half. At the receiver, one piece of reference signals is extracted and then correlated with its corresponding information-bearing part. The BER expressions of the MDCSK and the proposed scheme are derived and analyzed over different channels, and verified by simulations. Comparing with the corresponding schemes, it is found that the BER of the proposed scheme is by 2-3 orders of magnitude lower.

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.

DPSK over inverse pulse position modulation with high extinction ratio for optical label switching

AbstractOptical label switching (OLS) is a promising solution for rapidly growing packet based internet traffic and data switching in data center. Most proposed schemes apply orthogonal modulation, which superimpose a nonamplitude modulated label signal onto a Manchester coded or pulse position modulated (PPM) ASK payload signal. The extinction ratio (ER) has to be reduced for overlaid signal. To avoid the quality degradation of payload signal from low ER, a differential phase shift keying (DPSK) over inverse PPM is proposed in this paper. Due to the high mark ratio of the inverse PPM, the proposed DPSK over inverse PPM modulation achieves a high ER for the ASK signal while induces limited crosstalk to the DPSK signal. Compare with the previously proposed schemes, the test results show the proposed DPSK over inverse 4PPM modulation achieves an optimum ER improvement of at least 6 dB to support an extended of at least 10.5 km.

M-ary DPSK coded binary to gray, BCD to gray, and octal to binary all-optical code converters based on SOA-MZI configuration at 500 Gb/s.

Gray codes are broadly used as the cyclic codes to assist error correction in optical communications. In this paper, we have proposed the novel design of three different types of all-optical gray code converters based on the semiconductor optical amplifier (SOA) Mach-Zehnder interferometer (MZI) configuration. The XOR and OR gates are the basic devices used for the proposed design of binary to gray, binary-coded decimal (BCD) to gray, and octal to binary code converters. For the first time, to the best of the authors' knowledge, a high data rate of 500 Gbps is achieved for the three types of all-optical code converters using the SOA-MZI configuration by exploiting an M-ary differential phase shift keying (DPSK) modulation scheme. The performance factors of the proposed all-optical code converters like extinction ratio, bit error rate, and quality factor are calculated.

Analysis of all-optical wavelength converter based on FWM effect in HNLF for coherent 100 Gbps dual-polarized DQPSK signal

All optical wavelength converter (AOWC) play important functionalities to enhance the network reconfiguration, efficient wavelength routing and assignment, non-blocking capacity in future dynamic optical access networks. In optical access networks, bandwidth limitation and wavelength continuity constraints lead to inefficient utilization of wavelength resources. AOWCs are the premier option to cope with these network constraints. On the other hand, advanced modulation formats have been extensively analyzed and used to achieve the high spectral efficiency. Since advanced modulation formats are more sensitive to amplitude and phase noise, AOWC are more suitable to achieve minimum power penalty and maximum conversion efficiency. In this paper, AOWC based on four wave mixing (FWM) in highly nonlinear fiber (HNLF) for coherent 100 Gbps dual-polarized differential quadrature phase shift keying (DP-DQPSK) has been designed. The performance of AOWC is optimized at different probe input power, different pump power and wavelength to achieve the maximum conversion efficiency. After the multiwavelength conversion based on 0.7 km HNLF, the power penalty for converted 100 Gbps DP-DQPSK signals is less than 4.15 dB at BER of 10-9 and maximum conversion efficiency of −10.58 dB has been achieved.