Pulse Position Modulation Scheme Research Articles

A 930 m/180 Gbps*User Underwater Coherent Optical Code-Division Multiple-Access Network Based on Hybrid 256-Differential Pulse Position Modulation and Weighted Modified Prime Code Sequence

Currently, there are three types of optical communication networks based on the communication channel between the transmitter and receiver: the optical fiber channel, visible light channel, and optical wireless channel networks. The last type has several advantages for underwater communication, wireless sensors, and military communication networks. However, this type of optical network suffers from weather conditions in free-space communications and attenuation owing to the scattering and absorption mechanisms for underwater communication. In this study, we present a new transceiver architecture of a coherent optical code-division multiple-access (OCDMA) system based on a hybrid M-ary differential pulse position modulation scheme and a spreading code sequence called weighted modified prime code for underwater communication to minimize channel dispersion, increase the transmission rate per second, enhance the network bit error rate (BER) performance, and improve network security. Using an OCDMA system, we can simultaneously expand the network coverage area and increase the number of users sharing the network over the same channel bandwidth. The simulation results in this study proved that the proposed system can accommodate 1310 active users and a network throughput of 180 Gbps*user over a transmission distance of 930 m without any repeater at a 10−9 BER performance, compared to the 45 Gbps*user network throughput and 100 m transmission distance reported in the literature.

Design of Chaotic-Based PPM-PI-DCSK Modulation for Wireless Communications

In this letter, a joint pulse position modulation (PPM) and permutation index differential chaos shift keying (PI-DCSK) modulation scheme (PPM-PI-DCSK) is proposed to increase the data rate and improve performance. In PPM-PI-DCSK, the bit stream is divided into blocks of mp+mc+1 bits, where mp bits are modulated by PPM, mc bits are modulated by PI modulation, and the last one bit is modulated by DCSK. The theoretical bit error rate (BER) performance of the proposed PPM-PI-DCSK is derived over multipath Rayleigh fading channels and validated via simulations. Simulation results show that the proposed PPM-PI-DCSK outperforms the benchmark DCSK-based schemes. Furthermore, the performance superiority is also demonstrated by the frequency-modulated PPM-PI-DCSK over a typical ultra-wideband (UWB) channel. This demonstrates the superiority and feasibility of the proposed scheme in practical applications.

Performance Evaluation of Pulse Position Modulation Scheme in Automatic Dependent Surveillance Broadcast System

this paper presents a new formula for calculating the Bit Error Rate (BER) and the Packet Error Rate (PER) for binary pulse position modulation scheme which had been used in Automatic Dependent Surveillance Broadcast (ADS-B) system, ADS-B system is used in air traffic surveillance and control. ADS-B system uses the Binary Pulse Position Modulation (BPPM) scheme in the link between the aircraft and the ground station. The results show that the simulated bit-error rate and packet error rate are approximately matches the theoretical one; these results have been obtained for both coherent and non-coherent detection. As a result, mathematical formulas to represent the probability of error for BPPM are also derived for both coherent and no-coherent detection scheme.

P‐3.19: Demonstration of Underwater Wireless Optical Communication System Using a Green Micro‐LED and FPGA‐based PPM Modulation

Underwater wireless optical communication (UWOC) is one of the attractive technologies to realize ocean exploration system. The research on its communication rate and system construction has attracted the attention of many scholars. This paper proposed an UWOC system based on FPGA with a Micro-LED as light source. Field Programmable Gate Array (FPGA) was used to build an UWOC system under the pulse position modulation (PPM), and error detection module was added to the system to verify the system performance. In this paper, we demonstrated firstly that the framework of the system and used the ISE development software to design the system structure of PPM scheme, which included the error test module. Then, the simulation software was used to verify the realization results of the FPGA transmitter and receiver. Through simulation and experimental test, we have realized and demonstrated a FPGA-based 50Mbps UWOC system with PPM modulation scheme utilizing the green Micro-LED.

Wireless Information and Power Transfer for IoT: Pulse Position Modulation, Integrated Receiver, and Experimental Validation

Simultaneous wireless information and power transfer (SWIPT) has emerged as a viable technique to energize and connect low-power autonomous devices and enable future Internet of Things (IoT). A major challenge of SWIPT is the energy consumption of the receiver of such low-power devices. An attractive low-power solution consists of an integrated information decoder (ID) and energy harvester (EH) architecture for SWIPT receiver (IntRx) where the received radiofrequency (RF) signal is first rectified before being used for information decoding. Such architecture eliminates the need for energy-consuming RF components, such as local oscillators and mixers. This article proposes a novel modulation and demodulation method for the IntRx SWIPT architecture based on pulse position modulation (PPM) where information is encoded in the position of the pulse. The new method transmits high amplitude pulses to increase the peak-to-average power ratio (PAPR) of the transmit signal and exploits the EH’s nonlinearity so as to boost the harvested dc power. Simultaneously, the information can be decoded from the rectifier signal by simply finding the position of the pulse in a certain symbol duration. We have analyzed both the information and the power transfer performance of the newly proposed PPM for IntRx SWIPT theoretically, numerically, and experimentally. To that end, we have established a SWIPT system testbed in an indoor environment by prototyping a base station to transfer information-power signal and the IntRx SWIPT receiver, including ID and EH blocks. The performance evaluation of the PPM was carried out in various conditions, and the results have been compared and contrasted to conventional signals. Theoretical, numerical, and experimental results highlight the significant benefits of the proposed PPM scheme to enhance the power transfer performance and operate information decoding with low-power consumption.

Design of Transmitter and Receiver Architectures for Differential Amplitude Pulse-Position Modulation Scheme

Design of Transmitter and Receiver Architectures for Differential Amplitude Pulse-Position Modulation Scheme

Adaptive optics compensation of M-ary pulse position modulated communication systems in anisotropic non-Kolmogorov turbulent atmosphere

Adaptive optics compensation effect on the performance of an optical wireless communication system (OWC) employing M-ary pulse position modulation (PPM) scheme in anisotropic non-Kolmogorov turbulent atmosphere is investigated. Avalanche photodetector (APD) is used at the receiver side and log-normal channel that models the weak turbulence conditions is utilized. Anisotropy, generally resulting in better performance in OWC systems operating in the turbulent medium, combined with the adaptive optics applications will enhance the bit-error-rate (BER) of the OWC systems significantly. Results are obtained depending on various parameters for both the turbulent atmosphere and the receiver. Our work gives OWC system designers a perspective to optimize their design.

Dimming controlled multi header hybrid PPM (MH-HPPM) for visible light communication

Visible Light Communication (VLC), which gives communication alongside illumination, has increased a great deal of enthusiasm amongst researchers. VLC system needs to consider dimming control to offer effective communication while illuminating. In this paper, a dimming control scheme based on pulse position modulaton (PPM) and inverse PPM is proposed, which supports different dimming levels. PPM supports low dimming value whereas inverse-PPM has an inherent property of supporting higher dimming value for the same block length. Hence, the proposed scheme utilizes both PPM and inverse-PPM to achieve different dimming target values. This paper presents the algorithm for encoding and decoding of multi-header hybrid pulse position modulation (MH-HPPM) scheme and also shows the NI Labview SubVI code for generating the MH-HPPM frame under dimming values of 0.25, 0.33, 0.5, 0.67 and 0.75. Simulations are executed in MATLAB 2017a to simulate random input bits using the proposed scheme in the VLC system for different dimming values and evaluate the BER performance of the scheme. The simulation result shows that the proposed scheme performs better for dimming value $$\alpha = 0.25$$ , block length $$K = 4$$ , is bandwidth efficient and hence can be considered as an alternate dimming control scheme.

SER performance investigation of a MPPM relay-aided FSO system with three decision thresholds over EW fading channel considering pointing errors

The symbol error rate (SER) performance of a multi-hop parallel free-space optical (FSO) communication system with multiple pulse position modulation (MPPM) scheme considering three different decision threshold schemes, fixed decision threshold (FDT), optimized decision threshold (ODT), and dynamic decision threshold (DDT) has been investigated over exponentiated Weibull (EW) atmospheric turbulence channel combiningthe impact of the fading induced by pointing errors. On the basis of the decode-and-forward (DF) protocol, the cumulative distribution function (CDF) and probability density function (PDF) in terms of the Meijer’ s G-function for this considered FSO communication system are derived with the max–min criterion as the best path selection scheme. After that, the closed-form SER expressions for three threshold schemes are obtained by Gauss–Laguerre quadrature function and then confirmed by Monte Carlo (MC) simulation. The SER performance is further analyzed systematically under different turbulence conditions, receiver aperture sizes, jitter variances, and structure parameters (R and C) for three decision threshold schemes. The results show that pointing errors will deteriorate the system performance, while the multi-hop parallel transmission can improve the SER performance and expand the communication range. Furthermore, ODT and DDT schemes can significantly overcome the effect of the error floor of FDT scheme. This work benefits the development of the MPPM based relay-aided FSO system.

Cramér–Rao Bounds for Beam Tracking With Photon Counting Detector Arrays in Free-Space Optical Communications

Optical beam center position on an array of detectors is an important parameter that is essential for estimating the angle-of-arrival of the incoming signal beam. In this paper, we have examined the beam position estimation problem for photon-counting detector arrays, and to this end, we have derived and analyzed the Cramer-Rao lower bounds on the mean-square error of unbiased estimators of beam position. Furthermore, we have also derived the Cramer-Rao lower bounds of other system parameters such as signal peak intensity, and dark current noise power, on the array. In this sense, we have considered robust estimation of beam position in which none of the parameters are assumed to be known beforehand. Additionally, we have derived the Cramer-Rao lower bounds of beam and noise parameters for observations based on both pilot and data symbols of a pulse position modulation (PPM) scheme. Finally, we have considered a two-step estimation problem in which the signal peak and dark current noise intensities are estimated using a method of moments estimator, and the beam center position is estimated with the help of a maximum likelihood estimator.

Performance enhancement of hybrid diversity for M-ary modified pulse-position modulation and spatial modulation of MIMO-FSO systems under the atmospheric turbulence effects with geometric spreading

In this paper, we propose a novel model for hybrid spatial diversity of M-ary pulse position modulation (M-ary PPM) and spatial modulation (SM) with a multiple-input multiple-output (MIMO) links (i.e., optical receiver diversity) in a free-space optical (FSO) communication system under the atmospheric turbulence (AT) effects with geometric spreading (GS). In the proposed design, the spatial index modulator (SIM) and modified pulse position modulation (MPPM) schemes are combined to improve the system efficiency of the spatial diversity for the M-ary PPM modulated MIMO–FSO communication. In this work, we investigate and enhance the performance of the MIMO-FSO link using a digital pulse position modulation (DPPM) and on–off keying non-return-to-zero (OOK–NRZ). We propose a MIMO-based FSO link using spatial diversity and M-ary PPM modulation technique to compensate for the performance degradation due to geometric losses and atmospheric attenuation. Here, we have combined the N-SM with L-MPPM (N-SM/L-MPPM) and (M × N MIMO) to improve the system performance and provide high bandwidth and a higher throughput under the impact of the AT and GS. We analyze the GS impact on the performance of MIMO–FSO systems using SM over the Gamma–Gamma (GG) model. The performance is achieved by using the PPM technique, so the AT influences and fading are mitigated hence the ability to combat AT and the FSO link systems are enhanced sufficiently. Also, we improve the performance of the proposed link using a novel hybrid of SM/PPM and DPPM over GG to maximize the range and enhance the receiver sensitivity. Simulation results obtained for the bit-error-rate (BER) and average transmitted optical power for the DPPM and OOK modulation against various AT conditions are compared with the spatial diversity techniques and proved that both of the FSO systems based MIMO–SM/MPPM offers better performance in the receiver sensitivity and channel capacity. The obtained results show that the conjunction of the receiver diversity and SM/M-ary MPPM is a magnificent solution for mitigating the strong turbulence (ST) and GS effects. The proposed design provides an excellent optical signal-to-noise ratio (SNR) and high-sensitivity for the SIM/PPM-MIMO in the ST regime and GS. The numerical results report that the DPPM sensitivity improves about 10–11 dB at a distance of 2.5 km and the BER of 10−12 more than an equivalent OOK–NRZ modulation. The SIM/PPM-MIMO offers about 4 dB, 2 dB optical SNR improvements over without SIM/PPM-MIMO for the no turbulence and ST with GS for the FSO link, respectively. This work could be beneficial to the practical implementation of the hybrid spatial diversity for the SM/M-ary MPPM based MIMO-FSO links under the AT effects with GS.

Average bit error rate performance of free-space optical systems over double generalized gamma fading channels based on avalanche photodiode detector

The performance of free-space optical (FSO) communication systems based on avalanche photodiodes (APDs) is investigated over the aggregated double generalized gamma (double GG) fading channels. The approximate average bit error rate (ABER) expression is theoretically derived in terms of the double GG distributions under moderate and strong turbulent atmospheric conditions considering thermal noise and shot noise. The union bound and Hermite polynomials are then used to estimate the ABER performance of M-ary pulse-position modulation (PPM)-based systems and orthogonal frequency division multiplexing scheme (OFDM)-based systems. The ABER performance is studied with different receiver noise temperatures, modulation orders, turbulence strengths, and average photon counts assuming plane wave and spherical wave propagations. The results show that adopting an optimal average APD gain affected by the receiver temperature minimizes the ABER value for both wave propagations. In addition, the present APD-based system offers better ABER performance than that of a PIN-based FSO system over the double GG fading channels at two receiver noise temperatures of 200 and 400 K for both the PPM and OFDM schemes. We provide a reference for FSO system design.

SmartVLC: Co-Designing Smart Lighting and Communication for Visible Light Networks

Visible Light Communication (VLC) based on LEDs has been a hot topic investigated for over a decade. However, most of the research efforts assume the intensity of LED light is constant. This hypothesis is not true when Smart Lighting is introduced to VLC, which requires LEDs to adapt their brightness based on the intensity of natural ambient light. Smart lighting saves power consumption and improves user comfort. However, intensity adaptation severely affects the throughput performance of data communication. In this paper, we propose SmartVLC , a system that can maximize the throughput (benefit communication) while still maintaining the LEDs’ illumination function (benefit smart lighting). A novel Adaptive Multiple Pulse Position Modulation (AMPPM) scheme is proposed to support fine-grained dimming levels to avoid flickering while maximizing the throughput under each dimming level. SmartVLC is implemented on off-the-shelf commodity hardware. Several real-life challenges in both hardware and software are addressed to make it a robust real-time system. Comprehensive experiments are carried out to evaluate the system performance under multifaceted scenarios. Experimental results demonstrate that SmartVLC supports a communication distance up to 3.6m, and improves the throughput achieved with two state-of-the-art approaches by 40 and 12 percent on average, respectively, without bringing any flickering to users.

IEEE 802.15.6 WBAN Standard Compliant IR-UWB Time-Hopping PPM Transmitter using SRRC signaling pulse

This paper develops the design of an IEEE 802.15.6 Impulse-Radio (IR) Ultra-Wideband (UWB) transmitter for Wireless Body Area Networks (WBAN) in 180-nm CMOS technology. The transmitter operates at the mandatory data rate of 0.487 Mbps and employs a pulse position controller (PPC) to place the Square Root Raised Cosine (SRRC) pulse for a time-hopping pulse position modulation (TH-PPM) scheme. This transmitter features a novel piece-wise linear approximation (PWLA) approach for generation of SRRC signaling pulse. It is found that the generated PWLA SRRC pulse is fully compliant with the WBAN spectral mask. The proposed PWLA approach has the potential to approximate an arbitrary signaling waveform with a high degree of accuracy and hence should be useful in transceiver realizations.

Error performance of deep space optical communication with M-ary pulse position modulation over coronal turbulence channels.

Free space optical (FSO) communication is a promising technology for future deep space exploration, but it encounters coronal turbulence during superior solar conjunction. In this paper, the bit-error rate (BER) performance of deep space FSO communication systems is evaluated for optical waves propagating in the non-Kolmogorov coronal turbulence. By virtue of its high energy efficiency, the pulse position modulation (PPM) technique is adopted to mitigate the influence of turbulence under lognormal distribution channels. The effects of the parameters of the coronal turbulence and of the FSO system, such as the turbulence outer scale, spectral index, symbol number, data bit rate, equivalent load resistor, and average gain, on the BER are investigated and discussed in this paper. In addition, the performance improvement from M-ary PPM and binary phase-shift keying subcarrier intensity modulation is studied. The results of a numerical evaluation illustrate that a deep space FSO communication system with PPM scheme can well be used to mitigate the impact of coronal turbulence.

Bit-error rate investigation of satellite-to-ground downlink optical communication employing spatial diversity and modulation techniques

In this paper, the error performance of multiple apertures receiver system under different modulation schemes is evaluated for satellite-to-ground downlink optical communications. Gamma–Gamma channel model is used for the consideration of moderate to strong atmospheric turbulence. Error rate expression equations of maximum ratio combining (MRC), equal gain combining (EGC), and selection combining (SC) techniques are derived for M-ary pulse position modulation (M-PPM) and M-ary differential PPM (M-DPPM) modulation schemes. Bit-error rate (BER) performances of M-PPM and M-DPPM modulated MRC, EGC, and SC direct detection receiver systems are compared with a single monolithic aperture receiver system. Performances of downlink direct detection multiple apertures receiver system are also compared among on–off keying (OOK), M-PPM, and M-DPPM modulation schemes. Numerical calculations and Monte Carlo (MC) simulations are used to exam the results of our analysis. It is found that, for M-PPM and M-DPPM, the effect of atmospheric turbulence can be reduced by MRC and EGC receiver system, and SC receiver system can show its advantages compared to a single aperture receiver system in the case of large zenith angles. The downlink BER performances of OOK, 8-PPM, and 8-DPPM multiple apertures receiver system are decreased according to the order of 8-PPM, 8-DPPM, and OOK.

Underwater laser communication with sloped pulse modulation in turbid water

In this article, we propose the demonstration of an underwater wireless laser communication link operating at data rates of up to 100 Mbps over a band-limited turbid water channel using a modified pulse position modulation scheme with a sloped pulse. The communication link uses an avalanche photodiode module as the receiver. The bit error rate of a 5.4 × 10−6 by 450-nm blue laser diode in turbid water with 1.4 Nephelometric Turbidity Unit was below the forward error correction limit. Our demonstrated underwater wireless laser communication system is simple to use and maintains a high data transmission rate.

Covert underwater communication by camouflaging sea piling sounds

To achieve covert underwater acoustic communication, a unique technique of mimicking genuine sea-piling sounds as carrier to convey information is presented. It differs from traditional low signal to noise ratio covert underwater acoustic communication. The communication signal can be detected, but it could not be recognized from the perspective of camouflage to realize covert acoustic communication in the sea. According to the features of sea-piling sounds, a quasi-constant period based pulse position modulation scheme is proposed. First we put each piling sound with identical time interval in time domain and it is moved off the original position with a dedicated time delay which is calculated by modulated information. To make the communication signal akin to the piling sounds, the synchronization header is designed by time hopping pulse position modulation scheme with real piling sounds. At the receiver, basis pursuit algorithm under the theory of compressive sensing is used for channel estimation, and passive phase conjugation technique is used for channel equalization to eliminate the impacts of multipath channel. The feasibility and efficiency of the proposed method are verified by simulation and pool experiment.

Gain-switched seed laser for Deep Space communication applications

Deep Space (DS) communication plays an important role in space exploration programs, especially in interplanetary flights projects. To resolve limitations of a well-known microwave link, an optical communication is considered. In the article a gain-switched seed laser for high power transmitter in a Master Oscillator Power Amplifier (MOPA) architecture is presented. This optical signal source is able to generate picosecond pulses on demand and is suitable for high speed data link over a long range. The laser is dedicated to the pulse position modulation (PPM) scheme for low power consuming, high capacity and energy efficient optical communication. Full Text: PDF ReferencesH. Hemmati, Deep Space Optical Communications (Jet Propulsion Laboratory 2005), John Wiley & Sons, 2006. CrossRef T. Tolker-Nielsen and G. Oppenhauser, “In-Orbit Test Result of an Operational Intersatellite Link between ARTEMIS and SPOT 4,” FreeSpace Laser Communication Technologies XIV, Proceedings of SPIE, vol. 4639, pp. 1–15, San Jose, California, January 2002. CrossRef D. M. Boroson, et al., "Overview and results of the Lunar Laser Communication Demonstration", Proc SPIE 8971, 89710S (2014). CrossRef D. M. Boroson, A. Biswas, B. L. Edwards, "MLCD: overview of NASA's Mars laser communications demonstration system", P. Soc. Photo-Opt. Ins. 5338 (2004). CrossRef H. Hemmati, A. Biswas, I. B. Djordjevic, "Deep-Space Optical Communications: Future Perspectives and Applications", Proc. of the IEEE 99.11, (2011). CrossRef H. Kaushal, G. Kaddoum, "Optical Communication in Space: Challenges and Mitigation Techniques", IEEE Commun Surv Tut. 19.1, 57 (2017). CrossRef B. Moision, J. Hamkins, M. Cheng, "Deep-space optical communications downlink budget: modulation and coding", IPN Prog. Rep. 42.154, 1 (2005). DirectLink

Biorthogonal PPM for Transmitted Reference IR-UWB Communication Systems

Research of impulse radio ultra-wideband (IR- UWB) systems has been extensively increasing in recent years due to their high power efficiency, high data rates and low hardware complexity. The choice of the modulation scheme used in an IR-UWB system has a great impact on its overall performances. In this paper, the biorthogonal pulse position modulation (BPPM) scheme for the application in transmitted reference (TR) IR-UWB communication systems is proposed. Performances of the BPPM scheme over two different IEEE 805.15.3a channel models in a multi-user environment are analyzed and compared to the performances of the pulse position modulation (PPM) scheme. The results show that the BPPM scheme outperforms the PPM scheme in terms of bit error rate (BER), data rate and hardware complexity. Additionally, the influence of different system parameters on the BPPM performances in TR IR-UWB systems is analyzed and possible trade-offs are proposed.