Coherent Binary Phase Shift Keying Research Articles

Performance analysis of a RIS-assisted RoFSO communication system over Malaga distribution for smart city applications.

Radio over free space optics (RoFSO) is one of the potential technologies that can satisfy the requirements of 5G services in a smart city. However, as RoFSO is line-of-sight (LOS) communication, one of its limitations is the occurrence of a skip zone in the targeted areas. In this work, a reconfigurable intelligent surface (RIS) is proposed as the solution to overcome this connection difficulty, which prevents signal blocking by generating LOS connections. These RIS modules extend the communication channel coverage, making it more intelligent and controllable. The performance analysis based on outage probability, ergodic channel capacity, and bit error rate has been performed using heterodyne detection. Malaga distribution has been used to model atmospheric turbulence. The exact closed-form expressions of the probability density function and cumulative distribution function of the end-to-end signal-to-noise ratio are derived. Exploiting these derived statistics, system performance is investigated through the ergodic channel capacity, outage probability, and average bit error rate for M-ary quadrature amplitude modulation and two binary modulation schemes: non-coherent binary frequency-shift keying and coherent binary phase-shift keying. Numerical results are compared among different turbulence conditions, link lengths, and scattering errors. The results show that the proposed RIS-assisted RoFSO technology has the potential to be effective for 5G smart city applications.

Adding RLL Properties to Four CCSDS LDPC Codes without Increasing Their Redundancy

This paper presents the construction of Run Length Limited (RLL) Error Control Codes (ECCs) from four Low Density Parity Check (LDPC) Codes specified by Consultative Committee for Space Data Systems (CCSDS). The obtained RLL-ECCs present a practical alternative to the CCSDS codes with pseudo-randomizers. Their advantage is that the maximal runlengths of equal symbols in their codeword sequences are guaranteed, which is not the case if the common approach with pseudo-randomizers is used. The other advantages are that no additional redundancy is introduced into encoded codewords and that the encoding and decoding procedures of the original error control CCSDS codes do not have to be modified in the following cases. In the first case if hard decoding is used and the transmission channel can be modeled as a Binary Symmetric Channel (BSC) or in the second case if soft decoding and coherent Binary Phase Shift Keying (BPSK) modulation is used and the appropriate transmission channel model is an Additive White Gaussian Noise (AWGN) channel.

Performance of Reconfigurable-Intelligent-Surface-Assisted Satellite Quasi-Stationary Aircraft–Terrestrial Laser Communication System

This paper proposes the use of quasi-stationary aircraft and reconfigurable intelligent surfaces (RIS) to improve the system performance in satellite–terrestrial laser communication downlink. Single-input multiple-output (SIMO) technology is applied to the relay node of a quasi-stationary aircraft. The closed expression of the bit error rate (BER) of an RIS-assisted satellite quasi-stationary aircraft–terrestrial laser communication system (RIS-SHTLC) is derived under the M-distributed atmospheric turbulence model while considering the influence of atmospheric turbulence and pointing errors caused by RIS jitter. The effects of coherent binary frequency shift keying (CBFSK), coherent binary phase-shift keying (CBPSK), non-coherent binary frequency shift keying (NBFSK), and differential binary phase-shift keying (DBPSK) on the performance of an RIS-SHTLC system are simulated and analyzed under weak turbulence. The results show that the RIS-SHTLC system with CBPSK modulation has the best communication performance. Simultaneously, the relationships between the average signal-to-noise ratio (SNR) and BER of the RIS-SHTLC system under different RIS elements are simulated and analyzed, and compared with the traditional SHTLC system. In addition, the influence of the zenith angle, receiving aperture and divergence angle on the performance of the system is studied. Finally, Monte Carlo simulations are used to validate the analytical results.

Run length limited CCSDS convolutional codes for optical communications

Abstract This paper presents the construction of RLL-ECCs (run length limited error control codes) from three selected ECCs specified by Consultative Committee for Space Data Systems (CCSDS) for optical communications. The RLL-ECCs obtained present a practical alternative to CCSDS codes with pseudo-randomizers. Their advantage is that the maximal run lengths of equal symbols in their codeword sequences are guaranteed, which is not the case if the common approach with pseudo-randomizers is used. The other advantages are that no additional redundancy is introduced into encoded codewords and that the encoding and decoding procedures of the original error control CCSDS codes do not have to be modified in the following cases: Firstly, if hard decoding is used and the transmission channel can be modeled as a BSC (binary symmetric channel) and secondly, if soft decoding and coherent BPSK (binary phase shift keying) modulation is used and the appropriate transmission channel model is an AWGN (additive white Gaussian noise) channel.

Systematic Performance Analysis of Hybrid FSO/RF System over Generalized Fading Channels with Pointing Errors

Hybrid free space optical (FSO)/radio frequency (RF) system has attracted extensive attention because of its advantages of both the FSO and RF links. From the viewpoint of overall system performance, this paper presents a systematic analysis method of communication performance and security performance of the hybrid FSO/RF system with the Málaga turbulence channel and the α−μ fading channel. The hybrid FSO/RF system adopts the diversity method of maximum ratio combining (MRC) to receive signals. The new expressions of communication performance parameters (i.e., the bit error rate, the outage probability, the ergodic channel capacity) of the only FSO system and the hybrid system are obtained. Then, the new expressions of the security performance parameters (i.e., the security outage probability and the strictly positive secrecy capacity) of the hybrid system with the FSO or RF links eavesdropping are derived, respectively. Our derived analytical expressions present an efficient tool to investigate the impact of system parameters on the overall performance of the hybrid system, namely modulation scheme, turbulence intensity, pointing errors, target rate, and eavesdropper output signal-to-noise ratio. The simulation results show that compared with the only FSO system, the hybrid system can significantly improve the communication performance of the system; the communication performance of the hybrid system using coherent binary phase shift keying (CBPSK) modulation is obviously better than the other two modulation technologies; with the deterioration of atmospheric environment (increasing turbulence intensity and pointing errors), the communication performance and security performance of the hybrid system will decline; both RF link eavesdropping and FSO link eavesdropping have a greater impact on the security performance of the hybrid systems; whether it is FSO link eavesdropping or RF link eavesdropping, the reduction of target rate and output signal-to-noise ratio of the eavesdropper can improve the security performance of the hybrid system.

Pilot Symbol Error Re - Orthogonalization in 2 × 2 MIMO Systems of Wireless Communication

Abstract A 2×2 MIMO wireless communication system with channel estimation is simulated, in which two transmit, and two receive antennas are employed. The orthogonal pilot signal approach is used for the channel estimation, where the Hadamard sequences are used for piloting. Data are modulated by coherent binary phase-shift keying, whereupon an orthogonal space-time block coding subsystem encodes information symbols by using the Alamouti code. Based on the simulation, it is ascertained a possibility to decrease the bit-error rate by substituting the Hadamard sequences for the sequences having irregular structures, and constituting the eight known orthogonal bases. Considering a de-orthogonalization caused by two any pilot sequence symbol errors, the bit-error rate is decreased by almost 2.9 %. If de-orthogonalizations are caused by two repeated indefinite, and definite pilot sequence symbol errors, the decrements are almost 16 % and 10 %, respectively. Whichever sequences are used for piloting, the 2×2 MIMO system is ascertained to be resistant to the de-orthogonalization if the frame is of 128 to 256 symbols piloted with 32 to 64 symbols, respectively.

A 0.9 pJ/b, Reference Clock Free, Delay-Based, All-Digital Coherent BPSK Demodulator

This letter proposes a novel reference clock free, delaybased coherent binary phase-shift keying (BPSK) demodulator suitable for biomedical devices which receive power and data through the same wireless link. The proposed BPSK demodulator mixes the BPSK input signal and its copy delayed by a half of the carrier period to generate a data Hipping signal whose rising edges indicate when the phases of the BPSK signal Hip. The data are then recovered by sampling the BPSK input signal using the derived data Hipping signal. A phase selector recovers the coherent clock with a 50% duty cycle by selecting either the delayed BPSK input or its complement according to the recovered data. The open-loop operation of the proposed BPSK demodulator enables it to achieve a data rate as high as the carrier frequency. The all-digital implementation makes the demodulator compact, low power, and able to operate at 0.5 V. A test chip running with a 13.56-MHz carrier has been designed and fabricated. Measurement results show that at 0.9 V and a data rate of 13.56 Mb/s, the proposed demodulator only consumes 12.2 μW, corresponding to an FoM of 0.90 pJ/b. This FoM is at least 61 times better than those of the state-of-the-art designs.

Carrier Frequency Offset Estimation for BPSK Signals in Coherent Optical Communications

In this paper, a algorithm which is used for carrier frequency offset (CFO) estimation is proposed in coherent optical communications system with binary phase-shift keying (BPSK) modulation. The proposed algorithm utilizes the frequency divider to broaden the range of the estimation algorithm. In a 5-GBaud coherent BPSK system, simulation results show that when 12dB signal-to-noise ratio (SNR) and 512 samples are utilized, a 8 frequency divider can expand the range of the frequency offset estimation from [-0.5GHz, +0.5GHz] to [-4GHz, +4GHz] and the CFO estimation error can be obtained less than 5MHz. The paper presents a novel algorithm that features the large estimation range for carrier frequency offset while estimation error is not enlarged. The experimental results verified the effectiveness of the proposed algorithm.

On the error rate of coherent binary modulation techniques in mobile communication systems over generalized fading channels impaired by generalized Gaussian noise

In the this paper, the performance of coherent binary digital modulation techniques is investigated. Specifically, we derive exact closed-form expressions for the average bit error rate (BER) of coherent binary phase shift keying (BPSK) and frequency shift keying (BFSK) in the α-μ fading channels impaired by generalized Gaussian noise. The derived expressions take into account the mobility of the wireless receiver. In this paper, we employ the random waypoint (RWP) model to study the effect of mobility on the system performance. Some representative analytical results are presented to investigate the effects of the fading parameters, noise shaping parameter, and network topology on the system performance. In addition, Monte-Carlo simulations are provided to validate the accuracy of the analytical results.

Performance of a bi-directional relaying system with one full duplex relay

Full duplex communication system has the potential to double the spectral efficiency compared to traditional half duplex communication system. However self interference in full duplex relay is considered as the major concern to the performance of system. In this paper, performance of two way relaying communication system is studied with a full duplex relay. Specifically, the probability density function (PDF) of the signal-to-interference-plus-noise ratio (SINR) is derived. By using the derived PDF, closed form expressions for average bit error rate (BER) is derived for various binary modulation schemes such as, coherent binary phase shift keying (BPSK), differential BPSK, coherent binary frequency shift keying (BFSK), and non-coherent BFSK. Moreover, the ergodic capacity of the considered system is also analyzed.

Use of Matched Filter in Direct Sequence Spread Spectrum Techniques

Objectives: The protection of signal against jamming is accomplished using Spread Spectrum (SS) techniques. In this research paper, noise rejecting property of the matched filter and Binary Phase Shift Keying (BPSK) modulation is used in Direct Sequence Spread Spectrum (DSSS) system for secure communication. Methods/Statistical Analysis: Here, DSSS system has been developed and simulated using C-programming language on windows platform. In order to perform the simulation, different parameters are initialized and message bits are generated by random function. With the help of binary message signal and PN sequence, a SS signal is generated which is modulated using BPSK modulation technique at the transmitter side. In the channel, noise/jamming signal is added to the transmitted signal. Then the received signal is demodulated using coherent BPSK receiver (i.e., correlation receiver) and matched filtering is followed by despreading the demodulated signal at the receiver side. Finally, the received binary message bits are detected by threshold detector and various parameters such as input SNR, output SNR, probability of error are calculated. Findings: It has been found that matched filter is a linear filter which has a noise rejection property (means jamming signals can be treated just like other random noise) and hence provides signal security. This particular property of matched filter is used in DSSS communication. As far as matched filter is concerned, it cannot remove the total effect of interference but still the waveforms can be detected in the presence of noise/jamming signal. So, a matched filter receiver is supposed to be an ideal receiver for a signal which is corrupted by AWGN/jamming signal. Here, an average probability of symbol error decreases because it maximizes the output signal to noise ratio. These parameters are supposed to be the most important factors that determine the efficiency of performance of the system. Applications: DSSS systems using matched filter are strong contender for mobile and personnel communications, due to their very large user handling capacity. They also have better transmission quality and capability by incorporating wireless services such as data, short transaction messages, and multimedia etc.

BER performance and data throughput of body sensor networks for reliable biological signal transmission over the human body

According to the IEEE 802.15 task group 6, human body communication (HBC) is a wireless body area network (WBAN) that operates at frequency band 5–50 MHz. In particular, communication between nodes is through body surface to body surface, and the human body acts as the transmission channel. This paper designs the link budget signaling parameters required for reliable transmission of biological signals over the IEEE 802.15.6a HBC channel model, and investigates the bit-error-rate (BER) and data throughput performances of different modulation schemes. These modulation schemes include non-coherent binary frequency shift keying (NcBFSK) with non-coherent detection, in addition to the commonly used schemes for HBC communications, namely coherent binary phase shift keying (CBPSK), coherent binary frequency shift keying (CBFSK), and on-off keying (OOK). According to the numerical results based on theoretical analysis, experimental results, as well as Monte-Carlo simulations, NcBFSK with non-coherent detection and bandwidth-integration window product , CBPSK, CBFSK, and OOK, represent appropriate solutions for the reliable transmission of biological signals over HBC-based WBANs. The results are based on and 1 Mbps data rate for low data rate applications, and and data rate = 10 Mbps for high data rate applications.

A proposed combining technique for partially coherent optical signaling

In this paper, we propose a new least squares (LS) combining technique for coherent optical signals suffer from laser phase noise (partially coherent systems) and receiver shot noise. To assess the advantage of this method, we investigate the error rate performance of both homodyne and heterodyne partially coherent binary phase-shift keying (BPSK) systems. We also derive the gain penalties of the signal-to-noise ratio (SNR) due to the partial recovery of the incoming laser phase to verify the appropriateness of the new combining method in mitigating laser phase noise. For design purposes, we provide tabulated results for the number of required photoelectrons to achieve a certain error rate level for the systems under investigation. The evaluation results show that the proposed technique has the ability to improve the error rate performance, and hence, reduce the SNR gain penalties caused by the laser phase noise. Finally, we show that the error rate performance of ideal systems (no phase error) can be achieved through this method by increasing the number of bit segmentations up to a reasonable level.

Chaos‐based BPSK communication system

A novel broadband chaos-based coherent binary phase shift keying (BPSK) communication system is proposed and it is demonstrated that its theoretical probability of error expression matches that of a conventional narrowband BPSK system. The result is confirmed with the corresponding empirical bit error rate (BER) simulation. Most importantly, it is shown that the proposed system outperforms the chaotic communication systems in terms of BER while also being more practicable. The proposed system thus holds high promise as the chaotic communication systems pose implementation difficulties, lack robust synchronisation techniques and are generally considered of academic interest only.

Block error rate of optical wireless communication systems over atmospheric turbulence channels

Block error rate performance of subcarrier intensity modulation based optical wireless communication systems is analysed over Gamma–Gamma and lognormal atmospheric turbulence channels. The analysis is applicable to non-coherent binary modulations and coherent binary phase shift keying. The special cases of K-distributed strong turbulence channel and negative exponential turbulence channel are also considered. The closed-form expressions of block error rate in the Gamma–Gamma turbulence channels are derived using a series expansion of the modified Bessel function. For the lognormal turbulence channels, the Gauss–Laguerre quadrature method can be used to estimate the block error rate accurately.

Novel Blind Equalizer for Coherent DP-BPSK Transmission Systems: Theory and Experiment

Adaptive blind equalization based on modulus algorithm is very efficient to carry out polarization separation and inter-symbol interference compensation in a coherent dual-polarization quaternary-phase-shift-keying transmission system. Its performance is, however, very poor when coherent dual-polarization binary-phase-shift-keying (BPSK) modulation is considered. In this letter, we propose a new blind equalizer adapted to any PSK constellation and we theoretically show its convergence. Experimental BER measurements and convergence analysis are performed in a 40 Gbps coherent dual-polarization BPSK system under different physical impairments. We show that our equalizer outperforms existing blind algorithms.

Confidence Intervals Verification for Simulated Error Rate Performance of Wireless Communication System

In this paper, we derived an efficient simulation method to evaluate the error rate of wireless communication system. Coherent binary phase-shift keying system is considered with imperfect channel phase recovery. The results presented demonstrate the system performance under very realistic Nakagami-m fading and additive white Gaussian noise channel. On the other hand, the accuracy of the obtained results is verified through running the simulation under a good confidence interval reliability of 95 %. We see that as the number of simulation runs N increases, the simulated error rate becomes closer to the actual one and the confidence interval difference reduces. Hence our results are expected to be of significant practical use for such scenarios.

Signal Processing by Generalized Receiver in DS-CDMA Wireless Communication Systems with Optimal Combining and Partial Cancellation

Symbol error rate (SER) of quadrature subbranch hybrid selection/maximal-ratio combining (HS/MRC) scheme for 1-D modulations in Rayleigh fading under employment of the generalized receiver (GR), which is constructed based on the generalized approach to signal processing (GASP) in noise, is investigated. diversity input branches are split into in-phase and quadrature subbranches. -ary pulse amplitude modulation, including coherent binary phase-shift keying (BPSK), with quadrature subbranch HS/MRC is investigated. GR SER performance for quadrature HS/MRC and HS/MRC schemes is investigated and compared with the conventional HS/MRC receiver. Comparison shows that the GR with quadrature subbranch HS/MRC and HS/MRC schemes outperforms the traditional HS/MRC receiver. Procedure of partial cancellation factor (PCF) selection for the first stage of hard-decision partial parallel interference cancellation (PPIC) using GR employed by direct-sequence code-division multiple access (DS-CDMA) systems under multipath fading channel in the case of periodic code scenario is proposed. Optimal PCF range is derived based on Price's theorem. Simulation confirms that the bit error rate (BER) performance is very close to potentially achieved one and surpasses the BER performance of real PCF for DS-CDMA systems discussed in the literature.

Performance Analysis of System with Micro- and Macrodiversity Reception in Correlated Gamma Shadowed Rician Fading Channels

In this paper, the performance of wireless system employing microdiversity to mitigate the effects of short-term fading and macrodiversity to reduce long-term fading (shadowing) effects is studied. The system model assumes implementation of maximal-ratio combining (MRC) at the microlevel and selection combining (SC) at the macrolevel. The received signal envelope follows a Rician distribution and it also suffers gamma shadowing. Novel expressions for the probability density function (PDF), cumulative distribution function (CDF), and moment-generating function (MGF) of the output signal-to-noise ratio (SNR) are obtained. Several useful performance criteria, such as the moments of the output SNR and outage probability are analytically derived. Moreover, the average bit error probability (ABEP) for noncoherent binary differential phase-shift keying (BDPSK) is calculated using the MGF based approach while the ABEP for coherent binary phase-shift keying (BPSK) is studied by averaging the conditional bit error probability over the PDF. Numerical results are graphically presented to show the effects of various system parameters to the system performance, as well as the enhancement due to use of the combination of micro- and macrodiversity. Some of numerical results are complemented by equivalent computer simulated results which validate the accuracy of the proposed analysis. The agreement between the Rician-gamma and Rician-lognormal fading model is also established.

Multiple tone interference of multicarrier frequency-hopping BPSK system for a Rayleigh fading channel with channel estimation errors

In this paper, we analyze the error probability performance of an uncoded multicarrier frequency-hopping coherent binary phase-shift keying (MC-FH/BPSK) signal transmitted over a Rayleigh fading channel with multitone interference (MTI) and channel estimation errors. The channel estimation errors are modeled as Gaussian random variables. The performance in presence of worst case MTI is evaluated as a function of signal to noise ratio (SNR), signal to jamming ratio, and channel estimation errors. The effect of channel estimation errors on the error probability performance is investigated in presence and absence of MTI. It is shown, from the analytical results that when channel estimation errors are not neglected, the asymptotic error probability performance for high SNR exhibits an error floor even in the absence of MTI. Worst case MTI causes large increase in this error floor. It is also shown that increasing the subband order L enhances the system performance against multitone interference.