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Shadowed Beaulieu-Xie (SBX) is a composite fading model suitable for an environment with a random number of non-line-of-sight and line-of-sight signals encountered in the wireless communication system. There are many effects that undergo in the wireless channel that may degrade the performance of the system. Diversity is one popular technique to mitigate the effects of fading. Investigation of the influence of various parameters of SBX fading channels on the performance of dual-branch selection combining (SC) diversity receiver is carried out. In this paper, mathematical expressions for the probability density function (PDF) of the output signal-to-noise ratio of dual-SC diversity receiver are calculated for SBX fading channels. Outage probability and average bit error rate (ABER) for different kinds of modulation methods are obtained using the PDF-based method. A unified ABER expression for coherent and non-coherent modulations for dual-SC diversity receivers over SBX fading channels is also derived. The effect of shadowing and fading parameters on the performance of dual-SC diversity receivers is studied. [ABSTRACT FROM AUTHOR]

In this paper, the performance of a dual-hop mixed radio frequency (RF)/underwater wireless optical communication (UWOC) system with amplifying and forwarding (AF) relaying is investigated. The diversity combining technology were combined with unifying Fisher-Snedecor ( $ \mathcal{F} $ F ), extended generalized- $ {\mathcal{K}} $ K (EGK), and $ \alpha - \mu $ α − μ distribution for atmospheric turbulence in foggy conditions to analyze the probability density function (PDF) of RF links. The UWOC link experiences mixed exponential generalized gamma (EGG) fading. By utilizing diversity combination methods and considering the statistical effects of atmospheric turbulence, random fog, and underwater turbulence, we derive the expression for the PDF of the RF/UWOC system. In addition, the tight asymptotic expression for the outage probability and average bit error rate under high signal-to-noise ratio (SNR) is provided. The analytical expressions are verified by Monte Carlo method, and the effects of channel number on RF/UWOC system performance under various atmospheric, underwater and weather conditions are demonstrated. [ABSTRACT FROM AUTHOR]

This study examines how well a heterogeneous dual-hop terrestrial radio frequency and underwater acoustic downlink system maintain confidentiality. It includes an RF source, an intermediate decode-and-forward relay, an underwater multi-hydrophone destination, and a nearby eavesdropper. Eavesdropper overhears underwater acoustic signal transmitted by the relay. RF and underwater acoustic links undergo Nakagami-m and Rayleigh fading, respectively. Due to the propagation delay of underwater scenario, both destination and eavesdropper links are associated with outdated channel state information which also employs maximal-ratio combining. The closed form expressions of secrecy outage probability, strictly positive secrecy capacity, and intercept probability are derived. Monte-Carlo simulations are obtained to certify the analytical expressions. [ABSTRACT FROM AUTHOR]

This paper investigates the symbol error rate (SER) and coverage probability of single reconfigurable intelligent surface (S-RIS) and double reconfigurable intelligent surface (D-RIS) systems operating over Weibull fading channels. In the S-RIS system, the RIS is positioned between the base station and user link, while in the D-RIS system, RIS-1 and RIS-2 are placed near the base station and user respectively. By leveraging the central limit theorem, we derive the statistical parameters of the received signal-to-noise ratio (SNR) and subsequently closed-form expressions for SER and coverage probability of both systems using the moment-generating function. Also, we determine the optimal location of the RISs in D-RIS system from the simulations of SER. Comparative analysis reveals that the D-RIS system exhibits superior error performance and provides better coverage than the S-RIS system, despite having an equal number of reflecting elements. In addition, we provide an energy consumption gain analysis of the D-RIS system. [ABSTRACT FROM AUTHOR]

Turbo-Coded multiple-input multiple-output orthogonal frequency division multiplexing Channel Estimation, using Chaotic Grey Wolf Optimizer and the Genetic Algorithm (TC-MIMO-OFDM-Hybrid-CGWO-GA), is proposed in this manuscript. To enhance the performance of the bit error rate (BER), the proposed turbo code lessens the maximal correlation of the channel in the frequency domain. Initially, the channel is estimated using LS-MMSE individually using Chaotic Grey Wolf Optimizer (CGWO) and the LS-MMSE is combined with a genetic algorithm to scale the best channel for reducing the error. The encoding and decoding methods are done with the help of Turbo-codes for LS channel estimation. Then, the performance of the proposed method is analyzed with different performance metrics, such as the bit error rate, mean square error, channel estimation, computational cost, overhead, and symbol error rate. From the analysis, the proposed method attains lower computational costs of 99.67%, 98.38%, 92.34% and 97.45%, lower bit error rates of 98.33%, 89.34%, 83.12% and 88.96% and lower mean square errors of 93.15%, 91.25%, 79.90% and 92.88% analyzed to the existing methods, such as TSO-CE-TC-MIMO-OFDM, MFPA-CE-MIMO-OFDM, OSBS-CEA-MIMO-OFDM, and IAMO-CE-MIMO-OFDM. [ABSTRACT FROM AUTHOR]

Providing reliable service to cell edge users has been a practical challenge for network operators due to the deep fading effects and limited base station (BS) resources. The low received signal strength causes the Quality of Service (QoS) degradation of the cell edge users and hence demands appropriate solutions to improve the user connectivity. To address this issue, this article proposes a two-tier partial cooperative relaying scheme, deployed in a non-orthogonal multiple access (NOMA)-based downlink network that serves the edge users with the minimum required QoS. Comparative performance analysis has been presented for two relaying schemes: amplify-and-forward (AF) and partial decode-and-forward (DF) in terms of outage probability and overall sum rate of the edge users. Additionally, the maximal ratio combining (MRC) diversity technique is integrated with the relaying network to further enhance the QoS of cell edge users. The impact of successive interference cancellation (SIC) on the outage performance has been thoroughly investigated. It has been established through extensive simulation that the partial DF technique is a promising relaying technique to improve the overall performance of cell edge users. [ABSTRACT FROM AUTHOR]

In this study, the performance analysis of dual-hop power line communication (PLC)/ η − μ and PLC/ λ − μ L-branch systems by using the decode-and-forward (DF) protocol is presented in detail. The introduced work provides novel closed-form expressions of the probability density function (PDF) of the instantaneous signal-to-noise ratio (SNR) of the considered systems. Taking the proposed PDFs into account, we also derive closed-form expressions of the error rate and channel capacity (CC) performance for the dual-hop PLC/ η − μ and PLC/ λ − μ L-branch DF systems. Furthermore, an exhaustive comparative study of different modulation types such as non-coherent M-ary frequency-shift keying, square quadrature amplitude modulation (SQAM), and cross quadrature amplitude modulation (×QAM) is presented by using the proposed closed-form error rate expressions. Also, the exact expressions for the CC with channel inversion with a fixed-rate (CIFR) transmission policy are proposed. Finally, all the theoretical findings are confirmed through numerical results obtained by using the exact expressions. [ABSTRACT FROM AUTHOR]

Electromagnetic nano communication (EMNC) is an evolving field of modern communication technology. Terahertz imaging, sensing, food safety and security, quality control and simultaneous localisation and mapping, which all together make it a suitable use case for 6 G, are the most lively applications of EMNC. This manuscript proposes unified expressions of error rate under different modulation schemes for EMNC. For this, mixture gamma (MG) fading distribution, including almost all the fading channels, under dual selection combining (SC) diversity is developed and employed. Also, generalised Gaussian distribution (GGD), which is appropriate for the EMNC system under an aqueous medium, is employed in the analysis. Specifically, analytical expressions for BER of BPSK, M-PAM and M-QAM schemes over MG fading under dual SC diversity are derived in the presence of GGD noise. Proposed analytical expressions are numerically compared with those available in the literature without SC diversity. Comparison shows that irrespective of the value of fading severity ' m ' and/or noise shaping parameter ' p ', dual SC offers a significant improvement in BER. It is most important to mention that proposed expressions are unified in nature because a variety of results can be reproduced for different values of ' N ' and ' p '. [ABSTRACT FROM AUTHOR]

Average Bit Error Rate (BER), outage probability and average channel capacity expressions of a Modulating Retro-Reflector (MRR) optical communication system based on an Airy beam under weak turbulence are derived. The effects of propagation distance, width parameter and exponential truncation factor of the Airy beam itself on the communication performance of the system are discussed. Meanwhile, the performance of the system based on the Gaussian beam is compared with the same turbulence condition and propagation distance. The simulation results show that under the same conditions, the system based on the Airy beam shows a lower outage probability, average BER and larger average channel capacity compared to the system based on the Gaussian beam. Moreover, the advantages of the Airy beam are more significant as the average signal-to-noise ratio (SNR) increases. [ABSTRACT FROM AUTHOR]

Non-orthogonal multiple access (NOMA) and full-duplex (FD) have recently emerged as a potential candidate for the fifth-generation and beyond (B5G) cellular networks with the target of increasing spectral efficiency and guaranteeing the quality-of-services (QoS). This paper proposes an orthogonal frequency division multiple access (OFDMA) based FD cooperative device-to-device (C-D2D) communications system, wherein a D2D transmitter (DT) acts as an FD relay to support simultaneous bidirectional communication between a base station (BS) and a cellular user (CU). In addition, a power splitting protocol using NOMA is incorporated for the FD C-D2D system to share the resources between the cellular and D2D user. Further, the successive interference cancellation (SIC) is used to decode the signals, while self-interference suppression (SIS) is employed at DT to mitigate self-interference (SI). The analytical expressions for achievable rates of the cellular and D2D links and their outage probabilities for the FD and half-duplex (HD) systems are derived. Outage trade-offs between FD/HD relaying have been analyzed. Results show that the proposed model enhances the overall outage performance of the cellular and D2D users. Moreover, for high cellular outage constraints, DT as an FD relay outperforms the conventional HD C-D2D communications system wherein DT acts as an HD relay. [ABSTRACT FROM AUTHOR]

Most Wireless Sensor Networks (WSN) and Internet of Things (IoT) often involve remotely located nodes which are power constrained and can operate with low power and low rate. Such a node can harvest energy from dedicated Radio Frequency (RF) signals to gather the energy required for information transmission. In this paper, we consider the performance analysis of a wireless-powered communication network (WPCN), where a source node harvests energy from two RF sources, which are also the destination or user nodes. Information transmission is accomplished using the power domain Non-Orthogonal Multiple Access (NOMA) technique. The outage analysis of WPCN is carried out under energy harvesting (EH) constraints. We have also developed a closed-form expression for the outage probability and validated the analytical results with simulation results. The effect of various network parameters, such as NOMA power allocation coefficients, EH efficiency and fractional time constant on the outage probability of the network has also been studied. [ABSTRACT FROM AUTHOR]

In this study, analytical expressions are developed for average symbol error rate (ASER) of rectangular quadrature amplitude modulation (RQAM) scheme over α − μ fading channels. Initially, the ASER expression for RQAM under α − μ fading channels is acquired by applying Chernoff approximation of Gaussian Q -function. Further, another ASER expression of RQAM scheme covering α − μ fading conditions is derived by adopting Chiani approximation of Gaussian Q -function. [ABSTRACT FROM AUTHOR]

In a non-orthogonal multiple access (NOMA) system, most crucial function at the transmitter is power allocation followed by superposition coding and at the receiver end successive interference cancellation (SIC). The overall system throughput and performance of the system depends on user clustering, power allocation scheme and SIC at receiver, which is expected to have minimal error. In this paper, we compare the performance of different power allocation algorithms through symbol error rate versus signal to noise ratio plot randomising Rayleigh channel conditions. Simulations are done for the power-domain NOMA system. We propose Eigenvalue-based power allocation in NOMA, which performs better than the traditional counterparts. The simulation is carried out for two-user system using MATLAB. [ABSTRACT FROM AUTHOR]

Interference is considered as the major problem in the next-generation wireless systems to attain higher throughput. The conventional interference cancelation techniques attain a theoretical breach in endorsing the wireless systems. However, the interference in the signals causes an error or imprecise estimation of the channel for future fifth-generation (5 G) transmissions. Thus, this paper proposes a technique, named Fractional Sequential Likelihood Ascent Search (Fractional-SLAS) for mitigating the interference in massive Multiple Input Multiple Output (MIMO) systems in 5 G technology. The proposed Fractional-SLAS is the integration of Fractional calculus (FC) and Sequential Likelihood Ascent Search Detector (SLAS). Initially, the signals are transmitted through the transmitter and undergo the encoding and modulation process. Then, the obtained modulated signals are fetched using the transmitting antenna that transmits the signals to the receiver. At the receiver side, interference is generated due to the number of cross antennas. Thus, the interference in the signals is eradicated by applying the proposed Fractional-SLAS at the receiver end. Hence, the proposed interference mitigation method is completely eradicated from the signals without any delay or loss in the quality of the transmitted signal. The proposed Fractional-SLAS provides superior performance with minimal Bit Error Rate (BER), Symbol Error Rate (SER), and throughput with values 0.00006 dB, 0.00006 dB, and 0.96 bps. [ABSTRACT FROM AUTHOR]

Wireless underground sensor network (WUSN) is widely used in agriculture, frontier defense, and other fields with great research value. This paper takes the propagation characteristics of the electromagnetic waves that propagate in WUSN as research target, and systematically tests the effect of influence factors on the communication quality of electromagnetic waves. The influence factors are chosen on the basis of the propagation theory of electromagnetic waves. Specifically, the influence factors include the burial depth of sensor sub-node, the horizontal distance between nodes, the communication frequency, and the thickness of snow. Moreover, the experiments are carried out in normal and snow-covered soil. The propagation characteristic of electromagnetic waves is measured by received signal strength (RSS) and symbol error rate (SER). Finally, the selection of communication frequency in different application scenarios is concluded. The conclusions have a great significance for guiding the arrangement of WUSN nodes in different scenarios. [ABSTRACT FROM AUTHOR]

Extensive literature exists for simple and exact expressions of symbol error rate (SER) over fading channels under different modulation schemes whose boundaries meet at right angles. In cases where boundaries do not meet at right angles, integrals of special function in the expressions make the exact calculation most complex. In such cases only approximate solutions are possible. Also, it is noteworthy to mention that when detection is performed with proper use of the phase (phase-jitter-based approach), noise performance of the receiver improves significantly. This paper applies phase-jitter PDF-based approach to present exact and closed-form SER expression of MPSK scheme over Mixture Gamma (MG) distribution for an arbitrary array of signal points. The proposed expression is generic as MG distribution can be approximated in almost all fading/shadowed fading channel models. As a proof to the authenticity, SERs of MPSK scheme over Rayleigh and Nakagami-m fading channels are deduced from the proposed SER over generalised MG distribution. Further, a significant improvement in SER has been achieved with phase-jitter-based approach as compared to conventional (non-phase-jitter-based) approach. Finally, to confirm the correctness of the proposed expression, results are validated through comparison with the existing results and Monte Carlo simulation. [ABSTRACT FROM AUTHOR]

In this paper, the performance analysis of wireless communication system over shadowed-Rice (SR) composite fading channel has been investigated and analysed. The unified analytical expressions of the average symbol error probability (ASEP) for several coherent and non-coherent modulation schemes separately with different constellation sizes are derived for composite fading channel under two different fade mitigation methods, with maximal ratio combining (MRC) microdiversity (Method 1) and MRC applied over the composite fading channel (Method 2). Furthermore, an asymptotic analysis is carried out and a closed-form expression of the ASEP with Method 2 is presented. Analytical expressions of the corresponding average probability of energy detection (PD) are formulated for both the methods. Finally, the derived PD expression is utilised to analyse the performance of cooperative system assuming erroneous feedback channel. Analysis of optimisation of detection threshold as well as number of cognitive users to minimise the total error rate is also carried out. The closed-form expressions are validated by comparing them with exact numerical results and Monte Carlo simulation. [ABSTRACT FROM AUTHOR]

We apply amplitude corrections to a truncated Bessel beam that has propagated through turbulent atmosphere modelled by random phase screens. These corrections are realized via transmitting an unmodulated beam in parallel to the one carrying the 4 amplitude shift keying (ASK) modulated message signal. On the receiver side, the amplitude corrections are obtained by dividing the intensity of the unmodulated beam by its free space equivalence. The corrections are then used to restore the amplitude distortions of the beam carrying the 4ASK modulated message signal and in the determination of decision boundaries for the received 4ASK symbols. The success of the system is visually inspected by comparing the received intensity profiles before and after the application of corrections. Furthermore, simulation analysis of symbol error rate (SER) is made, where the proposed set-up is found to be quite insensitive to wavelength difference between the unmodulated and modulated beams. On the other hand, the difference in the structure constant values of these two beams seems to have profound effect on system performance. [ABSTRACT FROM AUTHOR]

Some new relations for the Owen function are obtained including differentiation and integration formulas, integral representations and series. Applications of the Owen function in probability theory and in communication theory are shown. [ABSTRACT FROM AUTHOR]

In this article, a signal-to-noise ratio (SNR)-based hybrid decode-amplify-forward scheme in a distributed Alamouti-coded cooperative network is proposed. Considering a flat Rayleigh fading channel environment, the MATLAB simulation and analysis are carried out. In the cooperative scheme, two relays are employed, where each relay is transmitting each row Alamouti code. The selection of SNR threshold depends on the target rate information. The closed form expressions of symbol error rate (SER), the outage probability and average channel capacity with tight upper bounds are derived and compared with the simulation done in MATLAB environment. Furthermore, the impact of relay location on the SER performance is analysed. It is observed that the proposed hybrid relaying technique outperforms the individual amplify and forward and decode and forward ones in the distributed Alamouti-coded cooperative network. [ABSTRACT FROM AUTHOR]