scholarly journals Performance Analysis of RIS-Assisted FSO Communications over Fisher–Snedecor F Turbulence Channels

2021 ◽  
Vol 11 (21) ◽  
pp. 10149
Author(s):  
Caslav Stefanovic ◽  
Máximo Morales-Céspedes ◽  
Ana García Armada
Keyword(s):  
Fading Channels ◽  
Direct Detection ◽  
Signal To Noise Ratio ◽  
Moment Generating Function ◽  
Cumulative Distribution ◽  
Model Parameters ◽  
Free Space Optical ◽  
F Distribution ◽  
The Moment ◽  
Analytical Expressions

The Fisher–Snedecor (F-S) F distribution has recently been introduced as a tractable turbulence-induced (TI) fading model that fits well with the experimental data. This paper provides a performance evaluation of a free-space optical (FSO) re-configurable intelligent surface (RIS)-assisted communications (ACs) link over the F-S F TI fading channels, assuming the intensity modulation–direct detection (IM–DD) technique. In particular, novel and closed-form (C-F) analytical expressions for the probability density function (PDF) and cumulative distribution function (CDF) of the end-to-end signal-to-noise ratio (SNR) in terms of Gaussian hyper-geometric functions are efficiently derived. Capitalizing on the obtained results, novel C-F analytical expressions for the moment generating function (MMGF), outage probability (OP), average bit error rate (BER) and ergodic channel capacity (Cγ) of the FSO RIS-ACs system over the F-S F TI fading channels are provided and numerically evaluated under the various TI fading severity conditions. Furthermore, the second-order (S-O) statistical expressions for the level crossing rate (LCR) and average fade duration (AFD) are obtained and thoroughly examined for various FSO RIS-ACs system model parameters.

Dual-Hop Fixed Gain Relaying Transmissions with Semi-Blind in Asymmetric Multipath/Shadowing Fading Channels

2015 ◽  
Vol 9 (1) ◽  
pp. 82-90
Author(s):  
Weijun Cheng ◽  
Teng Chen
Keyword(s):  
Fading Channels ◽  
Cumulative Distribution Function ◽  
Signal To Noise Ratio ◽  
Ergodic Capacity ◽  
Moment Generating Function ◽  
Symbol Error Rate ◽  
Cumulative Distribution ◽  
Simulation Results ◽  
End To End ◽  
The Moment

In this paper, we investigate the end-to-end performance of a dual-hop fixed gain relaying system with semiblind relay under asymmetric fading environments. In such environments, the wireless links of the considered system undergo asymmetric multipath/shadowing fading conditions, where one link is subject to only the Nakagami-m fading, the other link is subject to the composite Nakagami-lognormal fading which is approximated by using mixture gamma fading model. First, the cumulative distribution function (CDF), the moment generating function (MGF) and the moments of the end-to-end signal-to-noise ratio (SNR) are derived under two asymmetric scenarios. Then, novel closed-form expressions of the outage probability, the average end-to-end SNR, the symbol error rate and the ergodic capacity for the dual-hop system are obtained based on the CDF and the MGF, respectively. Finally, some numerical and simulation results are shown and discussed to validate the accuracy of the analytical results under different scenarios, such as varying average SNR, fading parameters per hop, the choice of the semi-blind gain and the location of relaying nodes.

scholarly journals Exact Performance Analysis of Amplify-and-Forward Bidirectional Relaying over Nakagami-m Fading Channels with Arbitrary Parameters

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1277
Author(s):  
Dong Qin ◽  
Yuhao Wang ◽  
Tianqing Zhou
Keyword(s):  
Fading Channels ◽  
Signal To Noise Ratio ◽  
Ergodic Capacity ◽  
Moment Generating Function ◽  
Amplify And Forward ◽  
Relay Systems ◽  
Signal Error ◽  
Bidirectional Relaying ◽  
Fading Parameter ◽  
The Moment

The exact performance of amplify-and-forward (AF) bidirectional relay systems is studied in generalized and versatile Nakagami-m fading channels, where the parameter m is an arbitrary positive number. We consider three relaying modes: two, three, and four time slot bidirectional relaying. Closed form expressions of the moment generating function (MGF), higher order moments of signal-to-noise ratio (SNR), ergodic capacity, and average signal error probability (SEP) are derived, which are different from previous works. The obtained expressions are very concise, easy to calculate, and evaluated instantaneously without a complex summation operation, in contrast to the nested multifold numerical integrals and truncated infinite series expansions used in previous work, which lead to computational inefficiency, especially when the fading parameter m increases. Simulation results corroborate the correctness and tightness of the theoretical analysis.

scholarly journals Symbol Error Probability of DF Relay Selection over Arbitrary Nakagami-mFading Channels

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
George C. Alexandropoulos ◽  
Paschalis C. Sofotasios ◽  
Khuong Ho-Van ◽  
Steven Freear
Keyword(s):  
Fading Channels ◽  
Relay Selection ◽  
Error Probability ◽  
Signal To Noise Ratio ◽  
Moment Generating Function ◽  
Symbol Error Probability ◽  
Decode And Forward ◽  
Shift Keying ◽  
Relaying Systems ◽  
The Moment

We present a new analytical expression for the moment generating function (MGF) of the end-to-end signal-to-noise ratio of dual-hop decode-and-forward (DF) relaying systems with relay selection when operating over Nakagami-mfading channels. The derived MGF expression, which is valid for arbitrary values of the fading parameters of both hops, is subsequently utilized to evaluate the average symbol error probability (ASEP) ofM-ary phase shift keying modulation for the considered DF relaying scheme under various asymmetric fading conditions. It is shown that the MGF-based ASEP performance evaluation results are in excellent agreement with equivalent ones obtained by means of computer simulations, thus validating the correctness of the presented MGF expression.

On the Performance of the Layered-Division-Multiplexing using Maximal-Ratio Combining

2012 ◽  
Vol 16 (2) ◽  
pp. 52-62
Author(s):  
Tanapong Khumyat
Keyword(s):  
Fading Channels ◽  
Signal To Noise Ratio ◽  
Moment Generating Function ◽  
Symbol Error Rate ◽  
Maximal Ratio Combining ◽  
Gain Enhancement ◽  
Significant Performance ◽  
Average Symbol Error Rate ◽  
The Moment ◽  
Systems Simulation

This article proposes the diversity gain enhancement in layered division multiplexing (LDM) systems by applying maximal-ratio combining (MRC) technique. LDM systems is adopted as a baseline technology of the ATSC 3.0 systems which the two transmission layers are simultaneously transmitted over two different types of fading channels for fixed and mobile services. Hence, the performance analysis of each layer need to be evaluated on different type of fading channel. Starting with the moment generating function (MGF) of the MRC output signal-to-noise ratio (SNR), we propose the new method to derive closed-form expressions for average symbol-error rate (SER) of the proposed systems over Rayleigh and Nakagami-m fading channels in the presence of error propagation (EP) that is generated from the first layer detection. Analytical results show that the specific value of injection level at the transmitter need to be precisely defined to obtain the best mutual benefit for both LDM layers, and the proposed technique has significant performance advantage over conventional LDM systems. Simulation results demonstrate the tightness of the author’s analysis.

scholarly journals Performance Analysis of Output Threshold-Based Incremental Multiple-Relay Combining Scheme with Adaptive Modulation for Cooperative Networks

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Kyu-Sung Hwang ◽  
MinChul Ju
Keyword(s):  
Fading Channels ◽  
Error Rate ◽  
Spectral Efficiency ◽  
Signal To Noise Ratio ◽  
Adaptive Modulation ◽  
Moment Generating Function ◽  
Cooperative Networks ◽  
Cumulative Distribution ◽  
Amplify And Forward ◽  
Multiple Relay

In this paper, we propose an output threshold-based incremental multiple-relay combining scheme for cooperative amplify-and-forward relay networks with nonidentically distributed relay channels. Specifically, in order to achieve the required performance, we consider both conventional incremental relaying and multiple-relay selection where relays are adaptively selected based on a predetermined output threshold. Moreover, the adaptive modulation technique is adopted by our proposed scheme for satisfying both the spectral efficiency and the required error rate. For the proposed scheme, we first derive an upper bound of the output combined signal-to-noise ratio and then provide its statistics such as cumulative distribution function (CDF), probability density function (PDF), and moment generating function (MGF) over independent, nonidentically distributed Rayleigh fading channels. Additionally, we analyze the system performance in terms of average spectral efficiency, average bit error rate, outage probability, and system complexity. Finally, numerical examples show that our proposed scheme leads to a certain performance improvement in the cooperative networks.

Dual-Hop Amplify-and-Forward Variable Gain Relaying over Mixture Gamma Fading Channels

2015 ◽  
Vol 719-720 ◽  
pp. 767-772
Author(s):  
Wei Jun Cheng
Keyword(s):  
Fading Channels ◽  
Signal To Noise Ratio ◽  
Symbol Error Rate ◽  
Amplify And Forward ◽  
Variable Gain ◽  
Average Symbol Error Rate ◽  
Simulation Results ◽  
End To End ◽  
The Moment ◽  
Relaying System

In this paper, we present the end-to-end performance of a dual-hop amplify-and-forward variablegain relaying system over Mixture Gamma distribution. Novel closed-form expressions for the probability density function and the moment-generation function of the end-to-end Signal-to-noise ratio (SNR) are derived. Moreover, the average symbol error rate, the average SNR and the average capacity are found based on the above new expressions, respectively. These expressions are more simple and accuracy than the previous ones obtained by using generalized-K (KG) distribution. Finally, numerical and simulation results are shown to verify the accuracy of the analytical results.

scholarly journals Cascaded Rf-Fso-Vlc System using Df Relays

2019 ◽  
Vol 8 (10) ◽  
pp. 4357-4362
Keyword(s):  
Direct Detection ◽  
Detection System ◽  
Signal To Noise Ratio ◽  
Visible Light Communication ◽  
Heterodyne Detection ◽  
Core Network ◽  
Free Space Optical ◽  
Error Performance ◽  
Optical Link ◽  
Detection Techniques

This paper presents performance analysis of cascaded radio frequency-free space optical communication-visible light communication (RF-FSO-VLC) system. The proposed model comprises of the RF link as the core network, a terrestrial optical link for providing last mile connectivity with the indoor cell users communicating through VLC environment. The RF link undergoes Nakagami-m distributed fading, while the terrestrial optical link is modeled by Double Generalized Gamma (DGG) distributed turbulence and Rayleigh-distributed misalignment losses. VLC links are characterized by the randomness in users’ position. Using statistical properties of system signal-to-noise ratio (SNR), outage and error performance of the proposed system is evaluated depending on whether the relays and the destination decode either perfectly or erroneously. The numerical results show that the system performance varies depending on field-of view (FOV) of the detector and user’s position. This is because as FOV increases along with the height of the LED, the outage probability of the system increases. Error probability depends on the type of detection techniques, where a heterodyne detection system performs better than a direct detection system. Moreover, through results it is inferred that severe fading and misalignment losses result in poor error performance of the considered system errors on the performance of the considered cooperative system.

scholarly journals Ergodic Capacity Analysis of Full Duplex Relaying in the Presence of Co-Channel Interference in V2V Communications

Sensors ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 261 ◽  
Author(s):  
Khaled Eshteiwi ◽  
Georges Kaddoum ◽  
M. S. Alam
Keyword(s):  
Fading Channels ◽  
Ergodic Capacity ◽  
Moment Generating Function ◽  
Cooperative Relaying ◽  
Full Duplex ◽  
High Signal ◽  
Amplify And Forward ◽  
Channel Interference ◽  
V2v Communications ◽  
The Moment

We analyze the ergodic capacity of a dual-hop full duplex amplify-and-forward (AF) vehicle-to-vehicle (V2V) cooperative relaying system over Nakagami-m fading channels. In this context, the impacts of self-interference (SI) at the relay and co-channel interference (CCI) at the destination are taken into account in this analysis. Precisely, based on the analysis of the moment generating function (MGF) of the signal-to-interference-plus-noise ratio (SINR), new exact and lower bound expressions for the ergodic capacity are derived. The ergodic capacity upper bound is also derived based on the asymptotic outage probability of the approximated SINR. Monte-Carlo simulation results are presented to corroborate the derived analytical results. Our results show the significant impact of the considered interferences on the system performance. It is shown that the ergodic capacity is degraded when the average SI at the relay and/or the average CCI at the destination is increased. This highlights the importance of taking these phenomena into account in the performance evaluation in order to assess the practical limit of full duplex relaying (FDR) cooperative wireless communications. Interestingly, it is also observed that FDR with SI and CCI still shows a higher ergodic capacity than the interference-free half duplex relaying, especially at medium to high signal-to-noise ratios (SNRs).

scholarly journals Performance Analysis of AF Relays with Maximal Ratio Combining in Nakagami-m Fading Environments

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Dong Qin ◽  
Yuhao Wang ◽  
Tianqing Zhou
Keyword(s):  
Performance Metrics ◽  
Signal To Noise Ratio ◽  
Ergodic Capacity ◽  
Moment Generating Function ◽  
Maximal Ratio Combining ◽  
Modulation Scheme ◽  
Amplify And Forward ◽  
Generalized Gaussian Noise ◽  
The Moment ◽  
Fading Environments

This paper investigates the maximal ratio combining (MRC) performance of an amplify and forward (AF) relay system in Nakagami-m fading environments. The study considers a general scenario with distinct m fading parameters for the following three links, source to relay link, and source to destination link and relay to destination link. We derive new closed form expressions for the statistics of important performance metrics, including the moment generating function, outage probability, higher order moments of equivalent signal to noise ratio (SNR), ergodic capacity, and average symbol error probability (SEP) of common modulation types. In particular, we focus on analytical SEP expressions in the context of an additive white generalized Gaussian noise (AWGGN). As an active area of research, generalized noise receives much attention for its flexible model. However, analytical performance of modulation scheme in generalized noise type has not been found in open literature for AF relaying with MRC despite its practical usefulness. Without the help of analytical solutions, the SEP in generalized noise can only be obtained by a large number of repeated simulation experiments. Therefore, we present the general SEP expression by using special Fox’s H function. Simulation results verify the accuracy of our theoretical analysis and show that the diversity order of MRC criterion linearly depends upon Nakagami parameters of three links.

scholarly journals A Comparative Study of Relaying Schemes with Decode and Forward over Nakagami- Fading Channels

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
George C. Alexandropoulos ◽  
Agisilaos Papadogiannis ◽  
Paschalis C. Sofotasios
Keyword(s):  
Closed Form ◽  
Fading Channels ◽  
Signal To Noise Ratio ◽  
Wireless Systems ◽  
Nakagami Fading ◽  
Decode And Forward ◽  
Channel State ◽  
Modulation Methods ◽  
Nakagami Fading Channels ◽  
Analytical Expressions

Although relaying can be very beneficial for wireless systems, understanding which relaying schemes can achieve specific performance objectives under realistic fading is crucial. In this paper we present a general framework for modeling and evaluating the performance of dual-hop decode-and-forward (DF) relaying schemes over independent and not necessarily identically distributed (INID) Nakagami- fading channels. We obtain closed-form expressions for the statistics of the instantaneous output signal-to-noise ratio of repetitive transmission with selection diversity. Furthermore, we present a unified statistical overview of other three significant relaying schemes with DF, one based on repetitive transmission with maximal-ratio diversity and the other two based on relay selection (RS). To compare the considered schemes, we present closed-form and analytical expressions for the outage probability and the average symbol error probability under various modulation methods, respectively. Importantly, it is shown that when the channel state information for RS is perfect, RS-based schemes always outperform repetitive ones. Furthermore, when the direct link between the source and the destination nodes is sufficiently strong, relaying may not result in any gains, and it should be switched off.

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