Effective Throughput Analysis of α - η - κ - μ Fading Channels

Secrecy enhancement of RF backhaul system with parallel FSO communication link

Abstract: This paper analyzes the physical layer secrecy (PLS) performance of a hybrid free space optical and radio frequency (FSO/RF) communication system under a modified selection combining scheme. The transmission scheme takes into account secrecy performance as well as diversity gain and ease of implementation. The effects of FSO link, namely the FSO atmospheric turbulence and the FSO receiver pointing error, are included in the analysis while the power amplifier (PA) inefficiency for the RF transmission is considered to have more realistic understandings on the system performance. The exact analytical expressions for the performance indicators including the average secrecy capacity (ASC) and secrecy outage probability (SOP) of the investigated mixed FSO/RF system are derived. The asymptotic SOP analysis reveals useful insights into the performance of the investigated mixed system. Analytical and simulation results are presented to evaluate the PLS performance of the proposed mixed system as well as to compare the performance of other hybrid systems with different setups.

Effective Rate Evaluation of RIS-Assisted Communications Using the Sums of Cascaded α-μ Random Variates

Abstract: This paper begins with the characterization of the sum of $M$ versions of cascaded $\alpha $ - $\mu $ (equivalently, $N*(\alpha $ - $\mu$ )) distributed random variates (RVs), and later on, explores the feasibility and applicability of the obtained results in the recent proposed reconfigurable intelligent surface (RIS)-assisted communications. More specifically, the sum of cascaded $\alpha $ - $\mu $ distributed RVs is exactly characterized by the probability density function (PDF) expressed in terms of the programmable multivariate Fox’s $H$ -function, and approximated with the mixture of Gaussian (MoG) distribution. The approximation accuracy is further validated by the Kolmogorov-Smirnov (KS) goodness of fit test. Based on the obtained statistical results, a promising application, i.e., RIS-assisted communication, is considered and evaluated from the effective rate perspective. The exact, asymptotic, and approximated effective rate are derived with closed-form expressions. Finally, our analytical results are further validated using the Monte-Carlo simulation, their accuracy is confirmed with the analytical error indicator. One can conclude that (i) the exact effective rate expression is complex in the manner of mathematical representation; (ii) the MoG-based effective rate expression is simple and provides a highly tight approximation to the exact expression, besides it indeed acts as a highly tight upper bound for the exact effective rate expression; and (iii) the MoG-based solution outperforms the multivariate Fox’s $H$ -function based approach with reducing complexity.

On the performance of DF-based multi-hop system over α − κ − μ and α − κ − μ-extreme fading channels

Abstract: Several emerging application scenarios for the multi-hop wireless networking have been introduced in 5G and beyond networks, to provide ultra-low latency and much higher data rate to the end users. In this work, an integrated performance evaluation of a decode-and-forward (DF) multi-hop wireless communication system is undertaken over the non-linear generalized α − κ − μ and α − κ − μ -Extreme fading models. Novel closed-form expressions for the amount of fading (AoF), channel capacity under various adaptive transmission techniques are derived. Additionally, decoding error probability for short packet communication is derived and analyzed. The provided expressions are very useful in designing the channel/link quality for practical multi-hop communication networks. The effects of the fading parameters and the number of hops on the system performance are demonstrated. The correctness of the proposed solutions has been corroborated by comparing them with Monte Carlo simulation results.

On Hybrid-ARQ-Based Intelligent Reflecting Surface-Assisted Communication System

Abstract: The intelligent reflecting surface (IRS) is an emerging technique to extend the wireless coverage. In this letter, the performance of hybrid automatic repeat request (hybrid-ARQ) for an IRS-assisted system is analyzed. More specifically, the outage performance of the IRS-aided system using hybrid-ARQ protocol with chase combining is studied. Asymptotic analysis also shows that the outage performance improves better than linearly by increasing number of reflectors of the IRS-aided system. The results also verify the potential of combining the ARQ scheme in the link layer of the IRS-aided system and demonstrate that very small change of path loss condition can impact the performance largely.

Effective rate analysis of MISO over Beaulieu-Xie fading channel

Abstract: This paper presents the effective rate (ER) analysis of a multiple input single output (MISO) system over the Beaulieu-Xie (BX) fading. The closed-form expressions were derived for the exact and asymptotic cases (for high and low signal-to-noise ratio (SNR)). The BX fading channel is extremely useful for characterizing small cell networks, hyper-dense networks, and femtocells, etc. It can also be used for modeling the fading channels for high-speed trains. Numerical results were presented using the derived closed-form expressions and compared with the results obtained from Monte Carlo simulations. Our findings illustrated that the analytical results have a close match with simulation results. In addition, the numerical findings also provide the important insights into the impact of delay constraint and fading parameters on the ER of considered wireless scenario. It is found that the performance of system improves as dominant specular power and/or number of transmitter antennas increases or the delay constraint parameter decreases.

Effective capacity: a wireless link model for support of quality of service

Abstract: To facilitate the efficient support of quality of service (QoS) in next-generation wireless networks, it is essential to model a wireless channel in terms of connection-level QoS metrics such as data rate, delay, and delay-violation probability. However, the existing wireless channel models, i.e., physical-layer channel models, do not explicitly characterize a wireless channel in terms of these QoS metrics. In this paper, we propose and develop a link-layer channel model termed effective capacity (EC). In this approach, we first model a wireless link by two EC functions, namely, the probability of nonempty buffer, and the QoS exponent of a connection. Then, we propose a simple and efficient algorithm to estimate these EC functions. The physical-layer analogs of these two link-layer EC functions are the marginal distribution (e.g., Rayleigh-Ricean distribution) and the Doppler spectrum, respectively. The key advantages of the EC link-layer modeling and estimation are: 1) ease of translation into QoS guarantees, such as delay bounds; 2) simplicity of implementation; and 3) accuracy, and hence, efficiency in admission control and resource reservation. We illustrate the advantage of our approach with a set of simulation experiments, which show that the actual QoS metric is closely approximated by the QoS metric predicted by the EC link-layer model, under a wide range of conditions.

Matrix Analysis for Scientists and Engineers

Abstract: Preface 1. Introduction and review 2. Vector spaces 3. Linear transformations 4. Introduction to the Moore-Penrose pseudoinverse 5. Introduction to the singular value decomposition 6. Linear equations 7. Projections, inner product spaces, and norms 8. Linear least squares problems 9. Eigenvalues and eigenvectors 10. Canonical forms 11. Linear differential and difference equations 12. Generalized eigenvalue problems 13. Kronecker products Bibliography Index.

The $\alpha$ - $\mu$ Distribution: A Physical Fading Model for the Stacy Distribution

Abstract: This paper introduces a fading model, which explores the nonlinearity of the propagation medium. It derives the corresponding fading distribution-the alpha-mu distribution-which is in fact a rewritten form of the Stacy (generalized Gamma) distribution. This distribution includes several others such as Gamma (and its discrete versions Erlang and central Chi-squared), Nakagami-m (and its discrete version Chi), exponential, Weibull, one-sided Gaussian, and Rayleigh. Based on the fading model proposed here, higher order statistics are obtained in closed-form formulas. More specifically, level-crossing rate, average fade duration, and joint statistics (joint probability density function, general joint moments, and general correlation coefficient) of correlated alpha-mu variates are obtained, and they are directly related to the physical fading parameters

More Special Functions

Abstract: This chapter surveys a number of sets of special functions of importance in physics. Where appropriate, the survey includes generating functions, Rodrigues formulas, the relevant differential equation, orthogonality conditions, and applications. The discussion covers Hermite functions (with applications to the quantum harmonic oscillator and to molecular vibrations), Laguerre functions (with application to the hydrogen atom), Chebyshev polynomials (with application to numerical analysis), hypergeometric and confluent hypergeometric functions, the dilogarithm (with application to electronic structure computations), and elliptic integrals.