Securing ($$\alpha -\kappa -\mu$$)- Shadowed Fading Channels with Opportunistic Relaying: A PHY Security Analysis

In this paper, the physical layer security aspects of a wireless framework over α − κ − μ shadowed (AKMS) fading channel are examined by acquiring closed-form novel expressions of average secrecy capacity, secure outage probability (SOP), and strictly positive secrecy capacity. The lower bound of SOP is derived along with the asymptotic expression of SOP at the high signal-to-noise ratio regime in order to achieve secrecy diversity gain. Capitalizing on these expressions, the consequences due to the simultaneous occurrence of fading and shadowing are quantified. Finally, Monte-Carlo simulations are demonstrated to assess the correctness of the expressions.

A compound probability density function (pdf) model is used for the outage analysis of a multiple input multiple output (MIMO) scheme operating in shadowed fading channels. Instead of the lognormal pdf, the compound pdf uses a gamma distribution to account for shadowing, leading to a closed form expression for the pdf of the signal-to-noise ratio in a shadowed fading channel. While the mitigation of short term fading is achieved through the use of multiple transmitters and multiple receivers, the shadowing is mitigated with macrodiversity using two base stations. Taking into account the fact that shadowing has a larger correlation distance, the two base stations are treated to have nonzero correlation. It is shown that the expression for the outage probability in a MIMO scheme operating in shadowed fading channels can be written in a simple form eliminating the need for numerical evaluation of double integrals. Results demonstrate the usefulness of the approach for the analysis of MIMO schemes.

In this paper, a mixture gamma (MG) distribution that is highly accurate unified approximate approach is used to model the intractable statistical properties of α — κ — μ shadowed fading channels. The α — κ — μ shadowed fading channel contains the generalized α — κ — μ fading and gamma distribution which represent the impact of multipath fading and shadowing, respectively. The performance of communication systems with dual-receiver switch and stay combining (SSC) in non-identical α — κ — μ shadowed fading channels is evaluated via analyzing different performance metrics. Specifically, the outage probability (OP), average bit error probability (ABEP), average channel capacity (ACC) and average detection probability of energy detection (ED) that is widely utilized in cognitive radio (CR) and ultra-wide band (UWD) systems are derived. The derived expressions are verified by the numerical results for various scenarios. A significant improvement in the performance of wireless communications systems as well as ED can be observed when the fading parameters increase.

Outage analysis in wireless channels with multiple interferers subject to shadowing and fading using a compound pdf model

Through ordinary transmissions over wireless multicast networks are greatly hampered due to the simultaneous presence of fading and shadowing of wireless channels, secure transmissions can be enhanced by properly exploiting random attributes of the propagation medium. This study focuses on the utilization of those attributes to enhance the physical layer security (PLS) performance of a dual-hop wireless multicast network over κ - μ shadow-fading channel under the wiretapping attempts of multiple eavesdroppers. In order to improve the secrecy level, the best relay selection strategy among multiple relays is employed. Performance analysis is carried out based on the mathematical modeling in terms of analytical expressions of non-zero secrecy capacity probability, secure outage probability, and ergodic secrecy capacity over multicast relay networks. Capitalizing on those expressions, the effects of system parameters, i.e., fading, shadowing, the number of antennas, destination receivers, eavesdroppers, and relays, on the secrecy performance are investigated. Numerical results show that the detrimental impacts caused by fading and shadowing can be remarkably mitigated using the well-known opportunistic relaying technique. Moreover, the proposed model unifies secrecy analysis of several classical models, thereby exhibiting enormous versatility than the existing works.

In this study, the secrecy performance of the classic Wyner's wiretap model over shadowed fading channels is studied. More specifically, the authors derive two analytical expressions for the lower bound of secure outage probability at high signal-to-noise ratio regime and the probability of strictly positive secrecy capacity over shadowed fading channels, respectively. As there exist infinite series in the two derived expressions, they further obtain two simple and explicit approximate expressions for the lower bound of secure outage probability and the probability of strictly positive secrecy capacity with the aid of the moment matching method. It is shown that the match between the analytical results and simulations is very excellent for all parameters under considerations.

The effects of scatterers, fluctuation parameter and propagation clusters significantly affect the performance of κ-μ shadowed fading channel. On the other hand, opportunistic relaying is an efficient technique to improve the performance of fading channels reducing the effects of aforementioned parameters. Motivated by these issues, in this paper, a secure wireless multicasting scenario through κ-μ shadowed fading channel is considered in the presence of multiple eavesdroppers with opportunistic relaying. The main purpose of this paper is to ensure the security level in wireless multicasting compensating the loss of security due to the effects of power ratio between dominant and scattered waves, fluctuation parameter, and the number of propagation clusters, multicast users and eavesdroppers, by opportunistic relaying technique. The closed-form analytical expressions are derived for the probability of non-zero secrecy multicast capacity (PNSMC) and the secure outage probability for multicasting (SOPM) to understand the insight of the effects of above parameters. The results show that the loss of security in multicasting through κ-μ shadowed fading channel can be significantly enhanced using opportunistic relaying technique by compensating the effects of scatterers, fluctuation parameter, and the number of propagation clusters, multicast users and eavesdroppers.

In this paper, we analyze the security capability of single-input multiple-output wireless transmission systems over k-μ shadowed fading channels in the presence of multiple eavesdroppers. Our security analysis relies on an important standard, i.e., average secrecy capacity which is more difficult and suitable for analyzing active eavesdropping scenario than secure outage probability and probability of strictly positive secrecy capacity. The novel expression of average secrecy capacity over k-μ shadowed fading channels with multiple eavesdroppers is deduced. The results of Monte Carlo simulation fully prove the correctness of our theoretical derivation. Through the obtained results, we observe that large antenna quantity in the highest signal-to-noise ratio regime, small number of the eavesdroppers, and small signal-to-noise-ratio of eavesdropping link will enhance confidentiality of the system under consideration.

SummaryCooperative nonorthogonal multiple access (NOMA) system is an effective solution for the fifth generation (5G) wireless mobile communications systems. In this work, the achievable rate analysis of a NOMA communication network with decode‐and‐forward (DF) relaying under κ‐μ shadowed fading conditions is investigated. First, we develop an analytical framework for cumulative distribution function (CDF) of the considered system model. Then, the average achievable rate expressions for two different information bits namely s1 and s2 are derived based on the derived CDF for NOMA with DF relaying over κ‐μ shadowed fading channels. Furthermore, we also propose simplified average achievable rate expressions for the special cases of κ‐μ shadowed fading channels in order to facilitate the evaluation of the derived expressions. Some numerical examples on the achievable rate of the considered system are shown for different scenarios. Moreover, our derived analytical average achievable rate expressions are confirmed by the simulations results.

This paper analyzes the performance of wireless sensor networks over κ–μ shadowed fading channel. Average Bit Error Rate has been determined in case of peer to peer IEEE 802.15.4 link, whereas, Source to Sink Average Bit Error Rate has been determined in case of multi-hop communication. Results have been plotted for various parameters of κ–μ shadowed fading channel. It has been observed that in single-hop communication, the performance increases with increase inκ, μ andm, whereas, in multi-hop communication performance degrades with increase in number of hops.

In this paper, the secrecy performance of single-input–multiple-output systems over correlated $\kappa $ - $\mu $ shadowed fading channels is investigated. In particular, based on the classic Wyner’s wiretap model, we derive analytical expressions for secure outage probability (SOP) and the probability of strictly positive secrecy capacity (SPSC) over correlated $\kappa $ - $\mu $ shadowed fading channels. In order to further study the impact of channel parameters on the secrecy performance, novel SOP and the probability of SPSC over independent and identically distributed $\kappa $ - $\mu $ shadowed fading channels are also obtained. In addition, we discuss the asymptotic expressions of the SOP and the SPSC. The match between the analytical results and simulations is excellent for all parameters under considerations. It is interesting to find that the results show that when the signal-to-noise ratio of the main channel is lower than that of the eavesdropping channel, the larger value of correlation coefficient is helpful to improve the secrecy performance and vice versa.

A unified analysis of statistical models for describing fading, shadowing, and shadowed fading channels is presented from a pedagogical viewpoint. The different probability density functions such the Rayleigh, Nakagami, gamma, generalized gamma, Weibull, lognormal, Nakagami-lognormal, K distribution, generalized K distribution, and Nakagami inverse Gaussian distribution are presented and the relationships among them are detailed. These density functions are compared in terms of two quantitative measures, namely the amount of fading and outage probability. A general approach to fading and shadowed fading channels using a cluster based approach is also presented to link several of the distributions. It is expected that this overview will be very helpful to students and educators who are engaged in the study of wireless systems and the adverse impact of fading and shadowing in wireless data transmission.

Compound statistical models for shadowed fading channels

In this paper, exact closed-form expressions are derived for the outage probability (OP) of the maximal ratio combining (MRC) scheme in the κ-μ shadowed fading channels, in which both the independent and correlated shadowing components are considered. The scenario assumes the received desired signals are corrupted by the independent Rayleigh-faded co-channel interference (CCI) and background white Gaussian noise. To this end, first, the probability density function (PDF) of the κ-μ shadowed fading distribution is obtained in the form of a power series. Then the incomplete generalized moment-generating function (IG-MGF) of the received signal-to-interference-plus-noise ratio (SINR) is derived in the closed form. By using the IG-MGF results, closed-form expressions for the OP of MRC scheme are obtained over the κ-μ shadowed fading channels. Simulation results are included to validate the correctness of the analytical derivations. These new statistical results can be applied to the modeling and analysis of several wireless communication systems, such as body centric communications.

Exact closed-form expressions of the outage probability (OP) are obtained for the maximal ratio combining (MRC) diversity scheme in κ-μ shadowed fading channels with an arbitrary number of independent antennas. The scenario considered in this work assumes the joint presence of background white Gaussian noise and independent Rayleigh-faded interferers with arbitrary powers. The statistical characterizations, i.e., probability density function (PDF) and incomplete generalized moment-generating function (IG-MGF) of the κ-μ shadowed distribution are obtained in closed form. By utilizing the IG-MGF results, exact closed-form expressions for the OP of MRC are derived in κ-μ shadowed fading channels with mixed background noise and interference. Simulation results are included to validate the correctness of the analytical derivations. This set of new statistical results can be applied to the modeling and analysis of several wireless communication systems, such as body-centric communications.