generalized-K Fading Channels Research Articles

Simultaneous Wireless Information and Power Transfer Over KG Fading Channels

In this paper, we proposed a novel expression for the probability density function (PDF) and the cumulative density function (CDF) of the output SNR for the M-branch Selection Combining (M-SC) receiver over Generalized-K (KG) fading channels. Unlike conventional energy sources, the proposed scheme uses a Power splitter (PS) scheme at the receiver side. The received signal is split into information decoding and energy harvesting receiver with adjustable power levels. The expressions of our system consider arbitrary channel parameters and diversity branches. We analyze the proposed model and derive the closed-form expression for average SNR and average bit error rate (ABER) to evaluate the system performance. The obtained results are corroborated with the help of Monte-Carlo simulations. The effects of system parameters, such as power splitter ratio, modulation order, and shaping parameters of KGfading channels, are studied. This type of system will benefit reliable data transmission in an energy-limited scenario.

PERFORMANCE ANALYSIS OF MRC-SC MACRODIVERSITY RECEPTION OVER GENERALIZED FADING CHANNELS

This paper shows a detailed statistical characterization of a specific system configuration consisting of one multibranch maximal-ratio-combining (MRC) and one selection-combining (SC) micro-level base station, and SC back processing unit at macro level. Primarily, the scenario of the independent and identically distributed generalized-K fading channels is investigated. After that, the correlated branches at SC-based micro-level are assumed. The outage probability and the error probability performance for both cases are defined. According to the presented analytical analysis, numerical results are obtained. Also, the impact of the number of MRC and SC input branches, the impact of the fading/shadowing factor, the predefined outage threshold, the average signal-to-noise ratios and the correlation coefficient on the specified system performance is shown. Simulations validate the accuracy of the proposed analytical analysis.

Generic MGF‐based tight approximation for the error rate analysis

SummaryThe moment generating function (MGF)‐based approach is found as more profound as compared with probability density function (PDF)‐based counterpart for error rate analysis in any communication system. However, it fails in the case of several modulation schemes with constellation size M, such as M‐PSK, M‐QAM, and M‐PAM schemes among the others, due to the computational complexity of the involved integration. Though authors in the literature suggest alternate analytical expressions to overcome the problem it is solved only for M‐PSK and M‐QAM schemes. Hence, we present a generic MGF‐based tight approximation for the error rate analysis of different modulation schemes. Particularly, error rate analysis of M‐PAM, M‐AM, B‐PSK, B‐FSK, and orthogonal B‐FSK with non‐coherent (Non‐Co) detection modulation schemes are presented through known MGF based expressions without the evaluation of any integration. Also, a simple analytical expression for the M‐QAM modulation scheme is presented. Besides, the proposed MGF‐based analytical expressions are used to evaluate the error rate of M‐PSK, M‐PAM, and M‐AM modulation schemes over the generalized‐K (GK) fading channel, which is not presented in literature due to the computational complexity of involved integration. Newly, derived analytical expressions are validated through Monte Carlo simulation. The graphical results show the validity and accuracy of the proposed unified MGF‐based analytical expressions for error rate analysis of different modulation schemes over kμ‐gamma and GK fading channels, respectively.

Performance analysis of downlink-NOMA over generalized-k fading channels

Due to the increasing demand for higher capacity in mobile communication devices, non-orthogonal multiple access (NOMA) has become a promising technique. Compared to existing orthogonal multiple access methods, NOMA can serve multiple users with better spectral efficiency by allowing co-channel interference, thus its reliability performance over various channel models needs further research. In this paper, closed-form outage probability, average channel capacity and symbol error rate are derived for a downlink-NOMA system with an arbitrary number of users over generalized-K fading channels. Finally, theoretical findings are validated via Monte Carlo simulations for several channel parameters.

Bit Error Rate of R-QAM Signalling in Generalized K-Fading Channels

Bit Error Rate of R-QAM Signalling in Generalized K-Fading Channels

A Simple Evaluation for the Secrecy Outage Probability Over Generalized-K Fading Channels

A simple approximation for the secrecy outage probability (SOP) over generalized-K fading channels is developed. This approximation becomes tighter as the average signal-to-noise ratio (SNR) of the wiretap channel decreases. Based on this simple expression, we also analyze the asymptotic SOP in the high SNR region of the main channel. Besides simplifying the SOP expression significantly, this asymptotic SOP expression reveals the secrecy diversity order in a general case. Numerical results demonstrate the high accuracy of our proposed approximation results.

On Numerical Evaluation of Packet-Error Rate for Binary Phase-Modulated Signals Reception over Generalized-K Fading Channels

We present a numerical evaluation of packet error rate (PER) for digital binary phase modulations over wireless communication channels. The analysis is valid for a quasistatic fading communication channel, where multipath fading and shadowing appear simultaneously. The approach is based on numerical evaluation of signal-to-noise ratio threshold that is further used in PER computation. We analyze the threshold and PER dependence on signal power, multipath fading and shadowing severity, as well as packet length.

On the Capacity of Underlay Multihop Cognitive Relaying Over Generalized-K Composite Fading Channels

Cognitive radio (CR) is one of the candidate enabling technologies for future wireless communication systems. This paper is devoted to analyze the capacity of underlay cognitive multihop relaying over independent and non-identically distributed generalized-K fading channels. In doing so, we derive upper and lower-bounded expressions for the ergodic capacity and the outage probability of the secondary user (SU), respectively. By using these expressions, new insights in the performance of the cognitive multihop amplify-and-forward relaying are revealed. The obtained results provide interesting details on the joint effect of shadowing and multipath fading on the capacity of the SU in relay-assisted underlay CR networks. The analytical results are verified by Monte-Carlo simulations for different fading conditions.

Secrecy performance analysis of single-input multiple-output generalized-K fading channels

In this paper, the transmission of confidential messages through single-input multiple-output (SIMO) independent and identically generalized-K (KG) fading channels is considered, where the eavesdropper overhears the transmission from the transmitter to the receiver. Both the receiver and the eavesdropper are equipped with multiple antennas, and both active and passive eavesdroppings are considered where the channel state information of the eavesdropper’s channel is or is not available at the transmitter. The secrecy performance of SIMO KG systems is investigated. Analytical expressions for secrecy outage probability and average secrecy capacity of SIMO systems are derived via two different methods, in which KG distribution is approximated by the Gamma and mixture Gamma distributions, respectively. Numerical results are presented and verified via the Monte-Carlo simulation.

Multiuser Detection over Generalized-K Fading Channels with Laplace Noise

Background: Combined effect of fading and shadowing degrades the performance of multiple access wireless communication systems. The presence of impulsive type non-Gaussian noise along with inters symbol interference and multiple access interference further worsens the system performance. Methods: This paper presents a multiuser detection technique for direct sequence-code division multiple accesses systems over generalized-K fading channels in presence of impulsive noise modeled by Laplace distribution. Maximal ratio combining receive diversity technique is also incorporated to mitigate the effects of simultaneous presence of fading and shadowing. An M-decorrelator is proposed to robustly detect the binary phase shift keyed symbols. Performance of proposed M-decorrelator is evaluated by computing the average probability of error. Findings: The proposed M-decorrelator performs better in the simultaneous presence of fading, shadowing and impulsive noise when compared to least squares, Huber and Hampel M-estimator based detectors.

Performance Analysis of Physical Layer Security Over Generalized-$K$ Fading Channels Using a Mixture Gamma Distribution

In this letter, the secrecy performance of the classic Wyner's wiretap model over generalized-K fading channels is studied. The closed-form expressions for the average secrecy capacity, secure outage probability, and the probability of strictly positive secrecy capacity are derived. The new expressions provide a unified form, which can handle several of the well-known composite fading environments as special or limiting cases. Monte-Carlo simulations are performed to verify the proposed analysis models.

On the Secrecy Enhancement With Low-Complexity Large-Scale Transmit Selection in MIMO Generalized Composite Fading

This letter proposes a low-complexity antenna selection scheme based on large-scale fading to enhance the secrecy performance in independent and non-identical generalized-K fading channels. New analytical results for the secrecy outage probability and the probability of non-zero secrecy capacity are derived when the receiving terminals employ the maximum ratio combining scheme. In addition, simple and insightful approximations are obtained for the secrecy outage probability in the high signal to noise ratio regime, which shed light on the impact of key system parameters on the secrecy performance. Simulation results are provided to validate the analytical expressions.

Outage capacity evaluation of extended generalized-[formula omitted] fading channel in the presence of random blockage

In this paper, we analyse the outage and ergodic capacity performance of the extended generalized-K fading channel in the presence of possible temporary physical blockage between the source and the destination. Presented outage capacity analysis is general and can be used in analysis of wireless radio frequency or free-space optics systems. We establish the novel relation among significant parameters as outage capacity, probability of outage, probability of blockage, as well as severity and shaping parameters of multipath fading and shadowing. The theoretical results are expressed in terms of special Fox׳s H functions. The work clearly illustrates the usefulness of Fox׳s H and Meijer׳s G functions in analysing wireless communication systems. The analytical expression derived here enables us to determine the maximum error free data transmission rate for fixed value of outage probability under particular channel conditions. Using expressions for ergodic capacity previously reported in literature, we briefly analyse the impact of blockage on ergodic capacity, too. The numerical results show that the shadowing shaping factor has the considerable effect on outage capacity and is pronounced more extensively when probability of outage is lower. In addition, the results show that the effect of shadowing shaping factor is stronger for outage than ergodic capacity. The effect of multipath fading severity on outage capacity is stronger for lower values of shadowing spread. The link blockage causes significant decreasing of ergodic capacity and appearance of outage floor.

Performance analysis of semi-blind two-way AF relaying over generalized-k fading channels

In this paper, we present analytical expressions for the outage probability, average symbol error rate (SER), and average sum-rate of two-way dual-hop opportunistic amplify-and-forward (AF) relaying over independent and not necessarily identical generalized-k (KG) fading channels. New closed-form expression for the gain of non-regenerative semi-blind relays is derived. This expression is used to obtain the equivalent signal-to-noise ratio (SNR). Based on the above mentioned formulas, tight bounds of some performance metrics, the outage probability, average SER, and average sum-rate, are derived for the semi-blind and channel state information (CSI) relaying. In order to prove the exactness of the proposed mathematical analysis, a selection of numerical results is provided.

Performance Analysis of Dual-Hop Fixed-Gain Relay Systems over Extended Generalized-K Fading Channels

In current cooperative communication systems, a relay terminal is very often used as intermediate node and may degrade or improve the overall system performance, depending on the power imbalance between the hops. In this paper, an approach to estimate the performance of dual-hop fixed-gain relay system when each hop is subjected to extended generalized-K fading is presented. New closed form expressions are derived for the cumulative distribution function, the outage probability, and the ergodic capacity. Moreover, the average symbol error probability for coherent and non-coherent modulation schemes is derived. The accuracy of analytic results is verified through computer simulations.

Capacity and Error Probability Analysis of Diversity Reception Schemes Over Generalized- <named-content content-type="math" xlink:type="simple"><inline-formula><tex-math notation="TeX">$K$</tex-math></inline-formula></named-content> Fading Channels Using a Mixture Gamma Distribution

In this paper, we analyze the error probability and ergodic capacity performance for diversity reception schemes over generalized-K fading channels using a mixture gamma (MG) distribution. With high accuracy, the MG distribution can approximate a variety of composite fading channel models and provide mathematically tractable properties. In contrast to previous analysis approaches that require complicated signal-to-noise ratio (SNR) statistics, it is shown that a distribution of the received SNR for diversity reception schemes is composed of a weighted sum of gamma distributions by exploiting the properties of the MG distribution. Then, based on this result, we can derive the exact average symbol error probability and simple closed-form expressions of diversity and array gains for maximal ratio combining and selection combining. In addition, an expression of the ergodic capacity for these schemes is obtained in independent and identically distributed fading channels. Our results lead to meaningful insights for determining the system performance with parameters of the MG distribution. We show that our analysis can be expressed with any number of receiver branches over various fading conditions. Numerical results confirm that the derived error probability and ergodic capacity expressions match well with the empirical results.

Spectral and energy efficiency analysis of uplink heterogeneous networks with small-cells on edge

This paper presents a tractable mathematical framework to analyze the spectral and energy efficiency of an operator initiated deployment of the small-cells (e.g., femtocells) where the small-cell base stations are deliberately positioned around the edge of the macrocell. The considered deployment facilitates the cell-edge mobile users in terms of their coverage, spectral, and energy efficiency and is referred to as cell-on-edge (COE) configuration. The reduction in energy consumption is achieved by considering fast power control where the mobile users transmit with adaptive power to compensate the path loss, shadowing and fading. In particular, we develop a moment generating function (MGF) based approach to derive analytical bounds on the area spectral efficiency and exact expressions for the energy efficiency of the mobile users in the considered COE configuration over generalized-K fading channels. Besides the COE configuration, the derived bounds are also shown to be useful in evaluating the performance of random small-cell deployments, e.g., uniformly distributed small-cells. Simulation results are presented to demonstrate the improvements in spectral and energy efficiency of the COE configuration with respect to macro-only networks and other unplanned deployment strategies.

Effect of Generalized-K Fading on the Performance of Symmetric Coordinate Interleaved Orthogonal Designs

In this letter, an efficient method of evaluating the performance of space-time block codes (STBCs) from symmetrically structured coordinate interleaved orthogonal designs (CIODs) is presented over generalized-K MIMO fading channels. By effectively approximating the moment generating function (MGF), we derive approximate closed-form expressions for the symbol pairwise error rate (SPER) and corresponding tight approximate symbol error rate (SER) of STBCs from symmetric CIODs. Finally, various Monte-Carlo simulations are performed to validate our theoretical results.

Moment Generating Function Based Performance Analysis of Maximal-Ratio Combining Diversity Receivers in the Generalized-K Fading Channels

In this paper, we have analyzed the performance of maximal ratio combing (MRC) diversity receiver of the wireless communication systems over the composite fading environment, which is modelled by using the generalized-K distribution. However, this distribution has been considered as a versatile distribution for the precise modelling of a great variety of the short-term fading in conjunction with the long-term fading (shadow fading) channel conditions. In this proposed analysis, we have derived the mathematical expression for the moment generating function (MGF) of the generalized-K fading channel model that is used to evaluate a novel closed-form expression of the average bit error rate for (BER) the binary phase-shift keying /binary frequency-shift keying and average symbol error rate (SER) for the rectangular quadrature amplitude modulation scheme. We have also derived the mathematical expressions for the outage probability as well as the channel capacity for the generalized-K fading channel model.

Performance Analysis of Dual-Hop Systems with Decode-and-Forward Relays over Generalized Fading Channels

Dual-hop transmission systems employing decodeand-forward relay are studied in this paper. The examination has been done for independent, but not necessarily identical Extended Generalized-K fading channels. New, exact, closedform expressions are derived for the outage probability, the nth moments of the end-to-end signal-to-noise ratio (SNR), and the ergodic capacity. Moreover, the average symbol error probability (ASEP) for coherent and non-coherent modulation schemes is derived. Analytical results along with simulation results are obtained with excellent agreement.