Arbitrary Fading Parameters Research Articles

On the Performance Analysis of Multi-Hop Cooperative Relay Networks over Generalized-K Fading Channels

This letter analyzes an amplify-and-forward (AF) transmission based multi-hop cooperative relay network (MCRN) over Generalized-K fading channels. In this letter, highly simplified, novel asymptotic expressions for the average symbol error rate and the outage probability of MCRNs over Generalized-K fading channels (with arbitrary fading parameters) are presented. Both theoretical analysis and simulations explicitly reveal that for MCRNs over Generalized-K fading channels, a diversity order of 2k is achieved when shadowing is more severe than fading and a diversity order of 2m is achieved when fading is more severe than shadowing (where k and m represent the Generalized-K distribution shape parameters).

Performance Analysis of Multi-User, Multi-Hop Cooperative Relay Networks over Nakagami-m Fading Channels

This letter analyzes the performance of multi-user diversity in multi-hop cooperative relay networks (MCRNs). In this letter, we derive a novel, simplified, asymptotic expression for the average symbol error rate (ASER) of multi-user MCRNs operating over Rayleigh or Nakagami-m fading channels (with arbitrary fading parameters). Both theoretical analysis and simulations explicitly reveal that for multi-user MCRNs operating over Rayleigh or Nakagami-m fading channels, a diversity order of 2L or 2mL can respectively be achieved (where L represents the number of users and m is the Nakagami fading parameter).

Performance of Dual MRC Receiver for M-ary Modulations over Correlated Nakagami-m Fading Channels with Non-identical and Arbitrary Fading Parameter

Performance of Dual MRC Receiver for M-ary Modulations over Correlated Nakagami-m Fading Channels with Non-identical and Arbitrary Fading Parameter

Performance of rotated PSK modulation in Nakagami-m fading channels

This paper studies performance of Rotation & Component Interleaving Diversity (RCID) over frequency non-selective and slowly Nakagami-m fading channels for arbitrary fading parameter m. Briefly, RCID is to rotate signal constellation and use component interleaving at the transmitter and de-interleaving at the receiver. First, Symbol Error Probability (SEP) of the system is derived by using moment generating function based approach and optimum rotation angles minimizing SEP are found for M=2,4,8 Phase Shift Keying (PSK). Upper bound is also derived in order to obtain asymptotic diversity order. The analytical results are validated by the simulation results. Then, RCID is applied on receive antenna combining techniques and their error performances are studied by the simulations. The optimum rotation angles are also obtained for combining techniques with rotated M-PSK modulation. Results show that performance of the systems improves significantly and diversity order of the systems doubles as compared to those of the equivalent unrotated systems.

Bivariate nakagami-m distribution with arbitrary correlation and fading parameters

New, exact expressions concerning the bivariate Nakagami-m processes with arbitrary correlation and fading parameters are derived. More specifically, the following are obtained in the present work: joint moment generating function; joint probability density function; joint cumulative distribution function; power correlation coefficient; and several statistics related to the signal-to-noise ratio at the output of the selection combiner, namely, outage probability, probability density function, and mean SNR. The expressions make use of the well known generalized Laguerre polynomials. They are mathematically tractable and flexible enough to accommodate a myriad of correlation scenarios, useful in the analysis of a more general fading environment. We maintain, however, that a relation among the correlation coefficients of the corresponding Gaussian components must be kept so that convergence is attained.

Performance of MIMO System Through Nakagami Fading Channel with Arbitrary Fading Parameters

In this paper, the analytical and simulation results of the bit error rate (BER) performance for a multiple-input multiple-output (MIMO) system with an arbitrary number of transmit and receive antennas are developed for the uplink transmission. The fading channel is assumed to follow Nakagami-m distribution with correlation among branches. The BER is expressed in terms of Lauricella's multivariate hypergeometric function for both independent and correlated antenna branches for BPSK system.

Performance analysis of rectangular quadrature amplitude modulation with combined arbitrary transmit antenna selection and receive maximal ratio combining in Nakagami- m fading

The average symbol error probability (SEP) performance of arbitrary rectangular quadrature amplitude modulation in the context of arbitrarily ordered transmit antenna selection and receive maximal ratio combining diversity system is analysed. The channel gains are assumed to follow Nakagami-m fading distribution with in general arbitrary fading parameters. Exact expressions for the average SEP performance are derived for the general case of unequal in-phase and quadrature decision distances as well as distinct in-phase and quadrature modulation orders. The results generalise many previous case studies, and can be used to investigate the impact of various diversity-combining schemes and different modulation and channel parameters on the system average SEP performance.

Performance of maximal ratio combiners over correlated Nakagami-m fading channels with arbitrary fading parameters

In this letter, performance metrics of maximal ratio combiners (MRC) over correlated Nakagami-m fading are calculated with both arbitrary fading parameters and average powers. We derive the moment generating function (MGF) of the sum of correlated gamma variables with arbitrary fading parameters. Using the MGF-based approach, we obtain the variance of the signal-to-noise ratio (SNR) at the output of the combiner, the outage probability, the average symbol error rate for coherent multichannel reception, and the diversity gain. The results for an exponentially decaying model of the fading parameter are presented and discussed.

Generation of multivariate Weibull random variates

A simple and efficient method for generating correlated multivariate Weibull random variables with arbitrary fading parameters and arbitrary average powers is proposed. The multivariate Weibull random variables generated via this method can be used to simulate the performance of wireless communication systems with any diversity order or channel impulse response length, under arbitrary correlated Weibull fading conditions.

Non-coherent improved-gain diversity reception of binary orthogonal signals in Nakagami- q (Hoyt) mobile channels

A novel non-coherent receiver with diversity reception for binary orthogonal signals in non-identical Nakagami-q (Hoyt) fading channels (channels having arbitrary average fading powers and arbitrary fading parameters) is proposed. A closed-form expression for the average bit error probability of the proposed receiver is derived, which is given in terms of elementary functions, and can be readily evaluated numerically. In addition, the results clarify that the proposed receiver does not incur non-coherent combining loss, and at the same time, lower bounds the performance of the conventional non-coherent equal-gain combining (NC-EGC) receiver. Simulation results are provided to validate the mathematical analysis.

Second-order statistics for diversity-combining of non-identical correlated hoyt signals

In this paper, exact expressions for the level crossing rate (LCR) and average fade duration (AFD) for two-branch selection, equal-gain and maximal-ratio combining systems in a Hoyt fading environment are presented. The expressions apply to unbalanced, non-identical, correlated diversity channels and have been validated by specializing the general results to some particular cases whose solutions are known. In passing, the joint bidimensional envelope-phase Hoyt distribution with arbitrary fading parameters is obtained.

On the Correlated $K$-Distribution With Arbitrary Fading Parameters

The correlated bivariate K-distribution with arbitrary and not necessarily identical parameters is introduced and analyzed. Novel infinite series expressions for the joint probability density function and moments are derived for the general case where the associated bivariate distributions, i.e., Rayleigh and gamma, are both arbitrary correlated. These expressions generalize previously known analytical results obtained for identical parameter cases. Furthermore, considering independent gamma distributions, the cumulative distribution and characteristic functions are analytically obtained. Although the derived expressions can be used in a wide range of applications, this letter focuses on the performance analysis of dual branch diversity receivers. Specifically, the outage performance of dual selection diversity receivers operating over correlated K fading/shadowing channels is analytically evaluated. Moreover, for low normalized outage threshold values, closed-form expressions are obtained.

Performance Analysis of UWB Autocorrelation Receivers Over Nakagami-Fading Channels

We study the performance of the autocorrelation receiver (AcR) with the transmitted-reference (TR) signaling scheme in the multipath UWB channel, where the fading of each resolvable multipath component is characterized by: 1) Nakagami distribution; 2) arbitrary fading parameter; and 3) arbitrary average power. The analysis, compared to conventional Rake receivers, is complicated by the fact that the instantaneous signal-to-noise ratio (SNR) at the AcR output is a nonlinear function of the instantaneous SNR at the receiver input, the latter given by the sum of the SNRs of each resolvable multipath component. Based on the derivation of exact and approximated expressions for the probability density function (pdf) of the output SNR, we evaluate several indicators of the receiver performance, such as: 1) average SNR; 2) amount of fading; 3) outage probability; and 4) average bit-error probability (BEP); all are given in a closed-form. Remarkably, we show that the pdf of the output SNR can be modeled as a gamma distributed random variable, which allows us to write the average BEP in terms of the well-known hypergeometrical Gaussian function. An approximate, yet accurate, expression of the integration time minimizing the average BEP is also derived.

Generation of bivariate Nakagami‐m fading envelopes with arbitrary not necessary identical fading parameters

AbstractIn this paper, a generation procedure of two correlated Nakagami‐m random variables for arbitrary fading parameters values (not necessary identical) is described. For the generation of two correlated Nakagami‐m samples, the proposed method uses the generalized Rice distribution, which appears in the conditional distribution of two correlated Nakagami‐m variables. This procedure can be applied to simulate diversity systems such as selection combiners, equal‐gain combiners, and maximal‐ratio combiners as well as multiple‐input multiple‐output (MIMO) receiver systems, in Nakagami‐m channels. Copyright © 2006 John Wiley & Sons, Ltd.

Performance of dual selection combiners over correlated Nakagami-m fading with different fading parameters

This letter presents infinite series expressions for the outage probability, the probability density function, the average error probability for binary modulations, and the average signal-to-noise ratio of dual selection combiners over correlated fading with arbitrary fading parameters at each input of the combiner. The outage probability is calculated for both thermal noise and interference-limited scenarios. The results obtained for the outage probabilities specified for identical fading parameters at both branches of the combiner are contrasted with the results of other studies in the literature

Improved-performance noncoherent weighted-coefficients diversity combiner for DPSK and NC-FSK signals in nonidentical nakagami fading channels

It is well-known that noncoherent equal-gain combining (NC-EGC) is the simplest combining technique for noncoherent and differentially coherent communication systems. However, for nonidentical Nakagami-m channels (channels having nonuniform multipath intensity profile (MIP) and/or arbitrary non-integer fading parameters), the use of NC-EGC has three main disadvantages. First, its performance serves as a lossy upper bound to that of the optimum diversity combiner. Second, it results in complicated expressions for the system average error performance. Third, it incurs noncoherent combining loss (does not aid the use of diversity) at relatively low average signal-to-noise ratio (SNR). In this letter, we propose a modified version of the NC-EGC, which is a noncoherent combiner with weighting coefficients, to overcome the disadvantages of the conventional one. We show that this alternative combiner does provide improvements over the conventional N.C-EGC for all values of average SNRs, it does not incur any noncoherent combining loss, and it leads to a design of the receiver whose average error performance can be evaluated easily.

Performance of DS-CDMA Receivers With MRC in Nakagami-<tex>$m$</tex>Fading Channels With Arbitrary Fading Parameters

The receivers that combine spatial antenna diversity with temporal multipath diversity are known as two-dimensional (2-D) RAKE receivers. In this paper, we consider the outage probability and the bit error rate performance of a coherent binary phase shift keying 2-D RAKE receiver in the context of an asynchronous direct sequence (DS)-code division multiple access (CDMA) system operating in a Nakagami-m fading channel with real and arbitrary fading parameters. The closed-form expressions derived for the two wireless performance measures are easily evaluated numerically and enable the link designer to examine the effects of system parameters, such as the number of receive antennas, RAKE fingers per antenna, and asynchronous CDMA users in the cell, as well as channel conditions, such as the amount of fading in the combined paths and the multipath intensity profile of the channel on the link performance. In addition, the diversity loss due to correlated fading among the spatially separated RAKE fingers is quantified.

Another Look at the Performance of MRC Schemes in Nakagami-<tex>$m$</tex>Fading Channels With Arbitrary Parameters

In this letter, we take a close look at the performance of maximal ratio combining (MRC) schemes operating in a flat-Nakagami-m fading environment with arbitrary fading parameters. We derive an expression for the probability density function (pdf) of the output signal-to-noise ratio (SNR) by expressing the moment generating function of the output SNR in the form of multiple Barnes-type contour integrals. By evaluating the inverse transform and converting the multiple contour integrals into infinite series, we are able to derive an expression for the pdf of the output SNR when the Nakagami fading parameters along the diversity branches take on real and arbitrary values. Consequently, the average bit-error rate can now be expressed in terms of Lauricella's multivariate hypergeometric function, which can be easily evaluated numerically. Special cases of the main results reduce to known results in the literature. The results, which apply to independent as well as correlated diversity branches, will be useful for predicting the system performances when the Nakagami fading parameters are real and arbitrary.

Highly accurate κ-μ approximation to sum of M independent non-identical Ricean variates

A scheme to approximate the distribution of the sum of M independent, non-identically distributed Ricean random variables by the κ-μ distribution is proposed. To this end, appropriate κ-μ distribution parameters are derived. The summands are assumed to have arbitrary mean powers and arbitrary fading parameters. The differences between exact and approximate distribution curves are almost imperceptible.

Performance of Asynchronous MC-CDMA Systems with Maximal Ratio Combining in Frequency-Selective Fading Channels

The bit error rate (BER) performance of the asynchronous uplink channel of multicarrier code division multiple access (MC-CDMA) systems with maximal ratio combining (MRC) is analyzed. The study takes into account the effects of channel path correlations in generalized frequency-selective fading channels. Closed-form BER expressions are developed for correlated Nakagami fading channels with arbitrary fading parameters. For channels with correlated Rician fading paths, the BER formula developed is in one-dimensional integration form with finite integration limits, which is also easy to evaluate. The accuracy of the derived BER formulas are verified by computer simulations. The derived BER formulas are also useful in terms of computing other system performance measures such as error floor and user capacity.