Sum of gamma variates and performance of wireless communication systems over Nakagami-fading channels (original) (raw)
Related papers
2012
The probability distribution function (PDF) and cumulative density function of the sum of L independent but not necessarily identically distributed gamma variates, applicable to maximal ratio combining receiver outputs or in other words applicable to the performance analysis of diversity combining receivers operating over Nakagami-m fading channels, is presented in closed form in terms of Meijer G-function and Fox H-bar-function for integer valued fading parameters and non-integer valued fading parameters, respectively.
Progress In Electromagnetics Research B, 2012
In this paper, we have investigated the marginal moment generating function (MMGF) for the correlated Nakagami-m fading channel by using maximal-ratio combining (MRC) diversity scheme at receiver for the computation of channel capacity for various adaptive transmission schemes such as: 1) optimal simultaneous power and rate adaptation, 2) optimal rate adaptation with constant transmit power, 3) channel inversion with fixed rate, and 4) truncated channel inversion with fixed rate. The effects of diversity receiver as well as correlation coefficients on all these transmission schemes are discussed and the channel capacity obtained using this proposed approach for all schemes is compared with reported literature.
IEEE Transactions on Communications, 2004
In this letter, an alternative moments-based approach for the performance analysis of an -branch predetection equal gain combiner (EGC) over independent or correlated Nakagamifading channels is presented. Exact closed-form expressions are derived for the moments of the EGC output signal-to-noise ratio (SNR), while the corresponding moment-generating function (MGF) is accurately approximated with the aid of Padé approximants theory. Important performance criteria are studied; the average output SNR, which is expressed in closed form both for independent and correlative fading and for arbitrary system parameters, the average symbol-error probability for several coherent, noncoherent, and multilevel modulation schemes, and the outage probability, which are both accurately approximated using the well-known MGF approach. The proposed mathematical analysis is illustrated by various numerical results, and computer simulations have been performed to verify the validity and the accuracy of the theoretical approach.
Journal of Computational Electronics, 2011
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IEEE Transactions on Vehicular Technology, 2000
A statistical approach facilitating performance assessment in maximum-ratio combining (MRC)-like reception over independent nonidentically distributed (INID) Nakagami-m fading channels was investigated. Using the proposed method, generalized simple closed-form second-order statistics, i.e., level-crossing rate (LCR) and average fade duration (AFD), can be readily formulated. These second-order statistics can be classified as generalized because multiple (i.e., not limited to two) identically or nonidentically distributed diversity branches can be incorporated. These closed formulations can be accurately applied in various practical environments where nonidentically distributed branches are presented, e.g., single-user single-input-multiple-output (SU-SIMO) applications, relay networks, and macrodiversity reception in wideband code-division multiple access (W-CDMA) communications. The analytic formulations derived in this work were comprehensively verified in computer simulations. The derived closed forms were also carefully verified by comparison with those obtained using the true MRC in the degenerate scenarios, i.e., those in which only two diversity branches exist or where identically distributed diversity branches can be assumed. The derived closed formulations of the second-order statistics were shown to be generalized, accurate, easily evaluated, and clearly insightful with respect to their physical interpretation although they are approximate to those of the true MRC. Index Terms-Average fade duration (AFD), diversity combining, level-crossing rate (LCR), Nakagami-fading channel.
IEEE Transactions on Wireless Communications, 2000
There are several cases in wireless communications theory where the statistics of the sum of independent or correlated Nakagami-m random variables (RVs) is necessary to be known. However, a closed-form solution to the distribution of this sum does not exist when the number of constituent RVs exceeds two, even for the special case of Rayleigh fading. In this paper, we present an efficient closed-form approximation for the distribution of the sum of arbitrary correlated Nakagamim envelopes with identical and integer fading parameters. The distribution becomes exact for maximal correlation, while the tightness of the proposed approximation is validated statistically by using the Chi-square and the Kolmogorov-Smirnov goodnessof-fit tests. As an application, the approximation is used to study the performance of equal-gain combining (EGC) systems operating over arbitrary correlated Nakagami-m fading channels, by utilizing the available analytical results for the error-rate performance of an equivalent maximal-ratio combining (MRC) system.
Closed-form statistics for the sum of squared Nakagami-m variates and its applications
… , IEEE Transactions on, 2006
We present closed-form expressions for the probability density function (PDF) and the cumulative distribution function (CDF) of the sum of non-identical squared Nakagami-m random variables (RVs) with integer-order fading parameters. As it is shown, they can be written as a weighted sum of Erlang PDFs and CDFs, respectively, while the analysis includes both independent and correlated sums of RVs. The proposed formulation significantly improves previously published results, which are either in the form of infinite sums or higher order derivatives of the fading parameter m. The obtained formulas can be applied to the performance analysis of diversity combining receivers operating over Nakagami-m fading channels.
In this paper, a generalized Laguerre polynomial expansion for the probability density function and the cumulative distribution function of the sum of independent nonidentically distributed squared κ−μ random variables is proposed. Based on these statistical results, we investigate the performance of maximal-ratio-combining diversity techniques operating over κ−μ fading channels with arbitrary fading parameters. Our newly derived formulas are mathematically tractable and include as special cases several results available in the technical literature, namely, those of Rice and Nakagami-m fading channels. The proposed analysis is substantiated by numerically evaluated results compared with Monte Carlo simulations