Fading distribution

About: Fading distribution is a research topic. Over the lifetime, 5732 publications have been published within this topic receiving 114193 citations.

Exact evaluation of maximal-ratio and equal-gain diversity receivers for M-ary QAM on Nakagami fading channels

Abstract: Exact integral expressions are derived for calculating the symbol-error rate (SER) of multilevel quadrature amplitude modulation (MQAM) in conjunction with L-fold antenna diversity on arbitrary Nakagami fading channel. Both maximal-ratio combining (MRC) (in independent and correlated fading) and equal-gain combining (EGC) predetection (in independent fading) diversity techniques have been considered. Exact closed-form SER expressions for two restricted Nakagami fading cases (MRC reception) are also derived. An exact analysis of EGC for MQAM has not been reported previously, despite its practical interest. Remarkably, the exact SER integrals can also be replaced by a finite-series approximation formula. A useful procedure for computing the confluent hypergeometric series is also presented.

A unified performance analysis of digital communication with dual selective combining diversity over correlated Rayleigh and Nakagami-m fading channels

Abstract: Using a simple finite integral representation for the bivariate Rayleigh (1889) cumulative distribution function previously discovered by the authors, we present expressions for the outage probability and average error probability performances of a dual selective diversity system with correlated slow Rayleigh fading either in closed form (in particular for binary differential phase-shift keying) or in terms of a single integral with finite limits and an integrand composed of elementary (exponential and trigonometric) functions. Because of their simple form, these expressions readily allow numerical evaluation for cases of practical interest. The results are also extended to the case of slow Nakagami-m fading using an alternate representation of the generalized Marcum (1950) Q-function.

The Influence of Fading Spectrum on the Binary Error Probabilites of Incoherent and Differentially Coherent Matched Filter Recievers

Abstract: Previous derivations of the influence of fading on the error probabilities of binary data transmission systems have assumed that the fading rate is so slow that fluctuations within a bit may be ignored. This slow fading assumption is removed in the present paper which derives general expressions for the binary error probabilities of incoherent and differentially coherent matched filter receivers employing post-detection diversity combining. In the analysis it is assumed that the transmitted signals occupy a bandwidth much smaller than the coherence bandwidth of the medium so that "flat" fading may be assumed. In addition, it is assumed that the amplitude and phase fluctuations produced by the medium have the same statistical character as those of narrow-band Gaussian noise. The general analytical results are specialized to the cases of frequency shift keying using incoherent detection, and phase shift keying using differentially coherent detection, and to the cases of exponential and Gaussian fading correlation functions. For these special cases, signal-to-noise degradation curves are given as a function of fading bandwidth. The PSK system is degraded more rapidly with increasing fading bandwidth than is the FSK system. Curves are given which show the error probabilities and corresponding fading bandwidths for which the noncoherent FSK and the differentially coherent PSK systems break even. For lower error probabilities or higher fading bandwidths, the FSK system becomes superior to the PSK system in the sense of being able to provide the same error probability with less signal-to-noise ratio. The existence of an irreducible error probability is demonstrated for the incoherent and differentially coherent matched filter receivers. Thus, in general, an increase in transmitted signal power cannot reduce the error probability below a certain value depending upon the fading spectrum and order of diversity. Theoretical curves of irreducible error probability are given for the incoherent FSK and differentially coherent PSK systems. An important result of the analysis is that the shape of the fading spectrum can make a significant difference in the amount of signal-to-noise degradation. The results of the analysis also indicate that care must be exercised in employing a "slow fading" assumption since, if low bit error probabilities are desired, significant degradations in performance can occur even though the fading rate is quite low relative to the data rate.

Design and analysis of turbo codes on Rayleigh fading channels

Abstract: The performance of turbo codes using coherent BSPK signaling on Rayleigh fading channels is considered. In regions of low signal-to-noise, performance analysis uses simulations of typical turbo coding systems. For higher signal-to-noise regions beyond simulation capabilities, an average upper bound is used, where the average is over all possible interleaving schemes. Fully-interleaved and exponentially-correlated Rayleigh channels are explored. Furthermore, the design issues relevant to turbo codes are explored for the correlated fading channel.

The Fluctuating Two-Ray Fading Model: Statistical Characterization and Performance Analysis

Abstract: We introduce the fluctuating two-ray (FTR) fading model, a new statistical channel model that consists of two fluctuating specular components with random phases plus a diffuse component. The FTR model arises as the natural generalization of the two-wave with diffuse power (TWDP) fading model; this generalization allows its two specular components to exhibit a random amplitude fluctuation. Unlike the TWDP model, all the chief probability functions of the FTR fading model (PDF, CDF, and MGF) are expressed in closed-form, having a functional form similar to other state-of-the-art fading models. We also provide approximate closed-form expressions for the PDF and CDF in terms of a finite number of elementary functions, which allow for a simple evaluation of these statistics to an arbitrary level of precision. We show that the FTR fading model provides a much better fit than Rician fading for recent small-scale fading measurements in 28 GHz outdoor mm-wave channels. Finally, the performance of wireless communication systems over FTR fading is evaluated in terms of the bit error rate and the outage capacity, and the interplay between the FTR fading model parameters and the system performance is discussed. Monte Carlo simulations have been carried out in order to validate the obtained theoretical expressions.