Fading distribution

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

Statistical properties of the EGC output SNR over correlated Nakagami-m fading channels

Abstract: Previous studies have addressed with the performance analysis of L-branch equal gain combining (EGC) systems over independent Rayleigh- or Nakagami-m fading channels. In this paper, important statistical parameters, such as the /spl kappa/-moment, the /spl kappa/-central moment, the skewness, and the kurtosis of the output signal-to-noise ratio (SNR), in predetection EGC systems operating over correlated Nakagami-m fading channels are studied. Simple closed-form expressions for the mean and variance of the output SNR are presented and it is shown that our general results reduce to the specific noncorrelative fading case previously published. Moreover, significant performance criteria such as the amount of fading and the spectral efficiency in the low power regime, are investigated. Numerical results and simulations are presented to check the validity of the proposed mathematical analysis and to point out the impact of the fading correlation, the input SNRs unbalancing as well as the fading severity, on the EGC performance.

Prediction of State Transitions in Rayleigh Fading Channels

Abstract: This paper presents a channel-sampling scheme that allows robust estimation of channel transitions into and out of the fade state. The sampling scheme is based upon a second-order autoregressive (AR-2) model for the Rayleigh fading channel and a corresponding state-space representation in terms of fade and nonfade states. The threshold parameter that segments the fading signal into states is derived as a function of signal-to-noise ratio and a bit-error-rate performance metric. The sampling rates correspond to the values at which the mutual information of the process occupying a particular state, conditioned on two past observations of the channel, is maximized. The performance of the proposed sampling scheme in a model-based prediction algorithm is presented. The state of the received envelope is predicted with 98% accuracy. When applied to the estimation of channel gain, the sampling scheme in conjunction with a Kalman-filter-based AR-2 predictor yields one-step forecasts that accurately track the fading signal. Equalization of multipath channels using the estimated channel impulse response shows improved error performance over traditional recursive least squares equalizers

Analysis of minimum selection H-S/MRC in Rayleigh fading

Abstract: We analyze the error performance of an improved hybrid selection/maximal-ratio combining (H-S/MRC) technique called minimum selection H-S/MRC in flat Rayleigh fading for coherent digital modulation schemes. Here the minimum number of diversity branches are selected such that their combined signal-to-noise ratio is above a given threshold. We derive a closed-form expression for the distribution of the number of selected branches. This distribution is used to obtain the symbol error probability.

How Good Is PSK for Peak-Limited Fading Channels in the Low-SNR Regime?

Abstract: This paper investigates the achievable information rate of phase-shift keying (PSK) over frequency nonselective Rayleigh and Rician fading channels without channel state information (CSI). The fading process exhibits general temporal correlation characterized by its spectral density function. We consider both discrete-time and continuous-time channels, and find their asymptotics at low signal-to-noise ratio (SNR). Compared to known capacity upper bounds under peak constraints, these asymptotics lead to negligible rate loss in the low-SNR regime for slowly time-varying fading channels. We further specialize to case studies of Gauss-Markov and Clarke's fading models

A Unified Moment-Based Approach for the Evaluation of the Outage Probability With Noise and Interference

Abstract: In this paper, we develop a novel moment-based approach for the evaluation of the outage probability (OP) in a generalized fading environment with interference and noise. Our method is based on the derivation of a power series expansion of OP of the signal-to-interference-plus-noise ratio. It does not necessitate stringent requirements, the only major ones being the existence of a power series expansion of the cumulative distribution function of the desired user power and the knowledge of the cross moments of the interferers’ powers. The newly derived formula is shown to be applicable for most of the well-practical fading models of the desired user under some assumptions on the parameters of the powers’ distributions. A further advantage of our method is that it is applicable irrespective of the nature of the fading models of the interfering powers, the only requirement being the perfect knowledge of their cross moments. In order to illustrate the wide scope of applicability of our technique, we present a convergence study of the provided formula for the Generalized Gamma and the Rice fading models. Moreover, we show that our analysis has direct bearing on recent multi-channel applications using selection diversity techniques. Finally, we assess by simulations the accuracy of the proposed formula for various fading environments.