Fading distribution

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

SER of two-dimensional signalings in Rayleigh fading with channel estimation errors

Abstract: A general analytical framework for evaluating the performance of practical coherent two-dimensional (2-D) signaling in frequency flat Rayleigh fading with channel estimation is proposed in this paper. A new and simple analytical expression for the symbol error rate (SER) of an arbitrary 2-D constellation in Rayleigh fading in the presence of channel estimation errors is presented. This framework is applicable to many current channel estimation methods such as pilot symbol aided modulation and minimum mean square error estimation where the fading estimate is a complex Gaussian variable correlated with the channel fading. The sensitivity of various 2-D signaling formats to static and dynamic channel amplitude and phase estimation errors in Rayleigh fading can be easily studied using the derived formula. The new exact SER expression makes it possible to optimize constellation parameters and various parameters associated with channel estimation schemes. It also provides insights into choosing an appropriate signaling format for a fading environment with practical channel estimation methods used at the receiver.

Space-time coded QPSK for rapid fading channels

Abstract: This paper presents the design of space-time codes suitable for rapid fading channels. The codes are designed using the QPSK signal constellation. The design of the proposed codes utilizes two different encoding methods. The first method uses a large time diversity trellis encoder, and the second one uses the I-Q encoding technique. Both methods are expected to produce space-time codes that perform better than the codes presented in the literature. The proposed codes were simulated over different Rayleigh fading channels. Coding gains up to 3 dB have been observed over similar codes in the literature.

On understanding the nature of slow fading in LOS microcellular channels

Abstract: Our investigations in understanding the physical mechanism of the LOS microcellular channel reveal that the principle source of slow fading is the random interference pattern of a few strong contributing paths which causes what we term as deceptive shadowing. It is shown that in a comparative curve fitting of slow fading, Nakagami distribution also fits the fading data. Also in non-zero mean complex Gaussian channels, the segregation of slow and fast fading using moving mean normalization is illusionary as the fading parameters in both cases remain the same. We argue that radio link performance calculation based on the segregation of slow and fast fading are therefore unnecessary for Rice/lognormal or Nakagami/lognormal fading models and may be avoided in order to simplify complex analyses.

Performance Analysis of Wireless Systems With Doubly Selective Rayleigh Fading

Abstract: Theoretical error performances of wireless communication systems suffering from both doubly selective (time varying and frequency selective) Rayleigh fading and sampler timing offset are analyzed in this paper. Single-input-single-output systems with doubly selective fading channels are equivalently represented as discrete-time single-input-multiple-output (SIMO) systems with correlated frequency-flat fading channels, with the correlation information being determined by the combined effects of sampler timing phase, maximum Doppler spread, and power delay profile of the physical fading. Based on the equivalent SIMO system representation, closed-form error-probability expressions are derived as tight lower bounds for linearly modulated systems with fractionally spaced equalizers. The information on the sampler timing offset and the statistical properties of the physical channel fading, along with the effects of the fractionally spaced equalizer, are incorporated in the error-probability expressions. Simulation results show that the new analytical results can accurately predict the error performances of maximum-likelihood sequence estimation and maximum a posteriori equalizers for practical wireless communication systems in a wide range of signal-to-noise ratio. Moreover, some interesting observations about receiver oversampling and system timing phase sensitivity are obtained based on the new analytical results

Analytical Model for Outage Probability of Interference-Limited Systems over Extended Generalized-K Fading Channels

Abstract: In this letter, the novel analytical expressions for the probability density function, cumulative distribution function and moment generating function of the signal-to-interference ratio are derived for the interference-limited system operating over the extended generalized-K (EGK) fading channel. Since the EGK distribution can be used for modeling a great variety of fading channels, the new derived formulae have high level of generality and can be used for estimating the effects of interference and different composite fading channel conditions on system performance. The proposed analytical analysis is complemented by various outage performance results and confirmed by simulations.