Fading distribution

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

Model for computing aggregate interference from secondary cellular network in presence of correlated shadow fading

Abstract: The estimation of the total interference generated from a secondary system is essential for protecting the primary receivers. However, interference level estimation from a large number of secondary transmitters is a challenging problem. In this paper, we estimate the aggregate interference as an integration over the power spatial density in the secondary system's deployment area. We modify such integration-based model to contain the correlation in shadow fading. We apply the model on a cellular system downlink and study how well the proposed analytical model describes the interference level in correlated and non-correlated slow fading environment. The analysis indicates that for cell size less than five km the integration based model describes interference relatively well. For larger cell sizes, the interference is dominated by a few strong sources and has to be computed by summing over the power of all individual transmitters. It is also illustrated that the full correlated and independent slow fading provide two extremes of the amount of generated interference. The complex estimation of the impact of the fading cross correlation can be avoided by using those two extreme models as bounds to the interference level.

Energy detection of unknown signals in Gamma-shadowed Rician fading environments with diversity reception

Abstract: This study presents a comprehensive performance analysis of an energy detector over Gamma-shadowed Rician fading channels, namely Rician fading channels with the fluctuating line-of-sight components following the Gamma distribution. This composite multi-path/shadowing model has been shown to provide a remarkably accurate fading characterisation while leading to closed-form expressions for important channel statistics. Rapidly convergent infinite series representations are firstly derived for the average probability of detection and the area under the receiver operating characteristic curve for the no-diversity reception case. These results are then extended to the case of maximal ratio, equal gain and selection diversity. To this end, novel analytical expressions for the statistics of the end-to-end signal-to-noise ratio of equal gain and selection diversity receivers, operating over Gamma-shadowed Rician fading channels are derived. Analytical results are substantiated by Monte Carlo simulation, as well as by extensive numerically evaluated results.

Exact bit error rate calculations for synchronous MC-CDMA over a Rayleigh fading channel

Abstract: The bit error rate of a synchronous multicarrier code-division multiple-access system operating in a Rayleigh fading channel is calculated based on a moment generating function method, without any assumption on the distribution of multiple access interference. Two closed-form BER expressions are derived. Moreover, the BER can be accurately evaluated by using a Gauss-Chebyshev quadrature rule based numerical approach.

Service outage based power and rate allocation for parallel fading channels

Abstract: The service outage based allocation problem explores variable rate transmission schemes and combines the concepts of ergodic capacity and capacity versus outage for fading channels. A service outage occurs when the transmission rate is below a given basic rate r/sub o/. The allocation problem is to maximize the expected rate subject to the average power constraint and the constraint that the outage probability is less than /spl epsiv/. A general class of probabilistic power allocation schemes is considered in this problem. In an M-parallel fading channel model, the optimum power allocation scheme is derived and is shown to be deterministic except at channel states of a boundary set. The resulting service outage average rate is between the outage capacity times 1-/spl epsiv/ and the ergodic capacity.

On the Capacity of Generalized-K Fading Channels

Abstract: This paper investigates the capacity of generalized- K fading channels. This very general model describes accurately composite multipath/shadowing fading channels which are widely encountered in real-world environments. We derive closed-form expressions for three adaptive transmission techniques, namely, i) optimal rate adaptation with constant power, ii) optimal power and rate adaptation, and iii) channel inversion with fixed rate. The analytical expressions obtained match perfectly the results obtained by computer simulations. These expressions provide a good tool to assess the spectral efficiency of the aforementioned adaptive transmission techniques over composite channels.