Second‐order statistics of system with N‐branch microdiversity and L‐branch macrodiversity operating over gamma shadowed Nakagami‐m fading channels

Abstract

SUMMARYThe problem concerning short‐term fading and long‐term fading (shadowing) and their deleterious effects on wireless systems performance has been in focus for a long time. In this paper, motivated by the results of propagation measurements in land‐mobile and indoor‐mobile systems, and by the fact that gamma distribution can describe shadowing reliably, Nakagami‐m distribution is used to model the signal envelope and gamma distribution is used to model the average signal power. Receive diversity with maximal‐ratio combining and selection combining is implemented at the microlevel and macrolevel, respectively. The general case is explored, which assumes that microdiversity and macrodiversity are provided through arbitrary number of channels. Because shadowing has larger correlation distance than short‐term fading, correlated macrodiversity channels are studied. This paper investigates the dynamics of the received signal. A novel rapidly converging infinite‐series expression for average level crossing rate and average fade duration are obtained. Numerical results are graphically presented to examine the impact of fading severity, shadowing severity, number of diversity branches at the microlevel, number of base stations and correlation between base stations to the system's performance. Computer simulations are also performed to verify the validity and the accuracy of proposed theoretical analysis. Copyright © 2012 John Wiley & Sons, Ltd.

On geometric statistics with diversity in multipath scattering channels

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Outage Probability of Macrodiversity Reception in the Presence of Fading and Weibull Co-Channel Interference

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Second‐order statistics of multiuser relay cooperation systems over Nakagami‐m fading channels

“…Fortunately, the issues can be addressed by investigating the second-order statistics, that is, level crossing rate (LCR) and average fading duration (AFD). The LCR is defined as the number of times per unit duration that the envelope of a fading channel crosses a given value in the negative direction [26,27]. The AFD corresponds to the average length of time the envelop remains under this value once it crosses it in the negative direction [26,27].…”

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