Approximate Outage Analysis of Land Mobile Satellite Systems in Lognormally Shadowed Rician Channels

Abstract

Among the proposed models for land mobile satellite (LMS) channels, the shadowed Rice model proposed originally by Loo, has found wide applications in different frequency bands. In Loo's model, it is assumed that the received signal is affected by nonselective Rice fading with lognormal shadowing on the direct component only, while the diffuse scattered component has constant average power level. The resulting composite probability density function (PDF) includes an infinite-range integral and is not available in closed-form, thereby making the performance evaluation of LMS communication links in these channels cumbersome. To bypass this problem, in this paper an approximation method is developed which makes it possible to describe the envelope PDF as a sum of weighted Rice's PDFs. Therefore, in contrast with Loo's PDF, the proposed method leads to an easyto-use, closed-form approximate expression for the PDF and also for the most statistical characteristics, such as cumulative distribution function and moments of the signal envelop in shadowed Rice channels. Based on the derived expressions, the performance analysis of a single receiver operating over lognormally shadowed Rice channel is investigated in terms of the outage probability. Numerically evaluated results show the good accuracy of the proposed approximation method.

Performance Analysis of Land Mobile Satellite Communication Systems with Equal-Gain Combining over Shadowed-Rice Fading Channels

“…Presented numerical results in [8] show that the proposed approximate model matches very well with different sets of published channel data, Interestingly, the proposed model provides a similar fit to the experimental data as the well-accepted Loo's model but with significantly less computational burden.…”

“…In this paper based on the developed approximate model for SR fading channels in [8], the sum of independent SR distributed random variables has been considered and its CDF and PDF has been described using Beaulieu series. Analytical tractability of the developed model and its suitable form [8] leads to closed form expressions for the related Beaulieu series coefficients.…”

“…Analytical tractability of the developed model and its suitable form [8] leads to closed form expressions for the related Beaulieu series coefficients. The knowledge of these distributions is crucial for the performance analysis of LMS communication systems employing EGC diversity receiver over SR fading channels.…”

“…In this section, the proposed approximate SR model is introduced briefly [8]. Following [1], a SR random variable, R ∼ S R (b 0 , μ, σ ), is defined as a Rice random variable with random LOS component z, i.e.…”

“…In this section the CDF and the PDF of the sum of independent SR RVs are derived based on the proposed approximate SR model [8] and by using the Beaulieu series approach [11].…”