Diversity Reception over Correlated Ricean Fading Satellite Channels

In this paper, the performance of switch and stay combing (SSC) diversity receivers operating over correlated Ricean fading channels, is studied. By representing the bivariate Ricean distribution as infinite series the probability density function (PDF) of the SSC output signal-to-noise ratio (SNR) has been derived. Capitalizing on this PDF the moments of the output SNR and the corresponding cumulative distribution function (CDF) have been also obtained. Furthermore, an analytical expression for the moments generating function (MGF) is derived and by employing the MGF-based approach the average bit error probability (ABEP) for several modulation schemes is studied. Finally, various performance evaluation results, such as average output SNR (ASNR), amount of fading (AoF), outage probability (Pout) and ABEP are presented. INTRODUCTION The mobile radio channel is particularly dynamic due to multipath propagation, which has a strong negative impact on the average bit error probability (ABEP) of any modulation technique [1]. Diversity is a powerful communication receiver technique used to compensate for fading channel impairments. The most important diversity reception methods employed in digital communication receivers are maximal-ratio combining (MRC), equal gain combining (EGC), selection combining (SC) and switch and stay combing (SSC) [2]. Among them, SSC diversity is the least complex and can be used in conjunction with coherent, non-coherent and differentially coherent modulation schemes. It is well known that in many real life communication scenarios the combined signals are correlated [2]. A typical example for such signal correlation exists in small size mobile terminal units where the distance between diversity antenna is small. Due to this correlation between the signals received at the diversity branches, there is degradation in the diversity gain. As far as the Ricean distribution is concerned, it is often used to model propagation paths consisting of one strong direct line-of-sight (LoS) signal and many random reflected and usually weaker signals. Such fading environments are typically observed in microcellular and mobile satellite radio links [2]. Especially for mobile satellite communications, the Ricean distribution is used to accurately characterize the mobile satellite channel, for the