Performance of an adaptive fuzzy rule-based closed-loop power control in low earth orbit mobile satellite communication systems

In this paper we investigate the effect of an adaptive fuzzy closed-loop power control (CLPC) scheme on the performance of the DS/CDMA-based mobile satellite communication systems with a low earth orbit (LEO) satellite constellation in which the long round trip delay (RTD) and fading effect according to elevation angle should be considered. Since the RTD between mobile terminals (MT) and earth station (ES) via satellite in LEO is on the order of 10-20 ns and fading is more severe, a conventional closed-loop power control with fixed step size is much less effective than it is on a terrestrial channel. In order to cope with this performance degradation, we propose a closed-loop power control scheme by adaptive fuzzy rule-based step size decision method which is based on fuzzy logic control (FLC). So, in this paper, we compare the performance of the adaptive fuzzy closed-loop power control with that of the conventional fixed step closed-loop power control, we show that the proposed method makes better performance.