DOWNLINK DS-CDMA PERFORMANCE OVER A MOBILE SATELLITE CHANNEL

Code division multiple access (CDMA) has been proposed for personal co mmunications networks for both terrestrial and satellite links. In thi s paper, we analyze the performance of the downlink (i.e., the base-to -mobile link) of a low earth orbiting (LEO) mobile satellite channel. An important characteristic of this fading channel is that the desired signal and the multiple access interference from all spot beams of th e corresponding satellite fade simultaneously. In this respect, the sa tellite downlink is also different from its terrestrial counterpart. A two-state fading channel model is considered. In the nonshadowed stat e, the signal envelope is characterized by Rician statistics and in th e shadowed state by the Rayleigh statistics. We analyze the probabilit y of error performance when coherent detection, diversity, spectrum sh aring by two service providers, and forward error correction are emplo yed.