DS-CDMA satellite diversity reception for personal satellite communication: Satellite-to-mobile link performance analysis

The satellite to-mobile link of a mobile personal satellite communication system employing power-controlled direct-sequence code-division multiple access (DS-CDMA) and exploiting satellite diversity is analyzed and its performance compared with a more traditional communication system utilizing single-satellite reception. The semianalytical model developed has been thoroughly validated by means of extensive Monte Carlo computer simulations. System capacity and performance have been numerically evaluated in the presence of a realistic operating scenario, including antenna radiation pattern, imperfect power control, shadowing, and crosspolarization effects. It is shown how the capacity gain provided by diversity reception considerably shrinks in the presence of increasing traffic or in the case of mild shadowing conditions. Moreover, the quantitative results tend to indicate that to combat system capacity reduction due to the intrasystem interference, no more than two satellites sharing the same frequency slot must be active over the same region.