Effect on total system capacity due to imperfect power control for band sharing between CDMA based non-geostationary satellite-PCNs

The demand for global telephony services for mobile users requires the use of constellations of non-geostationary orbits. The proposed S-PCNs are Iridium, Inmarsat-P, Globalstar, Odyssey and Ellipso. The first two systems propose to use a time division multiple access (TDMA) scheme and the others code division multiple access (CDMA) scheme. It is claimed that CDMA based S-PCNs can share the allocated frequency bands due to the interference resistant property of CDMA. Spectrum sharing must be based on defined interference criteria being satisfied. The interference events are based on the statistics of carrier to interference ratio (C/I). For this a computer simulation was developed to model the dynamic nature of any constellation, and produces all the statistical values of C/I to a mobile in a fading channel. The simulation includes constellations results of proposed S-PCNs with multi-spotbeam antennas (MBA). We present the results of the investigation on the effect of imperfect power control on the total system capacity for a totally overlapped band sharing scenario. Results for a band segmented scenario are also presented for comparison.