Inmarsat P

The Inmarsat-P system is planned for the year 2000 and represents the preliminary stage for the future SPC system. Inmarsat-P no longer operates with GEO satellites, but with ten MEO satellites that orbit the earth in six hours on two polar orbits. The slow orbits result in cell dwell times of about 12 minutes, after which a handover to the next satellite takes place. The frequency bands for the uplink and downlink are L-band (1.6 GHz) and S-band (2.5 GHz). The link between the satellite and the gateway, or in the opposite direction, takes place at 11 GHz and 14 GHz, respectively. Each satellite has a cell structure supporting 61 cells. In addition, the possible utilization is 4000 channels per Inmarsat P satellite.

Dual- mode mobiles are to be usedin this system: Handsets that are suitable for both terrestrial cellular networks and satellite radio networks.