The Role of Satellite Systems in Future Aeronautical Communications

1. Aeronautical Communications Systems must be reliable and efficient. Connection to Aeronautical networks is considered to be achieved by satellites with large coverage areas especially over oceanic regions during long-haul flights. The service concept needs to take into account today's peculiarities of satellite communications, thus it must cope with the available or in near future available satellite technology and interworking must be performed at aircraft interface level with the satellite segment. Only restricted satellite data rates will be available in the near future, thus the bandwidth that is requested by standard interfaces of the wireless standards needs to be adapted to the available bandwidth (typically: 432 kb/s in downlink, 144 kb/s up-link (Inmarsat), or 5 Mb/s in down-link, 1.5 Mb/s in up-link. Furthermore, dynamic bandwidth management is needed to allocate higher bit rates from temporarily unused services to other services. Currently, few geostationary satellites such as the Inmarsat fleet are available for two-way communications that cover the land masses and the oceans. Ku-band may be used on a secondary allocation basis for Aeronautical Mobile Satellite services (AMSS) but bandwidth is scarce and coverage is mostly provided over continents. K/Ka-band satellites will be launched in the near future again here continental coverage is mainly intended.