Patent attributes
In a mobile communication system using a mobile-type radio relay apparatus that forms a plurality of cells toward the ground or the sea while moving in an upper airspace, a deterioration in communication quality, which is caused by a Doppler shift of a reception signal due to a relative movement of a radio relay apparatus with respect to a terminal apparatus of each of a plurality of cells or a feeder station on the ground or on the sea, is suppressed. The communication system comprises a mobile-type radio relay apparatus that is disposed movably by flying in an upper airspace, forms a plurality of cells from an antenna at a predetermined altitude toward the ground or the sea, and performs a radio communication with a terminal apparatus located in each of the plurality of cells. The communication system comprises an estimation section for estimating a Doppler shift in at least one of a radio communication of a service link between the terminal apparatus located in the cell and the radio relay apparatus and a radio communication of a feeder link between the radio relay apparatus and a feeder station on the ground or on the sea, and a correction section for correcting a frequency of the at least one radio communication based on an estimation result of the Doppler shift.
