A hybrid cellular radio communication system comprising - a network of terrestrial base stations (6, 8, 10, 12) interconnected together and connected to a terrestrial infrastructure, each able, in an associated frequency sub-band, to emit in a forward downlink (56, 58, 60, 62) and/or to receive in a reverse uplink (66, 68, 70, 72) service radiocommunication signals and defining, each by its radio range, an uplink and/or a downlink coverage of a terrestrial radiocommunication cell (76, 78, 80, 82), - at least one communication satellite (16, 18, 20) connected to the terrestrial infrastructure by at least one access station through a bidirectional backhaul link (26, 28), and able to emit in a forward satellite downlink (96, 98, 100, 102, 110) and/or to receive in a reverse satellite uplink (86, 88, 90, 92, 100) of the service radiocommunication signals distributed in satellite radiocommunication beams (130, 132, 134; 430, 432, 434), the satellite beams (130, 132, 134, 430, 432, 434) each being associated with a frequency band and each defining by its ground radio range an uplink and/or a downlink satellite coverage of a satellite umbrella cell (136, 138, 140, 436, 438, 440), - a set of communication service terminals (32, 34, 36, 38, 40, 42, 44, 46, 48) able to emit and/or receive the radiocommunication signals, and distributed in the terrestrial cells (76, 78, 80, 82) and satellite cells (136, 138, 140; 436, 438, 440), - means for allocating transmission resources, each being defined by a frequency sub-band and/or a time slot and/or a code, to the base stations (6, 8, 10, 12), respectively to the satellite beams (130, 132, 134, 430, 432, 434), the sub-bands being determined relative to a first frequency band allocated to all the base stations (6, 8, 10, 12) and to a second frequency band allocated to the satellite beams (130, 132, 134, 430, 432, 434), characterized in that the base stations (6, 8, 10, 12) are distributed in a discernable manner by satellite cell (136, 138, 140, 436, 438, 440) according to a time-invariant distribution function, and the system comprises means (52; 452) for maintaining the congruence, continuously and in the same link direction, of the coverage of each satellite cell (136, 138, 140, 436, 438, 440) relative to the coverages of the terrestrial cells (76, 78, 80, 82) associated to the base stations (6, 8, 10, 12) contained in said satellite cell, the coverage of a satellite cell (136; 436) being congruent with a predetermined set of terrestrial coverages when said predetermined set of coverages is totally included in the satellite coverage. - a network of terrestrial base stations (6, 8, 10, 12) interconnected together and connected to a terrestrial infrastructure, each able, in an associated frequency sub-band, to emit in a forward downlink (56, 58, 60, 62) and/or to receive in a reverse uplink (66, 68, 70, 72) service radiocommunication signals and defining, each by its radio range, an uplink and/or a downlink coverage of a terrestrial radiocommunication cell (76, 78, 80, 82), - at least one communication satellite (16, 18, 20) connected to the terrestrial infrastructure by at least one access station through a bidirectional backhaul link (26, 28), and able to emit in a forward satellite downlink (96, 98, 100, 102, 110) and/or to receive in a reverse satellite uplink (86, 88, 90, 92, 100) of the service radiocommunication signals distributed in satellite radiocommunication beams (130, 132, 134; 430, 432, 434), the satellite beams (130, 132, 134, 430, 432, 434) each being associated with a frequency band and each defining by its ground radio range an uplink and/or a downlink satellite coverage of a satellite umbrella cell (136, 138, 140, 436, 438, 440), - a set of communication service terminals (32, 34, 36, 38, 40, 42, 44, 46, 48) able to emit and/or receive the radiocommunication signals, and distributed in the terrestrial cells (76, 78, 80, 82) and satellite cells (136, 138, 140; 436, 438, 440), - means for allocating transmission resources, each being defined by a frequency sub-band and/or a time slot and/or a code, to the base stations (6, 8, 10, 12), respectively to the satellite beams (130, 132, 134, 430, 432, 434), the sub-bands being determined relative to a first frequency band allocated to all the base stations (6, 8, 10, 12) and to a second frequency band allocated to the satellite beams (130, 132, 134, 430, 432, 434),