A radio communication system comprising: a plurality of communication devices (11-1 - 11-n), wherein a first communication device among the plurality of communication devices transmits a signal addressed to a second communication device among the plurality of communication devices to a third communication device of one or more third communication devices among the plurality of communication devices; the third communication device relays the radio communication between the first communication device and the second communication device by transferring the signal to a next hop third communication device (11-3, 11-4) in a relay order among the one or more third communication devices or to the second communication device; each of the plurality of communication devices stores a common set of resource pools including a plurality of resources each of which specifies frequency and time usable by each of the plurality of communication devices for direct radio communication with a next hop communication device among the plurality of communication devices; the first communication device selects a resource pool from the set of resource pools, and transmits the signal to the third communication device by the use of a resource included in the selected resource pool; and in response to receiving the signal, each of the one or more third communication devices selects a resource pool from the set of resource pools based on a hop count at the respective third communication device indicating the number of transmission hops from the first communication device, and the resource pool selected by the first communication device, and transfers the signal to the next hop third communication device (11-3, 11-4) or to the second communication device by the use of a resource included in the selected resource pool. a plurality of communication devices (11-1 - 11-n), wherein a first communication device among the plurality of communication devices transmits a signal addressed to a second communication device among the plurality of communication devices to a third communication device of one or more third communication devices among the plurality of communication devices; the third communication device relays the radio communication between the first communication device and the second communication device by transferring the signal to a next hop third communication device (11-3, 11-4) in a relay order among the one or more third communication devices or to the second communication device; each of the plurality of communication devices stores a common set of resource pools including a plurality of resources each of which specifies frequency and time usable by each of the plurality of communication devices for direct radio communication with a next hop communication device among the plurality of communication devices; the first communication device selects a resource pool from the set of resource pools, and transmits the signal to the third communication device by the use of a resource included in the selected resource pool; and in response to receiving the signal, each of the one or more third communication devices selects a resource pool from the set of resource pools based on a hop count at the respective third communication device indicating the number of transmission hops from the first communication device, and the resource pool selected by the first communication device, and transfers the signal to the next hop third communication device (11-3, 11-4) or to the second communication device by the use of a resource included in the selected resource pool.