Wireless communication system, relay apparatus, wireless communication method and program

1 . A wireless communication system comprising: one or more first communication devices located in one or more small areas among a plurality of small areas into which a communication target area is divided; a relay device; and a second communication device, wherein

the relay device includes:

an antenna driver that drives one or more antennas to scan the plurality of small areas with one or more beams while emitting the beams to the communication target area, the beams each having an emission range narrower than the communication target area;

a receptor that acquires, from the antennas, a first wireless signal transmitted from the first communication devices located in the emission range;

a transmitter that transmits a second wireless signal depending on the first wireless signal to the second communication devices; and

a communication state measurer that derives a congestion degree of communication on a basis of a transmission frequency of the first wireless signal,

wherein

the communication state measurer that predicts the congestion degree of the relay device in the next orbiting by using the position information on the first communication devices in the current orbiting, and

the antenna driver drives the antennas to scan an inside of the communication target area with the beams at a scanning speed depending on the predicted congestion degree during the next orbiting.

2 . The wireless communication system according to claim 1 , wherein the antenna driver drives the antennas to reduce the scanning speed in a case where the congestion degree is greater than or equal to a threshold, and drives the antennas to increase the scanning speed in a case where the congestion degree is less than the threshold.

3 . The wireless communication system according to claim 1 , wherein the antenna driver drives the antennas to scan the plurality of small areas with the one or more beams in a state where the emission ranges are separated from each other.

4 . A wireless communication method executed by a wireless communication system including: one or more first communication devices located in one or more small areas among a plurality of small areas into which a communication target area is divided; a relay device; and a second communication device,

the wireless communication method comprising,

by the relay device:

driving one or more antennas to scan the plurality of small areas with one or more beams while emitting the beams to the communication target area, the beams each having an emission range narrower than the communication target area;

acquiring, from the antennas, a first wireless signal transmitted from the first communication devices located in the emission range; and

transmitting a second wireless signal depending on the first wireless signal to the second communication device; and

deriving a congestion degree of communication on a basis of a transmission frequency of the first wireless signal,

wherein

deriving a congestion degree of communication comprises predicting the congestion degree of the relay device in the next orbiting by using the position information on the first communication devices in the current orbiting, and

deriving one or more antennas comprises driving the antennas to scan an inside of the communication target area with the beams at a scanning speed depending on the predicted congestion degree during the next orbiting.

5 . A non-transitory computer readable medium storing a program for causing a computer to function as the relay device of the wireless communication system according to claim 1 .