Transmission control device, radio communication system, and calibration method

A radio communication system that includes a transmission control device and a plurality of transmission points connected to the transmission control device,

• the transmission control device comprising:
• a memory;
• and
• a processor connected to the memory, wherein
• the processor executes a process comprising:
• selecting a reference transmission point as a starting point of generating a link from among the plurality of transmission points of which each wirelessly transmits a signal;
• sequentially selecting the transmission points one by one for each hierarchy corresponding to a number of hops from the selected reference transmission point and retrieving ones of the transmission points for which radio quality between the ones and the selected transmission point satisfies a predetermined criterion;
• and
• generating a link between the selected transmission point and a transmission point, among the transmission points obtained as a result at the retrieving, not connected to others of the transmission points to connect the two transmission points, and
• each of the transmission points comprising:
• a transmitter circuit that performs a radio transmission process on a calibration signal and transmits the calibration signal after the radio transmission process via the generated link;
• and
• a receiver circuit that receives a calibration signal via the generated link and performs a radio reception process on the received calibration signal.

A calibration method comprising:

• selecting, using a processor, a reference transmission point as a starting point of generating a link from among a plurality of transmission points of which each wirelessly transmits a signal;
• sequentially selecting, using the processor, the transmission points one by one for each hierarchy corresponding to a number of hops from the selected reference transmission point and retrieving, using the processor, ones of the transmission points for which radio quality between the ones and the selected transmission point satisfies a predetermined criterion;
• and
• generating, using the processor, a link between the selected transmission point and a transmission point, among the transmission points obtained as a result at the retrieving, not connected to others of the transmission points to connect the two transmission points;
• transmitting and receiving a calibration signal via the link generated between the plurality of transmission points;
• and
• computing, using the processor, based on a channel estimation result that uses the calibration signal, a calibration coefficient calibrating a difference between transmission characteristics of a transmitter circuit and a receiver circuit included in the plurality of transmission points.