Interference canceling by variable division of feeder link transmission band in multiple-gateway HAPS system

A relay communication station incorporated in an aerial-staying type communication relay apparatus to relay a radio communication of a terminal apparatus, the relay communication station comprising:

• a feeder-link communication section that transmits and receives relay signals different from each other on a same frequency in feeder links between the feeder-link communication section and plural gateway stations that are time-synchronized with each other;
• and
• an interference suppression section that suppresses interference between plural feeder links formed with the plural gateway stations,
• wherein the feeder-link communication section receives pilot signals respectively transmitted from the plural gateway stations, and separates each of the received plural pilot signals with a filter,
• wherein the interference suppression section performs a first interference suppression process and a second interference suppression process by switching therebetween,
• wherein the first interference suppression process suppresses an interference signal that causes an interference by a transmission signal transmitted from the gateway station and received with a directional beam corresponding to another gateway station, by using a propagation path response estimated with one frequency in the transmission signal band as an estimation frequency based on a reception result of the pilot signal without dividing a transmission signal band of the feeder link, and
• wherein the second interference suppression process divides the transmission signal band of the feeder link into plural divided frequency bands and suppresses the interference signal by using a propagation path response estimated with one frequency in the divided frequency band as an estimation frequency based on the reception result of the pilot signal, for each of the divided frequency bands.

A feeder-link interference suppression method in a relay communication station that is incorporated in an aerial-staying type communication relay apparatus and relays a radio communication of a terminal apparatus, the feeder-link interference suppression method comprising:

• receiving pilot signals respectively transmitted from plural gateway stations that are time-synchronized with each other;
• separating each of the received plural pilot signals with a filter;
• and
• performing a first interference suppression process and a second interference suppression process by switching therebetween,
• wherein the first interference suppression process suppresses an interference signal that causes an interference by a transmission signal transmitted from the gateway station and received with a directional beam corresponding to another gateway station, by using a propagation path response estimated with one frequency in the transmission signal band as an estimation frequency based on a reception result of the pilot signal without dividing a transmission signal band of the feeder link, and
• wherein the second interference suppression process divides the transmission signal band of the feeder link into plural divided frequency bands and suppresses the interference signal by using a propagation path response estimated with one frequency in the divided frequency band as an estimation frequency based on the reception result of the pilot signal, for each of the divided frequency bands.

A non-transitory computer readable medium containing software that is executed by a computer or a processor installed in a relay communication station that is incorporated in an aerial-staying type communication relay apparatus and relays a radio communication of a terminal apparatus, the software comprising:

• executable code that transmits and receives relay signals different from each other on a same frequency in feeder links between the relay communication station and plural gateway stations that are time-synchronized with each other;
• executable code that receives pilot signals respectively transmitted from the plural gateway stations;
• executable code that separates each of the received plural pilot signals with a filter;
• and
• executable code that performs a first interference suppression process and a second interference suppression process by switching therebetween,
• wherein the first interference suppression process suppresses an interference signal that causes an interference by a transmission signal transmitted from the gateway station and received with a directional beam corresponding to another gateway station, by using a propagation path response estimated with one frequency in the transmission signal band as an estimation frequency based on a reception result of the pilot signal without dividing a transmission signal band of the feeder link, and
• wherein the second interference suppression process divides the transmission signal band of the feeder link into plural divided frequency bands and suppresses the interference signal by using a propagation path response estimated with one frequency in the divided frequency band as an estimation frequency based on the reception result of the pilot signal, for each of the divided frequency bands.