Abstract: In a drone-type radio relay apparatus, it is provided of an antenna system capable of suppressing an inclination of an antenna due to a strong wind during a stationary flight (hovering). The antenna system is provided with a long-shaped antenna 110 connected to a relay station via a cable, and an antenna guide mechanism that is fixed to a body of a drone and guides the antenna so as to be movable in an up-down direction of a basic attitude of the drone.

Abstract: It is prevented of degradation of communication quality caused by estimation errors of plural path differences between plural antennas for feeder link (FL antennas) incorporated in an aerial-staying type communication relay apparatus and plural gateway (GW) stations.

Abstract: It is provided of a system capable of estimating a current position of a terminal apparatus, even if a terminal apparatus for mobile communication is in a condition of non-receiving or inability to receive GNSS signals. A radio relay apparatus, in which a relay station mounted on a drone, transmits radio waves from a directional antenna toward the ground while flying in an upper airspace above a target area on the ground, and transmits position information on its own apparatus obtained based on the GNSS signal, to an information processing apparatus. The terminal apparatus measures a reception power or a reception quality of radio waves transmitted from the radio relay apparatus, and transmits reception measurement information regarding the measurement result of the reception power or the reception quality, to the information processing apparatus.

Abstract: It is provided of a system capable of estimating a current position of a terminal apparatus, even if a terminal apparatus for mobile communication is in a condition of non-receiving or inability to receive GNSS signals. A radio relay apparatus, in which a relay station mounted on a drone, transmits radio waves from a directional antenna toward the ground while flying in an upper airspace above a target area on the ground, and transmits position information on its own apparatus obtained based on the GNSS signal, to an information processing apparatus. The terminal apparatus measures a reception power or a reception quality of radio waves transmitted from the radio relay apparatus, and transmits reception measurement information regarding the measurement result of the reception power or the reception quality, to the information processing apparatus.

Abstract: A downlink interference is dynamically suppressed in a multi-feeder link of a same frequency between an aerial-floating type communication relay apparatus and plural gateway (GW) stations with a simple configuration.

Abstract: Interferences in multi-feeder links on a same frequency between an aerial-floating type communication relay apparatus and plural gateway (GW) stations are dynamically suppressed. Each of the plural GW stations transmits plural pilot signals with frequencies different from each other in the feeder link.

Abstract: It is dynamically suppressed of a downlink interference in a reverse link of a multi-feeder link of a same frequency between an aerial-staying type communication relay apparatus and plural gateway (GW) stations. A relay communication station of the communication relay apparatus estimates plural propagation path responses respectively between plural GW stations and an antenna for feeder link of the communication relay apparatus based on reception results of plural pilot signals received from each of plural GW stations. The relay communication station calculates a weight for suppressing an interference signal that causes an interference by a transmission signal transmitted from a relay communication station to the GW station and received by another GW station, based on the plural propagation path responses, with respect to each of the plural GW stations.

Abstract: Interference in multi-feeder links of a same frequency between an aerial-floating type communication relay apparatus and plural gateway (GW) stations is suppressed. A transmission signal band of a feeder link is divided into plural divided frequency bands, and plural propagation path responses between plural GW stations and an antenna for feeder link of the communication relay apparatus are respectively estimated with respect to each of plural divided frequency bands, by setting a center frequency of the divided frequency band as an estimation frequency, based on a reception result of the pilot signals respectively received from the plural GW stations and separated from each other. A weight for suppressing an interference signal that causes an interference by a transmission signal transmitted from the GW station and received with a directional beam corresponding to another GW station is calculated for each of the divided frequency bands based on the plural propagation path responses.

Abstract: While suppressing a power consumption of an aerial-floating type communication relay apparatus, an interference in a multi-feeder link of a same frequency between the communication relay apparatus and plural gateway (GW) stations is suppressed. A relay communication station of the communication relay apparatus performs a first interference suppression process and a second interference suppression process by switching therebetween. The first interference suppression process suppresses an interference signal that causes an interference by a transmission signal transmitted from a gateway station and received with a directional beam corresponding to another gateway station, by using a propagation path response estimated with one frequency in a transmission signal band as an estimation frequency based on a reception result of a pilot signal without dividing a transmission signal band of a feeder link.

Abstract: A downlink interference is dynamically suppressed in a multi-feeder link of a same frequency between an aerial-floating type communication relay apparatus and plural gateway (GW) stations with a simple configuration.

Abstract: It is dynamically suppressed of a downlink interference in a reverse link of a multi-feeder link of a same frequency between an aerial-staying type communication relay apparatus and plural gateway (GW) stations. A relay communication station of the communication relay apparatus estimates plural propagation path responses respectively between plural GW stations and an antenna for feeder link of the communication relay apparatus based on reception results of plural pilot signals received from each of plural GW stations. The relay communication station calculates a weight for suppressing an interference signal that causes an interference by a transmission signal transmitted from a relay communication station to the GW station and received by another GW station, based on the plural propagation path responses, with respect to each of the plural GW stations.

Abstract: While suppressing a power consumption of an aerial-floating type communication relay apparatus, an interference in a multi-feeder link of a same frequency between the communication relay apparatus and plural gateway (GW) stations is suppressed. A relay communication station of the communication relay apparatus performs a first interference suppression process and a second interference suppression process by switching therebetween. The first interference suppression process suppresses an interference signal that causes an interference by a transmission signal transmitted from a gateway station and received with a directional beam corresponding to another gateway station, by using a propagation path response estimated with one frequency in a transmission signal band as an estimation frequency based on a reception result of a pilot signal without dividing a transmission signal band of a feeder link.

Abstract: Interference in multi-feeder links of a same frequency between an aerial-floating type communication relay apparatus and plural gateway (GW) stations is suppressed. A transmission signal band of a feeder link is divided into plural divided frequency bands, and plural propagation path responses between plural GW stations and an antenna for feeder link of the communication relay apparatus are respectively estimated with respect to each of plural divided frequency bands, by setting a center frequency of the divided frequency band as an estimation frequency, based on a reception result of the pilot signals respectively received from the plural GW stations and separated from each other. A weight for suppressing an interference signal that causes an interference by a transmission signal transmitted from the GW station and received with a directional beam corresponding to another GW station is calculated for each of the divided frequency bands based on the plural propagation path responses.

Abstract: Interferences in multi-feeder links on a same frequency between an aerial-floating type communication relay apparatus and plural gateway (GW) stations are dynamically suppressed. Each of the plural GW stations transmits plural pilot signals with frequencies different from each other in the feeder link.

Abstract: Provide a system capable of improving a frequency utilization efficiency of a feeder link of an aerial-floating type communication relay apparatus. A system, which has an aerial-staying type communication relay apparatus that wirelessly communicates with a terminal apparatus, is provided with plural gateway stations that perform space-division multiplexing communication for transmitting and receiving different relay signals from each other on a same frequency in a feeder link with the aerial-stay type communication relay apparatus. Each of the plural gateway stations may be provided with an antenna control section that controls an antenna for feeder link so as to track the aerial-stay type communication relay apparatus.

Abstract: Provide a system capable of improving a frequency utilization efficiency of a feeder link of an aerial-floating type communication relay apparatus. A system, which has an aerial-staying type communication relay apparatus that wirelessly communicates with a terminal apparatus, is provided with plural gateway stations that perform space-division multiplexing communication for transmitting and receiving different relay signals from each other on a same frequency in a feeder link with the aerial-stay type communication relay apparatus. Each of the plural gateway stations may be provided with an antenna control section that controls an antenna for feeder link so as to track the aerial-stay type communication relay apparatus.

Abstract: A base station, a communication system and a time synchronization method between base stations are provided, which are capable of performing a time synchronization with another base station using a downlink signal of the other base station cell in which the own cell is located, without stopping transmission of the own base station even during operation.

Abstract: A base station, a communication system and a time synchronization method between base stations are provided, which are capable of performing a time synchronization with another base station using a downlink signal of the other base station cell in which the own cell is located, without stopping transmission of the own base station even during operation.

Abstract: A base station, a mobile communication system and a handover control method are provided, which are capable of preventing a handover failure and a ping-pong handover phenomenon which are caused by an interference from a neighboring cell to a serving cell. When a received power difference (S2?S1) between a received power S2 from a neighboring second base station, which is fed back from a mobile station, and a received power S1 from first base station, becomes larger than a predetermined threshold value, the first base station to which the mobile station is connected requests the second base station to stop a transmission of a downlink signal including at least one of a data signal and a control signal. In response to the transmission-stop request, the second base station performs a determination of a radio resource in which the transmission of the downlink signal is to be stopped and a notification of the radio resource to the first base station, and stops a transmission of a downlink signal.

Abstract: A base station apparatus capable of preventing occurrence of a communication delay when performing an inter-cell interference control using an ABS is provided. The base station apparatus is capable of performing an inter-cell interference control by setting an ABS pattern with one cycle of a predetermined number of subframes, and when the ABS pattern is to be switched, changes an MCS (Modulation and Coding Scheme) index value to be determined by an adaptive modulation control, for a communication within a predetermined period of time on or before a switching time of the switching, with respect to a subframe in which a communication with a mobile station apparatus is allowed before switching the ABS pattern.