Softbank Corporation

Hapsmobile Inc.

Ntt Mobile Communications Network, Inc.

Teruya Fujii

Takafumi Fujii

Takao Okamawari

Liang Zhang

Atsushi Nagate

Masaaki Yoshimi

Daigo Ogata

Katsunori Hamada

Shota Shiobara

Daisuke Maeda

Tatsuaki Wakabayashi

Junichi Miyakawa

Kiyohito Nagata

Mitsukuni Konishi

Kazuhiko Kakinuma

Sho Nabatame

Noboru Kanazawa

A base station and a radio communication system obtain a desired communication quality by suppressing an influence of interference between a cell in an upper-airspace area and a cell in a terrestrial area when a terminal apparatus is used in the upper-airspace area. The base station is provided with an antenna, a radio communication section for forming a first cell and a second cell above the first cell and performs radio communication via the antenna to and from terminal apparatuses in the different cells. A radio resource of the same frequency band is assigned to communicate with the terminal apparatus in either the first cell or the second cell in a same time period. When the radio resource is assigned to the terminal apparatus in the second cell, a transmission power control reduces transmission power that is applied to the terminal apparatus to which the radio resource is assigned.

Base station and radio communication system

Provided is a repeater-type radio relay system that can prevent loop interference of radio waves with the same frequency and does not require a frequency for relaying. The radio relay system is provided with one or more optical fibers for relaying an optical communication between a relay-source radio relay apparatus and a relay-destination radio relay apparatus. The relay-source radio relay apparatus has a network-side communication section for communicating with a mobile-communication network side, and an electro-optical signal conversion section of relay source for converting between an electrical signal in the mobile-communication network side received from the network-side communication section and an optical signal propagating through the optical fiber. The relay-destination radio relay apparatus has a terminal-side communication section for wirelessly communicating with the terminal apparatus side, and an electro-optical signal conversion section of relay destination for converting between an electric signal in the terminal apparatus side received from the terminal-side communication section and an optical signal propagating through the optical fiber.

Radio relay system

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 antennaconnected 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.

Antenna system and radio relay apparatus

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. The aerial-staying type communication relay apparatus estimates plural first path differences Δdrespectively between the plural GW stations and the plural FL antennas with reference to a main path, based on plural pilot reception signals received from the plural GW stations, obtains plural correction values corresponding to the plural first path differences, based on the plural pilot reception signals, estimates a propagation path response in the transmission signal band of the feeder link, based on plural corrected second path differences Δobtained by respectively correcting the plural first path differences with plural correction values, calculates and stores reception weights for suppressing interference signals, and applies the plural reception weights to reception signals received via the plural antennas for feeder link, with respect to each of the plural gateway stations.

Communication relay apparatus, system, interference suppression method and program

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. The information processing apparatus estimates the position of the terminal apparatus in the target area, based on the position information from the radio relay apparatus received in a flight time period during which the radio relay apparatus flies in the upper airspace above the target area and the reception measurement information from the terminal apparatus. The information processing apparatus may estimate the position where the reception power or the reception quality from the terminal apparatus is maximum, as the position of the terminal apparatus.

System, radio relay apparatus, information processing apparatus and method for specifying position of terminal apparatus

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. A plurality of pilot signals, which are spectrally spread using a plurality of spread codes orthogonal to each other, are transmitted and received between the relay communication station of the aerial-staying type communication relay apparatus and plural GW stations, a propagation path response between plural GW stations and an antenna for feeder link of the communication relay apparatus in a transmission signal band of the feeder link is estimated based on reception results in which the plural pilot signals are spectrally inverse-spread, plural weights respectively corresponding to the plural of GW stations are calculated based on the plural propagation path responses, and with respect to each of the plural GW stations, a signal to be transmitted and received via a directional beam corresponding to another GW station is multiplied by the weight corresponding to the other GW station and subtracted from a signal to be transmitted and received via the directional beam corresponding to the GW station.

Propagation path response estimation and interference canceling using spread-spectrum pilot signal in multi-feeder link of HAPS

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. A relay communication station of a communication relay apparatus: estimates a propagation path response by calculating plural path differences between the plural GW stations and an antenna for feeder link of a communication relay apparatus, based on reception results of the plural pilot signals received from each of the plural GW stations; calculates a weight for suppressing an interference signal that causes an interference by a transmission signal transmitted from the GW stations and received by a directional beam corresponding to other GW stations, based on the plural propagation path responses; and subtracts reception signals received respectively by the directional beams corresponding to the other GW stations and multiplied respectively by the weight corresponding to the other GW stations, from the reception signal received by the directional beam corresponding to each of the GW stations.

Interference canceling in HAPS multi-feeder link

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. The relay communication station adds or subtracts, for the transmission signal to be transmitted to the GW station, a transmission signal to be transmitted to another gateway station that is multiplied by the weight corresponding to the other gateway station, with respect to each of the plural GW stations.

Reverse-link interference canceling in HAPS multi-feeder link

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. A reception signal received with the directional beam corresponding to the other GW station is multiplied by the weight corresponding to the other GW station and subtracted from the reception signal received with the directional beam corresponding to the other GW station, for each of the divided frequency bands.

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

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. The second interference suppression process divides a transmission signal band of a 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 a reception result of a pilot signal, for each of the divided frequency bands.

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

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.

Feeder link communication system of HAPS

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. A base station receives a downlink signal that includes a downlink signal including a synchronization signal transmitted from the other base station and a downlink wraparound signal transmitted from own base station, removes an interference of the wraparound signal from the downlink received signal, with respect to a predetermined subframe in which the downlink wraparound signal from own base station interferes with the synchronization signal of the base station, among subframes of the downlink signal including the synchronization signal of the base station, performs a time synchronization processing with the base station by detecting a synchronization signal timing of the base station based on the downlink received signal from which the interference of wraparound signal is removed.

Base station, communication system and time synchronization method between base stations

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 (S&#x2212;S) between a received power Sfrom a neighboring second base station, which is fed back from a mobile station, and a received power Sfrom 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. The first base station allocates the radio resource notified from the second base station or a radio resource partially including the notified radio resource, as a radio resource used for the downlink signal to the mobile station.

Base station, mobile communication system and handover control method

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.

Base station apparatus

A communication terminal apparatus, a terrestrial cellular base station and a mobile communication system are provided, which are capable of being shared in a terrestrial cellular mobile communication system and a satellite mobile communication system, and preventing an interference between beams in a satellite mobile communication system while preventing an interference between both systems by a simple switching control of radio resources. Time slots of radio resources are allocated so as not to overlap with each other between the terrestrial cellular mobile communication system and the satellite mobile communication system and so as not to overlap with each other between adjacent beams corresponding to each of two or more beams of the satellite mobile communication system. When locating in a beam area covered by any one of two or more beams of the satellite mobile communication system, a radio communication of the satellite mobile communication system is performed using the time slots allocated to the beam covering the beam area.

Growing community of inventors

Tokyo, Japan

Teruya Fujii