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.

Abstract: 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.

Abstract: A deviation of time at which downlink signals synchronously transmitted from a macro-cell base station and a small-cell base station respectively reach a communication terminal apparatus can be made within an allowable range, without being affected by transmission delay in transmission cables of base station and propagation delay in radio transmission paths. The small-cell base station is provided with a radio transceiving section connected with antenna, a radio communication control section, a transmission cable connected with the radio transceiving section and the radio communication control section, and a downlink signal receiving section for receiving downlink signals transmitted from the macro-cell base station and the own base station respectively.

Abstract: A communication system, a base station and a communication control method are provided, which are capable of cooperatively transmitting data from a plurality of base stations to a plurality of communication terminals using a same radio resource. A first base station acquires a value of an interference suppression parameter that is applied to a transmission signal from the first base station so as to suppress interference from a second base station in a first communication terminal, when the first communication terminal locates in a cell border area. The second base station duplicates a desired data for a second communication terminal located in a cell of the second base station, and transmits the duplicated desired data to the first base station.

Abstract: 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, preventing an interference between both systems and improving a spectral efficiency in a downlink of the terrestrial cellular mobile communication system, by simple switching control of radio resources. When the communication terminal apparatus is located in an area of the terrestrial cellular mobile communication system, all of time slots allocated to the terrestrial cellular mobile communication system and at least a part of time slots allocated to the satellite mobile communication system are used in a downlink, and all of time slots allocated to the terrestrial cellular mobile communication system are used and time slots allocated to the satellite mobile communication system are not used in an uplink.

Abstract: Mobile communication systems and radio resource control methods are provided, by which interference between two or more base stations can be suppressed and an inter-cell adjusting control of radio resources for each of the two or more base stations can be simplified in a mobile communication system including two or more base stations, at least a part of each cell of the base stations being mutually overlapped. Two or more cell layers are configured by grouping the two or more base station. An inter-cell adjusting control of radio resources (for example, at least one of a synchronization control of time slots and an allocation control of time slots) between the two or more cell layers is performed. An inter-cell adjusting control of radio resources between two or more base stations included in the cell layer (for example, at least one of a synchronization control of time slots and an allocation control of time slots) for each of the cell layers is also performed.

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 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.

Abstract: A communication system, a base station and a communication control method are provided, which are capable of cooperatively transmitting data from a plurality of base stations to a plurality of communication terminals using a same radio resource. A first base station acquires a value of an interference suppression parameter that is applied to a transmission signal from the first base station so as to suppress interference from a second base station in a first communication terminal, when the first communication terminal locates in a cell border area. The second base station duplicates a desired data for a second communication terminal located in a cell of the second base station, and transmits the duplicated desired data to the first base station.

Abstract: 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, preventing an interference between both systems and improving a spectral efficiency in a downlink of the terrestrial cellular mobile communication system, by simple switching control of radio resources. When the communication terminal apparatus is located in an area of the terrestrial cellular mobile communication system, all of time slots allocated to the terrestrial cellular mobile communication system and at least a part of time slots allocated to the satellite mobile communication system are used in a downlink, and all of time slots allocated to the terrestrial cellular mobile communication system are used and time slots allocated to the satellite mobile communication system are not used in an uplink.

Abstract: A deviation of time at which downlink signals synchronously transmitted from a macro-cell base station and a small-cell base station respectively reach a communication terminal apparatus can be made within an allowable range, without being affected by transmission delay in transmission cables of base station and propagation delay in radio transmission paths. The small-cell base station is provided with a radio transceiving section connected with antenna, a radio communication control section, a transmission cable connected with the radio transceiving section and the radio communication control section, and a downlink signal receiving section for receiving downlink signals transmitted from the macro-cell base station and the own base station respectively.

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.

Abstract: Mobile communication systems and base station control apparatuses are provided, by which a spectral efficiency can be improved while preventing interference between a terrestrial cellular mobile communication system and a satellite mobile communication system, and mobile communication services using mobile station apparatuses can be provided more surely in an emergent condition in which a failure occurs in a part of terrestrial cellular base stations. A same frequency band is used for radio communications between a mobile station apparatus 10 and each of terrestrial cellular base stations 20 and a communication relay apparatus 41 of artificial satellite 40.

Abstract: Communication systems and communication methods capable of evaluating a voice quality in a voice communication of a communication network and a presence or absence of a call drop of the voice communication are provided. A voice communication of transceiving a test signal for voice communication quality evaluation between a communication terminal apparatus 100 and a voice communication evaluation system 400 via the communication network 300 is performed. A voice quality evaluation value is calculated based on the test signal before transmission and the test signal after reception in the voice communication. A presence or absence of a call drop of the voice communication is determined based on a presence or absence of reception interruption of the test signal.

Abstract: Methods and systems of measuring communication quality in a communication via a mobile communication network are provided. A connection status of a communication terminal apparatus to a mobile communication network is confirmed when a timing of transmitting a measurement data of the communication terminal apparatus side from the communication terminal apparatus to a server comes. The measurement data is transmitted from the communication apparatus to the server when determining that it is a status capable of transceiving the measurement data, based on the confirmation result of connection status, and the measurement data is not transmitted from the communication terminal apparatus to the server when determining it is not a status capable of transceiving the measurement data. A communication quality in the communication via the mobile communication network is measured based on the measurement data received by the server from the communication terminal apparatus.

Abstract: Communication systems and communication methods are provided, by which load of a communication network when measuring a voice communication quality can be suppressed. A test signal for voice communication quality evaluation is transmitted to a communication terminal apparatus via a communication network, and a received voice data encoded by a predetermined scheme for the test signal received with the communication terminal apparatus is received from the communication terminal apparatus. A received voice signal is generated from the received voice data received from the communication terminal apparatus, and a evaluation value of voice communication quality is calculated by comparing the generated received voice signal with the test signal before transmitting.

Abstract: Mobile communication systems and radio resource control methods are provided, by which interference between two or more base stations can be suppressed and an inter-cell adjusting control of radio resources for each of the two or more base stations can be simplified in a mobile communication system including two or more base stations, at least a part of each cell of the base stations being mutually overlapped. Two or more cell layers are configured by grouping the two or more base station. An inter-cell adjusting control of radio resources (for example, at least one of a synchronization control of time slots and an allocation control of time slots) between the two or more cell layers is performed. An inter-cell adjusting control of radio resources between two or more base stations included in the cell layer (for example, at least one of a synchronization control of time slots and an allocation control of time slots) for each of the cell layers is also performed.

Abstract: Methods and systems of measuring communication quality are provided, by which measurement schedules of communication quality can be managed and controlled easily. A plural measurement-time slot is set with respect to a communication line used for communication quality measurements between a plural communication terminal apparatus via a mobile communication network, wherein each measurement-time slot has a time corresponding to one measurement of communication quality and the plural measurement-time slot is continuously arranged at a predetermined period, and a plural measurement schedule for measuring communication quality in each of communications with the plural communication terminal apparatus to the plural measurement-time slot.

Abstract: Methods and systems of measuring communication quality are provided, by which various types of communication quality measurements can be flexibly performed as the measurement condition can be set or changed easily and optionally, while load of processing in the communication terminal apparatus can be suppressed. Measurement condition for measuring communication quality is delivered to a communication terminal apparatus capable of communicating via a mobile communication network and a communication with the communication terminal apparatus via the mobile communication network is performed at a predetermined timing that satisfies the measurement condition.

Abstract: Communication systems and communication methods capable of evaluating a voice quality in a voice communication of a communication network and a presence or absence of a call drop of the voice communication are provided. A voice communication of transceiving a test signal for voice communication quality evaluation between a communication terminal apparatus 100 and a voice communication evaluation system 400 via the communication network 300 is performed. A voice quality evaluation value is calculated based on the test signal before transmission and the test signal after reception in the voice communication. A presence or absence of a call drop of the voice communication is determined based on a presence or absence of reception interruption of the test signal.