Abstract: RRHs are physically independent from each other, are arranged in different positions, respectively, receive uplink signals from a radio terminal and transmit downlink signals to the radio terminal. A central processing unit receives the uplink signals from the plurality of RRHs and transmits the downlink signals to the plurality of RRHs. A setting unit sets a part or all of the RRHs as RRH(s) in a first group suitable for transmission of the downlink user data based on the uplink or downlink signals received by at least one of the RRHs. A transmission control unit controls the transmission of the downlink user data from the plurality of RRHs based on the setting.

Abstract: A terminal speed identification unit identifies the moving speed of a wireless terminal currently in communication. A ranging control unit sets the transmission cycle of a ranging signal of a wireless terminal moving at a speed greater than or equal to a predetermined speed shorter than the transmission cycle of a ranging signal of a wireless terminal moving at a speed below the predetermined speed. A transmission unit transmits a signal notifying the transmission cycle of a ranging signal to the wireless terminal. A reception unit receives a ranging signal from a wireless terminal currently in communication.

Abstract: When a determination is made that communication by an SM scheme is suitable, a setting unit performs switching from a communication level by an STC scheme to the communication level by the SM scheme, between the communication level at a first level of MCS by the space-time coding scheme and the communication level at a second level of MCS by the SM scheme. When a determination is made that communication by the SM scheme is unsuitable, the setting unit performs switching from the communication level by the STC scheme to the communication level by the spatial multiplexing scheme, between the communication level at a third level of MCS, which is higher than the first level, by the space-time coding scheme and a fourth level of the modulation scheme and the coding rate, which is higher than the second level, by the SM scheme.

Abstract: The present invention relates to a wireless communication system, a communication control method, and a relay station. The wireless communication system includes: a wireless terminal; a plurality of base stations; and a relay station, wherein the relay station defines a wirelessly communicable base station among the plurality of base stations as a candidate for a master station, in a case where a plurality of the candidates for the master station are present, acquires priority order setting information for setting priority orders of connection regarding the respective candidates for the master station, and sets the priority orders of the connection based on the priority order setting information. Then, in a case where the relay station has received a connection request from the wireless terminal, the control unit decides a candidate for the master station, which has a highest priority order of the connection, as an optimal master station.

Abstract: The present invention relates to a wireless communication system and a communication control method. The wireless communication system includes: a wireless terminal; a plurality of base stations; and a host-side base station, wherein, in a case where CoMP transmission/reception is requested, the host-side base station decides base stations cooperating therewith for the CoMP transmission/reception, opens wireless lines for base stations under connection to the wireless terminal, and sends a same signal thereto, thereby performs the CoMP transmission/reception, and each of a plurality of the base stations functions as a relay device in a case of transferring the signal with the host-side base station through the wireless line.

Abstract: A wireless communication device communicates with, using a plurality of antennas, a communication partner device including a plurality of antennas. The wireless communication device includes a communication unit, an interference intensity judgment unit, and a determination unit. The communication unit communicates with the communication partner device using the plurality of antennas and is configured to use a MIMO (multiple input multiple output) scheme when transmitting a signal to the communication partner device. The interference intensity judgment unit judges, based on predetermined criteria, whether or not an intensity of an interference wave included in a received signal at the communication partner device is high. The determination unit prohibits, upon the interference intensity judgment unit judging that the intensity of the interference wave is high, the communication unit from using the MIMO scheme when transmitting a signal.

Abstract: A radio base station (BS) includes: a radio communication unit (110) configured to transmit broadcast control data via an antenna unit (101) including a plurality of antennas (ANT1 to ANTn), the broadcast control data being data common to a plurality of radio terminals executing radio communication with the radio base station and being used to control the radio communication; a quality acquisition unit (121) configured to acquire quality information indicating quality of the radio communication between each of the plurality of radio terminals and the radio base station; and an identification unit (122) configured to identify, from the plurality of radio terminals, a degraded radio terminal having the quality lower than a threshold value, based on the quality information acquired by the quality acquisition unit (121). The radio communication unit (110) performs beam-forming transmission of the broadcast control data in the direction corresponding to the degraded radio terminal identified.

Abstract: A scheduling executing section calculates a predicted value of a transmission gain at a time when controlling transmission directivity in a plurality of antennas based on a known signal to be received in a frequency band of a use downlink radio resource and performing downlink communication with a communication terminal, and determines a communication terminal to which the use downlink radio resource is allocated based on the predicted value.

Abstract: When a determination is made that communication by an SM scheme is suitable, a setting unit performs switching from a communication level by an STC scheme to the communication level by the SM scheme, between the communication level at a first level of MCS by the space-time coding scheme and the communication level at a second level of MCS by the SM scheme. When a determination is made that communication by the SM scheme is unsuitable, the setting unit performs switching from the communication level by the STC scheme to the communication level by the spatial multiplexing scheme, between the communication level at a third level of MCS, which is higher than the first level, by the space-time coding scheme and a fourth level of the modulation scheme and the coding rate, which is higher than the second level, by the SM scheme.

Abstract: A communication level table storage unit stores a communication level table that defines correspondence between a communication level at least defined by MCS (modulation scheme and coding rate) and a range of required CINR at the communication level. A communication quality management unit obtains CINR of a received signal at another communication apparatus which is a communication partner. A setting unit refers to the communication level table, and when a difference between a representative value of a range of required CINR at a current communication level and a representative value of a range of required CINR of CINR at a communication level which is one level higher is more than or equal to a threshold value, sets a communication level such that the obtained CINR of the received signal is included in the range of required CINR.

Abstract: Upon receipt of sounding signals from a plurality of communication devices including a communication partner device, an evaluation value processing unit calculates an evaluation value indicative of a characteristic of a transmission path based on the sounding signals from the plurality of communication devices. A transmission scheme setting unit sets, based on the evaluation value, adaptive array transmission that achieves both null steering and beamforming or beamforming dedicated transmission as a transmission scheme to the communication partner device.

Abstract: An RF unit receives multicarrier signals via a plurality of antennas. A division unit divides the multicarrier signals received into a plurality of groups in the frequency domain. The division unit acquires the channel quality for each subcarrier, contained in the multicarrier signal, in the frequency domain, and defines the plurality of groups according to the channel quality. The processing unit performs adaptive array signal processing for each of the divided groups.

Abstract: When time at present is included in a high-traffic time period, an interference determining unit (37) determines that there is a possibility that a downlink signal to be received by any wireless terminal has interference with a pilot signal transmitted from a wireless base station. A pilot signal transmission control unit (40) controls the transmission of the pilot signal, which is included in an OFDMA frame or an OFDM frame. When it is determined that there is the possibility of interference, the pilot signal transmission control unit (40) stops the transmission of the pilot signal or reduces power of the pilot signal in a whole or a portion of a user data area.

Abstract: A communication quality managing unit (36) acquires or calculates a communication quality of a received signal at a different counterpart communication apparatus. A terminal model identifying unit (41) identifies a model of the different counterpart communication apparatus. A switchover table storing unit (39) stores a table, in which a communication quality corresponding to a requirement for switchover of a communication mode is set, for each model of the different counterpart communication apparatus. A switching unit (38) refers to the table on the basis of the communication quality and the model of the different counterpart communication apparatus to switch a setting of a communication mode for a transmitting signal from a non-spatial multiplexing mode to a spatial multiplexing mode or from the spatial multiplexing mode to the non-spatial multiplexing mode.

Abstract: A setting unit sets a communication mode for different one or more counterpart communication apparatuses to a non-spatial multiplexing mode or a spatial multiplexing mode. Setting unit switches the setting of the communication mode for the different one or more counterpart communication apparatuses from the non-spatial multiplexing mode to the spatial multiplexing mode, on the basis of a capability of a communication system having an own apparatus and the different one or more counterpart communication apparatuses. A transmitting unit processes a transmitting signal to the different one or more counterpart communication apparatuses to output the processed signal to a plurality of antennas, on the basis of the set communication mode.

Abstract: When switching a setting of a communication mode for a transmitting signal to a different communication apparatus from a non-spatial multiplexing mode to a spatial multiplexing mode on the basis of a first communication quality, a switching unit stores the first communication quality as a switchover reference value and then, when the first communication quality in a case of switching the setting of the communication mode for the transmitting signal to the different communication apparatus from the spatial multiplexing mode to the non-spatial multiplexing mode on the basis of a second communication quality is larger than the switchover reference value by a value which is equal to or more than a predetermined value, halts the switchover of the setting, to the spatial multiplexing mode, of the communication mode for the transmitting signal to the different communication apparatus until a predetermined requirement is satisfied.

Abstract: RRHs are physically independent from each other, are arranged in different positions, respectively, receive uplink signals from a radio terminal and transmit downlink signals to the radio terminal. A central processing unit receives the uplink signals from the plurality of RRHs and transmits the downlink signals to the plurality of RRHs. A setting unit sets a part or all of the RRHs as RRH(s) in a first group suitable for transmission of the downlink user data based on the uplink or downlink signals received by at least one of the RRHs. A transmission control unit controls the transmission of the downlink user data from the plurality of RRHs based on the setting.

Abstract: A terminal speed identification unit identifies the moving speed of a wireless terminal currently in communication. A ranging control unit sets the transmission cycle of a ranging signal of a wireless terminal moving at a speed greater than or equal to a predetermined speed shorter than the transmission cycle of a ranging signal of a wireless terminal moving at a speed below the predetermined speed. A transmission unit transmits a signal notifying the transmission cycle of a ranging signal to the wireless terminal. A reception unit receives a ranging signal from a wireless terminal currently in communication.

Abstract: A mode setting unit sets two or more wireless terminals at a collaborative spatial multiplex mode in which the same uplink data burst region is shared for usage, based on the throughput of uplink signals from a plurality of wireless terminals. A burst region notification unit notifies the two or more wireless terminals set at the collaborative spatial multiplex mode of the uplink data burst region shared between the two or more wireless terminals for usage. A switching unit switches, for a first type of wireless terminal transmitting a known signal from a plurality of antennas, the MIMO scheme of a downlink signal from the space-time coding type to the spatial multiplex type when a predetermined condition for communication quality and spatial correlation coefficient satisfy a predetermined condition.

Abstract: When the number of multiplexed connections of PSs to a CS is changed due to issuance of a connection request from other PS to the CS or the like, the CS selects a unique word pattern (new unique word) optimal for the new number of multiplexed connections, so as to request switching from an old unique word to a new unique word to each PS of the user who has established multiple access. When a response to the request for switching is received from the PS of each user, the CS transmits a synchronous burst signal including the new unique word to the PS, and the PS also returns the synchronous burst signal including the new unique word. Synchronization is thus established.