Abstract: A radio base station performs a beam search with a plurality of stages in which at least any of a beam width to be searched and the number of beam candidates to be searched is different, and transmits and receives data at a required rate. The radio base station performs the beam search including a first stage and a second stage after an end of the first stage having a beam width that is narrower than a beam width of the first stage and the number of beam candidates that is larger than the number of beam candidates of the first stage, starts transmitting and receiving the data immediately after the end of the first stage, when the required rate is a specified rate or less, and starts transmitting and receiving the data after an end of the second stage, when the required rate is more than the specified rate.

Abstract: Embodiments of the present disclosure provide a receiving device and a transmitting device. The receiving device according to the embodiments of the present disclosure includes: a transceiving unit, configured to receive multiple un-precoded data streams sent through a plurality of antenna ports in a transmitting device; and a control unit, configured to determine an equivalent digital baseband channel matrix for a respective one of the plurality of antenna ports based on information on the intensity of a line of sight (LOS) channel component, and demodulate the multiple data streams according to the equivalent digital baseband channel matrix. The transmitting device according to the embodiments of the present disclosure includes: a control unit, configured to determine multiple un-precoded data streams for a receiving device; and a transceiving unit, including a plurality of antenna ports, respective ones of the plurality of antenna ports being configured to send the multiple data streams.

Abstract: Provided in the present disclosure are a terminal and a sending device in a communication system. The sending device includes: a receiving unit, which is configured to receive position information of a terminal, and a control unit, which is configured to determine a first codeword in a first codebook and offset information according to the position information. The first codeword indicates initial phases of at least some array elements in a reconfigurable intelligent surface (RIS). The offset information indicates an offset relative to the at least one of the at least some array elements, the initial phases, and a reference position of the RIS.

Abstract: Provided in the embodiments of the present disclosure are a receiving device and a transmitting device. The receiving device according to the embodiments of the present disclosure includes: a control unit, configured to determine information on intensity of a light-of-sight (LOS) channel component in a communication channel; and a sending unit, configured to send the determined information to a transmitting device. The transmitting device according to the embodiments of the present disclosure includes: a transceiving unit, which includes a first antenna array; and a control unit, configured to obtain information about the intensity of a light-of-sight (LOS) channel component in a communication channel, and to determine a configuration mode of the first antenna array according to the information.

Abstract: Deterioration in communication characteristics is prevented by performing scheduling in which movement/stillness of user terminals is taken into consideration. Received-power measurement section 103 measures the power of a reference signal from each of the user terminals. Movement/stillness determination section 104 determines whether each of the user terminals is a moving terminal or an unmoving terminal based on over-time variations in received power at transmission points for each of the user terminals. Group selection section 105 groups the user terminals into a moving terminal group and an unmoving terminal group, and selects one of the groups as a signal-transmission target. Transmission control section 108 performs open-loop signal processing without precoding when the moving terminal group is selected, or performs closed-loop signal processing with precoding when the unmoving terminal group is selected.

Abstract: This base station has: a control unit that determines, on the basis of information shown by the movement of a terminal, a linking method for signal transmission by a plurality of wireless stations, and the number of streams of each wireless station; and a transmission unit that links the plurality of wireless stations according to the determined linking method, and transmits a signal to a terminal using the streams.

Abstract: This base station comprises: a control unit that allocates, on the basis of a doppler shift estimated using an uplink reference signal, a downlink reference signal common to a plurality of beams; and a transmission unit that transmits the common downlink reference signal via the plurality of beams. According to this base station communication method, the base station allocates, on the basis of a doppler shift estimated using an uplink reference signal, a downlink reference signal common to a plurality of beams, and transmits the common downlink reference signal via the plurality of beams.

Abstract: A control apparatus includes a control section that determines, for each terminal, a method for a coordinated operation performed between a plurality of radio apparatuses for signal transmission to the terminal, and a transmission section that outputs control information on the method determined.

Abstract: A communication apparatus is disclosed including a reception unit that receives an uplink signal; a control unit that determines one or more signal processes to be applied to the uplink signal, among a plurality of signal processes for the uplink signal; and a transmission unit that transmits to a backhaul the uplink signal that received the determined one or more signal processes. In another aspect, a communication method is also disclosed.

Abstract: A radio terminal that performs radio communication with a radio base station including a plurality of transmission points each including at least one antenna element and a signal processing unit connected to the plurality of transmission points includes a plurality of antenna elements, an estimating section that estimates path-loss between each of the plurality of antenna elements and the plurality of transmission points, and a calculating section that calculates a power control weight for controlling transmission power of the plurality of antenna elements based on the path-loss for the antenna element that has been estimated by the estimating section.

Abstract: Radio base station 10 in a radio communication system that performs MIMO transmission between a plurality of radio base stations and at least one user terminal 20 includes: precoding section 110 that applies precoding to data signals based on channel information indicating channels between radio base stations 10 and the user terminal; and communication section 112 that transmits the precoded data signals, in which the precoding in a first radio base station of the plurality of radio base stations is applied based on the channel information including at least a channel between the first radio base station and a first user terminal connected to a second radio base station other than the first radio base station.

Abstract: This base station comprises: a control unit that allocates, on the basis of a doppler shift estimated using an uplink reference signal, a downlink reference signal common to a plurality of beams; and a transmission unit that transmits the common downlink reference signal via the plurality of beams. According to this base station communication method, the base station allocates, on the basis of a doppler shift estimated using an uplink reference signal, a downlink reference signal common to a plurality of beams, and transmits the common downlink reference signal via the plurality of beams.

Abstract: A radio base station includes: an obtaining section that obtains a first communication quality of each of first communication terminals and obtains a second communication quality of each of second communication terminals having a lower communication speed than the first communication terminals; and a scheduler that schedules the first communication terminals based on the first communication qualities and schedules the second communication terminals based on the second communication qualities, and when the scheduler schedules the first communication terminals and the second communication terminals, the scheduler subjects the first communication terminals to space-division multiplexing and subjects the second communication terminals to frequency-division multiplexing or time-division multiplexing.

Abstract: In a radio base station including: a plurality of transmission points each including at least one antenna element; and a signal processing unit connected to the plurality of transmission points, the signal processing unit includes: an estimating section that estimates, in each of the antenna elements, a path-loss with a radio terminal; and a calculating section that calculates a power control weight for controlling transmission power of each of the antenna elements based on the path-loss of the antenna element, which is estimated by the estimating section.

Abstract: Deterioration in communication characteristics is prevented by performing scheduling in which movement/stillness of user terminals is taken into consideration. Received-power measurement section 103 measures the power of a reference signal from each of the user terminals. Movement/stillness determination section 104 determines whether each of the user terminals is a moving terminal or an unmoving terminal based on over-time variations in received power at transmission points for each of the user terminals. Group selection section 105 groups the user terminals into a moving terminal group and an unmoving terminal group, and selects one of the groups as a signal-transmission target. Transmission control section 108 performs open-loop signal processing without precoding when the moving terminal group is selected, or performs closed-loop signal processing with precoding when the unmoving terminal group is selected.

Abstract: In a radio communication system that performs beamforming in MIMO transmission between a radio base station and at least one user terminal, radio base station (10) includes: weight control section (104) that determines a beamforming weight used for the beamforming, for each of subbands formed by dividing a transmission band; and communication section (109) that transmits a signal to which the beamforming is applied using the beamforming weight.

Abstract: In user terminal 20, communication section 202 receives a data signal to which precoding based on first channel information indicating a channel between radio base station 10 and user terminal 20 estimated in first channel estimation and beamforming are applied. The first channel information is an equivalent channel matrix including a beamforming weight. Stage-2 channel estimation section 205 performs second channel estimation for estimating second channel information indicating a channel between radio base station 10 and user terminal 20. The second channel information is an equivalent channel matrix including the beamforming weight and a precoding matrix. Postcoding section 207 performs postcoding on the data signal based on the second channel information.

Abstract: A management apparatus in a wireless communication system including multiple transmission points transmitting reference signals, the management apparatus managing the transmission points, and a mobile station, includes: a management unit for managing first and second clusters generated by grouping one or more transmission points used to communicate with the mobile station among the multiple transmission points; and a control unit for controlling allocation of the reference signals transmitted from the multiple transmission points in the first and second clusters. The management unit detects that multiple cells formed by the transmission points in the first cluster overlap some of multiple cells formed by the transmission points in the second cluster. When the management unit detects the overlap, the control unit allocates the orthogonal reference signals to the multiple cells formed by the transmission points in the first cluster and the multiple cells formed by the transmission points in the second cluster.

Abstract: A user equipment UE includes: a measurer that measures, for each of a plurality of candidate beams, a benchmark pertaining to communication quality; a comparer that compares the benchmark with a first threshold value and a second threshold value; and a feedback unit that transmits the benchmark to the base station as feedback information pertaining to an interference beam if the benchmark is the first threshold value or higher and lower than the second threshold value, transmits the benchmark to the base station as feedback information pertaining to a desired beam if the benchmark is the second threshold value or higher, and transmits no feedback information to the base station if the benchmark is lower than the first threshold value, based on the comparison results of the comparer.

Abstract: Provided is a base station for communicating with mobile stations of a radio communication system including the base station and mobile stations including an obtaining unit that obtains a channel matrix for each mobile stations; a selector that selects, among the mobile stations, a combination of two or more mobile stations with which communication based on multi-user MIMO is to be performed; and a communication unit that communicates, based on multi-user MIMO, with the two or more mobile stations of the selected combination, wherein the selector calculates, for each of all combinations of two mobile stations of the two or more mobile stations, a correlation value between the channel matrices for the two mobile stations, and selects the combination of the two or more mobile stations, so that, for all the combinations of the two mobile stations, the correlation values is less than or equal to a predetermined value.