Abstract: The present invention provides a base station apparatus, a mobile terminal apparatus and a communication control method which can improve the accuracy of channel quality estimation. A communication control method includes the steps of: arranging a CSI-RS, which is a reference signal for downlink channel estimation, in resources of subframes for CSI-RS transmission; setting, in the subframes for CSI-RS transmission, resources to which the CSI-RS is allocated in neighboring areas, to be muting resources; and reporting transmission interval information, which indicates a transmission interval of subframes that are set at the same timing in a transmission cycle of a subframe for CSI-RS transmission in a subject area and in a transmission cycle of a subframe for CSI-RS transmission in the neighboring areas, to a mobile terminal apparatus.

Abstract: To provide a signaling method for enabling position information of muting resources to be signaled with a simplified configuration, base station apparatus and mobile terminal apparatus, the signaling method is characterized by having the steps of setting blank resources for a CSI-RS (Channel State Information-Reference Signal) that is a reference signal for downlink channel estimation, and transmitting a bitmap indicative of a position of the blank resources to a mobile terminal apparatus.

Abstract: To signal CSI-RS location indexes indicative of CSI-RS location positions in a resource block with high efficiency, a signaling method of CSI-RS is characterized by having the steps of locating a CSI-RS that is a reference signal for downlink channel estimation in resources for CSI-RS reserved to transmit the CSI-RS, generating a CSI-RS location index indicative of a location position of the CSI-RS located in the resources for CSI-RS, in the CSI-RS location index an index pattern varies corresponding to the number of CSI-RS ports so that an index pattern of the relatively low number of CSI-RS ports is a subset of an index pattern of the relatively high number of CSI-RS ports, and transmitting the generated CSI-RS location index to a mobile terminal apparatus.

Abstract: In each Mobile terminal, channel impulse characteristics from radio base stations to the mobile terminal is calculated. In a radio communication system, under the assumption that each of the mobile terminals performs optimum receiving beamforming in order to receive a data signal from a radio base station that actually sends the data signal to the mobile terminal, optimum receiving beamforming characteristics are estimated for each mobile terminal. Each of radio base stations that share optimum receiving beamforming characteristics calculates precoding characteristics for each mobile terminal according to the optimum receiving beamforming characteristics such that main beams are directed to mobile terminals to which the radio base station sends data signals and null beams are directed to mobile terminals to which the radio base station does not send data signals.

Abstract: A mobile communication terminal includes an interference rejection combining processor for obtaining a received signal vector with regard to each of multiple resource elements and for calculating receiving weights so as to suppress influence to a desired beam of electric wave sent from the desired base station by other beams, on the basis of the received signal vectors; a non-interference-rejection receiving weight calculator for calculating receiving weights so as not to suppress influence to the desired beam by other beams; a signal separator for separating a signal destined for the mobile communication terminal from signals destined for other mobile communication terminals; and an interference rejection combining determiner for determining whether the receiving weights to suppress influence by other beams or the receiving weights calculated by the non-interference-rejection receiving weight calculator should be used for signal separation by the signal separator, on the basis of an index representing a rela

Abstract: Provided are a base station apparatus, a mobile terminal apparatus and a communication control method capable of selecting a CSI-RS arrangement flexibly in accordance with a system configuration. The base station apparatus has a CSI-RS arrangement section (211) configured to arrange a CSI-RS in a resource reserved for broadcasting when a mobile terminal apparatus (10) is notified of position information of the CSI-RS by broadcasting or in a resource associated with an cell ID of a serving area when the mobile terminal apparatus (10) obtains the position of the CSI-RS based on the cell ID; an identification information generating section (212) configured to generate an identification bit for identifying whether the CSI-RS is arranged in the resource reserved for broadcasting or in the resource associated with the cell ID; and a transmission/reception section (203) configured to transmit the identification information to the mobile terminal apparatus.

Abstract: A mobile communication terminal including multiple receiving antennas demodulates an interfering UE-specific reference signal that might be used in another mobile communication terminal, and analyzes interference parameters specified by the interfering UE-specific reference signal demodulated by the interfering UE-specific reference signal demodulator, the interference parameters being parameters with regard to another beam sent to another mobile communication terminal from an interfering base station. Then, the mobile communication terminal calculates receiving weights so as to suppress influence to the desired beam from other beams, on the basis of desired beam parameters and the interference parameters.

Abstract: The present invention is designed to perform CQI measurement for adjacent cells without making the processes in the user terminal UE complex. A base station apparatus (eNodeB #1) provided in the serving cell has features of acquiring, from a base station apparatus (eNodeB #2) provided in an adjacent cell, the cell ID of the adjacent cell, and the position and transmission power of the CSI-RS, as parameters related to the CSI-RS of the adjacent cell, generating a broadcast signal including the above parameters related to the CSI-RS, and transmitting the generated signal to the user terminal (UE).

Abstract: A disclosed radio communication apparatus transmits a radio signal to multiple users via multiple transmit antenna groups at appropriate transmit power levels, each of the transmit antenna groups including one or more transmit antennas, the transmit antenna groups having respective transmit power constraints. The apparatus includes a precoding unit configured to perform precoding on signals modulated for individual users and generate transmit weights, an optimum transmit power calculation unit configured to receive the transmit weights from the precoding unit and use components of the transmit weights and respective transmit power limit values for the transmit antenna groups to calculate an initial value for a transmit power optimization problem for calculation of the appropriate transmit power levels for the users, and a transmission unit configured to transmit radio signals at the calculated transmit power levels.

Abstract: A disclosed radio communication apparatus transmits a radio signal to multiple users via multiple transmit antenna groups at appropriate transmit power levels, each of the transmit antenna groups including one or more transmit antennas, the transmit antenna groups having respective transmit power constraints. The apparatus includes a precoding unit configured to perform precoding on signals modulated for individual users and generate transmit weights, an optimum transmit power calculation unit configured to receive the transmit weights from the precoding unit and use components of the transmit weights and respective transmit power limit values for the transmit antenna groups to calculate an initial value for a transmit power optimization problem for calculation of the appropriate transmit power levels for the users, and a transmission unit configured to transmit radio signals at the calculated transmit power levels.

Abstract: To provide a radio base station apparatus, mobile terminal device and wireless communication method for transmitting and receiving downlink channel quality measurement reference signals in consideration of orthogonalization among transmission antennas, orthogonalization among cells, and interference estimation of high accuracy, in a wireless communication method of the invention, a radio base station apparatus generates channel quality measurement reference signals, performs randomization processing on the channel quality measurement reference signals to be mutually non-orthogonal among at least a part of cells, and orthogonalizes the channel quality measurement reference signals among transmission antennas to transmit to a mobile terminal device together with control information, and the mobile terminal device receives a downlink signal including the control information and the channel quality measurement reference signal, extracts the channel quality measurement reference signal using the control informatio

Abstract: To provide a radio base station apparatus, mobile terminal device and wireless communication method for transmitting and receiving downlink channel quality measurement reference signals in consideration of interference estimation of high accuracy, in a wireless communication method of the invention, a radio base station apparatus generates channel quality measurement reference signals, and maps the channel quality measurement reference signals to two adjacent symbols, and a mobile terminal device receives a downlink signal including the channel quality measurement reference signals mapped to two adjacent symbols, and performs interfering power estimation using the channel quality measurement reference signals mapped to two adjacent symbols.

Abstract: A wireless communication device that transmits a wireless signal by carrying out linear precoding processing using a plurality of transmission antennas is provided with: a phase pattern control unit for selecting a phase pattern that reduces peak-to-average power ratio; a phase rotation unit for carrying out phase rotation on a modulation signal using the phase pattern selected in the phase pattern control unit; a control signal generation unit for generating a control signal based on the phase pattern selected in the phase pattern control unit; and a preceding unit for carrying out linear precoding processing on output signals from the phase rotation unit and output signals from the control signal generation unit.

Abstract: A disclosed radio communication method includes precoding modulated information signal sequences to calculate transmit weight information, setting initial transmit power based on prior information including the calculated transmit weight information, generating an objective function of a user channel capacity for a constrained optimization problem based on the transmit weight information and the initial transmit power, generating a new objective function by adding a barrier function to the objective function, using an initial temporary barrier parameter to initiate iteration of an optimization operation for the new objective function, setting an initial barrier parameter based on comparison between the current and previous outputs, calculating transmit power to optimize the new objective function in accordance with an interior point method based on the initial transmit power and the initial barrier parameter and allocating the calculated transmit power to the respective transmit antennas.

Abstract: A disclosed radio communication apparatus includes a precoding unit, a optimum transmit power calculation unit and a transmission unit. The optimum transmit power calculation unit receives the transmit weight related information from the precoding unit and calculates a transmit power level to optimize an objective function in accordance with an interior point method. The objective function results from addition of a barrier function adjusted with a barrier parameter to an original objective function associated with a constrained optimization problem. The original objective function includes a function of respective channel capacities for individual users derived from the transmit weight related information. The optimum transmit power calculation unit adaptively updates a logarithm of the barrier parameter and uses a gradient obtained through a high-order derivative with the logarithm of the barrier parameter to calculate the transmit power level to optimize the resulting objective function.

Abstract: A disclosed radio communication apparatus includes a precoding unit, a optimum transmit power calculation unit and a transmission unit. The optimum transmit power calculation unit receives the transmit weight related information from the precoding unit and calculates a transmit power level to optimize an objective function in accordance with an interior point method. The objective function results from addition of a barrier function adjusted with a barrier parameter to an original objective function associated with a constrained optimization problem. The original objective function includes a function of respective channel capacities for individual users derived from the transmit weight related information. The optimum transmit power calculation unit adaptively updates a logarithm of the barrier parameter and uses a gradient obtained through a high-order derivative with the logarithm of the barrier parameter to calculate the transmit power level to optimize the resulting objective function.

Abstract: The radio communication system of the present invention is provided with a cluster pattern determining section 61 that determines the assignment of each cluster pattern to each cluster so as to suppress inter-cluster interference with other neighboring clusters less than or equal to a predetermined value, the cluster pattern is defining a directional pattern of which directional beams emitted from the respective radio base stations face each other for each identical frequency block between neighboring sectors in a cluster composed of neighboring cells, the each cluster pattern being in different combinations of directional patterns and frequency blocks.

Abstract: A disclosed radio communication apparatus includes a preceding unit configured to precode multiple streams, a splitting unit configured to split the precoded streams into two or more stream sets each including one or more streams, a sub power optimization unit configured to execute an iterative transmit power optimization algorithm on each of the split stream sets to determine respective transmit power levels for the individual stream sets, a power optimization unit configured to execute the iterative transmit power optimization algorithm by using the determined transmit power levels as initial values for the iterative transmit power optimization algorithm to determine respective transmit power levels for the individual streams, and a transmission unit configured to transmit radio signals from individual transmit antennas at the determined transmit power levels.

Abstract: The present invention provides a radio communication system which includes a plurality of radio base station apparatuses that transmit reference signals orthogonal to each other among a plurality of transmitting antennas and a mobile terminal apparatus that performs channel estimation based on the reference signals transmitted from the plurality of radio base station apparatuses, sets priority among a plurality of neighboring radio base station apparatuses and introduces a bias in the number of reference signals that can be allocated to each radio base station apparatus according to the priority from the radio resources shared among the plurality of neighboring radio base station apparatuses.

Abstract: A coordinated transmission method of the invention has the steps of selecting a directional pattern corresponding to an area in which a radio terminal locates, from among a plurality of directional patterns determined respectively corresponding to a plurality of resources in frequency domains where the plurality of directional patterns is configured so that a plurality of radio base stations surrounding the area transmits, to the area, directional beams of same frequency domain resources to face one another, while not transmitting the directional beams of the same frequency domain resources using the same frequency domain resources to areas adjacent to the area, and of distributing a signal to transmit to the radio terminal according to the selected directional pattern, determining a frequency domain and directions of directional beams regarding the distributed signal, and delivering the signal to each of the plurality of radio base stations that simultaneously transmits the signal to the radio terminal.