Abstract: To provide a radio communication method when a macro-base station and micro-base station are regarded as a plurality of transmission points and the plurality of transmission points performs downlink communications using a plurality of carriers, in the radio communication method of the invention, a macro-base station (10) forming a macro-cell determines whether or not a micro-base station transmits a non-data signal that is at least one of a synchronization signal, broadcast signal, measurement reference signal and downlink control signal using a capacity carrier (ST102), and transmits instruction information for instructing the micro-base station (20) to start transmission of the non-data signal using the capacity carrier to the micro-base station when it is determined that the micro-base station transmits the non-data signal (ST103), and the micro-base station (20) starts transmission of the non-data signal using the capacity carrier based on the instruction information from the macro-base station (10) (ST10

Abstract: The radio communication system of the present invention is provided with a cluster pattern determining section 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: 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.

Abstract: To provide a mobile terminal apparatus, radio base station apparatus and radio communication method that enable accurate precoding weights to be generated in coordinated multipoint transmission, a radio communication method of the invention is characterized in that a mobile terminal apparatus (10) performs channel estimation using a downlink reference signal, selects a PMI using the obtained channel estimation value, measures an IQI using at least the channel estimation value and the PMI, and transmits at least the PMI and IQI to a radio base station apparatus, and that the radio base station apparatus generates precoding weights using the PMI and IQI, and performs coordinated multipoint transmission utilizing MIMO transmission using the precoding weights.

Abstract: A communication system capable of achieving a high usage efficiency of frequencies without the need for cooperation of multiplexed users is disclosed. The communication system communicates over frequency channels set by dividing a frequency bandwidth assigned to the system and allows interference between channels by overlapping the adjacent frequency channels with each other in the frequency domain. A transmitting and receiving device, which transmits and receives a signal by allowing the interference between symbols at a waveform level for each channel to decrease the occupied bandwidth, is provided. The receiving device is provided with an Inter-Channel Interference (ICI) removal and Inter-Symbol Interference (ISI) compensation filter serving as either an ICI removal filter for removing the interference between channels or an ISI compensation filter for compensating the interference between symbols.

Abstract: To provide a base station apparatus, mobile terminal apparatus and scheduling method for enabling fairness of user throughput to be improved, a scheduling method is characterized by having the steps of notifying a mobile terminal apparatus of allocation information of radio resources to each cluster pattern with a plurality of cluster patterns comprised of clusters formed of a plurality of adjacent sectors predefined and with different radio resources allocated for each of the cluster patterns, receiving channel information•channel quality information corresponding to each of the cluster patterns for each of the radio resources from the mobile terminal apparatus, and controlling allocation of the radio resources to the mobile terminal apparatus, based on the channel information•channel quality information, where at least one of the cluster patterns is a coordinated cluster pattern to perform coordinated transmission between adjacent sectors in a cluster.

Abstract: A wireless communication method includes a mobile terminal for supporting precoding matrix feedback for multi-user and single-user multiple-input and multiple-output (MIMO) systems. The wireless communication method also includes obtaining, at the mobile terminal, channel state information comprising at least gain information and relative-phase information. Further, the method includes generating precoding matrices comprising bg, p1, p2, and p3 bit groups, wherein each of the precoding matrices are generated by quantization using at least the gain information and the relative-phase information between antenna elements. The method also includes selecting the best precoding matrix among the generated precoding matrices, and transmitting the bit sequence representing the selected precoding matrix to a base station.

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: 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: A radio communication apparatus and radio communication method are provided which coordinates a plurality of radio base station apparatuses in consideration of interference cancelling capability of mobile terminal apparatuses, and can thereby improve the throughput of the entire system even when the amount of information shared among a plurality of radio base station apparatuses is small. Ina system that performs multicell coordinated transmission in downlink, a radio communication method according to the present invention selects a set of mobile terminal apparatuses whose interference can be cancelled from a plurality of mobile terminal apparatus, when a plurality of radio base station apparatuses perform joint scheduling, using interference cancelling capability information fed back from each mobile terminal apparatus; then performs joint scheduling for the set of selected mobile terminal apparatuses.

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: A signal frequency band detection device is disclosed that is able to separately handle plural co-existing signals, and able to separately detect frequency bands used for transmission of these co-existing signals. The signal frequency band detection device includes a signal decomposition unit that decomposes a received signal into plural signal components with frequency bands of the signal components at least partially overlapping each other; and a frequency band detection unit that, based on respective electrical powers of the signal components, detects the respective frequency bands of the signal components.

Abstract: A communication apparatus used in a spectrum sharing environment in which multiple communication systems coexist using the same spectrum band is provided. The apparatus includes a transmission pulse shaper that performs bandwidth limitation on a pulse which is used to send data symbols; a monitoring unit that monitors in-band interference conditions from coexisting systems other than a target system to which the communication apparatus belongs, and availability of unused spectrum on adjacent channels of the target system; a controller that controls a pulse transmission period and a pulse width of the transmission pulse shaper based on the monitoring result; and a transmission unit that transmits the band-limited signal.

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 wireless transmitter comprises ID signal storage module for storing an ID signal that identifies a group to which a data signal to be transmitted belongs and provides, for each group, second or higher-order statistic properties unique to each group; modulator for modulating the data signal; wireless signal ID assignment module for associating the modulated signal thus modulated with the stored ID signal and for generating a signal to be transmitted, by assigning second or higher-order statistic properties that correspond with the ID signal to the modulated signal that is associated with the ID signal; and wireless signal transmission module for wirelessly transmitting the signal thus generated.