Abstract: A radio base station applies non-orthogonal multiple access to a plurality of user terminals and transmits downlink signals, and this radio base station has a scheduling section that selects a user set to apply non-orthogonal multiple access to from candidate user sets, and selects a combination of a modulation and coding scheme and transmission power based on combinations of candidate transmission power. The radio base station includes a control section that decides whether or not the combination of the modulation and coding scheme and transmission power selected in the scheduling section is included in combinations that are stipulated in advance, and controls the scheduling section in accordance with the decision. A transmission section applies the combination of the modulation and coding scheme and transmission power to user terminals that are included in the user set selected in the scheduling section, and transmits the downlink signals.

Abstract: To improve the frequency diversity effect and enhance reception quality characteristics in a mobile terminal apparatus even when the system bandwidth is extended, provided are a base station apparatus which maps transmission data to each user to a single or plurality of group bands among group bands configured by dividing a system band into a plurality of bands, and transmits the mapped transmission data on downlink, and a mobile terminal apparatus which receives the transmission data mapped to the group bands and demaps the transmission data.

Abstract: To appropriately allocate radio resources to downlink control information, in the enhanced downlink control channel, a radio communication method in which a radio base station transmits downlink control information to each user terminal via an enhanced downlink control channel frequency division multiplexed with a downlink shared data channel is provided. The method includes generating the downlink control information in eCCE unit, the eCCE being made up with a plurality of eREGs, and mapping the downlink control information in eREG unit to a plurality of resource regions for the enhanced downlink control channel. Each eREG is made up with a plurality of REs, and the radio base station performs mapping to each of the resource regions in such a manner that the enhanced resource element groups (eREGs) are uniform in number of resource elements. The REs that make up 1 eREG are distributed to a plurality of OFDM symbols.

Abstract: The object is achieved by providing a base station apparatus for performing time and frequency scheduling in uplink packet access with: an interference amount measurement part configured to measure an uplink interference amount for each interference amount measurement unit which comprises a predetermined period and a predetermined number of frequency blocks; an interference amount determination part configured to determine whether the uplink interference amount satisfies a predetermined condition; and an overload indicator reporting part configured to report an overload indicator to a neighboring cell when the predetermined condition is satisfied.

Abstract: The present invention is designed to provide a base station apparatus, a mobile terminal apparatus, a communication system and a communication method that cope with the shortage of downlink control channel capacity. For a mobile terminal apparatus that receives downlink signals using a resource region for downlink control signals and a resource region for downlink data signals, a base station apparatus is configured to set a plurality of virtual resources for downlink control signals in a plurality of physical resources that are arranged in a frequency direction in the resource region for downlink data signals, and allocate the downlink control signals, in a distributed manner, between virtual resources of a relatively low frequency band side and virtual resources of a relatively high frequency band side in a plurality of virtual resources.

Abstract: The present invention is designed to adequately measure the received quality of small cells on the user terminal side. A radio base station communicates with a user terminal by using a plurality of carriers into which a communication band is divided, and has a generating section that generates reference signals for allowing the user terminal to measure received quality, and an allocation section that controls the allocation of the reference signals, and, when one of the plurality of carriers is made subject to non-transmission, the allocation section configures a zero-power RS in a predetermined resource location of a specific carrier.

Abstract: The present invention is designed to provide a radio base station apparatus, a mobile terminal apparatus, a radio communication system and a radio communication method which can cope with an increased number of users. A radio base station apparatus is provided with: a signal generating section that generates a first downlink control signal and a second downlink control signal for a mobile terminal apparatus; a first multiplexing section that multiplexes the first downlink control signal on a control region up to a predetermined number of symbols from the top of a subframe; a second multiplexing section that frequency-division-multiplexes the second downlink control signal on radio resources from the next symbol in the control region to the last symbol of the subframe; and a transmission section that transmits the first downlink control signal multiplexed on the control region and the second downlink control signal multiplexed on the radio resources.

Abstract: The objective of the invention is to suppress, in a case of applying the RRH system in an environment having a plurality of cells (multi-cellular environment), the reduction of the throughput of the whole system. A base station, in the RRH system in which a plurality of antenna ports are dispersively placed in each of a plurality of cells, comprises: a selection unit that selects antenna ports, to which user terminals are to connect, from among the antenna ports of the cells in which the user terminals are existent; and a power setting unit that controls the transmission powers of the antenna ports. The selection unit and power setting unit set predetermined conditions for the target SINRs(t) of the user terminals and the transmission powers of the antenna ports, and select the antenna ports for the user terminals and control the transmission powers of the antenna ports such that the smallest one of the values of the SINRs of the user terminals of the plurality of cells is maximized.

Abstract: The present invention is designed to allow adequate communication even when a plurality of cells employ downlink transmission power control. A user terminal communicates with a radio base station that executes downlink transmission power control, and includes a receiving section that receives a first reference signal which is transmitted with fixed transmission power, and a second reference signal to which the downlink transmission power control is applied, a measurement section that measures the received power of the first reference signal and the second reference signal, and a transmission section that feeds back information related to the received power of the first reference signal and the second reference signal as a measurement report.

Abstract: A mobile station includes: a physical channel segmentation unit to receive radio signals including multiple orthogonal signals which are orthogonal to each other, and multiple non-orthogonal signals which are not orthogonal to each other; and data demodulating/decoding units to extract the non-orthogonal signal addressed to the mobile station from the multiple non-orthogonal signals by demodulating and cancelling the radio signal addressed to another mobile station by use of the orthogonal signals included in the radio signals received by the physical channel segmentation unit, and demodulate the signal included in the orthogonal signals and addressed to the mobile station, and the extracted non-orthogonal signal addressed to the mobile station.

Abstract: The present invention is designed to allow more DM-RS sequences to be allocated, and more DM-RS resources to be secured. The radio communication method of the present invention has a characteristic of generating DM-RS sequences using ZC sequences that are allocated in a new number of randomized sequences between the number of randomized sequences corresponding to a ZC sequence having a length of the largest prime number, not exceeding the ZC sequence length required in the uplink DM-RS, and the number of randomized sequences defined in Rel. 10 LTE.

Abstract: A base station that communicates with a mobile station by using a plurality of antenna ports includes a mapping information communication unit configured to generate mapping of reference signals for measuring channel state information of the antenna ports by combining, within a resource block, mappings of reference signals for measuring the channel state information, the mappings being defined for a predetermined number or less of the antenna ports, and configured to communicate information indicating the generated mapping to the mobile station; a multiplexer configured to multiplex the reference signals for measuring the channel state information in one or more resource elements in the resource block in accordance with the generated mapping; and a transmitter configured to transmit the reference signals for measuring the channel state information.

Abstract: The present invention is designed to detect an S-cell efficiently, in a short time, upon carrier aggregation in a HetNet. In a communication system where carrier aggregation is executed between a first carrier (CC #1) and a second carrier (CC #2), a macro base station apparatus (20A) generates a carrier detection signal that makes a mobile terminal apparatus (10) detect the second carrier (CC #2), such that carrier aggregation is executed with the first carrier (CC #1), and transmits the carrier detection signal to an RRH base station apparatus (20B) such that the carrier detection signal is transmitted from the RRH base station apparatus (20B) to the mobile terminal apparatus (10) in the second carrier (CC #2) in which the carrier detection signal can be allocated with a higher density than a reference signal of the first carrier (CC #1). The macro base station apparatus (20A) detects an S-cell based on the received quality of the carrier detection signal fed back from the mobile terminal apparatus (10).

Abstract: The present invention is designed to provide a radio base station apparatus, a mobile terminal apparatus, a radio communication system and a radio communication method which can cope with an increased number of users. A radio base station apparatus is provided with: a signal generating section that generates a first downlink control signal and a second downlink control signal for a mobile terminal apparatus; a first multiplexing section that multiplexes the first downlink control signal on a control region up to a predetermined number of symbols from the top of a subframe; a second multiplexing section that frequency-division-multiplexes the second downlink control signal on radio resources from the next symbol in the control region to the last symbol of the subframe; and a transmission section that transmits the first downlink control signal multiplexed on the control region and the second downlink control signal multiplexed on the radio resources.

Abstract: The present invention is designed to trigger a PUSCH dynamically or periodically in an S-cell upon carrier aggregation in a HetNet and transmit UCI efficiently. In the communication system of the present invention, a mobile terminal apparatus reserves physical uplink shared channel resources in a second carrier by higher layer signaling, and transmits uplink control information combining ACK/NACK for a physical downlink shared data channel allocated by a downlink scheduling assignment and a CQI report triggered by the downlink scheduling assignment, to a second base station apparatus, using one of the reserved physical uplink shared channel resources.

Abstract: The present invention is designed to measure interference with high accuracy in future systems that do not rely on CRSs. A base station apparatus has a determining section (401) that determines the resources to allocate desired signal measurement reference signals (CSI-RSs) and interference estimation reference signals to, and a reference signal generating section (405) that applies scrambling sequences and generates the interference estimation reference signal, and the scrambling sequences are controlled such that varying scrambling sequences are applied to the interference estimation reference signals between a plurality of transmission points or transmission point groups.

Abstract: To obtain a high frequency diversity effect while suppressing inter-code interference in code multiplexing transmission in an OFDM-based radio access scheme, a transmission apparatus is provided with an orthogonal spreading code generating section (10) that generates different spreading codes based on orthogonal code sequences, a phase rotation giving section (11) and spreading modulation section (12) which provide the information symbols or spreading codes with different phase rotation for each symbol sequence and then, spreads the information symbols with the spreading codes for each symbol sequence, and a multiplexing section (13) that multiplexes spread symbols of different symbol sequences, where the information symbols or the spreading codes are rotated by a phase rotation amount such that overlaps in a signal constellation in polar coordinates of spread symbols for transmitting different information symbols are controlled to within a required range.

Abstract: In a configuration in which a downlink control channel is enhanced, the present invention is designed to adequately allocate downlink control signals to radio resources for the enhanced control channel.

Abstract: The present invention is designed to enable uplink signal transmission power control that is suitable when non-orthogonal multiple access (NOMA) is used on the uplink.

Abstract: The present invention is designed to increase the capacity of backhaul links between radio base stations and relay stations.