Abstract: In an LTE-A system, there is a problem that it is difficult to perform stable communication in a case where there is a time when another system occupies an unlicensed band being used. There is provided a base station apparatus that communicates with a terminal device in a second frequency band different from a first frequency band capable of being used as a dedicated frequency band. The base station apparatus includes: a CS determination unit that performs carrier sense in a subframe of carrier sense configured in the second frequency band; a synchronization signal generation unit that generates a synchronization signal; and a wireless transmission unit that transmits the synchronization signal. In a case where the CS determination unit determines that another system does not perform communication in the second frequency band, the wireless transmission unit transmits the synchronization signal generated by the synchronization signal generation unit.

Abstract: A base station device according to the present invention receives wireless frames transmitted by terminal devices in nearby cells, estimates the state of the propagation channels between the terminal devices in the nearby cells and itself, based on the received signals thereof, and performs precoding on transmission data addressed to terminal devices in its own cell, based on the estimation results of the propagation channel state, and transmits.

Abstract: There are provided a base station apparatus, a terminal apparatus, and a communication method which are capable of realizing a LTE-A system with improved throughput by performing a CA technology including an unlicensed band while suppressing interference from an existing system. A base station apparatus according to the present invention is a base station apparatus which is included in a communication system that applies a communication scheme applied to a first frequency band capable of being used as a dedicated frequency band to a second frequency band different from the first frequency band and is capable of communicating with a terminal apparatus by using the second frequency band and the second frequency band. The base station apparatus synchronizes a frame number of a frame of a first signal transmitted using the first frequency band with a frame number of a frame of a second signal irrespective of whether or not the second signal transmitted using the second frequency band is transmitted.

Abstract: There are provided a base station apparatus, a terminal apparatus, and a communication method which are capable of realizing a LTE-A system with improved throughput by performing a CA technology including an unlicensed band while suppressing interference from an existing system. A base station apparatus according to the present invention, which is included in a communication system that applies a communication scheme applied to a first frequency band capable of being used as a dedicated frequency band to a second frequency band different from the first frequency band and is capable of communicating with a terminal apparatus by using the second frequency band and the second frequency band.

Abstract: Degradation in reception performance due to interference is reduced while suppressing control information from increasing. A terminal device receives a first reception signal and a second reception signal, includes a higher layer processing unit that determines NAICS information indicating whether it is indicated in a higher layer that NAICS has to be applied, and a control unit that performs control in such a manner that, in a case where the NAICS is configured in the higher layer, an ACK/NACK of the first reception signal is transmitted and an ACK/NACK of the second reception signal is not transmitted.

Abstract: The present invention provides a technology that sets an offset value with respect to a received power of a reference signal from each of base station apparatuses, taking into consideration a difference between precoding schemes, in a wireless communication system that supports multiple different precoding schemes. The base station apparatus according to the present invention communicates with at least one of terminal apparatuses using the multiple different precoding schemes. The base station apparatus according to the present invention includes a transmission unit that transmits to the terminal apparatus multiple offset values that are to be added by the terminal apparatus to the received power of the reference signal from the base station apparatus, in which the multiple offset values correspond to the multiple precoding schemes, respectively.

Abstract: A terminal apparatus that communicates with a base station apparatus includes: a higher layer on which NAICS information is configured from the base station apparatus; and a control unit that, in a case where the NAICS information has been configured, determines the number of layers, antenna port numbers, and scrambling identities of a signal addressed to the terminal apparatus and an interfering signal. The terminal apparatus further includes a receiving unit that receives downlink control information, and the control unit determines at least one of the number of layers, antenna port number, and scrambling identity of the interfering signal on the basis of the downlink control information.

Abstract: Provided are a base-station apparatus, a terminal apparatus, and a communication method that make it possible to realize a LTE-A system which, while suppressing interference from an existing system, improves throughput by applying CA to an unlicensed band. The base-station apparatus of the invention is included in a communication system, in which a first communication scheme applied to a frequency band that is able to be used exclusively is applied to a frequency band that is not able to be used exclusively, transmits a resource reservation signal which reserves the frequency band that is not able to be used exclusively to the frequency band that is not able to be used exclusively based on a second communication scheme different from the first communication scheme, and applies the first communication scheme to the frequency band that is not able to be used exclusively after transmitting the resource reservation signal.

Abstract: Provided are a base-station apparatus, a terminal apparatus, and a communication method that make it possible to realize a LTE-A system which, while suppressing interference from an existing system, improves throughput by applying CA to an unlicensed band.

Abstract: More efficient control and stably establishing, securing, and continuing communication using unlicensed bands, in use of the unlicensed bands.

Abstract: When an unlicensed band is used, a more efficient control is provided, and a communication is established, or ensured and continues by stably using the unlicensed band. According to the present invention, there is provided a base station apparatus which applies a communication scheme applied to a frequency band allowed to be dedicatedly used, to a frequency band of which dedicated use is not allowed, and enables a communicate with a terminal device by using the frequency band of which dedicated use is not allowed, along with the frequency band allowed to be dedicatedly used. In a state where the frequency band of which dedicated use is not allowed is not used for a communication with the terminal device, to which the communication scheme is applied, the terminal device is notified of control information, and thus the communication scheme is applied to the frequency band of which dedicated use is not allowed, and the terminal device is instructed to communicate with the base station apparatus.

Abstract: A terminal apparatus improves throughput while suppressing control information of an interfering signal. The terminal device includes: a higher layer that determines an instruction as to whether to apply NAICS; a receiving unit that receives downlink control information; and a control unit that, in a case where it has been specified on the higher layer that NAICS is applied, determines, on the basis of information that is contained in the downlink control information and indicates whether to perform interference cancellation or suppression, whether to perform interference cancellation or suppression. The receiving unit receives, in a user-specific search space, the downlink control information containing the information indicating whether to perform interference cancellation or suppression.

Abstract: A terminal device is intended to reduce a decrease in reception performance in response to inter-cell interference and inter-user interference even when multiple interference streams are received. The terminal device connected with a first base station apparatus receives a first interference signal serving as inter-user interference from the first base station apparatus, and a second interference signal serving as inter-cell interference from a second base station apparatus, demodulates at least one interference stream of the first interference signal using terminal information transmitted from the first base station, and suppresses the second interference signal using a reception weight.

Abstract: Degradation in reception performance due to interference is reduced while suppressing an increase in the amount of control information. There is provided a terminal device including; a higher layer that determines whether or not to apply NAICS; and a reception unit that receives downlink control information, in which, in a case where, with the higher layer, an indication that the NAICS has to be applied is provided, if the downlink control information is detected in a UE-specific search space, signal detection in compliance with the NAICS is performed, and in which, in the case where, with the higher layer, the indication that the NAICS has to be applied is provided, if the downlink control information is received in a common search space, signal detection in compliance with a linear scheme is performed.

Abstract: A terminal device, a base station apparatus, a transmission method, configured to perform interference cancellation at a higher accuracy level are provided. The terminal device reports, to the base station apparatus connected thereto, first channel information serving as channel information with the base station, and second channel information serving as channel information with an interfering base station. The channel information includes a channel quality indicator, and the terminal device reports, to the base station apparatus connected thereto, a first channel quality indicator serving as a channel quality indicator with the base station apparatus, and a second channel quality indicator serving as a channel quality indicator with the interfering base station.

Abstract: Provided is a base-station device, a terminal device, a transmission method, and a reception method that realize efficient transmission in a radio communication system that performs large-scale MU-MIMO transmission. The base-station device having a plurality of antennas and performing communication with a plurality of terminal devices simultaneously, includes a channel state information acquisition unit for acquiring channel state information with respect to the plurality of terminal devices; a signal spreading unit for performing spreading and multiplexing for a plurality of signals addressed to each of the terminal devices by using a spread code in a spatial direction of each of the terminal devices; and a precoding unit for applying precoding to the signals, which have been spread and multiplexed, based on the channel state information.

Abstract: Degradation in reception performance due to interference is reduced while suppressing control information from increasing. A higher layer that determines whether or not to apply NAICS and a reception unit that receives Downlink Control Information are included. In a case where, with the higher layer, an indication that the NAICS has to be applied is provided, if a first downlink control information format is received, signal detection in compliance with the NAICS is performed, and, in the case where, with the higher layer, the indication that the NAICS has to be applied is provided, if a second downlink control information format is received, signal detection in compliance with a linear scheme is performed. The first downlink control information format is constituted as at least one downlink control information format that is allocated only to a UE-specific search space.

Abstract: A terminal device acquires a parameter indispensable in canceling or suppressing an interference signal, cancels or suppresses interference with high precision, and reduces a degradation in reception performance due to the interference. There is provided a first terminal device that communicates with a base station apparatus, including: a higher layer processing unit that determines NAICS information indicating whether or not NAICS has to be used; a reception unit that receives downlink control information which is transmitted from the base station apparatus; and a control unit that changes interpretation of the downlink control information based on a configuration that is determined by the higher layer processing unit.

Abstract: A terminal device acquires a parameter indispensable in canceling or suppressing an interference signal, cancels or suppresses interference with high precision, and reduces a degradation in reception performance due to the interference.

Abstract: Good transmission performance is obtained even when the difference between the number of transmit antennas and the number of receive antennas is small. A modulation symbol is subjected to spreading and code multiplexing in a receive antenna direction of a terminal device, is subjected to precoding, and is transmitted. A spreading ratio of a spreading code for performing the spreading in the receive antenna direction is equal to the number of receive antennas of the terminal device. Spreading code multiplexing is performed in the receive antenna direction. Thus, it is possible to provide a base station apparatus and a terminal device providing good transmission performance by changing the number of multiplexing operations even when the difference between the number of transmit antennas and the number of receive antennas is small.