Abstract: Overhead related to precoding (beamforming weight) information to be notified over a backhaul may be reduced while maintaining an ICI reduction effect by coordinated CoMP among a plurality of nodes. A communication apparatus of the invention includes a reception unit that receives precoding information from user equipment, a selection unit that variably controls an amount of the precoding information, which is to be notified to another communication apparatus via a backhaul, in response to positions of frequency resources, and a transmission unit that transmits the precoding information to the other communication apparatus in accordance with the amount of the precoding information controlled by the selection unit.

Abstract: There is provided a wireless communication relay station apparatus and a wireless communication base station apparatus capable of allocating resources dynamically to each apparatus in accordance with traffic. A wireless communication relay station apparatus according to the invention includes a receiver that receives data from the wireless communication base station apparatus or the wireless communication mobile station apparatus, and a selector that selects data, within an uplink subframe or a downlink subframe, from: first data to be relayed from the own apparatus to the wireless communication base station apparatus; second data to be relayed from the own apparatus to the wireless communication mobile station apparatus; third data to be relayed from the wireless communication base station apparatus to the own apparatus; and fourth data to be relayed from the wireless communication mobile station apparatus to the own apparatus.

Abstract: Provided is a wireless relaying device, wherein system capacity can be increased by reducing power consumption required for relay processing at mobile stations equipped with relaying function. This is a relaying node (200) that relays communication between an originating node and a destination node, and that is provided with: a demodulation unit (203) that demodulates a signal transmitted from the originating node; a decoding unit (205) that obtains a signal destined for the relaying node (200), by decoding an amplitude bit from among a plurality of bits that comprise each of the symbols of the signal demodulated by the demodulation unit (203); and a modulation unit (208) that generates a relay signal destined for the destination node, by modulating a phase bit from among the plurality of bits that comprise each of the symbols of the signal demodulated by the demodulation unit (203).

Abstract: Interference between users in an MU-MIMO system is minimized by effective precoding, without increasing an overhead of control data. In a wireless communication system in which multiplex communication is possible between multiple UE1, UE2, and BS, a channel estimation and precoding selection unit 539 in BS estimates channels from the respective UE1, UE2 to the BS, determines a precoding matrix P from a projection matrix to make the two channel response matrices orthogonal or nearly orthogonal, and feeds back the precoding matrix P to UE2, and executes precoding on only UE2 of the two. A precoding unit 524 in the UE2 employs the precoding matrix P that has been notified to perform precoding of a data stream, and sends the precoded data stream to the BS.

Abstract: Disclosed are a wireless communication base station device and a division number determination method that improves the frequency diversity effect while maintaining channel estimation accuracy regardless of the number of divisions in the frequency domain of a transmission signal from a wireless communication terminal device. A determination unit (117) determines the number of divisions in the frequency domain of a transmission signal from a wireless communication terminal device. Here, the determination unit (117) increases the number of divisions in the frequency domain of the transmission signal from the wireless communication terminal device as the number of pilot blocks included in the transmission signal increases. In addition, a scheduling unit (118) schedules allocation to the frequency resources of the divided transmission signal according to the number of divisions determined by the determination unit (117).

Abstract: A wireless transmission apparatus able to reliably increase outage capacity according to the state of a propagation path.

Abstract: Disclosed is a wireless communication apparatus and wireless communication method wherein flexible frequency scheduling is performed without increasing the scale of the DFT (Discrete Fourier Transform) circuitry. For example, when resource allocation information is reported indicating whether or not a resource has been allocated to each of a plurality of RBGs (RB groups) into which the system bandwidth is divided, as in Type 0 allocation, if the number of reported RBs reported by the resource allocation information cannot be expressed as “2^n×3^m×5^l”, an allocated RB number setting section (208) sets the number of allocated resource blocks used in the actual transmission band, corresponding to the reported RB number, to the number of resource blocks that can be represented by any of “2^n×3^m×5^l”, and an allocated RB selection section (209); selects the allocated RB employed in the actual transmission band from the resource allocation information and allocated RB number.

Abstract: Provided is a wireless communication device which can improve the notification accuracy of the channel state information (CSI) without straining the feedback circuit. In this device, a channel estimator (105) uses a pilot signal input from a wireless receiver (102) to estimate the channel and obtain a plurality of path gains in each of a plurality of delay periods. Then, the channel estimator (105) outputs the plurality of path gains to a quantizer (107). The quantizer (107) quantizes the plurality of path gains in the number of notification bits corresponding to each of the plurality of delay periods based on the correspondence of the delay period and the number of notification bits input from a setting unit (106).

Abstract: A radio transmitting apparatus wherein even if a preamble sequence transmitted via any one of the antennas of the radio transmitting apparatus is detected, the order of the space diversity can be determined with reliability and data signals can be normally decoded. In this apparatus, a deciding unit (101) decides preamble sequences the number of which is equal to the order of the space diversity and further decides transmission block intervals the number of which is equal to or greater than the order of the space diversity. An allocating unit (102) sequentially allocates the preamble sequences, the number of which is equal to the order of the space diversity, to the respective antennas, the number of which is equal to the order of the space diversity, within the respective transmission block intervals. The allocating unit (102) allocates different ones of the preamble sequences to the respective antennas at the respective same transmission timings that are within the respective transmission block intervals.

Abstract: There are provided a communication device, a base station, a communication system, and a communication method that make it possible to yield a diversity effect by cooperative relay without involvement of disproportionateness in data received by an eNB even when one of parties has unsuccessfully exchanged data. After received an ACK signal from a repeater 1, a repeater 2 which has transmitted a NACK signal in procedure 7 transmits data S2 to the eNB by use of its own resource, thereby making its own resource available for the repeater 1 (the repeater 2 does not use its own resource, and the repeater 1 uses the resource of the repeater 2). In procedures 8, the repeater 1 has received the NACK signal from the repeater 2 and subsequently transmits data S1 to the eNB by use of its own resource. Subsequently, the repeater 1 which has received the MACK signal in procedure 9 determines that the resource of the repeater 2 is available and transmits data P1 to the eNB by use of the resource of the repeater 2.

Abstract: A wireless relay station apparatus for enabling a mobile station and a base station to reliably receive network coding data and to provide sufficient reception performance is provided. (1) A repeater divides data X received from a mobile station into important data and non-important data and divides data Y received from eNB into important data and non-important data. Next, (2) the repeater places the data so that important data Sx for the mobile station and important data Sy for the eNB do not overlap, XORs (exclusive ORs) them, and generates network coding data X (X) Y. (3) The repeater applies downlink propagation inverse characteristic H1?1 to important data portion Px (X) Sy for the mobile station and on the other hand, applies uplink propagation inverse characteristic H0?1 to important data portion Sx (X) Py for the eNB in the network coding data X (X) Y for transmission.

Abstract: Overhead related to precoding (beamforming weight) information to be notified over a backhaul may be reduced while maintaining an ICI reduction effect by coordinated CoMP among a plurality of nodes. A communication apparatus of the invention includes a reception unit that receives precoding information from user equipment, a selection unit that variably controls an amount of the precoding information, which is to be notified to another communication apparatus via a backhaul, in response to positions of frequency resources, and a transmission unit that transmits the precoding information to the other communication apparatus in accordance with the amount of the precoding information controlled by the selection unit.

Abstract: To prevent relaying wrong information by determining whether a radio signal is to be relayed in accordance with a function of error detection in the radio signal. A relay station apparatus according to an aspect of the invention is a relay station apparatus which relays a radio signal between a transmission station and a reception station, including: a receiver which is configured to receive the radio signal from the transmission station; and a relay determination section which is configured, in accordance with a function of error detection in the radio signal received by the receiver, to determine whether the signal is to be relayed or not, based on a first channel quality indicating a channel quality from the transmission station to the relay station apparatus.

Abstract: Provided is a mobile communication system capable of eliminating the use of a control channel for transmitting specific area information and suppressing the overhead caused by a frequency change process for a mobile station to receive the specific area information. In the mobile communication system, a relay station (20) has a coverage area (21) (specific area) and relays and transmits, in the coverage area (21), a signal received from a base station (10) to a mobile station (30). The relay station (20) adds, to the signal received from the base station (10), the offset of any of a frequency offset, a time offset, and a power offset depending on a risk indicated by risk information in the coverage area (21) (specific area) and transmits the signal after the addition of the offset to the mobile station (30) located in the coverage area (21).

Abstract: Interference between users in an MU-MIMO system is minimized by effective precoding, without increasing an overhead of control data. In a wireless communication system in which multiplex communication is possible between multiple UE1, UE2, and BS, a channel estimation and precoding selection unit 539 in BS estimates channels from the respective UE1, UE2 to the BS, determines a precoding matrix P from a projection matrix to make the two channel response matrices orthogonal or nearly orthogonal, and feeds back the precoding matrix P to UE2, and executes precoding on only UE2 of the two. A precoding unit 524 in the UE2 employs the precoding matrix P that has been notified to perform precoding of a data stream, and sends the precoded data stream to the BS.

Abstract: A method and device for adjusting a timing advance in a communication system composed of a mobile terminal and multiple base stations is provided. The method includes steps: the multiple base stations measures channel latencies and powers of channel responses between the mobile terminal and the multiple base stations separately; the non-serving base station in the multiple base stations reports the channel latency and the power measured to a serving base station; and the serving base station determines the timing advance of the uplink of the mobile terminal according to the channel latency and the power received and the channel latency and the power which are measured by the serving base station itself, and informs the mobile base station of the timing advance. By using the method and the device, the useful power received by the uplink multi-base stations can be optimized, and the interference power can be effectively reduced.

Abstract: Disclosed is a wireless communication apparatus and wireless communication method wherein flexible frequency scheduling is performed without increasing the scale of the DFT (Discrete Fourier Transform) circuitry.

Abstract: To prevent relaying wrong information by determining whether a radio signal is to be relayed in accordance with a function of error detection in the radio signal. A relay station apparatus according to an aspect of the invention is a relay station apparatus which relays a radio signal between a transmission station and a reception station, including: a receiver which is configured to receive the radio signal from the transmission station; and a relay determination section which is configured, in accordance with a function of error detection in the radio signal received by the receiver, to determine whether the signal is to be relayed or not, based on a first channel quality indicating a channel quality from the transmission station to the relay station apparatus.

Abstract: There is provided a wireless communication relay station apparatus and a wireless communication base station apparatus capable of allocating resources dynamically to each apparatus in accordance with traffic. A wireless communication relay station apparatus according to the invention includes a receiver that receives data from the wireless communication base station apparatus or the wireless communication mobile station apparatus, and a selector that selects data, within an uplink subframe or a downlink subframe, from: first data to be relayed from the own apparatus to the wireless communication base station apparatus; second data to be relayed from the own apparatus to the wireless communication mobile station apparatus; third data to be relayed from the wireless communication base station apparatus to the own apparatus; and fourth data to be relayed from the wireless communication mobile station apparatus to the own apparatus.

Abstract: Provided are a scheduling device and a scheduling method, in which the amount of signaling of frequency resource allocation information can be reduced while the system throughput is maintained. In a base station device (100), a scheduling unit (113) selects, as an allocation resource for a terminal to which resources are to be allocated, at most one cluster band in each of a plurality of allocatable ranges set within a system band and generates allocation resource information including information relating to the selected cluster, and an encoding unit (114), a modulation unit (115), and a transmission RF unit (116) which serve as a transmission means transmit the allocation resource information generated by the scheduling unit (113) to the terminal to which the resources are to be allocated.