Abstract: A wireless base station apparatus includes an interference report receiver configured to receive interference reports transmitted on a shared radio resource from a plurality of wireless terminals that are present in a plurality of adjacent cells that are adjacent to a target cell, the shared radio resource being comprised of a plurality of carriers and being shared between the plurality of adjacent cells, and an adaptive fractional frequency reuse controller configured to control adaptive fractional frequency reuse processing in a downlink of the target cell, based on the received interference reports showing a downlink reception quality, wherein the interference reports are transmitted using selected carriers from the plurality of carriers by the plurality of wireless terminals, based on the downlink reception quality.

Abstract: A digital filter circuit that implements a filtering process for a plurality of channels having different sampling rates with a small circuit complexity includes a delay circuit divided into first to mth groups of delay devices, processing stage division means for selectively supplying first to (m?1)th input delayed signals and output signals of the second to mth taps to the first to (m?1)th groups of delay devices, tap coefficient supply means for supplying first to mth selected tap coefficients, a multiplying circuit for multiplying outputs of the first to mth taps and the first to mth selected tap coefficients, an adding circuit for adding up first to mth multiplication results, an accumulative addition part for accumulatively adding the first to mth multiplication results and addition results of the plurality of adders, and an output data format generation part for generating an output format of a filtering process result of each of processing stages from the plurality of accumulative addition results and

Abstract: A base station, a mobile station and a retransmission control method for enabling communication to be more efficiently performed. In a communication system comprising a base station (100) and a mobile station (200), a time period required for the retransmission of a transport packet to complete is determined, and a retransmission control is performed, based on the required time period, to change the order of executing the retransmission of the transport packet and a handover. In this way, when it is estimated that the retransmission will complete soon, the retransmission is caused to complete in a handover source system, thereby avoiding waste of communication resources used in the preceding transmission and retransmission processes.

Abstract: It is possible to provide a radio reception device, a radio transmission device, a radio reception method, and a radio transmission method which can improve the channel estimation accuracy and the reception quality. The radio reception device (200) includes: reception units (203, 204) which receive a data sequence added by a reference signal for channel estimation of a spatial propagation path at a predetermined interval; demodulation units (205, 206) which demodulate the data sequence; a channel estimation unit (208) which estimates a propagation path fluctuation state according to the reference signal in the data sequence and outputs a channel estimation value obtained by interpolating or extrapolating the data sequence; and a decoding processing unit (210) which decodes the data sequence by using the interpolated or extrapolated channel estimation value.

Abstract: It is possible to provide a novel pilot transmission method which can calculate an accurate channel estimation value, a MIMO transmission device using the pilot transmission method, and a MIMO reception device which performs communication with the MIMO transmission device. The MIMO transmission device (100) includes a cyclic shift processing unit (150) which cyclically shifts a first pilot signal sequence spread by a spread code 1 and second pilot signal sequence spread by a spread code 2 with different shift amounts. The first pilot signal sequence and the second pilot signal sequence which have been cyclically shifted are transmitted from different transmitting antennas at the same pilot transmission symbol section. Thus, by changing the shift amount of the cyclic shift process executed on each pilot signal sequence spread by the respective spread codes, it is possible to improve the pilot separation accuracy at a reception side. This enables more accurate calculation of a channel estimation value.

Abstract: Provided is a MIMO transmission device which can effectively perform a pilot transmission by using a surplus sample generated in a pilot symbol while maintaining the pilot separation accuracy at a reception side. The MIMO transmission device (100) transmits a pilot symbol as follows. That is, in a first pilot transmission symbol section, a transmission section of a pilot signal transmitted from a first transmission antenna is partially overlapped by a pilot transmission section of a second transmission antenna. In a second pilot transmission symbol section, a pilot transmission section of the first transmission antenna is partially overlapped by a pilot transmission section of a third antenna. Among the pilot signals transmitted from the first antenna, the interference portions overlapped by transmission pilot signals from other antennas are different between the first pilot transmission symbol section and the second pilot transmission symbol section.

Abstract: It is possible to provide a novel pilot transmission method which can calculate an accurate channel estimation value, a MIMO transmission device using the pilot transmission method, and a MIMO reception device which communicates with the MIMO transmission device. The MIMO transmission device (100) includes phase adjustment units (130-1, 130-2) which are controlled by a pilot transmission control unit (170) to multiply parallel pilot signals by a phase adjustment coefficient group so as to adjust the pilot signal transmission timing. The pilot transmission control unit (170) differentiates the order of the transmitting antennas in accordance with the pilot transmission timing between an even-number subcarrier group and an odd-number subcarrier group. At a reception side, a path not influenced by the inter-path interference is extracted for each of the combinations of the transmitting antennas and the subcarrier groups.

Abstract: It is possible to provide a radio reception device, a radio transmission device, a radio reception method, and a radio transmission method which can improve the channel estimation accuracy and the reception quality. The radio reception device (200) includes: reception units (203, 204) which receive a data sequence added by a reference signal for channel estimation of a spatial propagation path at a predetermined interval; demodulation units (205, 206) which demodulate the data sequence; a channel estimation unit (208) which estimates a propagation path fluctuation state according to the reference signal in the data sequence and outputs a channel estimation value obtained by interpolating or extrapolating the data sequence; and a decoding processing unit (210) which decodes the data sequence by using the interpolated or extrapolated channel estimation value.

Abstract: It is possible to provide a transmission control method, a radio communication system, and a radio base station device which can reduce the time required until an inter-cell interference is reduced so as to improve the system throughput. A base station (200) includes: an FFT unit (210) which receives an interference report transmitted by using a common radio resource common to adjacent cells from a plurality of radio terminals (100) existing in different adjacent cells; and an adaptive FFR processing unit (230) which controls adaptive FFR processing in a downstream line of the local cell according to the reception interference report. Thus, by receiving an interference report directly from the radio terminals (100) existing in adjacent cells, it is possible to modify the transmission mode by considering the interference state in the adjacent cells. This eliminates the need of sending a report on a transmission mode modification which has been conventionally sent between adjacent base stations (200).

Abstract: A mobile station device for selecting a TPC command to improve the transmission quality of a packet in an upstream circuit more reliably, so that it reduces the re-transmission in the upstream circuit to improve a sector throughput. In this mobile station device, a demodulate unit (210) outputs a received signal of each base station device to an error correction decode unit (220) and a TPC command select unit (240). The error correction decode unit (220) outputs an ACK/NACK of each base station device to a data re-transmission control unit (230) and the TPC command select unit (240). The TPC command select unit (240) selects the TPC command of the highest priority on the basis of the information of the ACK/NACK. A transmission power control unit (280) determines the transmission power according to the contents of the TPC command of the highest priority.

Abstract: A wireless communication apparatus capable of performing an efficient communication even in a case of frequency multiplexing a plurality of OFDM symbols having GIs the lengths of which are different from each other in a multicarrier communication. In this wireless communication apparatus (100), encoding parts (102-1, 102-2) encode interleaved bit sequences (#1, #2). Modulating parts (103-1, 103-2) modulate the encoded bit sequences (#1, #2) to generate data symbols (#1, #2). Mapping parts (104-1, 104-2) map pilot symbols onto the subcarriers of OFDM symbols in which no ISI occurs, while mapping the data symbols (#1, #2) onto the subcarriers of the other OFDM symbols. IFFT parts (105-1, 105-2) perform IFFTs of the subcarriers, onto which the pilot symbols or the data symbols (#1, #2) have been mapped, to obtain the OFDM symbols (#1, #2).

Abstract: A base station, a mobile station and a retransmission control method for enabling communication to be more efficiently performed. In a communication system comprising a base station (100) and a mobile station (200), a time period required for the retransmission of a transport packet to complete is determined, and a retransmission control is performed, based on the required time period, to change the order of executing the retransmission of the transport packet and a handover. In this way, when it is estimated that the retransmission will complete soon, the retransmission is caused to complete in a handover source system, thereby avoiding waste of communication resources used in the preceding transmission and retransmission processes.

Abstract: A mobile station device for selecting a TPC command to improve the transmission quality of a packet in an upstream circuit more reliably, so that it reduces the re-transmission in the upstream circuit to improve a sector throughput. In this mobile station device, a demodulate unit (210) outputs a received signal of each base station device to an error correction decode unit (220) and a TPC command select unit (240). The error correction decode unit (220) outputs an ACK/NACK of each base station device to a data re-transmission control unit (230) and the TPC command select unit (240). The TPC command select unit (240) selects the TPC command of the highest priority on the basis of the information of the ACK/NACK. A transmission power control unit (280) determines the transmission power according to the contents of the TPC command of the highest priority.

Abstract: A mobile station apparatus selects an appropriate one of transmission rate instruction commands received from base station apparatuses to reduce the interference of the whole system and improve the sector throughput. In this mobile station apparatus (200), a demodulating section (210) outputs a received signal of each base station apparatus to an error correction decoding section (220), which then outputs the ACK/NACK and instruction command of each base station apparatus to a transmission rate control section (240), which then selects, based on the ACK/NACK information, from among the instruction commands received from the base station apparatuses, the instruction command that should be employed on a priority basis during an actual transmission rate control and that is received from a base station apparatus having a highest priority.

Abstract: There are provided a base station device, a mobile station device, and a transmission rate control method capable of appropriately controlling the transmission rate. In the base station device (100), an upstream scheduling unit (150) calculates a desired transmission power reduction ratio of a mobile station device whose transmission power is to be reduced among the mobile stations devices in which upstream packet communication is in progress and which is in the soft handover state, and transmits the desired transmission power reduction ratio. Thus, the mobile station device (300) which receives the desired transmission power reduction ratio can get a direct index concerning the transmission power reduction and it can select an appropriate transmission power and an appropriate transmission rate for it.

Abstract: A CRC judgment section 103 performs a CRC check on decoded data every transmission unit, and if there is an error in the data, updates a flag held in a flag holding section 106 from 0 to 1; an increment/decrement value calculation section 105 calculates a reference SIR increment/decrement value according to the state (0 or 1) of the flag; a reference SIR update section 107 adds the reference SIR increment/decrement value to the current reference SIR value to find a new reference SIR value; a comparison section 109 compares the received signal SIR value measured by an SIR measurement section 108 with the updated reference SIR value, and a transmission power control bit generation section 110 generates a transmission power control bit according to the result of the comparison.

Abstract: A sliding correlation between a received signal and a basic midamble is detected, and a delay profile is generated from a correlation value as a detection result of the sliding correlation, and thereafter averaging processing of the delay profiles is executed. Moreover, the path position of the received signal is detected from the averaged delay profile. In a CDMA communication system where the phase shift amount of a common midamble included in a transmitting signal changes according to the number of codes multiplexed, averaging processing with correlation value output from a correlator is surely executed either before or after correlation detection processing using the common midamble in order to improve the accuracy of path position estimation before the common midamble is identified.

Abstract: Turbo decoding section 102 performs turbo decoding on demodulated data, counting section 103 counts the number of iterations in turbo decoding, CRC decision section 104 performs CRC on the decoded data, increment/decrement value calculating section 105 calculates an increment or decrement value in reference SIR according to the presence or absence of an error and the number of iterations, reference SIR updating section 106 adds the increment or decrement value in reference SIR and a current reference SIR value to obtain a new reference SIR value, comparing section 108 compares an SIR value of a received signal measured in SIR measuring section 107 with the updated reference SIR value, and transmit power control bit generating section 109 generates a transmit power control bit according to the compared result.

Abstract: The base station apparatus compresses one-frame information of a broadcast channel to blocks of ½ of one frame or less and repeatedly sends this block in a one-frame time. The mobile station apparatus decodes the received signal in block units or added block units to carry out error detection. The mobile station apparatus receives and adds up the next block in the case that the error rate exceeds a threshold. The mobile station apparatus repeats this until the error rate falls below the threshold. When the error rate falls below the threshold, the mobile station apparatus stops reception of broadcast channel signals and uses the rest of time until a one-frame time elapses to monitor carrier information of a different mobile communication system for handover.

Abstract: The present invention carries out transmission/reception of broadcast channels using only the last downlink slot of subframes using signals having a TDMA structure according to a CDMA/TDD system, and thus flexibly handles various services and avoids problems of interference in self-operated services in particular. The base station communication apparatus repeatedly transmits information contained in broadcast channels by the number of times corresponding to the time-sharing number and appropriately allots uplink and downlink slots, thus making the most of the features of uplink open-loop transmission power control and base station transmission diversity.