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: Disclosed is a radio communication device capable of using a resource in which the signal cannot be received by all relay stations participating in cooperative relay for a cooperative relay. A signal-receivable frequency resource determination unit 104 determines a signal-receivable resource that can receive signals from the resources used for the cooperative relay on the basis of scheduling information, and a transmission selection unit 110 selects a radio communication relay method on the basis of a determination result of the determination unit.

Abstract: A wireless communication apparatus wherein the buffer size can be reduced without increasing the overhead of signalings. In this apparatus, a buffer (201) stores transport data. A radio receiving part (206) receives a response signal responsive to a transport data transmitted by the local apparatus; a response signal responsive to a transport data transmitted by another wireless communication apparatus; and relay data. A determining part (208) determines the smaller one of the two numbers: the number of ACK signals responsive to the transport data transmitted by the local apparatus and the number of ACK signals responsive to the transport data transmitted by the other wireless communication apparatus. The buffer (201) deletes transport data the number of which is equal to the difference between the number of ACK signals responsive to the transport data transmitted by the local apparatus and the number determined by the determining part (208).

Abstract: There are provided a wireless communication apparatus, a wireless communication method, and a wireless communication system capable of selectively utilizing the advantages of both centralized control and distributed control while a time needed for cell searching is suppressed. FIG. 4(a) represents an example in which a P-BCH and an S-SCH for the centralized control and a P-BCH and an S-SCH for the distributed control are frequency-divided, and the P-BCH and the S-SCH for the distributed control are transmitted to a distributed control resource. FIG. 4(b) represents an example in which a P-BCH and an S-SCH for the centralized control and a P-BCH and an S-SCH for the distributed control are time-divided, and the P-BCH and the S-SCH for the distributed control are transmitted to a centralized control resource. Since a relay station transmits the P-SCH as a centralized control resource, a mobile station can specify sub-frame timing by using only the centralized control resource.

Abstract: It is possible to provide a radio communication relay device, a radio communication base station device, a radio communication system, and a radio communication method which can effectively use resources and suppress a data delay and system complexity. When a terminal starts an upstream communication with a base station via a repeater in ST403, the base station simultaneously allocates to the terminal, a resource for an initial transmission and a resource for a retransmission by using Grant 1. If the repeater successfully receives UL data transmitted from the terminal in ST404, the repeater relays, in ST406, the UL data transmitted from the terminal, to the base station by using the resource for retransmission which has been allocated to the terminal.

Abstract: The error rate characteristic in a wireless communication apparatus for relaying communications between a mobile station and a base station is improved. For the modulation level of the resource for network coding, the modulation level from a relay station to the mobile station or the modulation level from the relay station to the base station, whichever is lower, is selected and thus the modulation level becomes QPSK. The relay station preferentially assigns S1 of a systematic bit of high importance, of S1+P1 to the network coding resource. The signal of S1+P1 not assigned to the network coding resource is assigned to the resource for the base station from the relay station. In the example, S1 is assigned to the resource for network coding and P1 is assigned to the resource for the base station from the relay station.

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: Provided is a mobile communication system which includes a plurality of RAT (Radio Access Technology) and can eliminate the need of a control channel for reporting RAT information so as to prevent congestion or shortage of the control channel capacity. In the mobile communication system, an LTE relay station (30) has a cover area (31) identical to a cover area (21) owned by a WLAN host station (20) and relays/transmits the signal received from an LTE base station (10) to a mobile station (40) in the cover area (31). The LTE relay station (30) adds to the signal received from the LTE base station (10), one of the offsets: a frequency offset, a time offset, and a power offset as information indicating that the mobile station (40) which receives a relay signal from the local station is located in the cover area (21) of WLAN and transmits the signal after offset addition to the mobile station (40) located in the cover area (31) (i.e., the cover area (21)).

Abstract: An assignment section 101 determines communication resource assignment to communication terminals based on a transmission rate at which communication is possible for each subcarrier of each communication terminal, and instructs a buffer section 102 to output forward transmission data. In addition, the assignment section 101 instructs a frame creation section 103 to perform forward transmission data symbolization, and also outputs a signal indicating communication resource assignment to each communication terminal. The buffer section 102 holds forward transmission data, and outputs forward transmission data to the frame creation section 103 in accordance with instructions from the assignment section 101. The frame creation section 103 symbolizes a resource assignment signal and transmission data to create a frame, which it outputs to a spreading section 104.

Abstract: A data receiving apparatus capable of minimizing data reception errors. In this apparatus, antenna 110 receives an RF signal and generates a received signal. Radio processor 120 performs frequency conversion processing upon the received signal. Received signal memory 130 stores the received signal thus frequency converted. Propagation path estimator 140 estimates propagation path characteristics from the stored received signal. SNR estimator 160 calculates the likelihood of the received signal using the received signal, an estimated value of the propagation path characteristics and a known signal stored in TSC memory 150. Viterbi equalizer 170 performs Viterbi equalization processing upon the received signal by using an estimated value of the propagation path characteristics and thereby generates demodulated data. Soft decision data generator 180 multiplies the likelihood by the demodulated data and thereby generates soft decision data.

Abstract: Signal component converging section 105 delays received signal components spread on a time axis to combine signal components based on an output of propagation path estimating section 104, maximum value detecting section 106 detects a sample timing of a signal component with the maximum power among signal components combined in signal component converging section 105, and tap coefficient estimating section 107 estimates a tap coefficient that minimizes a mean square of a difference between a replica signal and a received signal while assigning a tap coefficient of a fixed value (for example, 1) to a sampling timing providing the maximum power, and outputs the estimated tap coefficient to FFF in plural array combining section 102 and a replica generating section in Viterbi equalizer 108.

Abstract: The Viterbi calculation section 106 performs a Viterbi calculation by adding a branch metric to a path metric output from the metric selection section 105 and selecting a path having the smallest addition result and determines a surviving path having the smallest path metric and a second path having the second smallest path metric. The likelihood calculation section 107 compares each bit of the surviving path with the corresponding bit of the second path, sets lower likelihood for a bit having a different value than for a bit having the same value, and in this way calculates likelihood of each bit composing each symbol of the surviving path based on the relationship between the surviving path and the second path and further using mapping rules of the modulated signal. This makes it possible to calculate bit likelihood with a high degree of accuracy when demodulation is performed using Viterbi equalization to improve the error correcting capacity.

Abstract: The reverse rotation section phase-rotates received symbols in a direction opposite to the rotation direction on the transmitting side by an amount of phase rotation corresponding to each of a plurality of modulation schemes which are likely to be used on the transmitting side, the symbol decision section decides known symbols symbol by symbol in a training sequence section (known signal section), the error calculation section calculates decision errors, the comparison section compares the decided known symbols with a predetermined known symbol string corresponding to each of a plurality of modulation schemes which are likely to be used on the transmitting side in ascending order of the magnitude of errors and the modulation scheme decision section decides a modulation scheme to be used on the transmitting side according to the comparison result.

Abstract: A switch 404 sends an output of a reception processing section 402 to a training processing section 405 at a training processing time and to a demodulation processing section 407 by control of a timing control section 403. The training processing section 405 passes received signals through FFFs for the respective branches to perform array combination at the training processing time. A tap coefficient converting section 406 converts the tap coefficient of FFF estimated by the training processing section 405 to calculate a weighting factor. The demodulation processing section 407 weights the received signals using the calculated weighting factor to combine, and passes the combined signal through FFF. This makes it possible to reduce the amount of operations at the array combining time.

Abstract: In the case where empty slot detection section 119 detects an empty transmission slot to which no user data to be transmitted is assigned in a transmission signal whose frame is composed by communication frame composition section 118, empty slot detection section 119 notifies timing control section 115 of the empty transmission slot, switches switch 121, transmits the UW created by UW frame composition section 120 to the other communication station and the other communication station estimates a propagation environment using this UW and performs pre-coding.

Abstract: The processing up to initial value setting in adaptive algorithm in a communication terminal apparatus is omitted by the use of a tap coefficient set by the adaptive algorithm in a base station as an initial value, and thereby the load of the calculation of equalization processing in the communication terminal apparatus is decreased, and the processing time of the equalization processing is shortened.

Abstract: Converting section 201 converts I signal and Q signal in phase modulated signal of which delay wave distortion is cancelled into I′ signal and Q′ signal shown in I′-Q′ plane, respectively. Positive/negative decision section 202 outputs decoded bit in I′ signal as bit 3N+1. Positive/negative decision section 205 outputs an inversely rotated value by decoded bit in Q′ signal as bit 3N. Subtractor 206 outputs a decoded bit obtained by carrying out subtraction using the absolute value of I′ signal and absolute value of Q′ signal as bit 3N+2. Thus, it is possible to carry out decoding of phase modulated signal while keeping apparatus size and calculation amount.

Abstract: An assignment section 101 determines communication resource assignment to communication terminals based on a transmission rate at which communication is possible for each subcarrier of each communication terminal, and instructs a buffer section 102 to output forward transmission data. In addition, the assignment section 101 instructs a frame creation section 103 to perform forward transmission data symbolization, and also outputs a signal indicating communication resource assignment to each communication terminal. The buffer section 102 holds forward transmission data, and outputs forward transmission data to the frame creation section 103 in accordance with instructions from the assignment section 101. The frame creation section 103 symbolizes a resource assignment signal and transmission data to create a frame, which it outputs to a spreading section 104.

Abstract: A modulator and modulation method for orthogonally modulating digital baseband signals include interpolation filters that frequency convert the frequencies of an in-phase component and a quadrature phase component of a digital baseband signal to four times the frequency of an intermediate frequency. .DELTA..SIGMA. modulation circuits are provided and .DELTA..SIGMA. modulate the frequency converted signals. A low pass filter is provided to remove unnecessary components from the .DELTA..SIGMA. modulated signals. A switching circuit selects a signal that has passed through the low pass filter according to an order of an in-phase component, a code inverted component of a quadrature phase component, a code inverted component of the in-phase component and the quadrature phase component, and outputs these signals as a digital orthogonal signal. An N bit D/A converter converts the digital orthogonal signals into analog orthogonal signals.

Abstract: The data receiving system comprises a detecting section (13, 23, 33, 44, 54, 64, 75) for detecting an information field such as a flag indicating the identity of a control channel (FACCH) data when there are a plurality of information fields each indicating the identity of a received radio channel, and judging section (14, 25, 35, 46, 56, 66, 77) for determining the received radio channel based on the detection result of the detecting section.