Abstract: Provided are a transmission device and a transmission diversity method, which can suppress degradation of a transmission diversity performance even under the circumstances having a space correlation, in the case of performing a transmission diversity MIMO communication. The transmission device comprises an orthogonal conversion unit (201) for multiplexing an M-number of source symbols by an orthogonal conversion, to form an N-number of transmission symbols, and a beam forming unit (204) for changing the transmission symbols of the N-number one by one into beams by using the beam forming parameters of the N-number, thereby to transmit the transmission symbol beams timely sequentially one by one from a plurality of antennas.

Abstract: A communication apparatus capable of improving the spectrum usage rate of a system, especially, the spectrum usage rate in connection with both a fast fading and a channel estimation error as compared with the conventional sub-band adaptive method, while reducing the degree of the difficulty in achieving the adaptation, and further reducing the feedback overhead. In this apparatus, a sub-band group AMC parameter selecting part (318) selects an AMC parameter of each sub-band. An adaptive reception control part (503) must control an adaptive demodulating/decoding part (311), while controlling a parallel/serial converter (312) in a stage preceding the adaptive demodulation and decoding processes, and combining received symbols in the same sub-band group for demodulation and decoding.

Abstract: A decoding apparatus that is capable of calculating of the likelihood information at high speed while suppressing increases in processing amount and in circuit scale. In this apparatus, in computations of the backward probability in a backward probability computing section (112), while one processing system calculates the backward probability ?k from the backward probability ?k+2, the other processing system calculates the backward probability ?k?1 from the backward probability ?k+1 in parallel. Specifically considering the case of k=1, backward probabilities ?1, and ?0 are calculated in parallel in two processing systems. The calculated backward probabilities are stored in a storage section (114) on a window basis. Further, as in the backward probability, in a forward probability computing section (113), forward probabilities ?k and ?k+1 are calculated in parallel in two processing systems.

Abstract: Provided is a carrier allocation method in a multi cell OFDMA system capable of improving the system capacity and the bit error rate performance.

Abstract: A channel parameter generating method realizing limited feedback of a MIMO system. In this method, a channel parameter of a MIMO channel fed from a wireless receiver back to a wireless transmitter is generated.

Abstract: There is provided a down link multi-user time-space code precoding method including: a step (S401) where a base station acquires channel information on a plurality of user terminals and converts it into a channel matrix; a step (S402) for obtaining a such a conversion matrix that a matrix obtained by multiplying the channel matrix and the conversion matrix is a block diagonal orthogonal matrix; a step (S403) for obtaining a standardization factor of each user terminal by squaring the elements on the diagonal line of the block diagonal orthogonal matrix; a step (S404) for standardizing a transmitted symbol of each user by using the standardization factor; and a step (S405) for multiplying the conjugate transposed matrix and the conversion matrix of the block diagonal orthogonal matrix into standardized symbols successively from the left so as to obtain symbols after the processing and transmitting the processed symbols by the time-space code rule.

Abstract: A transmission bit and transmission power distributing method that can reduce the arithmetic amount in a multiantenna-input/multiantenna-output (MIMO) wireless communication system. This method comprises steps of calculating a signal-to-interference-noise ratio (SINR) gain after MIMO detection of each of transport substreams (S601, S602); optimizing, based on the acquired SINR gain, a transmission bit and transmission power distribution in the space domain for all transport substreams on a particular subcarrier in the frequency domain, thereby deciding a transmission bit and transmission power distribution parameters (S603, S604); and optimizing a transmission bit and transmission power distribution for adjacent subcarriers, by sequentially using the transmission bit and transmission power distribution parameters distributed on the subcarrier for which the transmission bit and transmission power distribution parameters have been decided (S605 to S610).

Abstract: A wireless communication method in which use of the HERQ technique brings about an improved throughput of data transmission. In this method, if the number of retransmissions n is equal or below an upper limit value (ST404: NO), a transmission mode k is computed for k=n mod 4 at the transmission side (ST405), sub-streams are grouped into combinations of sub-streams according to the channel status fed back from the transmission side if k=1 (ST 407), time-space block coding of the data of each group is performed (ST 408), the coded data is allocated to the corresponding antenna and retransmitted (ST409), and the retransmitted data is combined with the previously transmitted data and time-space block decoding is performed (ST410).

Abstract: A retransmitting method, a radio receiving apparatus and a multiantenna communication system that are capable of improving the system throughput.

Abstract: First normalizing means (12) normalizes first and second code streams (s1, s2). First spreading means (13) spreads the output of the first normalizing means (12). STTD coding means (14) subjects the first and second code streams (s1, S2) to STTD coding. Second normalizing means (15) normalizes the output of the STTD coding means (14). Second spreading means (16) spreads the output of the second normalizing means (15) by means of the same spreading code as that of the first normalizing means (12). Orthogonal transforming means (17) gives the negative signs to odd chips in a second path spread sequence of each code and exchanges the orders of the odd and even chips. Combining means (18) adds first and second spread sequences of the second path produced by orthogonally transforming the first and second spread sequences of the first path. With this, by using the orthogonality of the transmitted sequences at the receiving side, the reception signal can be detected with a lower complexity.

Abstract: A MIMO communication apparatus wherein HARQ technique is utilized, in a MIMO system, to simplify feedback information and hence reduce the amount of information to be transmitted, thereby saving the transmission resources of the system, while improving the efficiency of data transmission. Additionally, this MIMO communication apparatus has a simple structure, while being capable of performing a reliable data retransmission. This MIMO communication apparatus comprises means (buffer 202) for storing ACK/NACK information of each of data substreams generated and fed back by another MIMO communication apparatus; means (transmission efficiency estimating part 208) for estimating, based on the stored information, a transmission efficiency of each data substream; and means (antenna selecting part 203) for selecting, in accordance with a result of that estimation, a predetermined number of antennas having high transmission efficiencies.

Abstract: MIMO transmitting apparatus wherein data to be retransmitted and data to be transmitted anew are rearranged, thereby using HARQ technique to improve the reliability of the system transmission, while increasing the system throughput and improving the efficiency of the whole data transmission. In this apparatus, a retransmittal data selecting means (400) temporarily stores data, and outputs, as retransmittal data, the data when it is determined, based on feedback information, that the data must be retransmitted. A deinterleaving means (404) performs a deinterleaving process under control of an interleaving control means (408). The interleaving control means (408) controls, based on the feedback information, an interleaving process.

Abstract: A multi-antenna communication method capable of improving the retransmission performance in a multi-antenna transmission. In this method, firstly, the reception quality of a substream to be retransmitted is acquired (Step 401). Then, it is determined for the substream whether any transmission antennas, which satisfy a target value related to the foregoing reception quality when they are used for the retransmission, are existent among the transmission antennas that are candidate antennas to be used for there transmission (Step 405). Then, if there exist any transmission antennas satisfying the target value, a transmission antenna to which the poorest channel characteristic corresponds is selected from among those transmission antennas satisfying the target value, and the selected transmission antenna is designated as an antenna to be used for retransmitting the foregoing substream (Step 406).

Abstract: A MIMO transmitting apparatus wherein a low power consumption and a high performance can be achieved by taking the influence of variation in communication distance into account. In this apparatus, a low power consumption design part (701) selectively decides, based on the distance from the other end of communication, whether to perform a pre-coding. When deciding to perform the pre-coding, the low power consumption design part (701) instructs a modulating part (702) to perform a low-order QAM modulation, while instructing a pre-coding part (703) to perform a pre-coding. When instructed to perform a low-order QAM modulation, the modulating part (702) uses a low-order QAM modulation scheme to modulate an input information bit sequence. When instructed to perform a pre-coding, the pre-coding part (703) uses a pre-coding matrix to pre-process the input information bit sequence.

Abstract: A radio communication apparatus is disclosed that is capable of improving throughput even when accuracy of channel quality estimation is low and variation of channel quality estimation values is substantial. In this apparatus, MCS(SIR) acquisition section (201) acquires from MCS table (202) an MCS level (MCS(SIR)) corresponding to an SIR value. Comparison section (204) compares the acquired MCS level with the MCS level (MCS (p)) used in pervious control and stored in MCS (p) storage section (203). MCS determination section (205) determines an MCS level that has a predetermined level difference with respect the MCS (p) based on the comparison result. MCS determination section (205) acquires the modulation scheme and coding rate corresponding to the determined MCS level from MCS table (202) and controls rate matching section (103) and modulation section (105).

Abstract: A turbo decoder is disclosed that receives a demodulated input signal before a hard decision, including blocks each of multiple data units, and outputs a decoded signal block by block. The turbo decoder includes a decoding part outputting a decoded output signal and extrinsic likelihood information based on the input signal and preliminary likelihood information, the extrinsic likelihood information being used as the preliminary likelihood information in creating the next output signal; a specification part specifying a data unit of the block with respect to which no error is detected in error checking performed on each data unit of the hard decision output signal; and a replacement part inputting a signal sequence, created by replacing signal data before the hard decision with those after the hard decision with respect to the data unit specified by the specification part, to the decoding part as the input signal.

Abstract: A multi-rate wireless communication apparatus wherein a low complexity is exhibited for a problem of code congestion occurring when a system supports an application of a variable multimedia and wherein a dynamic code distribution is performed, thereby significantly reducing the number of re-distributions and hence reducing the system load. In this apparatus, a storing part (101) stores an optimum system code tree. A comparing part (102) determines, upon receipt of a new call, whether the system can accept the new call. A calculating part (103) performs a calculation based on the status of the code tree stored in the storing part (101) and based on a rate (t) required by the new call. A distributing part (104) distributes, based on a calculation result from the calculating part (103), an appropriate code to the new call, and changes, as occasion requires, the distributed code so as to optimize the system code tree, and further causes the storing part (101) to store the code tree as changed.

Abstract: A desired coding rate is obtained by encoding source data to produce first additional data; randomizing the source data to produce randomized data; encoding the randomized data to produce second additional data; selecting a number of bits from the first and second additional data to produce first selected data and second selected data, the number of selected bits is selected based upon a data length of the source data and a desired data length of an output sequence; and multiplexing the source data with the first and second selected data. At least one of the data length of the source data and the data length of the output sequence is variable.

Abstract: There is provided a method for detecting a symbol timing of a multi-antenna radio communication system. The method can significantly reduce a calculation amount in a space division multiplex OFDM system as compared to the conventional method, can detect an accurate symbol timing, and can easily be realized. In this method, at the symbol timing stage, a transmission side transmits a timing training sequence only from the first antenna. A reception side has a symbol timing divided into a rough timing stage and an accurate timing stage. In the rough timing stage, a phase correlation value between the reception signal of each antenna and its delay is calculated. The correlation value outputs of the respective antenna terminals are combined to decide the rough timing window. In the accurate timing stage, a convolution calculation is performed by using a real part of the reception symbol and a symbol of a real part of the training sequence.

Abstract: A wireless multimedia communication method for improving wireless video transmission quality by using physical layer channel status information (CSI) in a video application layer. In this method, the transmitting end decides the maximum transmission rate (Rmax) of the system based on both SNR information of receiving antennas fed back from the receiving end and a bit error rate required by the system. At the same time, a hierarchical encoding method is used, in the video application layer, to divide a bit stream into a basic layer and an expansion layer. In a case of employing an FGS encoding method, the transmission is caused to start with the basic layer, and the number of bits is increased in the expansion layer just until the bit rate of the video stream has become below Rmax.