Abstract: A transmission method according to the present invention has been conceived assuming an environment where two information source nodes independently communicate with one destination node, and thus is applicable to such a simple topology. The transmission method provides an inter-node cooperation relationship which provides a sufficient advantageous effect even in an environment in which there is a difference in the power levels of the received signals that reach the address node via two routes. The transmission method is performed by a node U1 (40) and a node U2 that is located closer to the node D (60) than the node U1 (40) to transmit signals to a node D (60) which iteratively detects a log likelihood ratio between mutually corresponding pairs of bits included in the signals at constellation points.

Abstract: Each of first radio communication devices includes; a frequency spread unit which spreads frequency of a transmitted signal to generate a frequency-spread signal; and a mapping unit which allocates the frequency-spread signal to a subcarrier according to the mapping information which specifies a subcarrier. A second radio communication device includes: a demapping unit which extracts from a received signal a signal of the subcarrier specified by the mapping information; and an inverse frequency spread unit which inverse-frequency-spreads the extracted signal. The first radio communication device or the second radio communication device includes a use subcarrier decision unit that decides a subcarrier to which the frequency-spread-signal is allocated according to a communication path capacity of each subcarrier of each antenna used for transmission by the first radio communication devices and generates mapping information used to specify the decided subcarrier.

Abstract: A clipping rate is controlled in spectrum shaping according to a propagation path to thereby improve transmission characteristics and perform communication at a stable transmission rate. Propagation path characteristics are detected by a propagation path information detection unit 5 for detecting propagation path information fed back from a base station device and a water filling principle for distributing energy by a primary spectrum shaping unit 6 according to the propagation path characteristics is applied to transmission spectrum obtained by a DFT unit 4. Clipping information in secondary spectrum shaping fed back from the base station device is detected by a clipping information detection unit 7 to perform the secondary spectrum shaping by a secondary spectrum shaping unit 8. At this time, with the clipping rate by the secondary spectrum shaping unit 8, clipping rates of all transmission devices multiplexed in a scheduling unit 26 of the base station device are controlled adaptively.

Abstract: To provide a system that can accommodate a greater number of terminals within a limited band and can obtain a higher transmission rate. While the number of frequency signals (spectrums) output in parallel by performing a spread spectrum from the DFT unit of each terminal is 12, the number of sub-carriers constituting one sub-channel is set at 10 or 11. In this case, the users (users A and G) allocated to the sub-channels at both ends of the band will not perform transmission of one frequency signal at the end (one sub-carrier) of all the frequency signals output from the DFT unit, whereas the users (users B to F) allocated to the other sub-channels will not perform transmission of the frequency signals at the ends (two sub-carriers). This transmission can be realized by deleting (clipping) the associated number of signals from both ends or from one end of the frequency signals output from the DFT unit of each terminal and allocating the frequency signals after clipping, to individual sub-channels.

Abstract: The DFT 12 converts a modulated digital signal into a spectrum of a frequency band. A use frequency band notification unit in a reception device notifies a transmission device 1 of a use frequency band. A deletion unit 141 in the transmission device 1 deletes a spectrum of a band other than the use frequency band after shaping of a spectrum waveform based on the water filling principal by a shaping unit 13. Then, a digital signal for each data series concerning the spectrum obtained after deletion by the deletion unit 141 is synthesized by a synthesizing unit 16 and sent from the transmission device 1 to the reception device. A reception side conversion unit in the reception device converts the digital signal sent by the transmission unit into a spectrum of a frequency band. A turbo equalization unit performs turbo equalization on the converted spectrum.