| 摘要 |
PURPOSE:To enable an efficient decoding without redundancy by adding an offset in response to the occurrence probability of each signal of a code system generated from an information source to an inter-code distance at the maximum likelihood decoding, thereby deciding a transmission signal. CONSTITUTION:A transmission signal is decided by adding the offset in response to the occurrence probability of each signal of a code system generated from an information source to an inter-code distance at the time of the maximum likelihood decoding by the maximum likelihood decoding method applying the maximum likelihood decoding to a reception signal in the communication system. Moreover, the maximum likelihood decoder is provided with an inter-code distance calculation means 11 calculating an inter-code distance from a reception signal, an offset generating means 12 generating an offset in response to the occurrence probability of each signal of a code system generated from an information source and a deciding means 13 adding the offset to the inter-code distance to decide the transmission signal. A value corresponding to -(2Xsigma<2>)XlogeP(xi) is used for the offset, where P(xi) is the occurrence probability of xi and sigma<2> is the variance of the noise distribution in a transmission line. |
