| 摘要 |
PURPOSE:To obtain a code or a gain in the case of non-encoding by shifting the phase of a spread signal by a selected extent to conduct the spread signal and using the maximum likelihood decoding method to perform decoding on the reception side. CONSTITUTION:On the transmission side, an information bit string d(t) is subjected to serial/parallel conversion with Q bits as the unit by a serial/parallel converter 1 and is inputted to a convolutional code encoder 2 having an encoding rate Q/(Q+Q'). One of 2<(>Q<+>Q'<)> phases is selected in accordance with the output (Q+Q')-bit bit pattern from the convolutional code encoder 2, and the phase of the pseudo noise signal generated by a pseudo noise signal generator 4 is shifted in a delay circuit by the selected phase, and it is transmitted. For example, a trellis encoder is used as the encoder. Thus, a modulated spread spectrum signal s(t) is decoded by the maximum likelihood decoding method. |
