Abstract: A general purpose of the present invention includes providing a high-quality transmission in a multi-level modulation. Signal points to which symbols are to be assigned are not fixed and the positions of the signal points are varied for each transmission so as to reduce the symbols assigned only to the signal points having low error resilience. The assignment of bits in each symbol and an arrangement rule for the signal points in a QAM modulation scheme are varied per transmission so as to prevent any particular symbol from constantly exhibiting the low error resilience. The error rate is reduced and the throughput is enhanced.

Abstract: In a mobile radio terminal at transmission timing control device, transmit data spread-modulated is delayed by a timing control portion with a timing of reception as a reference by a predetermined period of time having based on a unit time corresponding to a chip clock and it is then provided to a filtering portion. The filtering portion limits the transmit data in band and a timing control portion times transmission with a slight adjustment with an oversampling clock, a quadruple in frequency of the chip clock, serving as a unit time. In a mobile radio terminal at a digital roll-off filter, input digital data is held in accordance with a data period by a shift register successively. A counter counts in accordance with an oversampling period of 1/m and it is reset in accordance with a data period.

Abstract: In a mobile radio terminal at transmission timing control device, transmit data spread-modulated is delayed by a timing control portion with a timing of reception as a reference by a predetermined period of time having based on a unit time corresponding to a chip clock and it is then provided to a filtering portion. The filtering portion limits the transmit data in band and a timing control portion times transmission with a slight adjustment with an oversampling clock, a quadruple in frequency of the chip clock, serving as a unit time. In a mobile radio terminal at a digital roll-off filter, input digital data is held in accordance with a data period by a shift register successively. A counter counts in accordance with an oversampling period of 1/m and it is reset in accordance with a data period.