Patent ID: 8379662

Claim:
A radio transmission apparatus comprising: a selecting section that selects a first signature sequence for use in an initial transmission by a first radio communication terminal apparatus from a first signature group comprising a plurality of signature sequences generated by cyclically shifting the same first Zadoff-Chu sequence, and selects a second signature sequence for use in a retransmission by a second radio communication terminal apparatus from a second signature group comprising a plurality of signature sequences generated by cyclically shifting the same second Zadoff-Chu sequence different from the first Zadoff-Chu sequence, the first and second radio communication terminal apparatuses being configured to transmit in a same time slot; and a transmission section that transmits identification information of the selected first and second signature sequences, wherein: the selecting section selects a first signature sequence for use in an initial transmission in a first time slot which is different from a first signature sequence for use in an initial transmission in a second time slot adjacent to the first time slot and a second signature sequence for use in a retransmission in the second time slot which is the same as the first signature sequence for use in the initial transmission in the first time slot.