A radio transmitting apparatus and a radio transmitting method wherein the throughput is improved and a fast initial access processing including an RA burst is accomplished. According to these apparatus and method, a signature table storing part (101) has a plurality of signature groups generated from a plurality of different Zadoff-Chu sequences with a set of signatures generated from one Zadoff-Chu sequence being one signature group. A signature sequence assignment control part (102) switches signature groups to be assigned to a UE for each of paging transmissions, thereby assigning a signature sequence, which is to be used for an initial RA, from the same signature group. A paging information generating part (104) causes the ID of the assigned signature sequence to be included into paging information, which is then transmitted to the UE.