Patent ID: 8311079

Claim:
A base station apparatus comprising: a transmitting unit configured to transmit data to a mobile station and transmit, to the mobile station, control information related to the data on a control channel element (CCE), an index of resource used for transmission of an ACK (ACKnowledgement) or NACK (Negative ACKnowledgement) by the mobile station is associated with the CCE number; and a receiving unit configured to receive the ACK or NACK corresponding to the data, the ACK or NACK being spread with an orthogonal sequence, which is one of plural orthogonal sequences, and with a sequence defined by a cyclic shift value, which is one of plural cyclic shift values and which is associated with the orthogonal sequence, and the ACK or NACK being transmitted from the mobile station, wherein: the orthogonal sequence and the cyclic shift are determined from the index of resource associated with the CCE number; each of the plural orthogonal sequences is an orthogonal sequence comprised of 4 codes and having a length 4; the plural orthogonal sequences include a first orthogonal sequence and a second orthogonal sequence, wherein a sequence comprised of 2 codes in the first half of the first orthogonal sequence is not orthogonal to a sequence comprised of 2 codes in the first half of the second orthogonal sequence, and a sequence comprised of 2 codes in the second half of the first orthogonal sequence is not orthogonal to a sequence comprised of 2 codes in the second half of the second orthogonal sequence; and a cyclic shift value associated with the first orthogonal sequence is different from a cyclic shift value associated with the second orthogonal sequence.