Wireless communication apparatus and response signal spreading method

A radio communication apparatus comprising:

• a first spreading unit configured to spread a response signal with a cyclically shifted sequence, which is generated by cyclically shifting a sequence using one of plural cyclic shift values, to produce a first spread response signal;
• a second spreading unit configured to spread the first spread response signal with one of plural orthogonal sequences to produce a second spread response signal;
• and
• a transmitting unit configured to transmit the second spread response signal,
• wherein said second spreading unit uses a different orthogonal sequence for each of adjacent cyclic shift values that are shifted by one unit value between them.

A radio communication apparatus comprising:

• a first spreading unit configured to spread a response signal with a cyclically shifted sequence, which is generated by cyclically shifting a sequence using one of plural cyclic shift values, to produce a first spread response signal;
• a second spreading unit configured to spread the first spread response signal with one of plural orthogonal sequences to produce a second spread response signal;
• and
• a transmitting unit configured to transmit the second spread response signal using a resource,
• wherein the resource is related to a different cyclic shift value for each of two of the plural orthogonal sequences, and
• wherein said first and second spreading units use a cyclic shift value and an orthogonal sequence, respectively, which are determined from the resource.

A response signal spreading method comprising:

• first-spreading a response signal with a cyclically shifted sequence, which is generated by cyclically shifting a sequence using one of plural cyclic shift values;
• and
• second-spreading the first-spread response signal with one of plural orthogonal sequences,
• wherein, in the first-spreading, the cyclically shifted sequence generated using a different cyclic shift value is used for each of two of the plural orthogonal sequences.

A response signal spreading method comprising:

• first-spreading a response signal with a cyclically shifted sequence, which is generated by cyclically shifting a sequence using one of plural cyclic shift values;
• and
• second-spreading the first-spread response signal with one of plural orthogonal sequences,
• wherein, in the second-spreading, a different orthogonal sequence is used for each of adjacent cyclic shift values that are shifted by one unit value between them.